Mold Design Precision Conflict
When designing molds, it is common to encounter precision conflicts. A precision conflict occurs when a mold must meet more than one design requirement, but the combined requirements are impossible to satisfy due to conflicting requirements. This issue can cause problems with the quality of parts produced, lead time delays and costs associated with revising the mold design. As such, it is important to understand the key factors involved in precision conflicts and effective methods to resolve them.
When designing injection molds, the mold must be accurately ordered to ensure that the injected plastic fills each cavity completely and uniformly with the best fit and finish quality. The tool designer must pay special attention to the achieved snap fit tolerances and corner radii on the part. The tool designer must also ensure a good tolerance stack up from part features, base and interlock fit including undercut features.
The potential for precision conflict arises when each of the design needs calls for a different dimensional tolerance. For example, when the undercut and fit of two mated sections share the same dimension, the required tolerances are conflicting. The moldmaker may not be able to machine parts that meet both requirements. This would lead to a situation where the mold design needs to be changed or rejected.
When precision conflicts like this arise, the mold designer must take a more holistic approach and evaluate the entire design process. While it may be tempting to just adjust a single part dimension to solve the problem, an experienced designer will often look upstream in the design process to identify the cause of the conflict and then address that issue.
The designer can then examine the parts’ manufacturing processes and calculations to determine which dimensions can be shifted or adjusted to determine a viable solution. Identifying which tolerance is most important to the design will also help guide the designer towards a more successful solution. The designer may also modify the molding process to compensate for any dimensional preferences in order to get the desired result.
Regardless of the precise nature of the precision conflict, a successful resolution will involve careful consideration of all the elements in the design process. From the start of the conception all the way through to the material selection and production steps, all elements must be taken into consideration to create a solution that works for all parties. By taking a holistic approach to the design process, an experienced designer will be able to mitigate the risks posed by precision conflicts and ensure that the best possible design is produced in the shortest amount of time.
