Machining

Modern injection equipment enables the production of complex plastic parts with very high precision.  However, there are cases where it is either not possible or else prohibitively expensive to implement creation of all desired part features in the tool.  There are also instances where extremely tight final part tolerances cannot be achieved with the consistency needed for an economically acceptable molding operation.  Machining of parts can enable precision features with extremely close tolerances to be added after molding, often greatly simplifying mold design and improving productivity.  Machining is also widely used to make small numbers of relatively simple parts with high precision from rod or slab stock.

Standard wood and metal working equipment and tools are used to machine plastics.  Tools should be sharp and an efficient chip removal system should be provided.  Cutting rates should be low enough to avoid excessive heat generation, which could cause localized melting and impair the precision of the cut.  Any coolant used must be such as not to attack the plastic material.  Ticona’s engineering resins have generally good chemical resistance such that typical coolants do not attack them.  However, to avoid surface crazing, oil-containing coolants should not be used in machining Topas® cyclic olefin copolymer (COC).

Detailed machining recommendations depend on the specific material being machined.  The best source of such practical recommendations will usually be the supplier of the particular rod or slab stock that is being machined.