Center for Wood Sciences CAS Wood Based Panels Module 1: Process Technology Mat formation September 7 12, 2015 Biel, CH
Content Mat formation basic requirements - dosing and metering bins - particle spreading and mat control - particle separation principles Mat forming lines Mat forming and spreading heads for particleboard production (Dieffenbacher) Spreading head for very fine material for fine particles for fine particles for core layer particles - process control Mat forming and spreading heads for particleboard production (Metso) Metso ClassiFormerTM series Content Mat forming lines for particleboard (Siempelkamp) Surface layer spreading heads Core layer spreading heads Mat forming line for OSB (Dieffenbacher, Metso, Siempelkamp) Surface layer formation for strands Core layer formation for strands Additional forming line equipment Mat formation MDF Metso UniformerTM Siempelkamp Starformer Dieffenbacher Conform CFM Process control Conform CFM mat forming line 2
Mat formation Mat formation basic requirements To achieve a uniform panel quality mat formation has to meet particular requirements! Particleboard OSB MDF Constant particle flow (mass / volume control during entire spreading process) Even and continuous particle spreading across the entire width / length of the mat Mass flow control before particle spreading Particle spreading Continuous or layer by layer increasing flake size from surface to core; no particle orientation. SL fine particles, CL coarse particles, optional outer layer of SL with fine particles Symmetric particle size distribution across mat thickness Strand spreading No strand size distribution across mat layer thickness; SL strands > CL strands 3-layer OSB strand orientation SL = II, CL = in relation to production direction; optional CL with additional fines fraction Symmetrical top/bottom SL Mass / volume flow control during fibre spreading Fibre spreading No fibre size differentiation during spreading, (actually) no preferred fibre orientation Homogenous fibre distribution across mat thickness Final mat weight control ( within pre-set limits) after mat formation - before pre-compaction / hot-press 3
Mat formation Mat formation basic requirements a continuous process Furnish distribution Equalisation Short-term buffer requires particular processing units, consisting of Dosing / metering bin Equalizing feed-in particles Dosing / metering outfeed particles Furnish flow weighing and metering Spreading head Distributing particles continuously according to size (shape, weight) Furnish spreading (mat formation) Vertically symmetry required mat structure and mat thickness ( panel thickness) may require several mat formation units! Forming belt Continuous mat transport to downstream processing Weight scale Control of mat formation accuracy 4
Mat formation Mat formation dosing and metering bin Separator even distribution of feed in particles across the entire width of the metering bin. Bin (volume) short-term intermediate buffer to ensure a constant particle flow Bottom belt conveyor continuous, constant particle flow to spreading head Weight scale sensor to control the pre-set particle flow by adjusting the belt speed. Separator Belt scale / bottom belt conveyor Objectives optimization of spreading accuracy avoidance of raw material losses ensuring steady and continuous particle flow Dosing / metering bins for particleboard production (Dieffenbacher 2013) 5
Mat formation Mat formation dosing and metering bins Extraction spike rolls in dosing and metering bin for particleboard production (Dieffenbacher 2013) Extraction spike rolls (front end) and top back-rakes in a dosing and metering bin for particleboard production (Dieffenbacher 2013) 6
Mat formation Mat formation particle spreading and mat weight control Even and continuous particle spreading Uniformity of particle spreading determines panel properties and panel property variation. Requirements to spreading depend on Raw material type (furnish, particle shape, mass) Final product Plant capacity This also determines the operating principle of the spreading head and the required number of spreading systems, which together make up a mat forming line. Mat weight scale Continuous determination of the mat weight to detect deviations in mass per unit area and immediate readjustment of furnish flow ( control loop). Continuous mat weight monitoring to achieve constant spreading Core layer spreading head (Dieffenbacher 2013) Dieffenbacher 2013 Mat scale (Dieffenbacher 2013) 7
Mat formation Mat formation particle separation and spreading principles PB-production surface and core flake fractions consist of non-uniform particles, i.e., small and large particles in each fraction. To achieve a uniform particle size distribution across mat thickness ( smooth size transmission) during mat formation the particles have to be separated accordingly. Three different separation methods have been developed. re1 Predominant separation effect: by weight of the particles Predominant separation effect: by size of the particles Separation controlled by roll surface texture and roll distance (gaps particle size) Rotating spike roll Forming belt movement Light (small) particles Heavy (large) particles Small particles Large particles Small particles Large particles Ballistic particle separation Wind particle separation Textured roll separation used for separation of core layer used for separation of surface used for separation of both flakesre2 layer flakes re3 surface and core layer flakesre4 8
Folie 8 re1 re2 re3 re4 fine particles have to be placed in the surface layer, coarse particle have to be placed in the core layers of the mat JBR; 28.08.2013 trowing... hurling of particles, flying distance is depending on particle weight (mass) JBR; 29.08.2013 flying distance of particles is depending on particle size JBR; 29.08.2013 particles fall down on the forming belt due to their weight (-> gravitational pull) - location / particle distribution depend on roll texture and gap between the rolls JBR; 29.08.2013
Mat formation Mat forming lines According to individual characteristics of wood based panels, e.g., single layer, homogeneous furnish mat for MDF or CSL, three-layer mat for PB, or OSB, the mat forming line design has to meet various technological requirements. The entire forming line may consists of one to four forming heads, including attached dosing and metering bin, a weight control system for the ready spread mat, or just after each layer forming unit an edge trimming station, a mat cross cutting saw, only for single or multi daylight hot-presses metal detector, pre-compression unit, a mat reject precaution. Almost exclusively two machinery suppliers - including their subsidiaries dominate the market of mat forming systems Dieffenbacher GmbH & Co. KG(www.dieffenbacher.de, (Sunds, Metso) ) Siempelkamp GmbH & Co. KG(www.siempelkamp.com, IMAL, CMC Texpan) 9
Mat formation Mat forming lines (Siempelkamp 2003) WindFormer SL Crown rollers CageFormer CL WindFormer Crown rollers Metal detector SL Crown rollers Pre-press Mat reject Particleboard forming and press line Particleboard forming and press line DiscFormer FinFormer FinFormer DiscFormer Mat trimming Metal detector Mat reject Pre-press OSB forming and press line Star Former Mat forming and leveling head Pre-press Mat trimming Mat reject MDF forming and press line 10
Mat formation - PB Mat formation and spreading heads for particleboard production The CONFORM CFS spreading head series (Dieffenbacher 2013) covers different spreading systems for individual requirements in particleboard production, depending on production programme ( panel structure, surface smoothness ), production capacity and, e.g., raw material used. Application Throughput per meter Spreading method spreading width Very fine surface layer 25 m³/h Air / wind former (adjustable) Single layer 2 x 15 m³/h Combined air/mechanical (dual) Fine surface layer (homogeneous board surface) 30 m³/h Mechanical rollerbed former Core layer 50 m³/h Mechanical without cross profile control Core layer 75 m³/h Mechanical with cross profile control Dieffenbacher 2013 11
Mat formation - PB (Dieffenbacher 2011) 12
Mat formation - PB Example Wind forming station 1.200 m³/d particleboard (3) (1) (1) (1) (2) (2) (5) (4) (4) (1) Shuttle belts with UDB dosing bin (2) WSK windformer with glue lump screens (3) Core layer with disc separator and HSR spreading head (4) separate material return for overspreading material for each layer (5) partiell CL and complete matscale Several measuring and protection devices ( metal separators etc.) Dieffenbacher 2013 13
Mat formation - PB Example Wind forming station 3.000 m³/d particleboard (1) (1) (1) (3) (3) (2) (2) Dieffenbacher 2013 (4) (4) (4) (4) (1) swivel belts with SDW dosing bin with integrated weight scales (2) high capacity WSK windformer with glue lump screens (3) Core layer with disc separator and RS spreading head for controlled and adjustabel cross distribution (4) total mat scale and material return for each layer for overspreading material for maximum material savings Several measuring and protection devices ( metal separators etc.) Forming / Press line (Siempelkamp 4:30 min) 14
Mat formation - PB Spreading head for surface layer particles (very) fine particles The CONFORM CFS spreading head (Dieffenbacher 2005) is particularly designed for spreading very fine particle surface layers of particleboards. Particle separation is based on the wind or air forming principle. Feed flap Spreading capacity approx. 25 m 3 h -1 m -1 Diffusor with register Spreading rollers Screens Resin lump screen Air inlet (adjustable fan speed) Vitiated air (exhaust) Slide gates Air volume approx. 1.000 m 3 h -1 m -1 Air volume approx. 5.000 m 3 h -1 m -1 additional fine particle separation Dieffenbacher 2013 15
Mat formation - PB Spreading head for surface layer particles The WindFormer spreading head (Siempelkamp 2003) is a pneumatic or airflow-based spreading system for surface layer furnish with high separation capacity, precise mat forming, i.e., consistent particle size distribution, and adjustable separation between fine and coarse surface layer particles. Particle throughput per meter forming width 90 170 m 3 h -1 WindFormer for particleboard surface layer mat formation (Siempelkamp 2003) WindFormer for particleboard surface layer mat formation (Siempelkamp (IMAL 2015) 2003) 16
Mat formation - PB Spreading head for core layer particles The CONFORM CFS core layer spreading head is a mechanical spreading system parti-cularly tailored for distributing the core particle fraction. Different designs enable core layers with and without cross profile adjustment ( with / without particle separation spreading). Advantages of systems with cross profile control No particle separation High accuracy in flow distribution Uniform mat formation, optimum raw density distribution Uniform panel quality also with reduced board density Selectable density profiles No exhaust of vitiated air Modular design of components No re-adjustment when changing board density Core layer spreading without cross profile control Air relief hood Spreading capacity approx. 30 m 3 h -1 m -2 Feed-in flap Splitting rake Spoke rollers Air relief hood Dieffenbacher 2013 17
Mat formation - PB Spreading head for core layer particles The CONFORM CFS core layer spreading head with cross profile adjustment Feed-in flap Splitting rake Spreading capacity 75 m 3 h -1 m -2 Distribution rollers Rake Slide gate Discharge screw Air relief hood Air relief hood Spoke rollers Dieffenbacher 2013 18
Mat formation - PB Spreading head for core layer particles The CageFormer spreading head (Siempelkamp 2003) is a mechancal spreading system for core layer furnish with high separation capacity, precise mat forming, i.e., consistent particle size distribution, and adjustable separation between fine and coarse core layer particles. Particle throughput per meter forming width approx. 90 170 m 3 h -1 CageFormer for particleboard core layer mat formation (Siempelkamp 2003) 19
Mat formation - PB Spreading head for core layer particles Conform CFS Core layer spreading head (Dieffenbacher 2013) with cross profile control (Dieffenbacher 2013) 20
Mat formation - PB Mat forming stations Mat forming station at BHT-Kunz particleboard plant (Dieffenbacher 2013) Mat forming station at Nolte particleboard plant (Dieffenbacher 2013) 21
Mat formation - PB Dust spreading at particleboard production Particular dust spreading heads are usually installed at the beginning and at the end of a forming station; they spread a thin layer of fine, dry or lightly moistened particles, aimed to protect the press platens from sticking particles when isocyanate resin (PMDI) is used. Downstream the process these layers are sanded off after the trimming station. Alternatively a release agent could be used for the same purpose. (CMC Texpan 2005) Dust spreading head at BHT-Kunz particleboard plant (Dieffenbacher 2013) 22
Mat formation - PB Mat forming stations process control CONFORM CFS mat forming Station control system PC on-screen display of actual gate position, and desired and actual density distribution Partial removal of material from the particle stream with slide gates in the case of deviation from desired density distribution over the spreading width Return of removed particle stream to the spreader bins (Dieffenbacher 2013) Control screen of Conform CFS surface layer spreading head (Dieffenbacher 2013) 23
Mat formation - PB Mat forming stations process control Features and Advantages of particleboard forming control loops The metering scale controls material feed quickly and precisely to the spreader head The material mass flow is controlled before mat forming with fast response The total mat weight (b.d.) is controlled and monitored by a superimposed loop All set values are automatically calculated from the raw board data Filling level of the metering bins is measured continuously and controlled to target Material distribution across the machine is also measured and loop controlled Highly precise controlled forming with fast response significantly contributes to Constantly high board quality at minimum material consumption Reduced amount of downgrades and rejects High efficiency of production plant 24
Mat formation - PB 25
Mat formation - PB Mat forming stations ClassiFormer TM mat forming stations for particleboard Compact forming line for small to high capacities For structural and furniture boards with normal lamination demands Reliable forming machine with high forming accuracy Different kind of raw materials Modular system with compact design for modernization ClassiFormer TM mat forming station (Dieffenbacher 2011) 26
Mat formation - PB Mat forming stations ClassiFormer TM mat forming stations for particleboard Unifeed TM rollers developed for a wide range of raw materials Moving spreading units are required for single or multi-daylight hot presses Dieffenbacher moving mat forming station ClassiFormer TM SF spreading unit (Dieffenbacher 2011) 27
Mat formation - PB Example Compact ClassiFormer - capacities 8 up to 500 m³/d particleboard SC combined forming head (Dieffenbacher 2011) 28
Mat formation - PB Example ClassiFormer capacities 8 up to 1.200 m³/d particleboard CC compact forming head (Dieffenbacher 2011) 29
Mat formation - PB Example ClassiFormer capacities 8 up to 3.000 m³/d particleboard SL forming head CL forming head (Dieffenbacher 2011) 30
Mat formation - PB Spreading heads for surface and core layer particles SL Crown rollers CL Crown rollers SL Crown rollers SL Crown rollers CL CageFormer SL Crown rollers CrownFormer for particleboard surface and core layer mat formation Crown rollers (Siempelkamp 2003) 31
Mat formation - OSB Dieffenbacher 2011 32
Mat formation - OSB Mat formation Oriented Strand Board Strand* orientation in the respective layer is much more important than strand size distribution within each layer. Strand orientation, in particular in the surface layers, is significantly determining mechanical properties, e.g., bending MOE and MOR. This requires particularly designed spreader heads for each layer. SL CL SL * Strand size: l x b x t 150 200 x 5 25 x 0,3 0,5 mm Degree of orientation 80 %, l = 150 mm (Dieffenbacher 2013) 33
Mat forming line Oriented Strand Board Example High capacity up to 2.000 m³/d OSB forming line with defined strand properties 2 cross orienter and 2 length orienter Mat formation - OSB Dieffenbacher 2011 High capacity OSB forming station for multi opening presses; with defined strand properties. 6 head forming station for maximum throughput with intermediate layer 34
Mat formation - OSB Mat forming line Oriented Strand Board OSB strand bin increased buffer volume of the bin enables high flow rate while maintaining a good equalizing function metering scale (as option) is incorporated into the bin and is a unique feature which improves the forming accuracy Laser filling level sensors ensure reliable signals for the controls Manually adjustable edge density Filling level laser Guided air flow Discharge rollers (Dieffenbacher 2011) Weight scale 35
Mat formation - OSB Mat forming line Oriented Strand Board OSB material flow lengthwise orientation Swivel screw conveyor Forming and metering bin Disc arrangement for strand length orientation variable distances between adjacent discs (Siempelkamp 2002) OSB-length orienter with automatic height adjustment and over-size removal (Dieffenbacher 2011) 36
Mat formation - OSB Mat forming line Oriented Strand Board OSB material flow lengthwise orientation - spreading head for improved length orientation Swivel screw conveyor Forming and metering bin Good strand orientation (Dieffenbacher 2011) OSB-cross orienter with automatic height adjustment (Dieffenbacher 2011) 37
Mat formation - OSB Mat forming line Oriented Strand Board OSB material flow crosswise orientation Double swivel screw conveyor Forming and metering bin Cross-orientation rollers with pocket forming wings (Siempelkamp 2002) OSB-cross orienter with automatic height adjustment (Dieffenbacher 2011) 38
Mat formation - OSB CONFORM CFO OSB mat forming line Conform CFO OSB surface layer spreading head (Dieffenbacher 2013) Dissolving rollers in Conform CFO OSB surface layer spreading head (Dieffenbacher 2013) 39
Mat formation - OSB Surface and core layer formation OSB spreading systems DiscFormer mat forming rollers (Siempelkamp 2003) FinFormer mat forming head (Siempelkamp 2003) DiscFormer and FinFormer for OSB face and core layer mat formation (Siempelkamp 2003) 40
Mat formation - OSB Additional forming line equipment Equalizing roller at OSB plant AINSWORTH LUMBER CO LTD (once Footner Forest products Ltd./CAN) (Dieffenbacher 2013) Forming belt with mat trimming saw and metal detector at OSB plant AINSWORTH LUMBER CO LTD (Dieffenbacher 2013) 41
Mat formation - OSB Additional forming line equipment OSB forming line Mat reject system (Dieffenbacher 2013) Mat trim saw width adjustment at Norbord OSB plant (Dieffenbacher 2013) 42
Mat formation - MDF (Dieffenbacher 2011) 43
Mat formation - MDF Mat formation Medium Density Fibreboard Also MDF mat formation requires a dosing bin with an integrated weight scale, and a spreader system. Due to the loose, fluffy fibre consistency, handling and spreading is different. Additionally no particular particle orientation is requested, thus only one forming station is used to achieve a homogenous and uniform fibre mat. Fibre infeed system From fibre storage bin Z-Sifter TM Cleaning Conditioning Dosing and metering bin Uniformer TM Forming head Pre-press Mat reject system Hot-press (Dieffenbacher 2011 (previously Metso panelboard 2004) 44
Mat formation - MDF Mat formation Medium Density Fibreboard (Dieffenbacher 2015) 2011) (1) (6) High speed outfeed rollers for fiber dissolving ROLLER FORMING HEAD Guided fiber flow by multi chamber principle roller designs. The most Less air speed with controlled air flow (4) (2) (3) Universal machines, suitable for all requirements, different established in the MDFproduction (1) Forming bin (2) Spreading head (3) Equalizing roller unit with profile former (4) Discharge head with integrated dissolving rollers (5) Mat scale VACUUM FORMING STATION Forming station with spiked rollers is tailored for thin (6) Distribution gate boards THDF thickness 1 mm high quality standards strength and surface quality (5) 45
Mat formation - MDF Mat formation Medium Density Fibreboard The dosing and metering bin guarantees accurate fibre flow to the spreader head. A built in back-rake conveyor on top keeps the fibres in the bin at constant height when they reach the doffing roller section. Discharge rate is controlled by variable speed of the bottom belt conveyor. Condensation on the surface of the inner bin wall and electrostatic charging, and thus fibre sticking, is avoided by using plywood bin walls. Fibre infeed consists of a sloping feeder plate and a spreader roller at the end of the plate. Homogenous fibre flow to the spreader head as well as forming accuracy is ensured by: Infeed and distribution of fibres over the entire dosing bin width, Fibre back-rake conveyor on top of the bin, Design and speed control of the doffing roll section, Geometry of doffing roll housing, Feeding / directing the fibres down to the mat conveyor, Forming roller design and level control, Mat weight scale, Adjustable floor. The achieved fibre flow is without high air turbulence and dust generation. (acc. to Metso panelboard 2004) 46
Mat formation - MDF Mat formation Medium Density Fibreboard MDF mat forming station. Spreader head with different roller sections for fibre spreading, evening and mat height adjustment (levelling or scalping) (Siempelkamp 2002) Fibre bin MDF mat forming head with disintegration rollers Doffing rollers Rollers for fibre spreading and levelling Scalping rollers Dosing and metering bin Star Former MDF mat forming head Leveling head Forming belt (Siempelkamp 2010) 47
Mat formation - MDF Mat formation Medium Density Fibreboard Doffing roller section: disintegration of fibre pile to continuous fibre flow; speed control to meet capacity demands and to reduce air turbulence. Levelling rollers: redistribution of fibre mat density variations, i.e., density peaks. Evening out rollers: disintegration of fibre lumps, smooth mat surface. homogenous, uniform, and smooth fibre mat Doffing rollers Feeder plate Spreader roller Levelling rollers Evening out rollers (Metso panelboard 2004) 48
Mat formation - MDF Mat formation Medium Density Fibreboard Forming bin and discharge head Discharge head with dissolving rollers and Multi chamber principle Guided fiber flow by multi chamber principle Less air speed with controlled air flow (Dieffenbacher 2011) Fast rotating outfeed rollers dissolve fibrelumps Small gaps between spikes 49
Mat formation - MDF Mat formation Medium Density Fibreboard Forming head Height adjustable forming head for various board production Optimized fiber flow and roller arrangement Separate adjustable roller speed New roller design Prepared for integration (Dieffenbacher 2011) Position for thick boards Swivelmounted roller desk Position for thin boards Swivelmounted roller desk 50
Mat formation - MDF Mat formation Medium Density Fibreboard Scalping unit for optimal weight tolerances Minimum scalping with Profile former, particularly for thin and HDF boards (Dieffenbacher 2011) 51
Mat formation - MDF Mat formation Medium Density Fibreboard Scalping unit for optimal weight tolerances Scalping unit (Dieffenbacher 2011) 52
Mat formation - MDF Mat formation Medium Density Fibreboard Fibermat before / after equalizing Profile former (Dieffenbacher 2011) 53
Mat formation - MDF Mat formation Medium Density Fibreboard Scalping to reduce weight tolerances BINOS Scalper X-Ray Scanner (Dieffensor) mat density variation segmented scalper Dieffensor [1:25 m] Pre-pressing Hot-pressing Mat forming Segmented Scalper Individually controlled scalping segments Modern control console Gangway for easy maintenance Software module for automatic control of the scalping segments (Binos 2015 / GreCon 2015) 54
Mat formation Scalper ( GreCon FORMATOR) Mat formation also suitable for PB, OSB, HDF and other WBP types Small density variation crosswise the production direction material savings! Reduced lengthwise density variation (parallel to production direction) material savings and quality improvement! 55
Mat formation Mat formation Scalper Adjusting the area weight of spread particles during mat formation Calculation / removal of excess material before hot pressing ( furnish recycling) Each segment is individually driven Individual height adjustment of each segment to cut an area or single profile of the spread mat, while the removed material is fed back into the spreading process Optimization continuous measurement of mat density (parallel and perpendicular to production direction) and individual con-trol of scalper rolls Principle is transferable to other woodbased panel production lines (PB, OSB ) Binos 2015 56
Mat formation - MDF Mat formation - Medium Density Fibreboard CONFORM CFM mat forming line process control (Dieffenbacher 2013) 57
Overview / Intro 58