This document provides information on planing machines and their components. It discusses different types of planer knives and the factors to consider when selecting knives, such as the material being processed. It describes various knife materials like chrome vanadium steel, high speed steel, and tungsten carbide. The document outlines knife geometry specifications, including rake angle, bevel angle, clearance angle, and peripheral cutting speed. It also addresses pitch distance, chip formation, riving, cutter projection, and maintenance of planing machines.

1. WT4603Wood Processing Safety & PracticeAutumn Semester 2011Lecture Unit 3 (Week 4)PLANING MACHINES, HAND ROUTERS & COMPONENT B

2. Lecturer: Mr. Joseph Lyster

3. joseph.lyster@ul.ie

4. Notes prepared by: Mr. Joseph Lyster

5. Notes available on www.slideshare.net/WT4603WT4603Surface PlanerPlaner Knives Important factors when selecting a planer knife Suitability for cutter blockMaterial being processedFinish requiredVolume being machinedClamping and setting mechanismsDepartment of Manufacturing & Operations Engineering

6. Surface PlanerWT4603Planers can have 2,3,4,6……. Cutter knives.Most smaller machines such as those found in schools will have 2,3 or 4 knives.Department of Manufacturing & Operations Engineering

7. Surface PlanerWT4603Knives can be made from Chrome Vanadium steel alloy. This is suitable for machining softwoods and non abrasive hardwoods. However with advances in machining technology better materials have been developed to machine wood and wood composites. Chrome Vanadium knives dull quickly on harder more dense material. This requires more sharpening, setting up and leads to a lot of time wastage.Department of Manufacturing & Operations Engineering

8. Surface PlanerWT4603High Speed Steel (HSS) is a cobalt steel alloy with a small percentage of Tungsten added. It is more suitable for machining all types of wood than the chrome steel compounds.Department of Manufacturing & Operations Engineering

9. Surface PlanerWT4603Abrasive stock should be machined using solid or tipped cutters.Tungsten Carbide (TC) is the best tool compound for machining manufactured boards.For general work HSS cutters are preferred to TC Cutters can be re-sharpened easily.A keener edge can be achieved on HSS giving a better finishDepartment of Manufacturing & Operations Engineering

10. Surface PlanerWT4603The reason for this is that steel compounds are smelted and shaped by rolling and forging while the metal is close to melting point.The molecules of the compound flow and align themselves in response to this pressure giving the material maximum strength and edge holding capabilitiesDepartment of Manufacturing & Operations Engineering

11. WT4603Surface PlanerTungsten carbide is a sintered compound. The fine grain powder from which the cutter will eventually will be made is compressed into a mould ( the ‘blank’ un-edged cutter required) under extremely high temperature (1500C) and pressure to form a solid block.Tungsten does not flow – it retains a granular structure and will chip rather than deform if abused.Department of Manufacturing & Operations Engineering

12. Surface PlanerWT4603Because if its brittle nature TC cutters require a more obtuse sharpness angle than the HSS cutters (more support for the cutting edge). This makes it less satisfactory for cutting softwoods than HSS knives which can be ground to a more acute cutting angle.Department of Manufacturing & Operations Engineering

13. WT4603Surface PlanerDepartment of Manufacturing & Operations Engineering

14. WT4603Knife Cutter geometryRake or Cutting angleAngle created between the face of the cutting knife and the centre of the cutter blockCan have a wide rangeSoftwoods 27° to 35 °Hardwoods 15° to 25 °Department of Manufacturing & Operations Engineering

15. WT4603Knife Cutter GeometryBevel or Lip AngleAngle formed to give the cutting edgeMinimum of usually 35°Greater for tipped cuttersDepartment of Manufacturing & Operations Engineering

16. WT4603Knife Cutter GeometryClearance AngleAngle formed between a line tangential to cutting circle and the bevel angle of the knifeMust be presentHas a bearing on the life of the cutting edgeUsually 10° to 15°Department of Manufacturing & Operations Engineering

17. WT4603Knife Cutter GeometryPeripheral Cutting SpeedA constant speed in the range of 35-45 m/s will give best resultsIncrease in speed may cause loss of dynamic balance due to vibrationsPoor finishIncreased noise levelsDepartment of Manufacturing & Operations Engineering

18. WT4603Pitch distanceCombination of a rotary cut and a linear feed will leave the surface of the material with a series of arcs on it called Curtate TrochoidsThe pitch and depth of these arcs will determine how smooth the surface finish will beDepartment of Manufacturing & Operations Engineering

19. Department of Materials Science & TechnologyUniversity of LimerickWT4603Pitch Distance2mm to 3mm for non obvious joinery and painted external work. 1mm to 1.5 mm for internal painted work.0.5mm to 1mm for hardwood joinery and furniture.Department of Manufacturing & Operations Engineering

20. WT4603Pitch DistanceThe SI unit of time is the second , but the minute is acceptable. Feed rate on wood working machines is expressed in metres per minute. (m/min) The formula for the pitch of the cutter marks is given by: f p = -------nR where p = pitch of cutter mark f = feed rate n = number of effective cutters R = revolutions per minute of blockDepartment of Manufacturing & Operations Engineering

21. Pitch DistanceWT4603The unit for “p” will be metres (m) f m/min m minp = ---- = --------- = ----- x ------ = m nR 1/min min 1Department of Manufacturing & Operations Engineering

22. WT4603Pitch DistanceProblem 1 Calculate the cutter pitch of a 4 cutter block revolving at 4200 rev/min with a feed speed of 24m/min. F 24 24p = ------- = ------------ = --------- = 0.0014m = 1.4mmnR 4 x 4200 16800(Internal painted work)Department of Manufacturing & Operations Engineering

23. Pitch DistanceWT4603 If a graded surface is specified and the machine has a multi-speed feed gearbox, the same formula is used but “f” is expressed in terms of n ,p, and R. f p = -------  f = nRpnRDepartment of Manufacturing & Operations Engineering

24. Pitch DistanceProblem 2 From a cutter block which rotates at 4200 rev/min and has two cutting knives, a surface finish of a 4mm pitch is required. At what speed should the feed gearbox be set. f = nRp = 2 x 0.004 x 4200 = 33.6 m/min WT4603Department of Manufacturing & Operations Engineering

25. WT4603Chip formationDepartment of Manufacturing & Operations Engineering

26. WT4603RivingDepartment of Manufacturing & Operations Engineering

27. RivingWT4603Cracking occurs below the cut depthDepartment of Manufacturing & Operations Engineering

28. WT4603AOn the surface planer the in-feed table (A) acts as chip breaker and the downward pressure exerted by the operator also makes it act as the pressure bar.Department of Manufacturing & Operations Engineering

29. WT4603Chip formationDepartment of Manufacturing & Operations Engineering

30. WT4603Chip formationChip breaking aid and pressure bar prevent riving and splinteringDepartment of Manufacturing & Operations Engineering

31. WT4603Circular cutter blockReduced noise levels

32. Better balance

33. Safer clamping mechanism

34. Can run head at higher speeds (RPM)

35. Can produce better finish

36. Easier and quicker maintenanceDepartment of Manufacturing & Operations Engineering

37. WT4603Circular cutter blockClamping bolts are in tensionDepartment of Manufacturing & Operations Engineering

38. WT4603Knife clamping mechanismDepartment of Manufacturing & Operations Engineering

39. WT4603Knife clamping mechanismDepartment of Manufacturing & Operations Engineering

40. Cutter projectionWT4603Use of a limiter to achieve limited cutter projectionDepartment of Manufacturing & Operations Engineering

41. Cutter designWT4603Cutters should preferably be designed to be used in dimensionally similar pairs, formed to the same profile. Pairs should be mounted directly opposite one another. The manufacturer should ensure that instructions on balancing the pairs of cutters after grinding are given to the user.Department of Manufacturing & Operations Engineering

42. Cutter projectionWT4603The design of cutter blocks should, as far as is practicable, be such as to prevent excessive cutter projection. Where the mounting arrangement permits projection which could subject the cutter to unsafe stresses, the maximum permissible projection for given cutter types should be specified in the user’s instructions.Department of Manufacturing & Operations Engineering

43. Hand-fed machinesWT4603For machines designed for hand-fed operations, where cutters are necessarily exposed, the use of chip limiting cutters should be recommended For other hand and semi-mechanical feed operations, cutter blocks should have as little cutter projection as is practicable.Department of Manufacturing & Operations Engineering

44. WT4603Surface PlanerCutter and Machine Maintenance Involves: Grinding and setting of knives Roller and pressure bar setting Prevention of resin build up on table and rollers. Attention to: bearing wear

45. feed complex adjustments

46. rise and fall tableDepartment of Manufacturing & Operations Engineering

47. Surface PlanerWT4603The grinding angle of a cutter can vary between 30 to 35This is increased to 40 for hardwoods (cutting edge lasts longer)Department of Manufacturing & Operations Engineering

48. WT4603Surface PlanerOverheating May produce micro cracks in the cutting edge which can run into gaps when the cutter is used.May cause the cutter to bow due to expansion.Department of Manufacturing & Operations Engineering

49. WT4603Surface PlanerOverheating can be avoidedBy taking light cuts.By ensuring that the grind wheel is ‘dressed’ when required to ensure that the face is open and not glazed when grinding the knives.By using a ‘soft’ grinding wheel on HSS cutters – the soft structure of the wheel allows its grains to break away as soon as they are blunt revealing sharper ones.By wet grinding – this is the grinding of cutters while partially submerged in a mixture of water and soluble oil. The water is a coolant to prevent frictional heat developing and to disperse it should it occur. The oil prevents rust in the cutters and it provides a degree of cutting lubrication.Department of Manufacturing & Operations Engineering

50. WT4603Surface PlanerSetting Cutters in Block Before setting the following points should be checked. The out feed table and cutter block must be clean and free from dust resin. Method of adjusting cutters.Area where setting device is used from should be free from resin and damage.Straightness of cutters.Cutters correctly balanced both in weight and end for end.Department of Manufacturing & Operations Engineering

51. WT4603Surface PlanerSetting devicesThere are a number of cutter setting devices.This device and procedure will often be supplied with the machine.They can be loosely placed into the following four categories: Bridge device Precision cutter setter device Pin locater device Wooden straight edge device Cutters require accurate setting in the block because if the knives are not revolving in the same cutting circle a poor finish will be produced.Department of Manufacturing & Operations Engineering

52. WT4603Setting Cutter KnivesSetting of knives will greatly depend on the type of cutter blockKnife cutter projectionChip breakerKnife parallel to tableAll knives in the same peripheral cutting circle(Refer to machine manual for setting)Department of Manufacturing & Operations Engineering

53. WT4603Setting Planer KnivesWhen planing wooden material a number of factors combine to generate the flat surface.Number of cutting knives in the blockSpeed of the revolving blockFeed speed of the materialKnife cutter designChip breaking aidsNature and species of the materialDepartment of Manufacturing & Operations Engineering

54. Knife cutter design & Chip breaking aidsThese factors combine to produce an acceptable surface finishTip of the cutter splits away the chipThe chip is forced away from the stock and up along the face of the cutter which is exerting a tearing effect on the grain fibreAs the knife exits the stock the chip is either cut or will “rive” or tear deeply along the grain line and lift as a long heavy splinterWT4603Department of Manufacturing & Operations Engineering

55. Knife cutter design & Chip breaking aidsThe cutter projection and the shape of the block face cause the severed chip to bend back causing a crack across its widthThis makes long grain riving less likely(Chip breaker not shown)WT4603Department of Manufacturing & Operations Engineering

56. WT4603Knife cutter design & Chip breaking aidsSharp tooling (a) will aid in the chip bending back and cracking across its widthBlunt tooling (b) will aid rivingDepartment of Manufacturing & Operations Engineering

57. WT4603Chip FormationBefore knife makes its cutDepartment of Manufacturing & Operations Engineering

58. WT4603Chip FormationChip to be formedDepartment of Manufacturing & Operations Engineering

59. WT4603Chip FormationaChip breaker will help prevent riving (a)Department of Manufacturing & Operations Engineering

60. WT4603Knife cutter design & Chip breaking aids Large cutting angle which gives the knife a lifting action which will cause rivingGrinding a face bevel reduces the risk of riving as it changes the cutting angleDepartment of Manufacturing & Operations Engineering

61. WT4603Face bevel on cutter knife (B)Department of Manufacturing & Operations Engineering

62. WT4603Surface PlaningDepartment of Manufacturing & Operations Engineering

63. WT4603Surface PlaningDepartment of Manufacturing & Operations Engineering

64. WT4603Surface PlaningDepartment of Manufacturing & Operations Engineering

65. WT4603Surface PlaningDepartment of Manufacturing & Operations Engineering

66. WT4603Surface PlaningDepartment of Manufacturing & Operations Engineering

67. WT4603Surface PlaningDepartment of Manufacturing & Operations Engineering

68. WT4603Surface PlaningDepartment of Manufacturing & Operations Engineering

69. WT4603Surface PlaningDepartment of Manufacturing & Operations Engineering

70. WT4603Surface PlaningDepartment of Manufacturing & Operations Engineering

71. WT4603Surface PlaningDepartment of Manufacturing & Operations Engineering

72. WT4603Surface PlaningDepartment of Manufacturing & Operations Engineering

73. WT4603Surface PlaningDepartment of Manufacturing & Operations Engineering

74. WT4603Surface PlaningDepartment of Manufacturing & Operations Engineering

75. WT4603Surface PlaningDepartment of Manufacturing & Operations Engineering

76. WT4603Hand Router Consists of cutter rotating at between 800 to 30,000 RPM being driven by a vertically mounted motor set on a flat based frameworkDepartment of Manufacturing & Operations Engineering

77. WT4603Hand RouterDepartment of Manufacturing & Operations Engineering

78. WT4603Hand RouterDepartment of Manufacturing & Operations Engineering

79. WT4603Hand RouterCutting groovesCutting rebatesCutting slots and recessesCutting beads or mouldingsCutting dovetailsCutting dovetailed slots and groovesEdge trimmingProfiling (jigs/formers)Department of Manufacturing & Operations Engineering

80. WT4603Hand Router: PowerLarge powerful routers are heavy and can be difficult to handle for light work.Generally in schools the type of work that the router will have to perform will be light to medium work.As a rough guide to classifying routers:400 W to 600W are for light duty 750 W to 1200W are for medium duty 1250 W upwards are for heavy dutyDepartment of Manufacturing & Operations Engineering

81. WT4603ColletDepartment of Manufacturing & Operations Engineering

82. WT4603Collet A tapered sleeve that is made in a number of segments that is used to hold the shaft of a cutter or bit.Department of Manufacturing & Operations Engineering

83. WT4603Collet needs to be cleaned regularlyMust prevent rustMust prevent wearCan clean with solvents but must spray with WD40 afterwardsDepartment of Manufacturing & Operations Engineering

84. WT4603Cutters (Router bits)Two types of cutter

85. High Speed Steel (HSS)

86. Tungsten Carbide Tipped (TCT)

87. HSS work well on softwood because of their keen edge but will blunt quickly

88. TCT cutters perform much better than HSS on hardwoods and MDF

89. Cutters should be cleaned regularly with white spirit and fine scraper to remove dirt, resin and debris.

90. Cutters should also be inspected for damage prior to operating.Department of Manufacturing & Operations Engineering

91. WT4603Cutters (Router bits) A router bit is a tool for woodworking giving a quality finish to the material. It cuts wood providing a way to give a clean and even a decorative edge to woodwork. The following is some basic information about router bits to get you started in your woodworking efforts. Here are the there main parts of a router bit:The shank- the part of the router bit that is inserted into the collet (the sleeve of the router).The cutting edge- this part cuts and removes the wood. They are available in several sizes and shapes. The pilot- the guide for the router in order to make a correct cut. It can be an extension of the shank or a ball bearing attachment.Department of Manufacturing & Operations Engineering

92. WT4603Cutters (Router bits)Cutters can have disposable or interchangeable profiles.Department of Manufacturing & Operations Engineering

93. WT4603Cutters (Router bits)Cutter diameter will have a direct effect on the power required form the router motor.Department of Manufacturing & Operations Engineering

94. WT4603Cutter selection & feed directionDepartment of Manufacturing & Operations Engineering

95. WT4603Feed directionIf you feed a router into a piece of material without using a guide fence or bearing guide you will find that the router will pull to one side.

96. If you push the router into the material from position (A), the router will pull to your left.

97. If you pull the router into the material toward you from position (B), the router will pull to your right.

98. This occurs as the cutter will climb on the material in front of the cutting edge.

99. This motion must be utilised when using guide fences.Department of Manufacturing & Operations Engineering

100. WT4603Feed direction & the fenceTo process a straight housing or trench you can use a straight edge guide (A) or the guide fence that is supplied with the router(B).Department of Manufacturing & Operations Engineering

101. WT4603FFeed direction & the fenceIn the photo the fence is securely clamped in position.

102. The router is being fed in the direction (F).

103. The router will try to pull to the operators left hand side.

104. With the fence clamped on the left of the router, the router will push against it as it is fed into the material.(Green arrows)

105. If the fence were on the right hand side (when viewed from the operators position) of the router, it would pull away from the fence and result in the trench being crocked.Department of Manufacturing & Operations Engineering

106. WT4603The groove is produced as the router is moved forward.

107. Local extraction will remove the bulk of the dust produced.

108. Some may be blown back in the direction of the operator.( )

109. A suitable lab coat will protect the operators clothing.

110. Appropriate dust mask should be used.

111. Feeding the router in the opposite direction will cause any dust to be blown away from the operator.

112. This will require the guide fence to be set up on the right hand side of the router and operator. FFeed direction & the fenceDepartment of Manufacturing & Operations Engineering

113. WT4603Guide fenceGuide fence fixed to the router.Can be fixed from either side.Department of Manufacturing & Operations Engineering

114. WT4603FPUsing the guide fenceWhen feeding the router forward (F) the router will tend to pull to the operators left hand side.The fence should be set on the right hand side of the router.When the cutter engages in the material it will pull to the left as indicated by the green arrow (P) and keep the fence tight against the materials edge.Material should be securely calmped or placed on a non-slip router mat.Department of Manufacturing & Operations Engineering

115. WT4603Profiles can be processed on material using templates.Templates can have the required profile as an internal shape or an external profile.To process the section marked (A)In the photo an internal template can be used to guide the router to produce the profile.Feed direction can be established using the right hand rule.Department of Manufacturing & Operations Engineering

116. WT4603Department of Manufacturing & Operations Engineering

117. WT4603Using the template guide Fit the template guide to the router base plate.Set cutter plunge depth.Place over template at the starting position (A).Switch on the router and then plunge to depth (B).Feed router in a clockwise direction.Department of Manufacturing & Operations Engineering

118. WT4603ROUTER PULLS TO THE LEFTFENCE PULLED TOWARDS WORKPIECEFEEDDIRECTIONRouter Station 1Carry out the following operations:Isolate the router. Select V- groove cutting bit.Fit the bit in the router securely.Set the depth of the cut to 3mm.Machine the profile shown on the drawing using the guide fence. (Note: Guide fence is set. Do not adjust.)Isolate the router.Remove the cutter from the router.Department of Manufacturing & Operations Engineering

119. WT4603Router Station 3Carry out the following operations:Isolate the router.Select Ø 6mm cutting bit.Fit the bit in the router securely.Set the depth of the cut to 5mm.Set the depth turret to machine to a depth of 10mm on the second pass.Fit the guide fence to the router.Set the guide fence to the dimension shown on the drawing.Machine the profile shown on the drawing using the guide fence.Isolate the router.Remove the guide fence and Ø 6mm cutting bit from the router.Department of Manufacturing & Operations Engineering

120. WT4603Router Station 4Carry out the following operations:Isolate the router.Select Ø 12mm cutting bit cutting bit.Fit the bit in the router securely.Fix the template guide to the base of the router.Set material in the template.Set the depth of the cut to 5mm.Set the depth turret to machine to a depth of 10mm on the second pass.Machine the profiles of the template using the template guide.Isolate the router.Remove the template guide and Ø 12mm cutting bit from the router.Department of Manufacturing & Operations Engineering

121. WT4603WEEK 4: LABSComponent BYou will be provided with two pieces of un-sawn material, both measuring 1020 x 145 x 25.

122. You will label both pieces B1 and B2, respectively.B1Table Top1451020Back/Side Rails & Drawer FrontB21451020Department of Manufacturing & Operations Engineering

123. WT4603WEEK 4: LABSComponent B Cutting ListDepartment of Manufacturing & Operations Engineering

124. WT4603B1 = Table TopB1 must be planed all round (P.A.R) to 1020 x 140 x 22

125. The process for B1 will involve the following:

126. Surface plane/thickness to 140 x 22

127. Rip B1 @ 67mm (x2)

128. Thickness to 65mm (x2)

129. Cross cut to 500mm (x4)Department of Manufacturing & Operations Engineering

130. WT4603B2 = Back and Side RailsB2 must be planed all round (P.A.R) to 1020 x 140 x 20

131. The process for B2 will involve the following:

132. Surface plane/thickness to 140 x 20

133. Rip B2 @ 132mm (x1)

134. Thickness to 130mm (x1)

135. Cross cut 1 = Side Rails @ 158mm (x2)

136. Cross cut 2 = Drawer Front @ 272mm (x1)

137. Cross cut 3 = Back Rail @ 312mm (x1)Department of Manufacturing & Operations Engineering

138. WT4603Processing Sequence:Surface plane face side/face edge for B1 & B2Thickness 1 = B1 Table Top to 140 x 22Thickness 2 = B2 Side/Back rails/Drawer Front to 140 x 20Rip 1 = B1 Table Top @ 67mm (x2)Thickness 3 = B1 Table Top to 65mm (x2)Rip 2 = B2 Side/Back rails/Drawer Front @ 132mm (x1)Thickness 4 = B2 Side/Back rails/Drawer Front to 130mm (x1)Cross cut 1 = B1 Table Top @ 500mm (x4)Cross cut 2 = B2 Side Rails @ 158mm (x2)Cross cut 3 = B2 Drawer Front @ 272mm (x1)Cross cut 4 = B2 Back Rail @ 312mm (x1)Department of Manufacturing & Operations Engineering

139. WT4603Department of Manufacturing & Operations Engineering

140. WT4603Department of Manufacturing & Operations Engineering