1.4 OPERATION PLANNING WITH METCAPP
MetCAPP [Institute for Advances Manufacturing Science, 1991] [Zdeblick, 1985] [Barocky and Zdeblick, 1984] is the result of many years of development of machining data. Initially the work began as a handbook containing many machining recommendations. Eventually it evolved to become a computerized database containing the information (CutTech). After that it was enhanced with a cutting sequence planner (CutPlan), and eventually a front end was added to allow specification of machining features (MetCAPP). This software includes an interface library to allow it to be used by other computer programs. In this thesis, CutTech was provided with some manufacturing feature information, as well as material, and a machine. From this the software was able to suggest multistep machining operations to produce machined features. This software is used to emphasize the fact that other CAPP systems play an important role in complementing BCAPP.
There are a number of functions that the operation planner recognizes for MetCAPP. These are,
CUTTING ( MACHINE string ) - defines a machine with the name ‘string’.
CUTTING ( MATERIAL string ) - defines a material with the name ‘string’.
CUTTING ( FEATURE string ) - defines a feature with the name ‘string’.
CUTTING ( PARAMETERS x0...xn ) - defines a variable list of parameters’.
These are the minimum definition requirements for CutTech to make a recommendation. CutTech contains a list of common machines, and materials found in modern machining, and it will look up the properties of these. There are also a limited number of features (an extensive list may be found in the MetCAPP manuals). The parameter list is required so that required information about the features can be provided. This list is variable in length, because the required parameter list varies in size for each feature. The values for the parameter list should also be found through reference to the MetCAPP manuals. An example of a MetCAPP operation plan is given below for a hole.
Seq.# Machine Passes Time Operation Description
SUB_OP 5 Center Drill Non-Insertable 1 0.008000 Center Drill Non-Insertabl
I ! Center Drill ! 0.7500 ! No ! 3.250 ! M10
1 ! DLS-007 ! 0.7500 ! No ! 0.750 ! M7
2 ! DLS-008 ! 0.7500 ! No ! 0.750 ! M7
3 ! DLS-009 ! 1.0000 ! No ! 1.000 ! M7
4 ! DLS-010 ! 1.0000 ! No ! 1.000 ! M7
5 ! DLS-005 ! 0.5000 ! No ! 0.500 ! M7
SUB_OP 10 Drill Non-Insertable 1 0.031000 Drill Non-Insertable
I ! Non Insert Drill ! 0.4844 ! No ! 1.484 ! M10
1 ! DLS-118 ! 0.4688 ! No ! 4.313 ! M7
2 ! DLS-119 ! 0.4844 ! No ! 4.375 ! M7
3 ! DLS-279 ! 0.4688 ! No ! 4.313 ! M42
4 ! DLS-280 ! 0.4844 ! No ! 4.375 ! M42
SUB_OP 15 Bore Non-Insertable 1 0.017000 Bore Non-Insertable
I ! Non Insert Bore ! 0.500 ! 15.00 ! 0.015 ! C2
1 ! BRS-004 ! 0.500 ! 0.00 ! 0.008 ! C7
2 ! BRS-031 ! 0.406 ! 0.00 ! 0.008 ! C7
Figure 1.3 A CutTech Operation Plan for a Drilled Hole
This plan has three steps for rough drilling, then fine boring. Each operation is also followed by a list of tools. The first tool in the list is the first choice. The other tools are acceptable alternates. In the list given the first of three operations (#5) is ‘Center Drill Non-Insertable’. The operation will be done in one pass, in .008 hours. The tool parameters are listed below, with the tool at the top specifying the best tool choice.