Drawing is a sheet metalworking operation used to produce cup-shaped or box-shaped, or other complex-curved, hollow parts. 20.9 Define drawing in the context of sheet metalworking. Springback is the elastic recovery of the sheet metal after bending it is usually measured as the difference between the final included angle of the bent part and the angle of the tooling used to make the bend, divided by the angle of the tooling. 20.8 What is springback in sheet metal bending? Answer. In principle the bend allowance equals the length of the bent metal along its neutral axis. The bend allowance is intended to compensate for stretching of the sheet metal that occurs in a bending operation when the bend radius is small relative to the stock thickness.

20.7 For what is the bend allowance intended to compensate? Answer.

In edge bending, the punch forces a cantilevered sheet metal section over a die edge to obtain the desired bend angle. In V-bending, a simple punch and die that each have the included angle are used to bend the part. 20.6 Describe each of the two types of sheet metal bending operations: V-bending and edge bending. A notching operation cuts out a portion of the sheet metal from the interior of the sheet or strip, while a seminotching operation removes a portion of the sheet metal from the interior of the sheet or strip. 20.5 What is the difference between a notching operation and a seminotching operation? Answer. A parting operation cuts a slug between adjacent parts in the strip. A cutoff operation separates parts from a strip by shearing one edge of each part in sequence. 20.4 What is the difference between a cutoff operation and a parting operation? Answer. The die diameter equals the blank diameter, and the punch diameter is smaller by twice the clearance. 20.3 In blanking of a circular sheet metal part, is the clearance applied to the punch diameter or the die diameter? Answer. (b) The machine tool is called a stamping press. (a) The tooling is called a punch-and-die. 20.2 In conventional sheet metalworking operations, (a) what is the name of the tooling and (b) what is the name of the machine tool used in the operations? Answer. The three basic types of sheet metalworking operations are (1) cutting, (2) bending, and (3) drawing. Kumpulan sola teknik pembentukan Solutions for Fundamentals of Modern Manufacturing, 3/e (published by Wiley) © MPGroover 2007 20 SHEET METALWORKING Review Questions 20.1 Identify the three basic types of sheet metalworking operations.

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