This article focuses on manufacturing-related failures of injection-molded plastic parts, although the concepts apply to all plastic manufacturing processes It provides detailed examples of failures due to improper material handling, drying, mixing of additives, and molecular packing and orientation. It also presents examples of failures stemming from material degradation improper use of metal inserts, weak weld lines, insufficient curing of thermosets, and inadequate mixing and impregnation in the case of thermoset composites.

Distortion often is observed in the analysis of other types of failures, and consideration of the distortion can be an important part of the analysis. This article first considers that true distortion occurs when it was unexpected and in which the distortion is associated with a functional failure. Then, a more general consideration of distortion in failure analysis is introduced. Several common aspects of failure by distortion are discussed and suitable examples of distortion failures are presented for illustration. The article provides information on methods to compute load limits, errors in the specification of the material, and faulty process and their corrective measures to meet specifications. It discusses the general process of material failure analysis and special types of distortion and deformation failure.

This article presents an overview of common heat treating problems arising due to poor part design, material incapabilities, difficult engineering requirements, incorrect heat treatment practice, and nonuniform quenching with emphasis on distortion and cracking of quenched and tempered steels. It provides useful information on selection of steels for heat treatment, and discusses the causes of residual stresses, distortion (size and shape), and size changes due to hardening and tempering. The article elucidates the control techniques for such distortions. It describes the importance of decarburizing, and discusses the problems caused by heating, cracking, quenching, typical steel grades, and design.