Attaining Zero Defects In Component Quality

Cooperation and communication between customer and supplier can result in a win-win situation for both of them.

By Victor Suben, P. E.

As incongruous as it may seem, I began my engineering career in the aerospace industry. After two or three stops along the way, I arrived in the personal products industry. One of the aerospace companies at which I worked instituted a zero defects policy. Zero defects meant that management wanted no components rejected for reasons of either poor quality, or failure to meet the specification’s requirements.

My first involvement with the personal products industry was with a mass marketer of skin care and color cosmetic products. To control the cost of goods, the company’s policy was to purchase packaging components from the sources with the lowest prices. The popular belief at the time was that the concept of zero defects was something that only the United States government could afford. The accepted means of controlling costs was to utilize high speed, automated production methods. What management did not realize at first was that with increased automation and faster production speed, it became increasingly important to have components of uniform quality.

Plastic primary packaging components are produced in molds having multiple cavities. In most cases, each cavity produces parts with the same configuration. Thus, for example, each time an 18 cavity tool closes, and the plastic resin is injected (assuming an injection molding operation) 18 identical parts will be ejected when the tool opens again. At least that’s the way it is supposed to work.

Some of the producers of low cost packaging components would reduce cycle time, or take other measures to control their own costs and to meet their sales commitments. Sometimes these measures resulted in some components that had insufficient wall thickness or neck finishes that were not collinear with the container, or some other flaw. In a high speed, automated filling environment, such defects could cause the equipment to jam, thereby temporarily halting production. Obviously, such production stoppages had a negative impact on the cost of goods.

Some defective parts never made it to the production line. In those years the quality assurance (QA) department performed statistical inspections that were proportional to the size of the shipment. If there were many defective parts in a shipment, the chances are they would be discovered and the shipment rejected during a QA inspection. Although the shipment would be returned to the supplier (usually at the supplier’s cost), the components were not available for production, thereby interfering with scheduled production runs. However, many times the statistical sampling techniques failed to discover the defective parts.

Defects Cause a Lot of Problems

Defective parts that did make it to the production line caused havoc in their own way. For example, if one cavity of a 10 cavity tool produced defective parts, then every time one of those parts would pass through the filling equipment, it could cause the machine to jam. Customarily, suppliers package their components without regard to keeping them separated by cavity. As the components pass through the filling equipment, there might be several defective units in the space of one hour that might cause the equipment to jam, and then the next jam might not occur until several hours later.

To a casual observer, such jams might appear to be a random phenomenon. However, inspection of the parts that caused the equipment to jam quickly revealed the fact that these jams were not random but were systemic, and usually related to cavities in the production tool.

The above problems and analyses made it clear that a package testing laboratory was needed to reduce the number of stoppages due to faulty packaging components. Once the decision was made to establish such a laboratory, we quickly procured the appropriate equipment and staff. With the necessary infrastructure in place, we developed procedures to ensure our suppliers’ ability to produce components with acceptable quality.

Our policy at the time was that at each stage in the development of a new package, the components would be systematically tested. This meant that components from a unit tool or advanced cavity tool would be thoroughly tested. If deficiencies were discovered, they would be reviewed with the supplier who would make the appropriate adjustments and submit a new set of components for testing. Once all the characteristics of the components from the unit tool were acceptable, the supplier was permitted to build a production tool, and to have a trial run.

Parts that were produced during the trial run were separated by cavity of the tool. These parts would also be subjected to the complete battery of tests. Again, any deficiencies found as a result of these tests would be brought to the supplier’s attention that would then make the necessary corrections and submit additional parts for testing. In the final phase of the qualification of a new tool, components from the first production run were also thoroughly evaluated to ensure that the parts still met our specifications.

The above procedures quickly identified suppliers capable of producing parts with an acceptable level of quality. We also found that by buying components that were a little more expensive, we got acceptable quality parts at each step of the process thereby reducing the development time.

Supplier Certification

In another project, the company encouraged certain suppliers to participate in a plan to become certified to perform development testing of new packages. Once certified, the supplier would perform the necessary development testing of unit tool pieces, parts from an initial trial of the production tool, and finally parts from the first production run.

To certify suppliers to perform developmental testing, we began by sharing our detailed test procedures with them. Representatives of our company would visit the supplier’s facility to see whether they had the appropriate equipment and personnel for performing the necessary tests. Once these parameters had been evaluated and deemed satisfactory, we would embark on the certification program.

The certification program involved performing a certain number of duplicate tests. When the supplier submitted components, the results of their testing would accompany the sample set. After the in-house lab had performed the same tests that the supplier had, the results of both sets of tests would be compared. If there were disparities between the results, the cause of the differences would be identified in discussions with the supplier. Once these issues were resolved, the program would go forward.

Once certified, a supplier only needed to submit its test reports to the company at each stage of the development program. The company, in turn, would perform periodic audits to ensure that there were no subtle shifts in the supplier’s procedures. Of course having the supplier perform all the development and QA testing does shift a large responsibility to that manufacturer. However, there are benefits to the supplier as well. After producing parts in a unit tool, the supplier can immediately see whether there are any problems, and remedial procedures can be started without delay. On the other hand, if parts had to be sent to the finished goods company, they would have to wait in a queue with other parts to be tested. This would slow the development procedure because each stage of the process would have to suffer through the same sort of delays.

Ideally, it would be beneficial to have the two certification programs instituted at a each company. Suppliers that could be certified for both the development phase and the production phase have the potential for significant competitive advantage for the following reasons:
1. By reducing the time required for the development of a new package, the supplier helps the customer to bring new products to market more quickly.
2. By ensuring that there are no rejects, parts needed for scheduled production runs are always available on time.
3. By always having parts with acceptable quality, the supplier is not faced with either duplicating the shipment, or culling or re-working the parts, which would add to the supplier’s costs.
4. By always producing parts with acceptable quality and shipping them on time, the supplier can become a preferred source when a new package is required for a new program.

In recognition of the added burden placed on the supplier’s shoulders, several years ago a proposal was put forward to reward the supplier for good performance. This proposal suggested that after a certain number of shipments that arrived on time and in which there were no defects, the supplier would be paid a premium for the parts. On the other hand, if there were problems with late shipments or unsatisfactory quality, the price paid for the parts would be reduced.

Communication is the Key Ingredient

For programs such as these to be successful, there needs to be open communication between the customer and the supplier, as well as good communication within the customer’s company. Within the customer company, good communication means that all groups involved in the decision to award new business to a given supplier are always made aware of the supplier’s performance.