High scrap rate

Insistence on all dimensions as critical will result in the process being restricted to one narrow set of operating conditions, usually at a low production rate, with a high scrap rate and high product costs. In cases where the dimensions are critical, it may be that the extrusion process should be discarded in favor of molding or machining of the product. However controlling all dimensions can be accomplished at a cost. 

There is a high scrap rate, or the cost of scrap is high. 

The results of tests on molded test pieces and finished products can in many cases be influenced by the way the material has been processed. This in turn is influenced by the materials processability. Indeed there are very many cases of product failure resulting from processability changes, while misunderstandings and lack of information can also result in reduced output rates, high scrap rates, and general production inefficiencies. 

Use of self-adhesive labels is another option, but this approach poses similar problems. Labeling operations can have high scrap rates (up to 30% in some operations) due to off-center placement of labels, which may slip before the adhesive is fully set, or which may tear or be scuffed during handling. 

One of the problems with recychng automotive plastics is paint removal. This applies not only to end-of-life vehicles but also to thermoplastic olefin (TPO) painted parts, which have a high scrap rate. Polymer Sciences Inc. announced plans in late 1999 to build recycling facilities in Duncan, SC, and somewhere in Europe, using the company s mechanical process for stripping paint from TPO parts before they are gronnd and pelletized. However, the plant was not built, and the company now fists paint removal as a technology that it has available for sale or license. ... 

Physic damage caused by handling can ruin assemblies and cause a high scrap rate of components or assemblies. Scrap is costly and must be avoided to achieve an efficient and high-quality operation. 

High sulfur contents in steels can cause cracking and flaring of rolled section ends. Possibility of jamming when introduced to a subsequent set of rolls. High scrap rates and downtime can be experienced if this occurs. 

---