WOOD CUTTING MACHINE

PRESENTED BY:

SABAPATHI.N.M (731811114082)

INTRODUCTION

• Nowadays, the wood cutting process is considered as a technological scheme. It consists of several connected and relatively inseparable parts (Marko, Holik 2000). The technological system called ―cutting process‖

• consists of four parts – subsystems: a workpiece cutting conditions, a cutting mechanism and a cutting tool

SAWING WOOD BASED PANELS

• The grain directions of the wood particles in fibre boards and particleboards are random, saw blades with cross cutting forms should be used.

• Certain types of cutter (portable circular saws and jig saws) cut on the upstroke, and the wanted or decorated face should therefore be placed facing downward (see Figure 2.2).

• Bench circular saws, on the other hand, cut on the down stroke thus necessitating feeding the panel in face uppermost.

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SAW BLADE SETTING • Circular saw blades should be set as low as possible to prevent

chipping and scoring as the panel passes the rear of the saw blade. The height of the saw blade should be positions as to maintain the correct hook angle relative to the panel surface (see Figures 3.1). The projection of the saw above the panel has a direct influence on the cleanliness of the cut.

• Breaking out or chipping of the top surface will occur if it is insufficient and on the bottom if it is too great.Control of the panel during machining is important, panels should be properly supported and pressed down firmly against the cutting table and guides to avoid vibration.

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Plywood

Sawing • The blade of a circular saw should enter the panel on the good face.

This usually means that the panel is face down with a hand held saw and face up on a bench saw. TCT blades are recommended as the adhesives commonly used in plywood can lead to heavy wear.

• The panel should be supported as close as possible to the blade and best results will be achieved with: ¨ a fast material feed speed ¨ counter sawing (panel fed in opposite direction to the saw rotation) ¨ a minimum protrusion of the saw above the panel surface To minimize the risk of splintering the corners of the panel it is best if the cuts at right angles to the face grain are made first and those parallel to the face grain are made afterwards .

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Routing • A high cutter speed and slow material feed speed usually produces

best results. TCT cutters should be used. • Cutters must be kept sharp as dull cutters will cause edges to ‗bell‘

or spread causing difficulties when laminating, edging or lipping close to the edges.

• Router cutters generally incorporate cutting angles in the range 15° to 25° and clearance angles in the range 15° to 18°.

Drilling • To achieve a clean finish, drilling should start from the good face of

the panel. Breaking out on the back of the panel can be avoided by drilling into a backing block.

• Speeds of 3000-4000 rpm produce the cleanest cut with least lipping around the hole. Conventional steel drills have bits with a point angle of 118°

Sanding • If a smooth surface is required, this can be achieved, depending on

the veneer species and quality, by sanding parallel to the face grain with a fine grade sandpaper.

• Face sanding should not be necessary; edge sanding may be done by hand or with orbital or belt sanders. . Increasing to 170° decreases surface lipping.

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• Check tile saw to make sure water is in blade tray. • Verify the saw is plugged in • Take your time. Sawing through tile slowly can help give you

cleaner cuts and reduce breakage. • Mark the work piece with a lead or grease pencil. • Set the work piece against the fence on the sliding saw bed and line

up the diamond blade with the cutting mark.

WORKING PROCEDURE

• Turn on the saw and wait for water to flow over the blade. • Hold the work piece on both sides of the cutting line and slowly feed it

into the blade. • As the cut nears completion, use push bar. Gently push the two halves

of the piece together to prevent the tile from breaking before the cut is complete.

• When the cut is complete, carefully slide the bed and cut tile back toward you until the tile is clear of the blade.

• Empty blade tray of dirty water. Do not pour water down sink, but please in hazardous waste container

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Pre-finished and faced panels

• For pre-decorated panels it is normal to cut down on to the decorated face. Chipping of the decorated surface can be eliminated by:

• ¨ Using a saw with ten or preferably more teeth per inch. • ¨ Keeping a low angle of cut. • ¨ Working to a knifed or scored line, the cut being made on the waste

side of the line or placing masking tape on the decorated face over the intended line of cut. Face bevel and top bevel angles of saw blades may need adjusting for veneered or other faced panels.

• When drilling through melamine faced panels the drill point angle should be between 80° and 90°.

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• It is recommended that plastic laminate veneered panels are reduced to finished component size by sawing and that spindling and routing cutters are only used on edges when the shape of the panel precludes sawing.

• If it is necessary to rough cut oversize, careless cutting can cause hairline cracks in the surface which can lead to chipping on subsequent operations.

Hardboards and Medium Boards

Sawing

• Can be cut with a hand saw or powered circular saws, band

saws and saws.

• To prevent chipping, hand saws with ten or more teeth per inch

are recommended, held at a low angle of cut to the panel and

with minimum tooth set.

• Too great a feed speed will result in rough fibrous cut edges.

• Control of the panel during machining is important, panels

should be properly supported and pressed down firmly against

the cutting table and guides to avoid vibration.

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Spindle and Routing. • Hardboards and medium boards can be routed and moulded using

conventional wood working tools and bits. PDT and TCT cutters should be used.

• Cutters must be kept sharp as dull cutters will cause edges to ‗bell‘ or spread causing difficulties with laminating, edging or lipping close to the edges.

• General feed speeds should be slower than for solid timber, and cutters should have the largest number of cutting edges possible

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OPERATION

• When cutting with this tool, the thickness of the blade is cut as well. Therefore, your cutting line should be on either the left or right side of the groove in the kerf board.

• Switch on the tool and wait until the blade attains full speed before lowering gently into the cut.

• When the blade contacts the workpiece, gradually bear down on the handle to perform the cut.

• When the cut is completed, switch off the tool and WAIT UNTIL THE BLADE HAS COME TO A COMPLETE STOP before returning the blade to its fully elevated position.

• A thin piece could otherwise contact the coasting blade and be thrown out dangerously.

Securing Work piece • Hold the work piece firmly against the guide fence. Exercise extreme

caution and keep your hands away from the blade area during operation.

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The Tool and its Parts

Handle Latch • This tool is equipped with a handle latch, which is used to lock the

handle in the lower position. To release from the lowered position, lower the handle slightly and turn the handle latch to the released position. To lock the handle in the lowered position, lower the handle fully and turn the handle latch to the locked position. When carrying the tool, lock the handle in the lowered position and secure the turn base by means of the grip.

Removing or Installing Saw Blade • CAUTION: Always be sure that the tool is switched off and unplugged

before removing or installing the blade. To remove the blade, use the socket wrench to loosen the hex bolt holding the center cover by turning it more than three turns counter clockwise. Raise the safety cover and center cover.

• To install the blade, mount the blade onto the spindle, making sure that the direction of the arrow on the surface of the blade is compatible with that on the blade case. Install the outer flange and hex bolt, and then use the socket wrench to tighten the hex bolt securely counter clockwise while pressing the shaft lock.

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Safety Cover • When lowering the handle, the safety cover rises by means of the guide arm.

The cover returns to its original position when the cut is completed and the handle is raised.

• NEVER DEFEAT OR REMOVE THE SAFETY COVER. In the interest of your personal safety, always maintain the safety cover in good working condition.

• Any irregular operation of the safety cover should be corrected immediately. NEVER USE THE TOOL WITH A FAULTY SAFETY COVER.

• If the see through safety cover becomes dirty, or sawdust adheres to it in such a way that the blade and/or workpiece is no longer easily visible, unplug the saw and clean the cover carefully with a damp cloth.

• Do not use solvents or petroleum-based cleaners on the plastic cover.

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Results and discussion

• The results were processed by the Comes Spider program. From the torque Mk course at cutting of beech by a circular saw with cemented carbide plates it was possible to see a great increase in its value at the beginning of the penetration of a tool (circular saw) into the cut.

• Then there was a certain decrease in this value, which was caused by the inertia of a circular saw, and then following fixation of the cutting process.

ADVANTAGES • It takes less time to finish the work. • Good surface finish can be obtained. • Simple in construction. • Speed of blade is high. • Cost is low.

APPLICATION • It is used in Wood working Industries. • It is used in furniture shop.

Conclusion

• In practice it is very important that the whole process of wood crosscutting should run with the lowest power consumption.

• There are many factors which influence its power consumption, e.g. material of the cutting tool, its geometry and optimal cutting forces (cutting speed vc, feed rate vf ).

• The cutting power is a very important factor of power consumption.