Design consultant engineers carefully select materials to meet stringent regula-tory and performance specifications,

often checking availability and costs, and, expecting moldmakers and molders to inform them before making substitutions. In an effort to reduce part costs or leadtimes, a client may sometimes ask a moldmaker and/or molder to substitute materials based on experience or availability. It is good practice to insist your design consultants approve the substitute. Clients sometimes don’t remember why a particular material was specified and may oversimplify the material requirements. Ambiguity on materials can lead to a lot of finger pointing later.