CIM Modelling and
between design and manufacturing by translating design specification into
manufacturing process detail. Hence, in general, process planning is a production
organization activity that transforms a product design into a set of instruction (sequence,
machine tool setup etc.) to manufacture machined part economically and competitively.
The information provided in design includes dimensional specification (geometric shape
and its feature) and technical specification (tolerance, surface finish etc.)
Now-a-days, process planning is applied to many manufacturing industries like metal
cutting, sheet metal forming, composite and ceramic fabrication and other manufacturing
processes. Figure 9.1 represents the various steps involved in developing a process plan.
Analysis of Part Requirements
Selection of Raw Workpiece
Operation and their Sequences
Selection of Machine
Selection of Tools, Work Holding Devices
(Fixtures) and Inspection Equipments
Determining Machine Conditions (Cutting Speed, Feed,
and Depth of Cut and Manufacturing Times (Processing
Time and LeadTime)
Various steps are discussed as follows :
The analysis of finished part requirement is the first step in process planning. Initially
the features of parts are analyzed. Examples of geometric feature include plane, cylinder,
cone step, edge and include fillet. These common features can be modified by the
addition of slots, pockets, grooves, holes and others. The second step is the selection of
raw work piece shape, size (dimensions and weight), material and other attributes are
determined. Weight and material of the raw part are determined by the functional
requirement of plan.
The next logical step in process planning is to determine the appropriate types of
processing operations and their sequences to transform the features, dimensions and
tolerances of a part from the raw to the finished state. There may be many ways to
produce a design some times constraints are also considered like some feature be
machined before or after other. Furthermore, the types of machine, available tools as
well as batch size influence the process sequence.
Next step to be followed in process planning is the selection of machine tools on which
these operations are made.