A smooth assembly process with a low failure rate also depends on all parts fitting together. Accuracy specifications must also be met. On the other hand, low cost is important to be competitive. To achieve all this, a good tolerance analysis is essential.
A Good Analysis Gives Certainty
In the absence of a tolerance analysis, tolerances are usually chosen on the basis of ‘experience’. This is not necessarily wrong. However, one designer may have more and/or better experience than another. In all cases, the justification for the chosen tolerances is mediocre at best. With a tolerance analysis, you have that good foundation and the chance of success is much greater. You will also be able to optimize between tolerance and cost.
Tolerance Analysis, a Budget in Mil/Millimeters
But what exactly is tolerance analysis? People often talk about creating a tolerance budget. And this is not a budget in euros, dollars or some other currency, but a budget in mil, millimeters (or another unit of length). The starting point is usually a specification that needs to be met. The second step is to gather the part tolerances that affect the specification. From there, you can perform your analysis and optimize all tolerances for the best cost-to-failure ratio.
A lot of Experience in Tolerance Analysis
I (Jaap Vink) have 25 years of experience with tolerance analysis. At ASML I helped to develop the structured, methodical approach. And of course I have done many analyses at ASML. I also developed an Excel template for tolerance analysis for ASML. This allows any mechanical designer to set up, calculate and present his analysis in the same way. Through the course, offered by Mikrocentrum, the mechanical designers at ASML learn to work with this Excel template.
After starting Vink System Design & Analysis, I also did analysis for other companies. Between 2015 and 2021 I taught Tolerance Analysis for Mikrocentrum. Both the open course and the in-company course. The course is suitable for many companies in all sectors. This is shown by the variety of companies I have taught:
- ACE Engineering bureau;
- Altran Automotive;
- BDR Thermea, central heating boilers;
- BoonEdam, revolving doors;
- Demcon Engineering bureau;
- TU Delft DEMO;
- KROHNE Flow meters;
- KUHN Agricultural Machinery;
- Neways Electronics;
- Petersime Zulte, egg incubators;
- Robojob CNC Automation;
- Spark design, design and functionality;
- VIRO Ingenieursbureau, all locations;
- Zodiac Aerospace.
Method – Way of Working
Of course theory is important in the tolerance analysis. But experience also counts. Perhaps the most important thing is the method of approach. Each design is different and has its own challenges.
However, you must be able to perform a tolerance analysis for every new (or existing) design. And you can only do that with a structured, methodical approach. Even if the design is complex or unclear, a methodical approach will always help you perform your analysis. Fortunately, with the Mikrocentrum course, you don’t have to find out for yourself.