There are more guidelines required to be taken into consideration while designing for manufacture with injection moulding. The easier it is for the toolmakers to build the mould, the faster will be the turnaround time, increasing the speed of the production and product will be out earlier for the consumers. Here are 10 more design guidelines to follow when designing for manufacture:
1. Take help of manufacturer about solid fixture or mounting locating features. Experience counts in this area, where the part is required hard and solid. Threaded components can be replaced by simple male-female mating parts easily. Simplicity, like everything else, is the key here.
2. Avoid small holes. Small holes may be too complicated to properly mould. This can cause tool breakage making it riskier. Both will drive the cost up.
3. A hole in the mould is preferred through-holes. This will help the mould to separate more effectively and will ensure the diameter of the hole is uniform.
4. Generally, there is a variance in angle or surface consistency as it depends on the material used. The consequence causes will be little as the variance is not noticeable to the human eye. However, it is a possibility that the design requires an exact surface or angle to specify a material that will hold its form, such as low carbon hot rolled steel.
5. Flatness should be applied both per unit and reasonable overall form tolerance. This will avert abrupt surface variation of the feature within a relatively small area.
6. Dimensional tolerance – Machine tool required to offset to allow dimensional tolerance. In the tooling of the mould, ‘Cutter compensation’ let for the size of the tool itself.
7. Take into considerate the stacked-up tolerance for mating parts. While building mating parts, consider the separate tolerances on both the male and female joining part. If the tolerances are required to consider with the relation to one other, if not this could cause the parts to not mate, causing costly redesigns.
8. Generally, the design requires a particular orientation, and then provides a design element to make this clear. If it is becoming difficult to design part with clear instruction built into its design as to where it is supposed to fit into the whole, it needs redesigning.
9. Practically uniform screw sizes should be used. Always consider the end-user in the design process. Using uniform screw sizes and ‘off the shelf’ components will make the design much more accessible to more end-user.
10. Keep the count of parts as down as possible. Each additional component to design increases the risk of something going wrong. As well as keeping simplicity to the design, the whole design as a whole should as simple as possible too. The key is to create a design that will maximize the injection moulding process.
Plastic injection moulding is an effective tool for creating
consistent, well-made parts to design. It just needs to make it as per the
requirement of the user, though, and the easier it will be made it for the Toolmakers;
the faster will be the outcome and return on the design.