APPLYING JIGS AND FIXTURES TO ENGINE-BLOCK MACHINING 250056

Stating first the several important factors affecting jig-and-fixture design, the author emphasizes the necessity for cooperation between the engineering and the tool-engineering department and says that, in the plant specified, the tool engineer determines the position of locating points for machining operations on the engine block. Details of the first machining operation are given and the methods of loading and clamping the work are outlined.

By adhering to accepted principles of design, and by utilizing all other means of cost-reduction, equipment of the plant with adequate jigs and fixtures is accomplished at minimum expense. Use of duplicate clamping parts on as many jigs as possible saves time and reduces the stock of replacement parts needed. Strength and rigidity of fixtures are essential. Heavy base-sections are necessary, bushing plates should have a section deep enough to prevent warping and ample chip-clearance should be provided between the fixture and the work. All locating surfaces should be self-cleaning. In conclusion, a specific example is given of the advantage gained by complete cooperation among the engineers and the departments concerned.