I am new to industry and finding it difficult to understand tolerancing method used in our company. We are using tolerances as 0.2mm, 0.1mm and 0.05mm for linear dimensions with no decimal, one decimal and two decimal places respectively.
As plastic molded parts behave differently than machined ones(for machined parts, we use ISO 2768-1 standard for tolerances), is there any specific method or standard for plastic parts?
I have uploaded a format we are using on our drawing sheets.
Hi Aniket,
The tolerancing is the same regardless of metals or plastics. The actual tolerances you can hold for metals and plastics should be different. In plastics the tolerances are wider.
Suhas
I came across a DIN standard which gives tolerances and acceptance conditions for plastic molded parts, DIN16742- a german standard. This standard deals with tolerances for linear dimensions of plastic based on material properties and manufacturing process/accuracy involved. But, i found it complex in some places, specially in criteria for accuracy involved in manufacturing. The standard classifies manufacturing process as normal production, accurate production, precision production and precision special production in increasing order of accuracy. The manufacturing process which we use possess some characteristics of accurate and some of precision production. Also, many places I found that the tolerances in standard are too tight to achieve with our manufacturing capability.
Is there any other standard ( preferably ISO) which can provide a base for tolerancing a plastic part in injection molding?
For sheet metals, we take ISO 2768-1 as base for tolerancing.
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