Shrinkage tolerances, recommended

As an example the shrinkage and in turn its tolerance of injection molded TPs will be affected as follows. (1) Higher cavity pressures will cause lower shrinkages. (2) Thick sections will shrink more than thin ones. (3) A cooler at the time of the product being ejected from the mold cavity will bring about a lower shrinkage. (4) A melt temperature of the material at the lower end of the recommended... 

Melt temperature (Tm) refers to a plastic when it melts or softens and begins to have flow tendency. It provides recommendation for processing temperature to be used and related to tolerance and shrinkage behavior of molded products. 

Factors—part shrinkage, dimensional tolerances, warpage, drafts and undercuts, location of holes, fillets and radii to promote resin flow and reduce stress concentration, wall thickness, weld and parting lines to improve appearance and avoid areas of high stress concentration, and the introduction of ribs, bosses and studs, and metal inserts to improve strength—are treated. Recommended safety factors as a function of load are given. 

---