FAQ-Press Tool technology

1.     What is press tool? 

2.     Where press tool is used?

3.     What is strip lay out?

4.     What d you mean by cutting force & stripping force?

5.     What dou you mean by hybrid punches?

6.     What is cutting clearence?

7.     What is the difference between blanking & piercing?

8.     What is knock out rod?     Where it is used?

9.     What do you mean by spring back?

10. What is the different type of piloting punch?

11. What is the diffrence between direct piloting & indirect piloting?

12. What is notching tool?

13. What is shedder?    It is used?

14. What is the diffrence between stop position &registrery position?

15. What is dinking tool?

16. Why side cutters are used?

17. What is the difference between cut off & parting off?

18. What is the difference between trimming & shaving operations?

19. Define deep drawing?

20. Define curling?

21. What are assembly tools?

22. List out some kind of press tool operations?

23. What do you mean by side cam operations?

24. What is the diffrence between bending & forming?

25. Define swanging & extrution?

26. What dou you mean by cold forming?

27. Define horning?

28. What are the six types of cold rolled steel?

29. What is unit stock?

30. What is piece part?

31. What dou you mean by stock material?

32. What is the diffrence between hot rolled steel & cold rolled steel?

33. Define shearing theory?  And its 3 stages?

34. What is the formula for finding press force?

35. What do you mean by optimum cutting clearence?

36. What are the effects of excecive & insufficient cutting clearence?

37. What do you mean by burr side?

38. How to determine the punch & die size for piercing & blanking?

39. When a guide plate tool is preffered?

40. What are the elements of guide plate tool?

41. What do you mean by stopper?

42. What do you mean by land? Mention its importance?

43. What is angular clearance and where it is used?

44. What is the purpose of a shank in a tool?

45. What is the function of a back plate?

46. Hardness of punch and die?

47. Why die is harder than punch?

48. What is the importance of fastners in a tool?

49. What is the box stripper?

50. What are the alloy berrillium copper and its percentage?

51. What is meant by deep drawing steel sheet?

52. What is meant by progressive operation in press tool and its different stage?

53.  what are advantages of progressive tool?

54. What are disadvantages of progressive tool?

55. What are the principles of bending?

56. How plastic deformation occurs in bending?

57. What are the bend elements?

58. What is neutral axis in bend elements?

59. What is the formula for calculating neutral and centre fibre?

60. What is the formula for finding the max and min radius in bending?

61. How bending dies are classified?

62. What is the v- bending die?

63. What is the speciality of u -bending die?

64. What is the fn of pressure pad in bending?

65. What is the formula finding v- bending force?

66. What is the effect of grain direction on bending?

67. Define gang piercing tool?

68. Define angular &side piercing tool?

69. Define fine blanking?

70. Define compound die system with fixed punch?

71. Define shaving?

72. Define press force?

73.  define v-ring?

74. Define planishing?

75. Define curling?

76. What is eyelet drawing?

77. Define reverse drawing?

78. What is drawing force?   Where it is used?

79. What is the need of flanging?

80. Define croping wire hooks?

81. What for shaving is done?

82. Explain about shaving direction?

83. What for air vent is provided in punch &die for drawing operation?

84. Explain the role of lubricants during deep drawing operation?

85. What is deep drawing?

86. With the help of sketch show different force acting on the component while drawing?

87. Eqn for find out the economic factore?

88. Define burr side?

89. In blanking, the burr side will be which direction?

90. In piercing, the burr side will be which direction?

91. What are the factors to be considered while deciding strip lay out?

92. What is stock material?

93. What are the factors to be considered before determine the best methode of positioing a blank in the strip lay out?

94. What is the different layout?

95. What is narrowing run & wide run?

96. What is a single row 2 pass method?

97. What is gange dies?

98. What is angular layout?

99. Classification of punches?

100.                    What is cutting punches& non-cutting punches?

101.                    What is seggrated & integrated punches?

102.                    What is perforator?

103.                    Where we are uesd keyed punches?

104.                    What is buckling punches?

105.                    Formula for calculating buckling?

106.                    The main factores to be considered designing of a die block?

107.                    Why punch wear faster than die?

108.                    Hardness of punch & die?

109.                    Die blocks are made out of?

110.                    How to find out the thickness of die block?

111.                    What are the adv. Of using die bush?

112.                    What are the factore to be considered while selection of split                       dies?

113.                    What is a liner?

114.                    What are the adv. Of liner?

115.                    The main adv. Of carbide dies?

116.                    Which is the operation we are using in carbide dies?

117.                    What you mean by neasting?

118.                    What are the functions of stoppers?

119.                    Diff. Types of stoppers?

120.                    What is a trigger stopper?

121.                    What is plain stopper?

122.                    Why the trigger stopper is also called automatic stopper?

123.                    Types of trigger stoppers?

124.                    What is a dissapearing pin stopper?

125.                    What is a finger stopper?

126.                    What is a stipper?

127.                    What are the functions of a stipper?

128.                    What are the types of stipper?

129.                    What you mean by hook pin stipper?

130.                    What are the diff. B/w travelling & box stipper?

131.                    Hooks pins are made out of?

132.                    How the presser pad stipper is actuacting?

133.                    What is the spring stipper?

134.                    Applications of spring stipper?

135.                    What is the types of spring stipper?

136.                    Differantiate b/w clamping stipper & non-clamping stipper?

137.                    The main adv. Of compensating washer?

138.                    What you mean by stripping force?

139.                    Formula for finding stripping force?

140.                    What are the factores effacting stripping force?

141.                    What is the a usage of pin gauges in prees tools?

142.                    Types of gauges?

143.                    What is bulge clearance?

144.                     

145.                    What is the usage of extenstion back gauges?

146.                    What is the requirement of strip support?

147.                    What you mean by strip support?

148.                    What is neasting gauges?

149.                    What are the three conditions to meet the best result of nest                       gauges?

150.                    What are the types of nest gauges?

151.                    What is pilots?

152.                    Main purpose of pilots?

153.                    How we can be finding out the pilot size?

154.                    What is the need of pilot?

155.                    Types of pilots?

156.                    Why the angle is provided on the pilots?

157.                    Which pilot is used for the soft materials?

158.                    How we can pilot nose profile?

159.                    What is direct piloting?

160.                    What is the difference between direct piloting and indirect piloting?

161.                     what are the methods of piloting?

162.                    What are the part conditions that required for the indirect piloting?

163.                    What you mean by piloting punches?

164.                    When we prefer direct piloting?

165.                    What are the functions of pilots?

166.                    Why the retractable pilots are spring loded?

167.                    What is scrap bridge?

168.                    What is a prograssive tool?

169.                    When a progressive tool is prefered?

170.                    What are the factors to be considered before producing a prograssive tool?

171.                    What is shut height?

172.                    What is the purpose of pilots?

173.                    What is mean by pilots?

174.                    Differents types of pilots?

175.                    Define retractable pilots?

176.                    Define the methodes of piloting?

177.                    Difference between direct and indirect piloting?

178.                    Define the seven conditions required in direct piloting?

179.                    What is bullet nose pilot?

180.                    What is mean by pilot in punches?

181.                    What are the advantages of die sets?

182.                    What is the importence of top and bottom plate in die set?

183.                    What is the fuctions of removable guide pillers?

184.                    Define three piller die set?

185.                    Define four piller die set?

186.                    Define two piller die set?

187.                    Define heavy duty die set?

188.                    Define floating adapter die set?

189.                    What is fool proofing?  

190.                    When we use center piller die set?

191.                    What is the importance of the die set in a press tool?

192.                    What are the factors to be consedered when selecting the die                 set? 

193.                    Which are the die set elements?

194.                     why we are using removable guide pillers?

195.                    Why we are using offset pillers?

196.                    Different types of guide bushes? 

197.                    Define ball bearing die set?

198.                    Direction of the feed is the important factor for selecting die set, why?

199.                    What is a blanking tool?

200.                     what is a piercing tool?

201.                    What is a cut off tool?

202.                    What is a broaching tool?

203.                    What is an extrooding tool?

204.                    What is a cold forming tool?

205.                    What is a side cam tool?

206.                    What is a forming tool?

207.                    What is a bending tool?

208.                    What is a trimming tool?

209.                    Why side cutters are used in press tools?

210.                    What do you mean by ejectors and shedders?

211.                    What is a knock out system?

212.                    Explain about different types of fastners?

213.                    Fit between dowel and hole?

214.                    Grade of dowel?

215.                    Different types of screws?

216.                    Why compound tool is prefered?

217.                    What do you mean by pit man?

218.                    What is shut height of a tool?

219.                    What is die space?

220.                    What are the classification of press?

221.                    What do you mean by die cushions?

222.                    How to feed the strip in to tool?

223.                    What are the strip feeding equipments?

224.                    What are the different types of feeding of strip into tool?

225.                     how the hydraulic press works?

226.                    What are coining dies?

227.                    What are angular & side piercing tool?

228.                    What are pivoted bending punch? & what are their use in

229.                    Progressive tool? 

230.                    Which materials are suitable for fine blanking?

231.                    What is a shavng allowence?

232.                    What is embossing?

233.                    What is coining?

234.                    What is flanging?

235.                    What is iorning?

236.                    What are the faults occuring during deep drawing?

237.                    How air vents are given?

238.                    What is annealing?

239.                    What is mean by extrusion?

240.                    How we can check die clearence?

241.                     what are the factors of tool life?

242.                    What is slug pulling?

243.                    What is gas nitriding?

244.                    What is iron nitriding?

245.                    What is transfer presses?

246.                    Type of transfer presses?

247.                    Difference b/w mechanical & hydraulic transfer presses?

248.                    What is cross bar punch presses?

249.                    What are the characteristics of tool & die steels?

250.                    What is cryogenic treatment?

251.                    Type of extrusion dies?

252.                    What is powder metullurgy process? Punch?

253.                    Determines the factors of tool life?

254.                    What is cutting draft angle?

255.                    Diff. B/w backward & forward extrusion dies?

256.                    What is automation?

257.                    What is press layout?

258.                    What is cross bar transfer press?

259.                    What is billet?

260.                    What is semi finished products?

261.                    How to prepare the billet or slug preparation?

262.                    Define billet seperation process in forging?

263.                    What is extrusion & it’s applications?

264.                    What are the 3 types of extrusion?

265.                    Define backward extrusion dies?

266.                    Diff. B/w forward extrusion die & combination die?

267.                    Explain about coining dies in the coining process?

268.                    Describe about punch desing in extrusion process?

269.                    Why stripping force of piercing punch is greater than blanking   punch?

270.                    In apress tool punch will wear faster than die, then why we are    hardening die more?

                                        compiled by d3_nttf ontc 2008-11 

Grinding Lathe Tools

Grinding Lathe Tools

Tool grinding is part science and part art, but can be an enjoyable side activity to working with the lathe. My goal here is to teach beginners enough to get them started with a few basic tools. Here are some additional resources:

You can, of course, buy ready-made carbide-tipped cutting tools.  If good quality, these work well and last a long time. The real advantage to grinding your own tools is not cost savings, but having the ability to make a tool for whatever purpose you may run across in your work.  For example, I have made some very small boring tools from 3/16" tool blanks which are quite handy for boring out a small hole, say .373 in diameter, to press-fit a 3/8" shaft.

The essence of lathe tool grinding, as I think of it, is to undercut the tip of the tool to provide 'relief' so that the metal just below the cutting tip does not contact the work. This concentrates enough cutting force on the tip to cut into the metal of the workpiece.

Most of the regular cutting tools I make are undercut on the front and left edge of the tool. Since most tools are designed to cut while moving from right to left (towards the headstock) it is not necessary to provide relief on the right side of the tool. Additionally, I usually grind a similar relief, or rake, on the top surface of the tool.

When you order your lathe, be sure to order about 10   5/16" x 2 1/2" High Speed Steel (HSS) tool blanks. (Note: the older, non-Sieg, Homier/Speedway lathes use 3/8" x 2 1/2" tools) I usually get mine from Enco. They are normally about $1 each but often go on sale for about $0.80.

The four sides of the blank are ground to a smooth, shiny finish. The ends are a coarse finish with a preformed angle of about 15 degrees.

  

We will use a simple four-step procedure to make our cutting tool

1. Grind the end relief
2. Grind the left side relief
3. Grind the top rake
4. Round the tip

Grinding the End Relief

First we will grind the end of the tool blank. Use the coarse wheel of your bench grinder and hold the tool blank angled downwards from the tip to the rear and with the tip pointing to the left about 10-15 degrees.. The tip of the tool blank should be a little below the center line of the wheel.

    

Grinding causes the tool blank to get quite hot so you will need to dip the end of the tool into a water bath every 15 seconds or so during the grinding operation. When you see the tip of the tool start to discolor from the heat its a good time to make a cooling dip. Fortunately, HSS does not conduct the heat to your fingers very fast, but you can get burned if you go too long between cooling dips.

 

Here's a picture of the tool after grinding the end:

 

Grinding the Left Side Relief

Now we'll grind the left side of the tool. The procedure is essentially the same except that we hold the tool with the side at about a 10 degree angle to the grinding wheel.

 

Grinding the Top Rake

Now we grind the top surface to form the rake. Be careful during this operation not to grind down the cutting edge or you will end up with a tool whose tip is below the center line of the lathe. If this happens, the tool will leave a little nub at the center of the workpiece when you make a facing cut. The usual remedy is to use a thin piece of shim stock under the tool to bring it back up to the center line. A much nicer solution is an adjustable-height tool holder.

After this operation we have a working tool with a very sharp tip. This tool is useful as-is for operations that need a sharp tip to turn down to an interior edge such as a shoulder.

Rounding the Tip

We will round the tip to form a tool that is useful for facing and turning. Hold the tool so the tip touches the wheel and with the tool tilted downward. Rotate the tool against the wheel to round the tip to about a 1/32" radius. 
 
 

Here's the finished tool in action making a finishing cut on a facing operation:

As a final step, you may wish to smooth the cutting tip on a fine diamond hone or oilstone. I've found that the tip tends to get smoothed pretty quickly after a few cuts, so I usually skip this step, but it does make a difference if you need a fine finish.

So now you know how to grind the most basic of cutting tools. There are many other types of tools that you can grind including shaping tools, cutoff tools and boring tools. Here's some additional info posted by Brian Pitt:

You usualy want to set the tool on center to about .003-.005 above center but almost never below (the workpiece will try to roll over the top and chatter) cutoff ,threading and most carbides should be on center while HSS for general turning can be a hair above to make up for the deflection of the workpiece and machine which will bring it back on center, it can also add a little burnishing action as the work rubs the front face of the bit and will give smoother finishes the side and top rake reduce the amount of cutting force and heat generated and help to control the chip by giving it a difrent angle to curl on depending on the material being cut , softer and stringier materials like aluminium and 1018 steel need more rake to give a knife like edge while materials that break up easily like brass and cast iron use less rake to keep the tool from digging in and grabbing

One of the most important facts often overlooked by beginners is that the cutting face of the grindstone wheel quickly becomes dulled and clogged with metal particles.  To maintain an agressive cutting face it is essential to refurbish the wheel face frequently with a dressing tool.  I use a dressing tool with a single industrial diamond point for this purpose. I got it from Enco for around $15.  I use this tool to refresh the grinder wheel after about every 10 minutes of grinding time. It makes a big difference.

Here's some great information on various types of tool rake, posted by Dub Thornton:

No, rake angles and front relief are NOT the same. Front relief is the angle ground into the front of  your tool which allows ONLY the front cutting edge to contact the workpiece. If the tool contacts the workpiece below the cutting edge, you will get a "rubbing" action, and the tool cannot bite into the workpiece. Side relief (or clearance) is the angle ground into the side of the tool which allows only the side cutting edge of the tool to contact the workpiece.

There are two rake angles, both on the top of the tool. Back Rake is the angle from the tip of the cutting tool toward the back of the tool. It may be either positive, neutral, or negative. If it slopes down from the tip of the tool toward the back of tool, it is positive rake, an upward slope would be negative rake, neutral is self explanatory.

Rake angles, particularly back rake, may be built into the tool holders. The old lantern type holders I grew up on usually had a positive back rake angle built in. This was a help when grinding your tools, as you did not have to grind any back rake into the tool itself. When grinding threads tho, a neutral back rake angle is desirable, thus one had to grind a negative rake angle (point of tool pointed downward) to compensate for the positive back rake angle built into the tool holders.

Side rake is the angle from the side cutting edge of the tool toward the opposite side of tool (across the top of the tool). It can also be ground for negative, neutral, or positive side rake. A negative rake angle is usually used for brittle materials, such as brass, which are notorious for "hogging in" as you cut. A positive rake angle would increase this "hogging in" action, while a negative rake angle will push the tool away from the work, eliminating the tendency to "hog in". "Hogging in" is an old term for the material grabbing the tool, pulling it into the material for a deeper cut than you are set up for. Backlash in your machine increases the possibility for such"hogging in". Many projects are spoiled, as well as tools broken, etc, by this action.

A very general rule of thumb. For heavy, roughing cuts, use less clearance and rake angles. This leaves more material in the cutting tool to withstand the pressures of heavy cutting, plus more "beef" in the tool, means more ability to carry heat away from the cutting edges. For finish cuts, and turning such "soft" materials as aluminum, use more clearance and more rake angles for a better finish. I have seen may references on this reflector to Top Rake, which is confusing to me, as it does not define whether side rake, or back rake is being referred to.

Compiled by Rahul KP 

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