Process Window Compensation versus Tool Steel Alterations for Heavy Wall Sections
Altering tool steel to eliminate heavy wall sections cuts cycle time and unit cost far more reliably than forcing process windows past physical thermal limits.
DIN 16742 TG6 Tolerances
Meaning
German industrial standards establish specific dimensional tolerance groups for molded plastic parts based on their material properties and processing characteristics. Through DIN 16742 TG6 tolerances, manufacturers apply a highly precise tolerance group designed for high-performance engineering polymers molded under tightly controlled process conditions. This standard governs the acceptable deviations for dimensions that require high repeatability, such as gear teeth and precision snap fits.
Material Requirement
Achieving tight dimensional control is highly dependent on the shrinkage behavior of the specific polymer resin used. In DIN 16742 TG6 tolerances, the standard is typically applied to materials with low and isotropic shrinkage, such as unfilled polycarbonate or polyoxymethylene. Trying to meet these tolerances with high-shrinkage semi-crystalline resins like unreinforced polypropylene is impractical and leads to high scrap rates.
For these resins, wider groups like TG8 are more appropriate.
Molding Control
Production of parts within these tight boundaries demands advanced closed-loop process control on the injection press. Under DIN 16742 TG6 tolerances, variables such as melt temperature, injection speed, and pack pressure must be held within exceptionally narrow limits. This precision molding prevents the minor thermal fluctuations that would otherwise push the parts outside the required limits.
Cost Impact
Specifying overly restrictive dimensional limits on a drawing raises both tooling and inspection expenses. Utilizing DIN 16742 TG6 tolerances increases the need for high-quality multi-cavity molds with premium cooling and frequent gauge calibration.