A very general quality rule that is true for the industry and for everyday life is that when you start controlling a process, it will start improving as well.
Quality issues on products manufactured in China do happen and they often impair business profitability, affect brand image on the market and can mean lost sales, product returns and factories stopping production.
The most traditional kind of inspection that is performed on exports from China is the final random inspection before shipment. After production is completed and all merchandise is ready and packed for shipment, inspectors randomly inspect batches of products to check compliance to the specifications and requirements, including cosmetics, function and packaging. It is based on a statistical approach know as AQL (Acceptable Quality Level) and defined during World War II for the US military, that allows to test only a small number of units out of a large batch of products.
For example, if you have regular shipments of 1,000 (similar) products exported out of China, you can reasonably expect that you won't receive more that one single defective unit every four shipments if you have inspected (successfully) 50 units (out of the 1,000) before each delivery. That's testing 200 units instead of 4,000.
With 5 percent of the effort, you can reach 99.75% confidence on the quality. Sounds like a good deal.
Those who have ever played cards, craps, or "rock-paper-scissors" know that, at the individual level, you cannot always rely on statistics. As a matter of fact, several issues affect the AQL approach which often are not, or cannot, totally be solved:
- The way the statistical model is applied: The assumptions taken to design the AQL model include that we are talking large numbers and that we are talking "homogeneous" batches of products that should be produced under the same conditions, same shift, same machine, same set-up with the same raw material batch.
- The way the inspection plan is defined: you usually don't test all the parameters, but limit yourself to the most critical, and some potential defects cannot be tracked by standard functional or cosmetic inspections (like internal intermittent failures or material content.
- The way inspection is operated: In China, I have seen some factory's own inspectors switching the unit under test, repairing it, or twisting the measurement equipment, so that the product passes and that they could give a positive report.
Nonetheless, final random inspections are an efficient way to significantly improve your confidence level in the quality, but they have to be designed and operated with professionalism.
Other measures you can take include other kind of product inspections like final inspections during production cycle. Performed on the shop floor at the factory site and during the production cycle, they minimize the reaction time in case of non conformities and may usually cover a 100 percent check. This is well adapted for large mass production volumes and when there are strict requirements for on-time shipments.
Inspections at loading (container stuffing) include supervision of the loading operations, to verify product quantity and smooth handling of the cargo. Upon completion, the containers are sealed so that, at destination, the receiver can trust that his shipment has arrived unspoiled.
The other dispositions that can be taken for the quality include laboratory testing, quality improvement and quality system audits, as well as specific advanced programs like 6-sigma. Moving up the supply chain and securing the production processes is supposed to help reducing the number of issues found during final product inspection.
If you have a customer waiting for a delivery, the best way to serve him is to consistently deliver the compliant products on time. A final product inspection that will eventually stop some shipments of bad quality will not be sufficient by itself because once the problem is identified; you are still left to solve it.
If you are at peace about your methods you can build upon them, but it is often advisable to get the services of a professional partner with the capability and experience to help set-up and operate the system in a cost efficient way.
From: Discussion Forums