James Bevan Bryan
In his 1984 paper titled "The Power of Deterministic Thinking in Machine Tool Accuracy", Mr. Bryan discussed the guiding design philosphy he and his colleagues developed while studying and building ultra-precision machine tools and instruments over decades. To help guide their work, he summerized the philosphy into eight rules. These rules are reproduced below for our review and guidance. [James Bevan Bryan, 1984]
The Eight Rules
- Don't depend on breakthroughs. Identify the weakest link in the system and concentrate on upgrading it.
- Be patient, it takes time to sort out the variables, but it can be done and the rewards are worth it.
- Keep design solutions as simple as possible.
- Don't assume anything, measure with good equipment and carefully designed tests.
- Don't use statistics indiscriminately, they are generally not necessary for the limited number of variables in a machine tool.
- Suspect temperature, dirt, loose joints, and friction as the most likely sources of apparent non-repeatability.
- Keep Loxham's law in mind. "An automatic machine is always operating perfectly. It may not be doing what is required, but that's because it isn't suitably arranged.
- Remember that "random results are the consequence of random procedures.