BUILDING A MOBILE WOOD CHIPPER             Engr. Segun R. Bello   Department of Agricultural Engineering Technology       ...
IntroductionWood chips have various uses such as being spread as a ground cover, being pressed intoparticleboard or fiberb...
General Machine DescriptionThe chipper consists of a chipper disc assembly, frame, a disc housing, an infeed chute andan e...
Plate 1: Infeed chute side plateAnvil and the Infeed Roller: The anvil and the infeed roller were constructed andinstalled...
Plate 3: Anvil and infeed roller (close up view)Chipper Side Plates: The side plates were cut from a flat metal plate, mar...
required by the machine to chip wood, the disc must be dynamically balanced and heavy tocarry the cutting inertia.        ...
The Disc Assembly: The chipper disc was balanced on a balancer built prior to weldingthe shaft to the disc. The balancer c...
for the first two welding passes then used 6013 electrodes for two more passes. A total offour beads each were made.The Di...
The Frame: The frame is built from two 2" x 2” angle irons faced together and welded toform square tubing. Angle iron form...
The machine consists of five functional component parts; infeed chute and bracket, chipperdisc assembly, an exhaust or dis...
PARTS LISTING                                                   DIMENSION    COMPONENT                MATERIAL            ...
Small pulley              125mm dia                                                         24PMF.02.104             1    ...
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Building a mobile chipper

  1. 1. BUILDING A MOBILE WOOD CHIPPER Engr. Segun R. Bello Department of Agricultural Engineering Technology Federal College of Agriculture, Ishiagu E-mail: segemi2002@yahoo.com Prof. Onilude M.ADepartment of Agricultural and Environmental Engineering University of Ibadan, Nigeria E-mail: ma.onilude@mail.ui.edu.ng
  2. 2. IntroductionWood chips have various uses such as being spread as a ground cover, being pressed intoparticleboard or fiberboards, or being fed into a digester during papermaking. The use ofwood waste in animal bedding is known to be widespread (CALU, 2005). Dry woodchip hasbeen used as an alternative to straw under sheep and cattle housed in sheds (Frost et al,2005). Initially woodchips are spread across the shed floor to a depth of 10cm (CALU, 2005).The farmers using the system have been pleased with the results compared with straw. Thewoodchip utilization in animal bedding is less labour intensive and stock remains clean withlow incidences of foot problems and reduced need to belly clip lambs before dispatch to theslaughterhouse. Chip compost has been re-used as bedding and as a growing medium fortree seedlings. There have also been research interests on the suitability of compostedwoodchip bedding as a substrate for growing exotic mushrooms (CALU, 2005).Wood waste converted to mulch covers the soil and absorbs the erosive impact of rainfalland reduces the flow velocity of runoff, significantly reducing soil loss from a site. Woodchip mulch may be applied after the site has been rough graded to control erosion. Itprovides a temporary cover that reduces soil loss and allows vehicular and foot traffic overthe area. Mulch also provides benefits to the site beyond erosion control. The wood chipsform a blanket over the soil, and moderate its temperature, conserving moisture andproviding an environment conducive to seed germination. Wood chip mulching is aversatile practice that is applicable on sites where sheet flow is maintained and slopes donot exceed 3:1(DNR Publication, 2004).The local herb producers equally improves the market value of their products by locallychipping roots and herbs to increase the surface area for increased water absorptionconsequent release of the chemical constituents required for curative uses.Chipping is a fast, simple and environmentally friendly way of disposing agricultural wastesto high quality fiber value which has various uses such as being spread as a ground cover,being pressed into particleboard or fiberboards, or being fed into a digester duringpapermaking as well as bottom cover and covering for paths with a low traffic pressure. Theuse of wood waste in animal bedding is known to be widespread (CALU, 2005).Due to the economic value of wood waste, a significant portion of them does notadequately meet the needs of the consumer industries. The complexity of differentattributes of wood waste and other considerations provides criteria for the selection ofmaterials and the design of suitable size reduction technology and equipment. Theequipments vary with respect to the forms of wood wastes that can be effectively handled,and the quality of the product produced. 2|P a g e
  3. 3. General Machine DescriptionThe chipper consists of a chipper disc assembly, frame, a disc housing, an infeed chute andan exhaust or discharge chute. The disc chipper employs a rotary cutting steel disc securedto a shaft and simply supported on friction bearings to cut wood into chips. The cutting discis formed from mild steel 25.4mm (1’) thick. There are 3 cutting knives; 200mm in lengthfixed to the cutting sides of the disc bolted directly to the rotating disc.In operation, the disc is spin by a suitable electric motor to drive the shaft and the disc. Thewood to be chipped enters the machine through the infeed chute, and resting on the anvilattached to the chute bracket. The wood is drawn against the anvil as the knife cut a chipwhich is ejected through the aperture and out of the chipper through the discharge spout.Machine Fabrication ProcedureThe design of my chipper revolves around the rotary action of the chipper disc and threeknives enveloped in a round housing and two side plates made from the same material. Theentire system was powered by a 15hp electric motor to drive the disc.Other components and shapes are produced from secondary machining operationsincluding cutting, grinding, and trimming, drilling, sawing, and turning. The conditions oftools used for machining has greater influence on component performance, hence adequatecare was taken to establish and maintain the optimum tool conditions. Detailed descriptionand fabrication process is discussed as follows:The Infeed Chute: The components of the infeed chute were designed to give protectionagainst both upper and lower limbs of operator from being pulled into the machine. 1/8"thick steel metal plate was used for the construction of the chute sides. The angle of oinclination of the chute to the side plate is 35 . Outer edge opening of the infeed chute is aminimum of 41” wide x 39” high. Opening at feed spout is designed to be a minimum of 14”wide x 12” high. It was constructed from 14 gauge steel on top, sides, and bottom up to thechute bracket. The external length from feed spout to ground level is 800mm. The chuteedges have a ¾ square pipe welded right round to prevent the sharp edges from causingaccident.Side Plate and Chute Bracket: The anvil and the chute bracket were constructed and oset at 35 angles and welded to the chute opening on the side plate. Other sides of thechute were also welded to the anvil support and in place. 3|P a g e
  4. 4. Plate 1: Infeed chute side plateAnvil and the Infeed Roller: The anvil and the infeed roller were constructed andinstalled to control the knife clearance and the material feed into the knife respectively. Plate 2: Anvil and Infeed rolerThe vertical height of the roller is limited to the maximum feed capacity of the machine(76.0mm). The roller also prevents log lifting when it comes in contact with the knifeespecially when the length is small. 4|P a g e
  5. 5. Plate 3: Anvil and infeed roller (close up view)Chipper Side Plates: The side plates were cut from a flat metal plate, marked and cutinto sides as shown and the housing was cut from and rolled into desired size on a hydraulicsheet metal rolling machine. The housing was then welded to the discharge housingpermanently. Plate 4: Chipper housing welded to the discharge side plateChipper Disc Assembly: This is concealed within the chipper housing and comprises ofthe disc, knife, and chip thrower. The function of the disc assembly is to develop enoughinertia to chip wood fed into it and to eject the chips through the chip discharge chute.The Chipper Disc: Blank material sourced from the Agodi Gate steel market was smoothand appeared to have been cut with an automated torch to 24” diameter. The roundnessactually saved a lot of work in squaring and cutting. Because of the initial cutting forces 5|P a g e
  6. 6. required by the machine to chip wood, the disc must be dynamically balanced and heavy tocarry the cutting inertia. Plate 5: Marked piece of steel recovered from local metal marketThe disc was laid out according to design specifications, marked and after a lot of cutting,trimming and grinding to required size and shape, the slots were grinded using a handgrinder.Knives: There are three knives and chip throwers arranged radially at an angle of 120o toeach other on a massive steel disc which develop a lot of kinetic energy and inertia to slicethrough wood fed into it. Each knife has a dimension of 190 x 76 x10mm and was fastenedto the disc by three 14mm countersunk bolts and nuts. The knives material was recoveredfrom an out of service swipe blade, cut into sizes and sharpened into double sided 9.0mmthick, 190.0mm (7”) long and 76.0mm (3”) wide. Once the knives get dull you can turn themaround. Plate 6: Disc showing mounted blades (Front side) 6|P a g e
  7. 7. The Disc Assembly: The chipper disc was balanced on a balancer built prior to weldingthe shaft to the disc. The balancer comprises of two bearings on each side of the stand witha V- grooved metal plate welded to each stand. The disc is fully assembled with knives andthe chip thrower is a piece of 50 x 50x 5mm angle iron 190mm in length and was attachedto the disc with three grade 8 1/2" bolts and LocTite nuts to prevent them from vibratingout. The shaft and disc assembly is positioned on the bearings for balancing. Plate 7: Disc showing mounted chip throwers (Back side)The Drive Shaft: The shaft was turned from a solid piece of 76.0mm (3") stock on a 9” x20” metal lathe. The 21" disc has a 2 1/2" center hole and fits over the widest portion of theshaft. Plate 8: The drive ShaftBefore welding the shaft to the disc it was ensured that all the knives and chip throwerholes were correct and also ensures that the shaft fits all the bearings properly. The disc wasthen centered and welded to the shaft by a 200 amp AC welder (ESAB) and 6011 electrodes 7|P a g e
  8. 8. for the first two welding passes then used 6013 electrodes for two more passes. A total offour beads each were made.The Discharge Chute: The chip delivery channel was made of gauge 14 mild steel plateformed into an s-shaped chute ending in a rectangular flat plate bracket for fasteners to themain housing. Plate 9: Discharge chuteChip discharge from the chute is accomplished by a combination of centrifugal force and aircreated by a separate impeller/thrower mounted on the discharge end of the disc. Thedischarge chute is equally equipped with a hand adjustable deflector at the end ofdischarge. This is attached to chute with one hinge and can be folded back for easy access torear of chipper. Plate 10: Chipper outlet 8|P a g e
  9. 9. The Frame: The frame is built from two 2" x 2” angle irons faced together and welded toform square tubing. Angle iron forms the platforms on which the chipper and the electricmotor were mounted. The frame was equipped with two wheels at the rear to ensuretransportability and optimal weight distribution. Plate 11: The chipper frame mounted on two wheelsThe Chipper: The outcome of machine design and fabrication is as shown in Plate 12. Theoverall dimensions of the machine are; Length: 1676.4mm, Width: 609.6mm and Height:800.0mm. The height is adequate for ergonomic reasons considering the bending andfeeding of the machine. Plate 12: The wood chipper 9|P a g e
  10. 10. The machine consists of five functional component parts; infeed chute and bracket, chipperdisc assembly, an exhaust or discharge chute, frame and power drive.Machine SpecificationsThe machine specifications are as shown in the table below. Table 3: Machine components and specification COMPONENTS SPECIFICATIONS Engine: Atlas 3-phase double winding 15hp synchronous electric motor Speed: 1440rpm, voltage 1.2v, frequency; 50Hz Chute opening at chipper disc; w180mm x h150mm /w450mm x Infeed Chute: h360mm at feed point Discharge chute: provided with directional flip cover. 900mm Discharge Chute from wheel Disc Size: 1100mm x 60mm, Disc Weight: 86kg, Disc Speed: 540 Chipper Disc: rpm Three knives made of hardened spring steel. 190mm x 76mm x Knives: 10mm double edged, reversible and re-sharpen able. Drive Belts: Industrial "V" B51/5L540 (two) Anvil: Made from hard wearing metal with easy external adjustment 38.2mm diameter steel roller, in-between the anvil and the Infeed Roller: knives Chipper Housing 12mm plate front and back, 6mm plate disc cover. Chip thrower Minimum feed rate approximately 80 feet per minute. The frame is a network of angle iron and squared pipes welded Frame Support: together. Land wheels: Wheels 15 x 6.00 Machine Capacity 76mm (3 inch) – rated to 3 inches whole log 10 | P a g e
  11. 11. PARTS LISTING DIMENSION COMPONENT MATERIAL QTY (L X B) MM 3mm (1/8”) 540 x 800 2 Infeed chute thick ms plate 600 x 800 2 3mm(1/8”) Discharge chute 1200x1200 1 thick ms plate 12.7mm (1/2”) 170 x 250 2 Infeed bracket thick ms plate 208 x 250 2 12.7mm (1/2”) Anvil 1 thick ms plate 170 x 250 12.7mm (1/2”) Side plates 2 thick ms plate 609.6 x 609.6 3mm (1/8”) Diameter =549.4 Disc housing 1 thick ms plate Width = 93 25.4mm (1”) Chipper disc Diameter = 533.4 2 thick ms plate Frame 2” x 2” square tube 50x50x1200 2 10mm (3/8”) 190 x 76 x 9 Knife 3 thick spring 60mm (3”) dia. ms steel Drive shaft 50 x 228.3 1 rod Motor seating 2” x 2” Ms angle iron 2 Side plate M19x1.5x50 6 Bearing seating M14x1.5x50 4 Knife (c/sunk) M14x1.5x50 9 Thrower M13x1.5x25 8 Bolt and nuts Anvil M17x1.5x25.4 3 Discharge M13x1.5x25 6 Motor seat M19x1.5x25 4 Infeed chute M19x1.5x50 2 seating M19x1.5x25 8 Side plate bracket 2”x2” Ms angle iron 80 x50 x 50 4 Bearing seat 2”x2” Ms angle iron 24PMF.02.017 2 Washer Split washer GB93-87 14 Bearing KG Bearing 38UCP208 2 15HP motor 3-phase low speed 1 Drive Wheel 3.5kg weight 1 pair Wheel shaft Ms Rod 1” diameter 1 Wheel bearing KG Pillow Bearing 25UCP206 2 11 | P a g e
  12. 12. Small pulley 125mm dia 24PMF.02.104 1 Double grooves 192mm dia Double Big pulley 24PMF.02.103 1 grooves Fiber reinforced rubber V- Belt B-62 17 x 1625 2 beltBibliographyBedair Steve, 2005. 5" Horizontal Wood Chipper. Gladewater, Texas 10-2005. Firefox document. Modified on 3 August 2008Bjurulf, Anders, 2006. Chip Geometry Methods to impact the geometry of market chips. Unpublished Doctoral thesis, Swedish University of Agricultural Sciences, Uppsala 2006BS EN 294:1992. Safety of machinery – Safety distances to prevent danger zones being reached by upper limbs British Standards Institution 1992CWC, 1997. Wood Waste Size Reduction Technology Study NIST MEP Environmental program (# CDL-97-3) www.cwc.org.Frost D., McLean B. and Wildig J., 2005. The Multi-Use of Woodchip - From Animal Bedding to Mushroom Production. Farm Woodland Forum Meeting, 29 June – 1 July 2005.Grieve J. David, 2004. Manufacturing Processes - MFRG 315. 17th December 2004. Retrieved from....Downloadsmachgeom1_filesmachgeom0.gif.Segun R. Bello and Musiliu A. Onilude (2011). Force Relations and Dynamics of Cutting Knife in a Vertical Disc Mobile Wood Chipper Leonardo Electronic Journal of Practices and Technologies Issue 18 17-36. Romania Academic Direct Pub. House, Academic Direct Organization URL:http://lejpt.academicdirect.org/A18/017_034.htmSpinelli Raffaele, Bruce R. Hartsough, and, Natascia Magagnotti, 2005.Testing Mobile Chippers for Chip Size Distribution. International Journal of Forest Engineering. http://www.lib.unb.ca/Texts/JFE/July05/spinelli.pdfWen-Hsiang Lai, 2000. Modeling of Cutting Forces in End Milling Operations. Tamkang Journal of Science and Engineering, Vol. 3, No. 1: 15-22 12 | P a g e

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