A very common questions we are asked is: “What tolerances can you generally achieve?”. However, giving out a-one-tolerance-fits-all answer would be unrealistic and too far away from manufacturing reality. Nevertheless we would like to give you a rough idea about tolerances.
Tolerances depend on numerous influencing factors such as
For that reason our engineers and technicians will need to carefully review each individual design. You will then be advised if we can or cannot achieve your desired tolerances and how you may need to alter the design to achieve your desired tolerances. If you have particular tolerance requirements, please feel free to get in touch with us today.
Below, please also find some further information on tolerances:
SLA and SLS models are typically +/- 0.1mm in X & Y and +/- 0.3mm in Z (XYZ as per the build orientation, not per your design orientation). This varies up or down for various geometries and sizes. If a customer needs a tight tolerance in a particular area, they can specify this in a 2D PDF, and we will machine or finish the part to suit.
Vacuum casting of polyurethane parts is primarily dependent upon the tolerance of the master model (see SL tolarances), then a tolerance of +/- 0.15% is applied as a general rule. This varies depending upon weak geometry. To ensure the accuracy of Star Prototype’s polyurethane parts, we usually machine a Tufnol fixture for post-heat-treatment. This ensures that the part does not shrink upon heat treatment.
Unless otherwise specified, we comply with the DIN 16901 standard tolerances for plastic injection moldings. It is possible with careful thermal, time, and pressure control to have very accurate parts. We need to know your requirements in advance so that we can manage key features in the tooling and molding process. As a general rule, you should never make more than one feature very accurate in the design. That feature can be repeated across the part, but to make a whole series of very different features very accurate is impossible for any molding company to achieve – you end up chasing your intolerances around the part. You get one feature right only to find another one slightly off.
Our general tolerances for CNC machining of metals is DIN-2768-1-fine and for plastics DIN-2768-1-medium. Tolerances are greatly affected by wall thicknesses, material choice, and geometry, so we will seek to advise as to achievable tolerances for each part. We pride ourselves on wishing to help our clients achieve their desired tolerances that are better than DIN-2768-1, but we work on a “best effort basis only” if the tolerances stated are tighter than our stated standards. The reason we refuse to be held accountable for very tighter tolerances is that we are a prototype factory and very tight tolerances present a huge risk due to the nature of our work.
Please feel free to contact us!