QualityInspection.org

Quality Assurance, Product Development, and Purchasing Strategies in China

Dimensional Control: Should Inspectors Write their Findings?

A few years back, I wrote an article related to dimensional control about the limitations of asking inspectors to write the exact values they find when checking measurements of items like garments and precision mechanical pieces. First, the numbers you can read in a report are not necessarily the reality, and I cited many ways this happens: Use of measurement instruments that are not calibrated (poor accuracy) or that lack precision Inadvertent human errors (misreading the instrument, … [Read more...]

What Is the Confidence Level when Working with AQL Tables?

A reader wrote to me and asked the following question about sampling plans by attributes: What is the "Confidence Level" when using the AQL Tables? How can we determine what the confidence levels are, and are there formulas we can use? That's a valid question. When playing with statistics, one often mentions a confidence interval. For example, "90% of the time, the value will be between 34.5 and 66.0". In theory, I guess one could do the same with the values in the AQL tables. There is a … [Read more...]

What Is The Minimum Viable Quality Management System For A New Manufacturer? [7 Steps]

I have often looked for best practices by looking at the automotive industry's practices when considering what the minimum viable quality management system for a new manufacturer can be. For example: ISO/TS 16949: Great Improvements Over ISO 9001 (Note: that standard is now called IATF 1m6949 and is even more work to apply) Best Practices for Qualifying a Chinese Factory (Note: that is called the PPAP) So, if IATF 16949 is "ISO 9001 ++", let's look at the opposite. What would "ISO … [Read more...]

How To Test Plastic Material Properties [Videos]

I recently published a list of videos on the injection molding process, and importers of hard goods made from plastics (or at least using plastic components) also need to know how to test plastic material properties. Why is plastic testing important? We'll explore it in this post and leave you better equipped to manage your supply chain. … [Read more...]

Does The Safety & Quality Of Products Sold On Amazon Pose Risks?

A few weeks ago, a journalist asked me whether products sold on Amazon present higher safety risks and whether their quality is inferior (relative to other distribution channels). My guess is that yes (I have no solid data to back that up. It would be quite difficult to come up with such data), for a similar product positioning (price & quality), those sold on Amazon present higher risks for consumers. Here's why. … [Read more...]

Traceability in Manufacturing: Do your Chinese Suppliers Do it Right?

I see buyers who spend a lot of time pushing their suppliers to do QC inspections on incoming components, to keep the production area clean, to give clear instructions to operators, and other basics. But I seldom hear them push for traceability in manufacturing, despite how important it is. I thought I should write about it again.   … [Read more...]

100% Inspection in a Third Party Facility in China: The How-To

I am guessing that about 96% of quality inspections done in China, on behalf of overseas buyers, are conducted in the supplier's facility on a set of randomly-picked samples. About 3% are done at the supplier's facility, on 100% of the pieces (typically, high-value items). And maybe 1% is done in a facility controlled by the buyer or a service provider engaged by the buyer. And it makes sense. In most cases, a random inspection (or a series of such inspections along the manufacturing cycle) … [Read more...]

How Much Does a Quality Inspection in China cost?

Understanding the cost of quality inspections in China I am always surprised by the expectations of some importers regarding the cost of quality inspections in a Chinese factory. Some importers get to talk about their project for some time, see where we would help them, and finally (almost as an afterthought) ask: "How much does a quality inspection in China cost?" The 2 categories of buyers when it comes to quality inspection costs I say "299 USD per day of work", and I can nearly hear … [Read more...]

The Special Inspection Levels in the AQL Tables

A few years ago I wrote about the inspection levels, but I regularly notice that some people are confused about the "special" levels (S1, S2, S3, and S4). Here is what the ISO 2859-1 standard says (emphasis is mine): The inspection level designates the relative amount of inspection. Three inspection levels, I, II and III, are given in Table 1 for general use. Unless otherwise specified, level II shall be used. Level I may be used when less discrimination is needed or level III when greater … [Read more...]