- There are many different manufacturing options that can be used depending upon budget, timing, and also volume of production. All of them except one pretty much requires that this part has to have essential tooling criteria built into the initial design. It really doesn't matter if we're using injection moulding or carbon fiber for the initial tool. We have to ensure that there is enough draft angle on the side walls to enable the part to be removed without damage. The amount of draft will depend upon the material used, shrinkage, type of texture that will be applied to the surface.
Typically we allow 1.5 degrees for every thousandth of a millimeter so that the more pronounced the texture the greater the required draft angle. Also another factor to consider is the depth of draw of the surface in question. Even with a carbon fiber part that is essentially hand built and the part can be carefully removed by the technician and facilitated with the correct application of releasing agents etcetera, there has to be a certain amount of draft incorporated into the design. Another important point to consider is how this part will be assembled.
The main body and handle could be formed as a one piece substrate and the soft handle surfaces could be a secondary operation like reaction injection moulding using polyurethene foam which would allow for the accommodation of color and texture. In this course we're going to make the assumption that the handle is a separate piece that will be attached to the main body. This allows for easier replacement of worn handle surfaces and also for a variety of handles to be used with varying contours and finishes. As I mentioned before there is one method of manufacturing that allows us the flexibility to virtually eliminate the need for worrying about draft angles and undercuts.
And that's rapid prototyping. Rapid prototyping technology has progressed to the point that it is possible to use carbon fiber, resin, plastic and powdered metal that is sintered in a secondary operation to create incredibly complex and mechanically strong shapes. It also allows a designer to have multiple thicknesses in the design which could be problematic when using conventional plastic injection moulding technology. Of course the down side is that rapid prototype parts can be more expensive initially but compared to the cost of manufacturing a complex tool incorporating multiple lifters, slides, and complex calling systems, as well as potentially compromising the overall design due to manufacturing restrictions like draft angles and sink marks etcetera, the initial high cost could be a worthwhile investment.
For our design we'll break the assembly into five distinct components: the handle, the main body, the switches and dials, the center pad, and the paddles in the back.
- Understanding the manufacturing strategy
- Direct modeling techniques
- Understanding project deliverables
- Creating the main body
- Creating a digital display
- Checking feasibility
- Creating handles with fillets
- Exporting for rapid prototyping
- Rendering the final model