Manufacturing Tolerances

Manufacturing Tolerances for Cuttinfs and Products


Semi-finished products for cutting blanks come to us from different vendors.
Some vendors supply boards with a thickness using a tolerance field only in the positive section, i.e. the actual board thickness is always greater than the thickness indicated in the description blank. Sheets are supplied in this way from materials PA6, PA66, PA6G, PA6G + oil, POM, PET, PEEK, PTFE, some PE boards etc.
Some vendors supply sheets with a thickness using the positive and negative portions of the tolerance field, that is, the actual thickness of the board may be smaller than the thickness indicated in the cuttings description.


When cutting the blank using a brake saw the board thickness remains untreated - within the semi-finished product’s (sheets) tolerance.
We try to do the cutting within tolerances according to DIN - in ISO 2768, but with the difference that we do not use a negative tolerance band. This is so that the customer can produce the required product from the blank, since we do not know what allowances for treatment they added to the order.
If the material with the required cuttings is low-quotient and only a small amount is needed, we buy the finished cuttings from a vendor abroad. The cuttings then comes within the vendor’s tolerance based on the cutting technology, which the given vendor uses. Such a cuttings is delivered to the customer without further treatment at TechPlasty.

If the customer requests a narrow tolerance sheets of some dimensions, they shall indicate this fact in the order. The cuttings thus becomes a product which passes through appropriate technologies (e.g. milling) so that the desired accuracy is reached, but the price of the product will take into account this production process.
In connection with these facts we also ask customers to state the required tolerance for cuttings in the orders where higher accuracy is required, as well as machining to this accuracy in TechPlasty. Otherwise, the blanks are supplied in the precision stated above.

Products from engineering plastics

For the deliveries of finished products we manufacture within the tolerances according to DIN - ISO 2768 m. In the manufacture of certain types of dimensionally stable plastic (PA66 + GF30, PEEK, PTFE + glass...) some of the dimensions can be made more precise by agreement and in justified exceptional cases.
To reduce the price of each product unless stated otherwise in the customer’s drawing, we keep the manufacturing tolerance of the used semi-finished products in the relevant dimension of the finished product - see paragraph on blanks.
Plastic of any kind is always a specific material with significantly different properties (dimensional stability, thermal expansion...) compared to metallic materials and requires a different approach already during the construction documentation’s creation.
In connection with these facts, we ask customers to state the desired product tolerance important for the proper functioning in drawings or sketches. It is always necessary to consider a compromise between proper function and the price of the product. We recommend consulting TechPlasty company employees in the design of components to achieve optimum accuracy and price.