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.

2. Lecturer: Mr. Joseph Lyster

3. joseph.lyster@ul.ie

4. Notes prepared by: Mr. Joseph Lyster

6. Surface Planer WT4603 Planers 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 Planer WT4603 Knives 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 Planer WT4603 High 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 Planer WT4603 Abrasive 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 finish Department of Manufacturing & Operations Engineering

10. Surface Planer WT4603 The 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 capabilities Department of Manufacturing & Operations Engineering

11. WT4603 Surface Planer Tungsten 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 Planer WT4603 Because 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. WT4603 Surface Planer Department of Manufacturing & Operations Engineering

14. WT4603 Knife Cutter geometry Rake or Cutting angle Angle created between the face of the cutting knife and the centre of the cutter block Can have a wide range Softwoods 27° to 35 ° Hardwoods 15° to 25 ° Department of Manufacturing & Operations Engineering

15. WT4603 Knife Cutter Geometry Bevel or Lip Angle Angle formed to give the cutting edge Minimum of usually 35° Greater for tipped cutters Department of Manufacturing & Operations Engineering

16. WT4603 Knife Cutter Geometry Clearance Angle Angle formed between a line tangential to cutting circle and the bevel angle of the knife Must be present Has a bearing on the life of the cutting edge Usually 10° to 15° Department of Manufacturing & Operations Engineering

17. WT4603 Knife Cutter Geometry Peripheral Cutting Speed A constant speed in the range of 35-45 m/s will give best results Increase in speed may cause loss of dynamic balance due to vibrations Poor finish Increased noise levels Department of Manufacturing & Operations Engineering

18. WT4603 Pitch distance Combination of a rotary cut and a linear feed will leave the surface of the material with a series of arcs on it called Curtate Trochoids The pitch and depth of these arcs will determine how smooth the surface finish will be Department of Manufacturing & Operations Engineering

19. Department of Materials Science & Technology University of Limerick WT4603 Pitch Distance 2mm 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. WT4603 Pitch Distance The 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 block Department of Manufacturing & Operations Engineering

21. Pitch Distance WT4603 The unit for “p” will be metres (m) f m/min m min p = ---- = --------- = ----- x ------ = m nR 1/min min 1 Department of Manufacturing & Operations Engineering

22. WT4603 Pitch Distance Problem 1 Calculate the cutter pitch of a 4 cutter block revolving at 4200 rev/min with a feed speed of 24m/min. F 24 24 p = ------- = ------------ = --------- = 0.0014m = 1.4mm nR 4 x 4200 16800 (Internal painted work) Department of Manufacturing & Operations Engineering

23. Pitch Distance WT4603 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 = nRp nR Department of Manufacturing & Operations Engineering

24. Pitch Distance Problem 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 WT4603 Department of Manufacturing & Operations Engineering

25. WT4603 Chip formation Department of Manufacturing & Operations Engineering

26. WT4603 Riving Department of Manufacturing & Operations Engineering

27. Riving WT4603 Cracking occurs below the cut depth Department of Manufacturing & Operations Engineering

28. WT4603 A On 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. WT4603 Chip formation Department of Manufacturing & Operations Engineering

30. WT4603 Chip formation Chip breaking aid and pressure bar prevent riving and splintering Department of Manufacturing & Operations Engineering

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. WT4603 Circular cutter block Clamping bolts are in tension Department of Manufacturing & Operations Engineering

38. WT4603 Knife clamping mechanism Department of Manufacturing & Operations Engineering

39. WT4603 Knife clamping mechanism Department of Manufacturing & Operations Engineering

40. Cutter projection WT4603 Use of a limiter to achieve limited cutter projection Department of Manufacturing & Operations Engineering

41. Cutter design WT4603 Cutters 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 projection WT4603 The 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 machines WT4603 For 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

45. feed complex adjustments

46. rise and fall tableDepartment of Manufacturing & Operations Engineering

47. Surface Planer WT4603 The 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. WT4603 Surface Planer Overheating 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. WT4603 Surface Planer Overheating can be avoided By 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. WT4603 Surface Planer Setting 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. WT4603 Surface Planer Setting devices There 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. WT4603 Setting Cutter Knives Setting of knives will greatly depend on the type of cutter block Knife cutter projection Chip breaker Knife parallel to table All knives in the same peripheral cutting circle (Refer to machine manual for setting) Department of Manufacturing & Operations Engineering

53. WT4603 Setting Planer Knives When planing wooden material a number of factors combine to generate the flat surface. Number of cutting knives in the block Speed of the revolving block Feed speed of the material Knife cutter design Chip breaking aids Nature and species of the material Department of Manufacturing & Operations Engineering

54. Knife cutter design & Chip breaking aids These factors combine to produce an acceptable surface finish Tip of the cutter splits away the chip The chip is forced away from the stock and up along the face of the cutter which is exerting a tearing effect on the grain fibre As 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 splinter WT4603 Department of Manufacturing & Operations Engineering

55. Knife cutter design & Chip breaking aids The cutter projection and the shape of the block face cause the severed chip to bend back causing a crack across its width This makes long grain riving less likely (Chip breaker not shown) WT4603 Department of Manufacturing & Operations Engineering

56. WT4603 Knife cutter design & Chip breaking aids Sharp tooling (a) will aid in the chip bending back and cracking across its width Blunt tooling (b) will aid riving Department of Manufacturing & Operations Engineering

57. WT4603 Chip Formation Before knife makes its cut Department of Manufacturing & Operations Engineering

58. WT4603 Chip Formation Chip to be formed Department of Manufacturing & Operations Engineering

59. WT4603 Chip Formation a Chip breaker will help prevent riving (a) Department of Manufacturing & Operations Engineering

60. WT4603 Knife cutter design & Chip breaking aids Large cutting angle which gives the knife a lifting action which will cause riving Grinding a face bevel reduces the risk of riving as it changes the cutting angle Department of Manufacturing & Operations Engineering

61. WT4603 Face bevel on cutter knife (B) Department of Manufacturing & Operations Engineering

62. WT4603 Surface Planing Department of Manufacturing & Operations Engineering

63. WT4603 Surface Planing Department of Manufacturing & Operations Engineering

64. WT4603 Surface Planing Department of Manufacturing & Operations Engineering

65. WT4603 Surface Planing Department of Manufacturing & Operations Engineering

66. WT4603 Surface Planing Department of Manufacturing & Operations Engineering

67. WT4603 Surface Planing Department of Manufacturing & Operations Engineering

68. WT4603 Surface Planing Department of Manufacturing & Operations Engineering

69. WT4603 Surface Planing Department of Manufacturing & Operations Engineering

70. WT4603 Surface Planing Department of Manufacturing & Operations Engineering

71. WT4603 Surface Planing Department of Manufacturing & Operations Engineering

72. WT4603 Surface Planing Department of Manufacturing & Operations Engineering

73. WT4603 Surface Planing Department of Manufacturing & Operations Engineering

74. WT4603 Surface Planing Department of Manufacturing & Operations Engineering

75. WT4603 Surface Planing Department of Manufacturing & Operations Engineering

76. WT4603 Hand Router Consists of cutter rotating at between 800 to 30,000 RPM being driven by a vertically mounted motor set on a flat based framework Department of Manufacturing & Operations Engineering

77. WT4603 Hand Router Department of Manufacturing & Operations Engineering

78. WT4603 Hand Router Department of Manufacturing & Operations Engineering

79. WT4603 Hand Router Cutting grooves Cutting rebates Cutting slots and recesses Cutting beads or mouldings Cutting dovetails Cutting dovetailed slots and grooves Edge trimming Profiling (jigs/formers) Department of Manufacturing & Operations Engineering

80. WT4603 Hand Router: Power Large 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 duty Department of Manufacturing & Operations Engineering

81. WT4603 Collet Department of Manufacturing & Operations Engineering

82. WT4603 Collet 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. WT4603 Collet needs to be cleaned regularly Must prevent rust Must prevent wear Can clean with solvents but must spray with WD40 afterwards Department of Manufacturing & Operations Engineering

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. WT4603 Cutters (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. WT4603 Cutters (Router bits) Cutters can have disposable or interchangeable profiles. Department of Manufacturing & Operations Engineering

93. WT4603 Cutters (Router bits) Cutter diameter will have a direct effect on the power required form the router motor. Department of Manufacturing & Operations Engineering

94. WT4603 Cutter selection & feed direction Department of Manufacturing & Operations Engineering

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. WT4603 Feed direction & the fence To 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

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

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. F Feed direction & the fence Department of Manufacturing & Operations Engineering

113. WT4603 Guide fence Guide fence fixed to the router. Can be fixed from either side. Department of Manufacturing & Operations Engineering

114. WT4603 F P Using the guide fence When 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. WT4603 Profiles 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. WT4603 Department of Manufacturing & Operations Engineering

117. WT4603 Using 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. WT4603 ROUTER PULLS TO THE LEFT FENCE PULLED TOWARDS WORKPIECE FEED DIRECTION Router Station 1 Carry 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. WT4603 Router Station 3 Carry 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. WT4603 Router Station 4 Carry 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

122. You will label both pieces B1 and B2, respectively.B1 Table Top 145 1020 Back/Side Rails & Drawer Front B2 145 1020 Department of Manufacturing & Operations Engineering

123. WT4603 WEEK 4: LABS Component B Cutting List Department of Manufacturing & Operations Engineering

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

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. WT4603 Processing Sequence: Surface plane face side/face edge for B1 & B2 Thickness 1 = B1 Table Top to 140 x 22 Thickness 2 = B2 Side/Back rails/Drawer Front to 140 x 20 Rip 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. WT4603 Department of Manufacturing & Operations Engineering

140. WT4603 Department of Manufacturing & Operations Engineering