Change search
Refine search result
123 1 - 50 of 115
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Axelsson, B.
    et al.
    Grundberg, Stig
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Lateral forces in wood cutting1991In: Proceedings of the Tenth International Wood Machining Seminar : Oktober 21 - 23, 1991 / [ed] Richard L. Lemaster, University of California at Berkeley , 1991Conference paper (Refereed)
  • 2. Axelsson, B.
    et al.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Lateral forces in wood cutting due to momentary disturbances in the wood structure1992In: Better wood products through science : All-Division 5 conference "Forest Products", Nancy, France, August 23 - 28, 1992 ; [proceedings], ENGREF , 1992Conference paper (Refereed)
  • 3. Axelsson, B.
    et al.
    Lundberg, S.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Cutting forces at and near a cutting edge1992In: Better wood products through science : All-Division 5 conference "Forest Products", Nancy, France, August 23 - 28, 1992 ; [proceedings], ENGREF , 1992Conference paper (Refereed)
  • 4.
    Axelsson, B.O.M.
    et al.
    Luleå tekniska universitet.
    Grundberg, Stig
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    The use of gray scale images when evaluating disturbances in cutting force due to changes in wood structure and tool shape1991In: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 49, no 12Article in journal (Refereed)
    Abstract [en]

    A method is presented for studying the effect of momentary disturbances due to variations in wood structure on the cutting force near the cutting edge. Force and density measurements are converted to a gray scale image. This method is very effective as regards the evaluation of experimental tests

  • 5.
    Axelsson, B.O.M.
    et al.
    Luleå tekniska universitet.
    Lundberg, Staffan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Studies of the main cutting force at and near a cutting edge1993In: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 51, no 1, p. 43-48Article in journal (Refereed)
    Abstract [en]

    The present work is a study of how various parameters affect the cutting forces at, and near a cutting edge when cutting wood at full speed and with all cutting edges of the tool. Statistical methods from experimental results are used to develop a model

  • 6.
    Berglund, Anders
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Fredriksson, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Improved log rotation using information from a computed tomography scanner2013In: Computers and Electronics in Agriculture, ISSN 0168-1699, E-ISSN 1872-7107, Vol. 90, p. 152-158Article in journal (Refereed)
    Abstract [en]

    The development of an industrial computed tomography scanner for the sawmilling industry raises the question of how to find a production strategy that uses a computed tomography scanner in the sawmill production line to its full potential. This study was focused on a Scandinavian sawmill processing Scots pine (Pinus sylvestris) and Norway spruce (Picea abies). The potential value increase when allowing an alternative log rotation other than the horns down position was investigated using a log breakdown simulation. The resulting data was analysed with respect to the size of the log rotational step, an introduced rotational error of the sawing machine and different price differences between the quality grades. It was also of interest to define the outer log properties that characterise the logs sawn for the greatest profit return close to the horns down position compared to logs sawn for a greater profit return in a different log rotation. Such characteristics can be used to reduce the number of degrees of freedom in an optimisation and consider instead other parameters, such as positioning and sawing pattern. Other defects such as pitch pockets, splits and rot are also of interest. The results shows that there is a potential value increase when applying the log rotation that maximises the value for each log instead of processing all logs in the horns down position. However, the potential value increase depends on the rotational error of the used sawing machine and the price differences between the quality grades. The log properties that differ between logs sawn for the greatest profit return close to the horns down position compared to a different log rotation are the bow height and the log taper. Unfortunately, predictability of log rotation for greatest profit return based on the outer properties of logs is poor. It is not possible to differentiate logs which would be sawn for the greatest profit return close to the horns down position from those where a different log rotation results in the greatest profit return, based only on their outer properties.

  • 7.
    Berglund, Anders
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Oja, Johan
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Customer adapted grading of Scots pine sawn timber using a multivariate method2015In: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 30, no 1, p. 87-97Article in journal (Refereed)
    Abstract [en]

    To define new grading rules, or to customize the ones in use in a rule-based automatic grading system of boards, is a time-consuming job for a sawmill engineer. This has the effect that changes are rarely made. The objective of this study was to continue the development of a method that replaces the calibration of grading rule settings by a holistic-subjective automatic grading, using multivariate models. The objective was also to investigate if this approach can improve sawmill profitability and at the same time have a satisfied customer. For the study, 323 Scots pine (Pinus sylvestris L.) boards were manually graded according to preferences of an important customer. That is, a customer that regularly purchases significant volumes of sawn timber. This manual grading was seen as reference grading in this work. The same boards were also scanned and graded by a rule-based automatic grading system, calibrated for the same customer. Multivariate models for prediction of board grade based on aggregated knot variables, obtained from the scanning, were calibrated using partial least squares regression. The results show that prediction of board grades by the multivariate models were more correct, with respect to the manual grading, than the grading by the rule-based automatic grading system. The prediction of board grades based on multivariate models resulted in 76-87% of the boards graded correctly, according to the manual grading, while the corresponding number was 63% for the rule-based automatic grading system.

  • 8.
    Berglund, Anders
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Dahlquist, Simon
    SP Trä.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Detection of saw mismatch in double arbor saw machines using laser triangulation2013In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 8, no 4, p. 219-225Article in journal (Refereed)
    Abstract [en]

    In the sawing process of a sawmill, not only are the target sizes of great importance. The saw mismatch that may occur in double arbor saw machines is also an essential parameter that affects the planing allowance, as well as the quality of the sawn products. In this study, a newly developed measurement equipment for detecting saw mismatch in the green sorting line of a sawmill has been evaluated in an initial experimental test. The obtained data has been compared to manual measurements of saw mismatch with good results. Also, based on a small sample, 75 – 95% of the boards with a maximal saw mismatch exceeding 0.5 mm are detected. The rate of detection depends on the number of cameras used.

  • 9. Berglund, Anders
    et al.
    Fredriksson, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Project: CT-Pro2012Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    Projektet är finansierat av WoodWisdom-Net, VINNOVA, Fachagentur Nachwachsende Rohstoffe e. V. och medverkande företag. Syftet med projektet är att visa att det är möjligt att extrahera ut viktig och detaljerad information från en timmerstock med hjälp av en speciellt utvecklad röntgenskanner och sedan utnyttja denna information i produktionsstategier för att öka värdet i den träindustiella värdekedjan.

  • 10.
    Berglund, Anders
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    An industrial test of measuring saw mismatch using laser triangulation2013Conference paper (Refereed)
    Abstract [en]

    Sawing yield is an important parameter for the sawmill profit. One way to increase the sawing yield is by a reduced saw kerf width, an adapted shrinking allowance, and a lower sawing allowance. The Swedish sawmills on the other hand see a risk of poorer sawing accuracy and sawing precision and at worst, more frequent saw blade failures. One problem with a reduced saw kerf width is the saw mismatch that may occur in double arbor saw machines. Saw mismatch occurs when the saw blades are displaced in axial direction with respect to each other due to wear, heat or mechanical disturbance. In this study the aim was to test the robustness of a laser triangulation unit used for measuring saw mismatch during sawmill operation. The aim was also to find a suitable response variable for saw mismatch which was evaluated by using the cant height, feed speed and average top diameter of the logs as predicting variables in a partial least squares regression. The goodness of prediction for each response variable was used to compare the response variables with each other. The results showed that the robustness when measuring saw mismatch by laser triangulation during ongoing sawmill production was satisfactory. The response variable with the best goodness of prediction (Q2 = 0.135) was defined using a sliding window with a size of 500 boards. Each element of the response variable was calculated as the share of boards within the sliding window exceeding a threshold value of 0.5 mm. This response variable was positively correlated with the cant height, feed speed and average top diameter of the log. Future work requires a designed experiment where the predicting variables are varied systematically and where the effect of characteristics and wear of the saw blades is also considered.

  • 11. Berglund, Anders
    et al.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Dahlquist, Simon
    SP Trä, Sverige.
    Projekt: Processuppföljning sågverk2013Other (Other (popular science, discussion, etc.))
  • 12. Billgren, Gunilla
    et al.
    Grönlund, Anders
    Träfönsters beständighet: [D. 1]1977Report (Other academic)
  • 13. Billgren, Gunilla
    et al.
    Grönlund, Anders
    Träfönsters beständighet: D. 2 Fönster utformade enligt aktuell SIS standard1978Report (Other academic)
  • 14.
    Breinig, Lorenz
    et al.
    Forstliche Versuchs- und Forschungsanstalt Baden-Württemberg (FVA).
    Berglund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Bruechert, Franka
    Forstliche Versuchs- und Forschungsanstalt Baden-Württemberg (FVA).
    Sauter, Udo
    Forstliche Versuchs- und Forschungsanstalt Baden-Württemberg (FVA).
    Effect of knot detection inaccuracy on value recovery improvement when using a CT log scanner for sawing control2013In: Forest products journal, ISSN 0015-7473, Vol. 63, no 7-8, p. 263-274Article in journal (Refereed)
    Abstract [en]

    Roundwood scanners utilizing X-ray computed tomography (CT) provide the information required for individual log-sawing optimization. However, errors in the automated detection of quality-relevant internal wood features for sawing control may lead to improper log positioning at breakdown, impairing the realization of value recovery potential. It is thus of interest to have an estimation of the impact of feature detection errors on the performance of sawing optimization. A sensitivity analysis was conducted to quantify the effect of errors in knot detection on a breakdown optimization by adjustment of log rotation. Therefore, sawing simulations were performed with the geometric descriptions of log shape and internal knots extracted from the CT scans of 57 Norway spruce (Picea abies (L.) Karst.) logs. Three types of artificially set knot description errors were tested under different pricing and product scenarios, each in different magnitudes as systematic or random error. Errors in knot diameter were found to have the greatest impact for both systematic and random errors. The effect of errors in dead knot border radial position was less pronounced but still substantial for higher error levels, while errors in knot rotational position could be neglected even for the highest magnitudes of error tested. The assumed price differentiation between product qualities had a major influence on the impact of the errors. It could be observed that with errors of higher magnitudes than those reported for present knot detection algorithms, an improvement in value recovery compared with outer-shape–based optimization still resulted in the simulated rotation optimization.

  • 15.
    Broman, Olof
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    The end-users´ requirements for the aesthetical features of scots pine wood1996In: Connection between silviculture and wood quality through modelling approaches and simulation softwares: Second Workshop, Berg-en-Kruger, Kruger National Park, South Africa, August 26-31, 1996 : proceedings / [ed] Gérard Nepveu, Nancy: INRA Editions, 1996, p. 343-352Conference paper (Refereed)
    Abstract [en]

    Wood has inherent aesthetic features which can give the final product competi­tive advantage over other materials. It is therefore important for the forest products industries to take advantage of those features of wood that have great influence on customers' choice of product. It is the final consumer's willingness to buy a product that is the motive power for the whole production process. Today, the forest products industry is not using any scientific method in order to utilize the aesthetic features of wood. Therefore methods to measure people's preferences for different wood features and also methods to measure these features in an objective way are needed.We have in an earlier study shown that it is possible to measure people's attitudes toward wood by a questionnaire technique. The results show that people prefer different blends of wood features. There are two qualitative differences that are of importance for people's impression and valuation of wood: The overall blending of wood features and divergent features that mismatch in a surface. It was found that divergent features are more important than the overall mixture of features. But if there are no defects that mismatch, the overall mixture will then be the key to a person's appreciation of a wood surface. In a new study, we have started to measure the different wood features in an objective way and developed statistical models of the relationship between the objective parameters and people's subjective preferences for different wood surfaces made of Scots pine (Pinus sylvestris). In this first attempt we have made very simple manual measurements of parameters such as knot size, knot type, knot shape and distribution of knots over the surface.The statistical analyses show that it is difficult to find any significant relation­ships between people's subjective preferences and the simple objective para­meters we have measured. It is evident that more sophisticated measure­ment tech­nique is needed. We must be able to measure parameters such as colour, grain pattern etc. Therefore we will use colour camera technique in future studies.

  • 16.
    Broman, Olof
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Nordvik, Enar
    Lundahl, Carl Gustav
    Estetiska kvaliteter och skillnader i preferenser för limfog: en jämförelse mellan två intervjumetoder2008Report (Other academic)
    Abstract [sv]

    Den produktgrupp som här studerats är limfog för Gör-Det-Själv-marknaden. Limfog är en vanlig produkt som konsumenter köper styckevis och där träets estetiska blandning av träegenskaper kan vara av betydelse för ett aktivt val eller köp av kunden. Projektets övergripande mål var att studera vanliga konsumenters olika känslighet (smakprofiler) för olika utseenden på trä. Huvudmålet med studien var att jämföra två metoder för preferensmätning; dels användandet av riktiga träytor (limfog) och dels digitala bilder av desamma för rangordning av produktalternativ. För att validera användbarheten av de båda metoderna jämfördes deras rangordningsresultat. Ett delmål med studien var att studera skillnader mellan preferenser för limfog som producerats enligt alternativa produktionssätt med traditionellt producerad limfog. Femton personer intervjuades i två omgångar. I den första intervjun fick personerna rangordna 11 limfogsytor med hjälp av datorbilder och en webapplikation. I den andra intervjun två veckor senare fick samma personer rangordna samma limfogsytor fast nu med riktiga träytor. Resultaten från intervjuerna visar att de båda metoderna gav likvärdiga resultat. Det fungerade bra att använda digitala bilder och utföra preferensstudier via utvecklad web-applikation. För båda metoderna gällde att 11 stycken produktalternativ var på gränsen till för många att ta ställning till för de intervjuade personerna. Detta gällde båda intervjumetoderna. Bildernas kvalitet visade sig vara viktigt och de små skillnader i rangordningsresultat mellan de två intervjumetoderna kan till viss del förklaras av bristande återgivning av färgnyanser. Metoden att rangordna de verkliga limfogsskivorna fungerade mycket bra. Principen att välja ömsom bäst och sämst och kontinuerligt plocka bort valda produktalternativ fungerade bra. Följande estetiska kvalitetsskillnader visade sig vara viktiga för intervjupersonerna: En jämn fördelning av kvistar över ytan (limfogen) tillika blandning av kvistutseende är viktigt för helhetsintrycket. Märgstråk upplevdes starkt negativt då de ses som streck i ytan, en artefakt. Detta gäller också hög grad av randighet som upplevdes negativt. Detta kan orsakas av splint-/kärnvedsvariationer, speciellt när limfogen producerats med låg lamellbredd. Negativt var också tjurvedsstråk som orsakar randighet i en yta, vilket stör den visuella balansen och harmonin. Den limfog som producerats inom ramen för en ny högutbytesstrategi rankades högre än den traditionellt tillverkade limfogen som var inköpt. Detta kan förklaras främst av en hög grad av färska kvistar (ej svarta och eller döda kvistar), som kommer sig av valet av råvara. Råvaran utgjordes av klentimmer medan råvaran till den traditionellt tillverkade limfogen kom från plank med ursprung från osorterat timmer. Slutsatsen är att för limfog så har valet av råvara minst lika stor betydelse än produktionssätt (lamellbredd, koniska lameller etc) för det estetiska uttrycket och kundtillfredsställelse.

  • 17.
    Broman, Olof
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Wixe, David
    LTU Skellefteå, Träteknologi.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Oja, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Råvarustyrning för materialeffektiv produktion av limfog: En studie utförd vid Norrfog AB2011Report (Other academic)
    Abstract [sv]

    Norrfog AB i Malå tillverkar limfogskivor i olika kvaliteter, bland annat till gör-det-själv- (GDS)-limfog, möbelfog och IKEAs hyllkoncept Ivar. Då Norrfog planerar att öka sin producerade volym av limfog ökar behovet av en effektiv styrning av rätt råvara till rätt slutprodukt. Samtidigt stiger råvarupriserna och det blir allt viktigare att maximera volyms- och värdeutbytet. Vid tidpunkten för studien: Norrfog AB köper klena furustockar och försorterar stockarna i diameterklasser med hjälp av en 2D-mätram. Ingen sortering sker på stocktyp och därmed blandas rotstockar, svartkviststockar och friskkviststockar. Stockarna sågas med en 2ex postning till plankor som efter torkning kapas upp till komponentlängder som därefter klyvs till färdiga lameller för limfogsproduktion. Huvudsyftet med detta projekt var att undersöka möjligheterna att styra rätt kvalitet av timmer till rätt slutprodukt; Ivarhyllan, GDS-limfog och möbelfog samt för- och nackdelar med att införa ett alternativt sågsätt – genomsågning. Inom ramen för studien fanns följande forsknings- och utvecklingsfrågor: •Stocklängdens betydelse för volymutbytet av limfog? •Stocktypens betydelse för kvaliteten på producerad limfog? •Går det att hitta rätt typ av stockar till en specifik produkt redan vid timmerplanen med hjälp av befintlig 2D-mätram och förbättrar 3D eller röntgen-skanning denna klassificering av stockar? •Finns det ett motstånd till fingerskarv bland konsumenter och vad anses vara ett önskvärt utseende på en träyta av limfog? Studien visar att den stocktyp som gav den bästa kvaliteten var friskkviststockarna, men även de stockar som sorterades som svartkvistiga visade sig innehålla mestadels friska kvistar i de aktuella timmerdimensionerna. Ett tydligt resultat var att rotstockar innehöll den lägsta kvaliteten med för många och/eller för stora svarta kvistar och det visade sig vara lämpligt att om möjligt sortera bort dessa stockar för att såga dessa separat till produkter med lägre krav på kvalitet. Sorteringsalgoritmer för olika mättekniker för timmer speciellt anpassade för att maximera utbytet kvalitet 1 i den färdiga limfogen testades. Med befintlig 2D-mätram sorterades 81 % av rotstockarna bort och med röntgenmätning ökade andelen bortsorterade rotstockar till 98 %. Ett viktigt resultat var att genomsågning gav i snitt 13 % högre volymutbyte än 2ex-sågning och att korta stockar gav ökat volymutbyte jämfört med fullängdsstockar. En separat undersökning angående skivornas utseende visar att fingerskarvade limfogskivor är något konsumenten kan tänka sig, så länge färgskiftningarna mellan lamellerna är små. Stora färgskiftningar och små svarta kvistar var det som respondenterna rankade som minst tilltalande för alla skivor oavsett fingerskarv eller inte.

  • 18. Brännström, Mattias
    et al.
    Oja, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Predicting board strength by X-ray scanning of logs: the impact of different measurement concepts2007In: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 22, no 1, p. 60-70Article in journal (Refereed)
    Abstract [en]

    The objective of this study was to compare the individual board strength predictions from an X-ray log scanner by using either two or four X-ray directions. The benefit of applying traceability between log and board was also studied. In total, 119 Norway spruce [Picea abies (L.) Karst.] sawlogs were scanned by an X-ray log scanner at the log sorting station of a sawmill and sawn into two centre pieces per log. Individual board traceability was enabled by following the rotational position of the log in the scanner and at the succeeding sawing. All boards were graded by a commercial strength grading machine before destructive testing was done. The resulting data were used to derive variables for building multivariate partial least squares strength prediction models. In the modelling a hierarchical modelling approach was used, where annual ring width, dry density and elasticity were also modelled. For all concepts studied the models' fit was similar. Only minor benefits could be found when using four directions and traceability compared with two directions and no traceability. One conclusion is that the result for traceability, from four directions in particular, is more sensitive for the interior knot reconstruction result. The strength prediction was on the same R2 level as for the strength grading machine

  • 19. Chiorescu, Sorin
    et al.
    Berg, P.
    Swedish Institute for Wood Technology Research.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    The fingerprint approach: using data generated by a 2-axis log scanner to accomplish traceability in the sawmill's log yard2003In: Forest products journal, ISSN 0015-7473, Vol. 53, no 2, p. 78-86Article in journal (Refereed)
    Abstract [en]

    Today the sawmill industry is in possession of sophisticated measuring devices for sawlogs. This equipment is employed in practice for measuring log dimensions, and the data gathered are used for sorting out sawlogs according to different criteria or for judging potential quality for future end-uses. However, a lot of these data are not fully utilized. Meanwhile, large knowledge gaps regarding the flow and the origin of the wood material persist in the sawmill's daily routine. For sawmills performing presorting of sawlogs, the most significant information gap is located between the log sorting station and the saw intake where the log batch identity disappears and the logs are mixed according to different sorting criteria. This study attempts to use the data generated by 2-axis log scanners to develop a traceability system, the fingerprint approach (a marking/reading free system), between the log sorting station and the saw intake. The originality of the fingerprint approach is based on the biological variability of the wood material; the assumption is that each sawlog is a unique individual with unique features. Measuring these features at the log sorting station and at the saw intake and then connecting them to a common database will in fact permit each individual sawlog to be followed within the sawmill and thus enable the development of an advanced raw material flow control. The results of this work entirely indicate the promising potential of the fingerprint approach, which is based on the hypothesis that logs are separate entities with individual features. Being able to separate logs at the individual level is essentially a question of taking advantage of the right log features, measuring them with high accuracy, and employing appropriate search/recognition algorithms. The log parameters and the measurement accuracy generated by the 2-axis log scanner used in this study were not enough to accomplish individual separation for more than 34 percent of the logs. An improvement of measurement accuracy by 30 percent would allow 50 percent of the logs to be individually separated.

  • 20. Chiorescu, Sorin
    et al.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Assessing the role of the harvester within the forestry-wood chain2001In: Forest products journal, ISSN 0015-7473, Vol. 51, no 2, p. 77-84Article in journal (Refereed)
    Abstract [en]

    In recent years, a lot of effort has been devoted to implementing the concept of an integrated forestry-wood chain. Good management of such a complex system requires a clear understanding of the effects that different factors involved may have on the final output of the chain. Raw material databases and simulation software capable of spanning the wood-processing operations have now been developed and are being used as a support tool in understanding and optimizing the forestry-wood chain. This paper reports results of simulation tests using the virtual SawMill software and the Swedish Pine Stem Bank database. The simulated scenario tries to mirror a very customer-oriented production philosophy. The bucking, the sawing, the crosscutting, and the board-grading procedures were simulated for different end-user requirements and a statistical model was built. The purpose of the model was to investigate the theoretical sensitivity of the final product to parameters such as external sawlog features (taper, ovality, bow), harvester measurement accuracy (for length and diameter), sawing pattern optimization, and log positioning in the saw line. Special emphasis was put on evaluating the role of the harvester within this "puzzle." The results show that small improvements of the harvester's measuring performance could lead to considerable improvements in the wood transformation chain.

  • 21. Chiorescu, Sorin
    et al.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    The fingerprint approach: using data generated by a 3D log scanner on debarked logs to accomplish traceability in the sawmill's log yard2004In: Forest products journal, ISSN 0015-7473, Vol. 54, no 12, p. 269-276Article in journal (Refereed)
    Abstract [en]

    Technological advances in the area of optical scanning have made sophisticated equipment such as three-dimensional (3D) log scanners available to the sawmill industry. In a typical Swedish sawmill, the measurements obtained from the 3D log scanner placed at the log sorting station is used exclusively for scaling and sorting the sawlogs. In the same way, the information obtained from the 3D log scanner placed at the saw intake is used exclusively for optimal positioning of the sawlog into the headrig. Meanwhile, large knowledge gaps regarding the flow and the origin of the sawlogs persist in the sawmill's daily routine. For the Swedish sawmills performing presorting of sawlogs, the most critical information gap exists between the log sorting station and the saw intake, where the forest log batch identity disappears, and the logs are mixed according to various sorting criteria. This study attempts to use the data generated by 3D log scanners together with advanced recognition algorithms to develop a traceability system, marking/reading free, between the log sorting station and the saw intake when working with debarked logs. The originality of the fingerprint approach rests on the hypothesis that logs are separate entities with individual features. Measuring these features with the same type of measuring device at both the log sorting station and at the saw intake and then connecting the data to a common database will permit each individual sawlog to be tracked within the sawmill and will thus make it possible to develop an advanced raw material flow control.

  • 22. Chiorescu, Sorin
    et al.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    The fingerprint method: using over-bark and under-bark log measurement data generated by three-dimensional log scanners in combination with radiofrequency identification tags to achieve traceability in the log yard at the sawmill2004In: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 19, no 4, p. 374-383Article in journal (Refereed)
    Abstract [en]

    In the forestry-wood chain the concept and the technologies of traceability are in a mature development phase. Important advances in marking and reading techniques have been made in different parts along the forestry-wood chain. For Swedish sawmills the most critical information gap is located between the log sorting station and the saw intake, where the forest log batch identity disappears and the logs are mixed according to different sorting criteria. This study utilizes radiofrequency identification tags for automatic log marking/reading to develop a traceability system for logs, which is free of marking/reading, between the log sorting station and the saw intake, i.e. the fingerprint method. The originality of the fingerprint approach rests on the hypothesis that logs are separate entities with individual features. The results show that the log parameters and the search algorithm developed, combined with the negative influence of the measurement uncertainty due to bark thickness and bark damage, made it possible to achieve an individual separation for 57% of the tested logs.

  • 23. Chiorescu, Sorin
    et al.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    The visual grading system for Scots pine logs in relation to the quality of sideboards produced2003In: Forest products journal, ISSN 0015-7473, Vol. 43, no 1, p. 53-60Article in journal (Refereed)
    Abstract [en]

    Presorting logs in the sawmill's log yard is one of the strategies used by the Swedish sawmilling industry in order to maximize profits. Almost 96 percent of Swedish sawmills perform the presorting of logs according to their dimension, most commonly by the top diameter. Only a very small number of sawmills use log grade information as a sorting criterion. However, the grade information at individual log level, together with the estimated volume, is always used for the calculation of log payment. The quality assessment of the log is done on a visual basis, i.e., the measurer grades the log on what he/she sees on the outside of the log. This judging should correspond to the expected quality of the Centerboards produced after sawing. Current studies have only related the centerboards' quality to the log quality grade arrived at by visual inspection. In view of the economic importance of the sideboards in the lumber yield and in the entire functioning of a sawmill, a real need for information on the recovery of sideboards in relation to log and centerboard quality is now arising and becoming a key issue. In this study, with the help of the entire Swedish Pine Stem Bank material, the relationship between the sideboard's quality and the log's quality and the relationship between the quality of sideboards and of centerboards were studied. Results show that sideboard quality cannot be predicted from the visual quality assessment of the logs. Nevertheless, fairly good correlation exists between sideboard quality and the quality of the corresponding centerboards. A financial analysis focusing on the relationship between the commercial values of the sawlogs and the corresponding lumber output for the Swedish Pine Stem Bank material is also included in this study. The study shows that the actual Swedish log pricing system should be improved because the commercial values of the logs are not in accord with the real values of the lumber produced.

  • 24. Chiorescu, Sorin
    et al.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Validation of a CT-based simulator against a sawmill yield2000In: Forest products journal, ISSN 0015-7473, Vol. 50, no 6, p. 69-76Article in journal (Refereed)
    Abstract [en]

    Over the past decade, the sawmill sector has made significant advancements in developing methods for measuring inner properties of sawlogs. Noninvasive scanning, e.g., x-ray scanning, has proven to have good prospects for on-line implementation in sawmills. When the internal scanning technique does come on-line in sawmills, software able to utilize the scanned information becomes a useful tool to control the sawing process. Thus, the validation of such a computed tomography (CT)-based software against sawmill cutting becomes an important step in the development of the whole scanning approach. This paper presents the results of an effort to simulate the 1-year lumber production of a medium-sized Swedish sawmill with the aid of a CT-based simulator, the virtual SawMill (vSM). This saw simulation program is able to utilize the parametrical description of the logs achieved from x-ray CT-scanning. When performing the simulation, the vSM used 625 Scots pine (Pinus sylvestris L.) logs from the Swedish Stem Bank as raw material supply for the sawing process. The simulated sawing process was adjusted to keep, as much as possible, the same attributes as the sawing process from the sawmill. The output data collected from the sawmill was compared with the simulated one with respect to the quality and the length distribution of the yielded boards. The results showed good agreement between the real and the simulated cutting for both quality and length criteria. This study suggests that the Swedish Stem Bank along with the vSM software could be used as an efficient tool in further research and strategic production planning.

  • 25.
    Cristovao, Luis
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Sitoe, Rui
    Eduardo Mondlane University.
    Main cutting force models for two species of tropical wood2011In: Proceedings of the 20th International Wood Machining Seminar, Skellefteå, 2011, p. 428-435Conference paper (Refereed)
  • 26. Cristovao, Luis
    et al.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Sitoe, Rui
    Main cutting force models for two species of tropical wood2012In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 7, no 3, p. 143-149Article in journal (Refereed)
    Abstract [en]

    The aim of the study was to evaluate the main cutting force for two species of tropical Mozambican wood and to develop predictive models. Cutting these hardwoods is difficult. Determination of cutting parameters is required to optimize cutting processes, machines and tools in the cutting operations. This determination would enable the forestry and wood sector to achieve higher financial results. Samples of a lesser-known wood species Pseudolachnostylis maprounaefolia (ntholo) and a well-known wood species Swartzia madagascariensis (ironwood) were machined in a test apparatus. A standard single saw tooth mounted on a piezoelectric load cell was used to evaluate the main cutting force. Data were captured using an A/D converter integrated with National Instruments LabVIEW software. The measured signals were recorded at a sampling frequency of 25 kHz. The experimental set-up used response surface methodology for developing predictive models. The experimental clearly determined the relationship between the main cutting force and edge radius, wood density, rake angle, chip thickness, moisture content (MC) and cutting direction (CD). Among the studied variables, chip thickness and CD had the highest effect on the main cutting force level while wood density, MC and rake angle had the lowest effect.

  • 27.
    Cristovao, Luis
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Industrial sawing of Pinus Sylvestris L.: power consumption2013In: Proceedings of the 21th International Wood Machining Seminar: August 4th – 7th, 2013, Tsukuba International Congress Center, Japan, 2013, p. 189-198Conference paper (Other academic)
    Abstract [en]

    Wood industry continues to strive to reduce production cost and increase productivity to maintain competiveness. Hence, knowledge of the effect of wood cutting parameters on power consumption would enable increase energy efficiency, thus, reduce operating costs and enhance profitability. Also measurement of power consumption gives knowledge of other specifics such as: tool edge wear, occurrence of catastrophic failures and other parameters which affect the quality of the sawn boards and the momentary efficiency of the break-down process. In this study, power consumption during sawing of Pinus sylvestris L. using double arbour circular saw was investigated. Both climb-sawing and counter-sawing were considered. The experiments were carried out, under normal production, in two Swedish sawmills. The relationship between cutting parameters and calculated power consumption is discussed. The experimental power consumption increased 11-35% during an 8 hour shift mainly due to increase of the tooth radius. Further, this study also showed the climb-sawing had higher power consumption than counter-sawing.

  • 28.
    Cristovao, Luis
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Industrial Sawing of Pinus Sylvestris L.: Power consumption2013In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 8, no 4, p. 6044-6053Article in journal (Refereed)
    Abstract [en]

    The wood industry continues to strive to reduce production costs and increase productivity to remain competitive. Knowledge of the effect of wood cutting parameters on power consumption could increase energy efficiency, reducing operating costs and increasing profitability. Measuring power consumption also provides information about other variables, such as tool edge wear, occurrence of catastrophic failures, and other parameters that affect the quality of the sawn boards and the momentary efficiency of the breakdown process. In this work, power consumption during sawing of Pinus sylvestris L. using a double arbor circular saw was investigated. Both climb-sawing and counter-sawing were considered. The experiments were carried out under normal production circumstances in two Swedish sawmills. The relationship between cutting parameters and theoretical power consumption was investigated. The experimental power consumption increased by 11 to 35% during an 8-h shift, mainly due to an increase in the tooth radius. Additionally, this study showed that climb-sawing consumed more power than counter-sawing.

  • 29.
    Cristovao, Luis
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Natural frequencies of roll-tensioned circular sawblades: Effects of roller loads, number of grooves and groove positions2012In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 7, no 2, p. 2209-2219Article in journal (Refereed)
  • 30. Cristovao, Luis
    et al.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Sitoe, Rui
    Ekevad, Mats
    Marklund, Birger
    Brittleness of cutting tools when cutting different wood species2009In: Proceedings of the 19th International Wood Machining Seminar / [ed] Handong Zhou; Nanfeng Zhu; Tao Ding, Nanjing: Nanjing Forestry University , 2009Conference paper (Refereed)
  • 31. Cristovao, Luis
    et al.
    Lhate, Imacio
    Swedish University of Agricultural Sciences.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Sitoe, Rui
    Department of Mechanical Engineering, Eduardo Mondlane University, Maputo.
    Tool wear for lesser known tropical wood species2011In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 6, no 3, p. 155-161Article in journal (Refereed)
    Abstract [en]

    This study investigated the relationship between tool wear and some chemical and physical properties for four different Mozambican lesser known tropical species,: Pseudolachnostylis maprounaefolia (ntholo), Sterculia appendiculata (metil), Acacia nigrescens (namuno) and Pericopsis angolensis (muanga). Tool wear is an important aspect for sawmilling and for the woodworking industry. For Mozambique, the utilization of available lesser known wood species will help to increase domestic industry and the economic usage viability of sustainable forest management. A set of experiments was performed on a shaper with a mechanical feed mechanism. Tools of a cemented carbide grade for woodworking were used, and the cutting parameters were fixed. Edge recession and tool wear radius were measured for monitoring tool wear. The wear mechanism was investigated using a scanning electron microscope. The experimental results showed that the chemical properties of the wood species have a great effect on tool wear. Wood silica content was the most important factor affecting tool wear. Wood density and extractives had a low influence on tool wear. The highest tool wear was observed in ntholo, which also had the highest ash and silica contents. A single parameter for evaluation of tool wear was not sufficient to describe the amount of total tool wear

  • 32.
    Ekevad, Mats
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Cristovao, Luis
    Grönlund, Anders
    Different methods for monitoring of flatness and tensioning in circular saw blades2009In: Proceedings of the 19th International Wood Machining Seminar / [ed] andong Zhou; Nanfeng Zhu; Tao Ding, Nanjing: Nanjing Forestry University , 2009, p. 78-86Conference paper (Refereed)
    Abstract [en]

    The performance of a circular-saw blade during sawing depends greatly on the mechanical and geometrical properties of the individual saw blade in question. In order to characterize an individual saw blade when manufacturing saw blades or when doing maintenance of the saw blades, flatness and tensioning are important aspects. Flatness and tensioning influence the lateral stability of the saw blade during sawing and thus affect the sawing result, e.g., the accuracy of the dimensions of the sawn timber. Tests and comparisons of different methods for characterizing individual saw blades were done. New and used saw blades with different amounts of tensioning and flatness were used. The tested saw blades had several radial slots and were intended for use in double-arbour saws with collars and no guides. The compared methods were static and dynamic flatness measurements, natural-frequency measurements and theoretical finite-element calculations with different excitation methods and boundary conditions.The results show some of the qualities of the different methods. The benefits and disadvantages are provided, as well. Especially tensioning can be accurately measured and predicted from natural frequency measurements and finite-element calculations

  • 33.
    Ekevad, Mats
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Cristovao, Luis
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Öhman, Micael
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Geometry of Kerf when Curve Sawing with a Circular Rip-Saw2013In: Proceedings of the 21th International Wood Machining Semina: August 4th – 7th, Tsukuba International Congress Center, Japan, 2013, p. 206-213Conference paper (Refereed)
    Abstract [en]

    Rip-sawing following the curvature of a crooked log means advantages for yield. However, the possibility to saw in a narrow curve with a circular saw blade is limited because of the inherent flat geometry of circular sawblades. For a double arbour circular saw the situation is even more problematic because the two blades have a certain overlap and thus the two arbours are not positioned in the same horizontal position. In this study a theoretical geometrical study of the creation of a kerf with a single circular sawblade and with a double arbour circular saw with two sawblades is viewed upon. Input parameters in the study for the double arbour saw are blade diameter, overlap, margin between blades, cant height, curve centre horizontal position and curve radius. Output is the geometry of the kerf that is cut by the teeth. Theoretical results for stiff saw blades show that the kerfs become in general curved and inclined (tilted) in the vertical direction and also that the width of the kerfs for double arbour saws become wider at the top and bottom of the cant than in the middle. Sawing takes place not only in the front part of the blades but also on the back of the blades (back sawing). Parts of the cutting edges of the teeth are cutting when back sawing and not the whole of the width of the teeth. A result is that boards that are cut out of the cant get varying thickness along their width because of the varying kerf width. A comparison with experimental thickness data from four test sawings at a sawmill indicates that the theoretical results are valid and that curve sawn boards become thinner than straight sawn boards.

  • 34.
    Ekevad, Mats
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Cristovao, Luis
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Öhman, Micael
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Geometry of kerf when curve sawing with a circular rip-saw2014In: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 72, no 6, p. 809-814Article in journal (Refereed)
    Abstract [en]

    Rip-sawing following the curvature of a crooked log means advantages for yield. However, the possibility to saw in a narrow curve with a circular saw blade is limited because of the inherently flat geometry of circular saw blades. For a double arbour circular saw the situation is even more problematic because the two blades have a certain overlap and thus, the two arbours are not positioned in the same horizontal position. In this study, a theoretical geometrical study of the creation of a kerf with a single circular saw blade and with a double arbour circular saw with two saw blades was examined. Results for stiff saw blades show that the kerfs become in general curved and inclined (tilted) in the vertical direction and also that the width of the kerfs for double arbour saws becomes wider at the top and bottom of the cant than in the middle. Additionally, the sawn boards obtain varying thickness along their width because of the varying kerf width. A comparison with experimental thickness data from four test sawings at a sawmill indicates that the theoretical results are valid and that curve sawn boards become thinner than straight sawn boards.

  • 35.
    Ekevad, Mats
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Salin, Jarl-Gunnar
    Grundberg, Stig
    Nyström, Jan
    Grönlund, Anders
    Modelling of adequate pretwist for obtaining straight timber2006In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 1, no 2, p. 76-84Article in journal (Refereed)
    Abstract [en]

    Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic-ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists

  • 36. Eklund, Urban
    et al.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Hagman, Olle
    Mesurement of cant feeding disturbances during sawing1999In: IWMS 14: 14e Séminaire international sur l'usinage du bois, 12-19 septembre 1999, Paris, Épinal, Cluny, France : actes du séminaire, Montpellier: CIRAD , 1999, p. 193-202Conference paper (Refereed)
  • 37. Flodin, Jens
    et al.
    Oja, Johan
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Fingerprint traceability of logs using the outer shape and the tracheid effect2008In: Forest products journal, ISSN 0015-7473, Vol. 58, no 4, p. 21-27Article in journal (Refereed)
    Abstract [en]

    Traceability in the sawmilling industry is a concept that, among other benefits, could be used to more effectively control and pinpoint errors in the production process. The fingerprint approach is a traceability concept that in earlier studies has shown good potential for tracing logs between the log sorting station and the saw intake. In these studies, bark has been identified as a large source of measurement inaccuracy. This study was set out to investigate whether the fingerprint recognition rate could be improved when compensating for bark with traditional bark functions or a new automatic bark assessment based on the tracheid effect. The results show that the fingerprint recognition rate can be improved by using more sophisticated bark compensation. Compared to no bark compensation, improvements can be made by using the existing bark functions, and even further improvements can be made by using automatic bark assessment based on the tracheid effect. The results further show that the butt-end reducer between the log sorting station and the saw intake has a very negative effect on the fingerprint recognition rate, but that significant improvements in the recognition rate can be achieved by excluding the section of the log's butt end that is affected by the butt-end reduction.

  • 38. Flodin, Jens
    et al.
    Oja, Johan
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Fingerprint traceability of sawn products using industrial measurement systems for x-ray log scanning and sawn timber surface scanning2008In: Forest products journal, ISSN 0015-7473, Vol. 58, no 11, p. 100-105Article in journal (Refereed)
    Abstract [en]

    Traceability in the sawmilling industry is a concept that, for example, could be used to more effectively control the production process and the utilization of raw material. The fingerprint approach is a traceability concept that rests on the principle that every piece of wood is a unique individual with unique properties and therefore can be identified and separated if a sufficient number of these properties are measured accurately enough. This study was made with the aim of making the fingerprint connection between logs and the center yield sawn from those logs using length and knot information. The material used was Scots pine logs from six different diameter groups sawn with a two-ex sawing pattern into six different dimensions of center-yield planks. The data from the logs were collected at the log sorting station by an industrial one-directional x-ray log scanner in combination with a 3-D optical scanner. The data from the sawn center yield were collected by an industrial cross-fed surface scanning system situated in the sawmill's green sorting station. The results show that over 95 percent of all planks could be matched to the right log. This gives a high potential for further development and realization of fingerprint tracing between the log sorting and the green sorting station into a practical application for process control and process improvement.

  • 39. Flodin, Jens
    et al.
    Oja, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Fingerprint traceability of sawn products using x-ray logscanning and sawn timber surface scanning2007In: Quality control for wood and wood products: COST Action E 53 the first conference, October 15th/17th, 2007, Warsaw, Poland / [ed] Marek Grześkiewicz, Warsaw: Warsaw University of Life Sciences , 2007, p. 39-42Conference paper (Refereed)
    Abstract [en]

    Traceability in the sawmilling industry is a concept that could be used to more effectively control the production processand the utilization of the raw material. The fingerprint approach is a traceability concept that rests on the idea that everypiece of wood is a unique individual with unique properties and hence can be identified and separated if a sufficientnumber of these properties are measured accurately enough. This study was hosted by a sawmill in northern Sweden andwas aimed at making the fingerprint connection between logs and the center yield sawn from those logs using length andknot information. The 140 logs involved in the study were of Scots pine with top diameters spanning the range from 153 to213 millimeters. The center yield sawn from these logs was of two dimensions. The smaller logs (153-187 mm) were sawnwith a 2 ex pattern to 50 by 100 mm, and the larger logs (174-213 mm) were sawn to 50 by 125 mm with a 2 ex pattern.The data from the logs were collected at the log sorting station by an industrial one-directional x-ray log scanner incombination with a 3-D optical scanner. The data from the sawn center yield were collected by an industrial cross-fedsurface scanning system situated in the sawmill's green sorting station. Both systems are used in the sawmill's normalcontinuous production. The results show that over 90% of all planks could be matched to the right log, which bespeaksa great potential for further development and realization of fingerprint tracing as a tool for process control and processimprovement.

  • 40.
    Fredriksson, Magnus
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Bomark, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    A trapeze edging method for cross laminated timber panel production2015In: Proceedings of the 22nd International Wood Machining Seminar / [ed] Roger Hernández; Claudia Cáceres, Quebec city, Kanada: Universite Laval , 2015, p. 323-332Conference paper (Refereed)
  • 41.
    Fredriksson, Magnus
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Bomark, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Using Small Diameter Logs for Cross Laminated Timber Production2015In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 10, no 1, p. 1477-1486Article in journal (Refereed)
    Abstract [en]

    Sawing small diameter logs results in lower yield compared to sawing large diameter logs. This is due to geometry; fitting rectangular blocks inside an approximately cylindrical shape is more difficult for small than for large diameters. If small diameter logs were sawn in a way that follows the outer shape, yield would increase. The present study considers whether this can be done by sawing flitches into trapeze shapes. These can be glued together into rectangular products. Cross laminated timber (CLT) products are suitable for this. The study was based on 4,860 softwood logs that where scanned, and the scanning data was used for sawing simulation. The log top diameters ranged from 92 to 434 mm. The volume yield of CLT production using trapeze edging was compared to cant sawing of boards. The trapeze edging and CLT production process improved yield compared to cant sawing by 17.4 percent units, for logs of a top diameter smaller than 185 mm. For all logs, the yield decreased using the trapeze edging method. To conclude, a trapeze edging method shows promise in terms of increasing volume yield for small diameter logs, if boards can be properly taken care of in a CLT production process

  • 42.
    Fredriksson, Magnus
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Fingerjointing simulation: first step to complete integration2011In: F D M Asia, ISSN 0218-7663, no Oct, p. 34-37Article in journal (Other (popular science, discussion, etc.))
  • 43. Grundberg, Stig
    et al.
    Axelsson, Bengt
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Verktygsförslitning: mätmetodik - inverkande faktorer1987Report (Other academic)
  • 44. Grundberg, Stig
    et al.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Feature extraction with the aid of an X-ray log scanner1998In: Proceedings from the 3rd International Seminar/Workshop on Scanning Technology and Image Processing on Wood: Skelleftea, Sweden, Aug. 17 - 19, 1998 / [ed] Owe Lindgren; Anders Grönlund; Olle Hagman, Luleå: Luleå tekniska universitet, 1998Conference paper (Refereed)
  • 45. Grundberg, Stig
    et al.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Log scanning: extraction of knot geometry in CT-volumes1992In: Proceedings from the Seminar/Workshop on Scanning Technology and Image Processing on Wood, Skellefteå, Sweden, Aug. 30 - Sept. 1, 1992, Skellefteå, 1992Conference paper (Refereed)
  • 46. Grundberg, Stig
    et al.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Methods for reducing data when scanning for internal log defects1991In: Proceedings: 4th International Conference on Scanning Technology in the Wood Industry, San Francisco, Calif: Forest Industries , 1991Conference paper (Refereed)
  • 47. Grundberg, Stig
    et al.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Simulated grading of logs with an X-ray Log Scanner: Grading accuracy compared with manual grading1997In: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 12, no 1, p. 70-76Article in journal (Refereed)
  • 48. Grundberg, Stig
    et al.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    The Development of a Log-Scanner for Scots Pine1995In: Proceedings from the 2nd International Seminar/Work­shop on Scanning Technology and Image Processing on Wood, Luleå: Högskolan i Luleå , 1995, p. 39-50Conference paper (Refereed)
  • 49. Grundberg, Stig
    et al.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Ulla
    The Swedish stem bank: a database for different silvicultural and wood properties1995Report (Other academic)
  • 50. Grundberg, Stig
    et al.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Lindgren, Owe
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Noggrannhet vid detektering av stockars inre kvalitet: avrapportering av steg 11989Report (Other academic)
123 1 - 50 of 115
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf