Why are tolerances on part dimensions important?

2 min read

Why are tolerances on part dimensions important?


The tolerance of a part’s dimensions is critical information when determining the part’s ability to fit with other parts in an assembly.  It’s the acceptable deviation between the maximum and minimum size of the part.  With this information the engineer knows what the importance of that dimension is on an assembly of several components.  Dimensions without tolerances leave the limits open.  By not setting a tolerance in critical areas, one can render the part unusable.   Parts with the correct tolerances will fit as required, including whether it is a sliding or press fit assembly.

Why aren’t tighter tolerances better?

Its key to find the balance between the tolerance that will ensure quality and the tolerance that is too tight.  If not found, the cost of manufacturing the parts to unnecessarily tight tolerances can go up.  Achieving control of tolerances is accomplished by tackling issues about size, intricacy, materials used and thickness.  These factors then, in turn, help to determine the manufacturing process that is used.

What are optimal soft material tolerances?

The optimal tolerance depends on the degree to which the soft material is permanently distorted during or after the part manufacturing process.  Standard block tolerances found on engineering templates often do not apply to many soft materials and are often too tight.   PGC Applications Engineers are eager to support your part development, bringing many resources to your project.  As a start, PGC can share standardized tolerance information from the industry group, Association for Rubber Products Manufacturers ( www.arpminc.com ).  ARPM has charted conservative, or safe-to-manufacture tolerances for a range of non-metallic materials, including solid and cellular rubbers.    Tighter, non-standard tolerances can usually be achieved with planning steps that bring PGC experience in the craft of high-volume non-metallic part manufacturing to your individual application circumstances.

Who determines tolerances?

PGC’s engineers are here to help support you to specify critical tolerances in your design. They will help to identify if a tolerance is too tight and suggest options.  System quality will not be compromised, and this can help keep costs down.

Please reach out to discuss your application today.