Overview
There are thousands of small decisions to be made as the design and manufacturing process for a product evolves. These decisions generally revolve around picking the appropriate compromise among a variety of competing factors; factors such as cost, speed, appearance, convenience, et cetera. These decisions are made easier when you pick one factor and “put a stake in the ground.” For us, that factor is quality.
The stories and images below are presented as our way of providing you some insight into the detail and depth of our attention to quality. When you get to the heart of the matter, quality is not about forms, meetings, tests, or ISO certifications; instead quality is an attitude, a discipline, and a perspective. Techniques and tools related to quality, such as ISO 9001 procedures, are like any other tools; they can be used correctly or used poorly.
Many of our sources are from China and Taiwan, places that are occasionally known for a lack of quality. We have found many factories that fail to understand quality, but also a few that “get it.” Direct experience with a supplier and their products is the best way to tell the difference. Finding the right suppliers takes a great deal of time and money, but it's an investment that provides a competitive advantage. Please don't bother to ask us who our suppliers are, in most cases we are not willing to discuss the subject.
Machine Production
To start with, let’s recognize that ultimate machine precision is not a suitable goal, unless of course, cost is not a concern. The links below are to QC documents that defines the level of precision appropriate for the PCNC. In this context, quality is not the degree of precision the machine is designed for; rather it is the ability to always meet the precision specifications.
The tests described in the QC documents are performed on every machine, with the exception of the Optodyne test described near the end of the document. That test is done on every 20th machine. The Optotyne laser Doppler displacement measuring system (www.optodyne.com) is an exceptional tool, normally only used to calibrate high-end machine tools. The link below is a video, a test on basic linearity for the X axis. The machine moves 10 mm at a time while the Optodyne is recording position. Two readouts on the laptop are command position and actual position, in mm.
One simple principle we used when looking for suppliers was to try and make sure that the product we were interested in was not the best thing they have ever made. The photo below is from a typical Chinese drill/mill factory, where the best product they know how to make is a simple drill/mill, similar to those found in discount catalogs. We worked with several such companies, all the way to delivering prototype CNC mills. None of them were good enough.
The manufacturers we have partnered with for production of PCNCs have extensive experience producing larger CNC machine tools for the domestic market in China. One of their VMCs is shown here, behind our friend and interpreter, Ms Chi Jing. One of the Chinese engineers put it pretty well when we were discussing some difficult details of producing the PCNC 1100 a few years ago: he used the American idiom “Piece of cake.” For them it was true, but for others we had presented challenges they simply could not meet.