Diamond tooling: productivity
key to composite fabrication

Abstract
RP and composite parts have become high volume, close tolerance and difficult to machine. With the use of new fillers and materials, the production time has increased, tooling cost has increased and the overall productivity has decreased.

The main reason for this productivity decrease has been the fact that the cutting tools for these materials were developed on a catch-as-catch-can basis. Internal expertise was either in carbide tooling or metal removal, rather than RP removal. This has resulted in the wrong tools being used for the wrong job. The requirements for the 90's have made diamond tooling the preferred method for production.

Designing the proper diamond tooling in many cases is the solution to productivity problems. Diamond, the hardest material known to man, has low initial costs and fast cutting rates without dulling or loading; therefore it is ideal for:

1. The tight tolerances of the space shuttle's heat shield and for components of our jet fighters or missiles.
2. Large quantity orders which are now being manufactured in the automotive and aerospace markets where every second of machine time or down time is critical to the cost of the product.
3. The new materials which are considerably different from those used 20 years ago. RP's are being reinforced with new, stronger materials such as, boron fibers, graphite fibers, glass fibers, polyester fibers, etc...
   

This paper describes the parameters for the proper design and application. Tool geometry and the proper diamond type are major choices for improved tool life. Examples of applications for plated and brazed tools are presented. This includes feeds, speeds, coolant, etc...

As tolerances become tighter and the materials become tougher to machine, diamond will continue to grow in its role as the "productivity maker" for RP's and composites.

Background

In developing an overall manufacturing strategy for producing a part, the material removal tool becomes one of the major considerations. In this consideration, there are 3 major parameters in the design function. First, we must decide on the manufacturing sequence of material removal and equipment. Second, the cutting tool material and third, the proper design and function of the tool.

Manufacturing criteria

The manufacturing sequence is one of the most critical and often the most overlooked component in any manufacturing sequence. Without looking at this first step properly, steps 2 and 3 may still not produce the best tool for the job. First decide whether it is a hand operation, semi-automatic machine operation or dramatic operation. What equipment is going to be used? What is the condition and RPM speed range? In looking at the configuration, one must determine in how many steps the machining can be done. Each step should be segregated in distinct units. These distinct units can then be combined or modified to develop and design a tool of Step 2.

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