Manufacturers defective goods

As indicated in Table 10.18, a zinc-rich primer is often recommended. It can be an organic zinc-epoxy or an inorganic zinc-ethyl-silicate primer. Zinc-rich primers are also used as so-called shop primers, or prefabrication primers, for temporary protection of semi-manufactured steel goods. After fabrication, e.g. of welded steel structures, the shop primer surface must be cleaned (degreased), and possible shop primer defects and weld joints have to be blast cleaned and coated with a primer before the whole structure is painted. Iron oxide is also used as a pigment in some shop primers. These must not be overpainted with a zinc-rich paint. 

Third party accreditation can be used to determine the defect level of the product during manufacturing. This practice can be adopted to prevent defective goods from entering the supply chain. Third party accreditation is based on product specification and compUance and can help to idaitily varying levels of defects in the product such as ... 

There is no liability on a manufacturer if there is the opportunity of intermediate examination particularly where this is expected, which it could not be in the case of a sealed opaque bottle. Nor for instance is a manufacturer liable to a workman injured by using defective goods the manufacturer supplied which an employer examines, sees are defective but decides to keep in use albeit only until they can be replaced. 

At the center of this development is the Auto-ID Center at Massachusetts Institute of Technology, which was founded three years ago and has seen membership grow rapidly to 67 companies interested in just how far this technical enhancement can take them. Sponsors such as Coca-Cola, the U.S. Department of Defense, Pfizer, and Johnson Johnson are just some of the firms poised to take advantage of what could be an excellent tool in the supply chain arsenal. Depending on the results of one test. Home Depot, Inc. reports it could eventually put RFID tags on all of the 50,000 products it sells (Ewalt, 2002, p. 17). One expected feature will be the ability to track items after purchase so manufacturers would find it easier to recall defective goods. Another will be to follow any thefts. 

West German legislation on liability of producers, e.g. rubber and plastics manufacturers and processesors, for defective goods, is discussed with reference to a law introduced in January 1990. (Second German French Rubber Symposium, Freiburg, Sept. 1989). 

Neural network classifiers. The neural network or other statistical classifiers impose strong requirements on the data and the inspection, however, when these are fulfilled then good fully automatic classification systems can be developed within a short period of time. This is for example the case if the inspection is a part of a manufacturing process, where the inspected pieces and the possible defect mechanisms are well known and the whole NDT inspection is done in repeatable conditions. In such cases it is possible to collect (or manufacture) as set of defect pieces, which can be used to obtain a training set. There are some commercially available tools (like ICEPAK [Chan, et al., 1988]) which can construct classifiers without any a-priori information, based only on the training sets of data. One has, however, always to remember about the limitations of this technique, otherwise serious misclassifications may go unnoticed. 

Quality system regulation The past good manufacturing practice (GMP) and process validation (PV) was renamed to quality system regulation (QSR). It is important for the medical device industry (that uses an extensive amount of plastics) and also in other product industries where they want to follow strict processing procedures. It sets up an important procedure for many plastic fabricators to consider that targets to ensure meeting zero defects. 

If an analytical test results in a lower value x, < x0, then the customer may reject the product as to be defective. Due to the variation in the results of analyses and their evaluation by means of statistical tests, however, a product of good quality may be rejected or a defective product may be approved according to the facts shown in Table 4.2 (see Sect. 4.3.1). Therefore, manufacturer and customer have to agree upon statistical limits (critical values) which minimize false-negative decisions (errors of the first kind which characterize the manufacturer risk) and false-positive decisions (errors of the second kind which represent the customer risk) as well as test expenditure. In principle, analytical precision and statistical security can be increased almost to an unlimited extent but this would be reflected by high costs for both manufacturers and customers. 

One of the misunderstandings with the traditional (western) way of quality thinking is that it is not needed to improve quality above the specification limit because the product is already good. But a product with increased quality (closer to the target) performs better and induces less complaints from customers. The latter reason is more important than most people think as it will not only save the manufacturer cost in replacing defective products, but it will also contribute to an increased confidence and goodwill of the customer towards the manufacturer. 

Poly(vinyl chloride) films are produced in two main forms—unplasticized and plasticized—and over the years different machines have been manufactured to handle the two types. When calendering unplasticized PVC there is a tendency for small particles, usually referred to as crumbs , to fall away from the edges of the film and from the feed nip. Such crumbs then could fall on to the finished film, where they would stick and form defects. To avoid this, producers of unplasticized film usually prefer an L configuration in which the product travels up the stack and surface contamination of this kind is prevented. With plasticized PVC the problem of crumbs does not occur to any great extent and, as it is an advantage to have good access to the part of the calender where the finished film is made, an inverted L configuration is the most popular. 

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