The Design Principles for Precision Mechanisms course is about the design of mechanisms for products, tools and equipment. A large number of the presented examples originate from the field of precision systems. However, most of the underlying principles are not confined to the world of precision. They are applicable to many other fields of mechanical engineering as well. Characteristic to all precision systems is the high level of determinacy required. Predictable and reproducible behavior are key-qualities that can only be achieved when mechanics and control systems (if present) are carefully designed and robust to disturbances. Their mechanical design is the subject of this course. To achieve excellent and predictable behavior, the mechanisms need to be, among other things, exactly constrained, free-of-backlash, extremely stiff and low in weight. A large number of the examples will be presented during the course.
An excellent example of a production tool with extremely accurate and fast servo positioning is the so-called ‘wafer stepper’ – a tool designed for patterning the surface of silicon wafers by optical lithography. The first machines, which served as a starting point for the Netherlands-based company ASML, were developed by Philips Research to support Philips’ semiconductor activities. The stepper’s accuracy is primarily the result of a high-precision optical projection system, advanced wafer and mask alignment and well-designed positioning systems that use interferometry-based displacement measurement. However, mere accuracy is not good enough. Achieving the necessary performance requires a combination of high accuracy, high speed and high reliability. Without it, it would be impossible to achieve low production costs. It is this combination of performance requirements that continuously imposes new challenges to the designer. Such developments are impossible without a thorough understanding of how to transform basic principles into working concepts. Providing that understanding is the goal of this cource.
The Design Principles for Precision Mechanisms book focuses on providing insights and proposing design concepts for precision mechanisms. It demonstrates ways to convert modeled realities (as can be found in so many learning books) into real constructions with predictable behavior. The book also shows the huge strength of thinking in ‘Degrees of Freedom’, and it helps to stimulate creativity by providing a large number of examples, plus many unconventional solutions and underlying trains of thought. Together with the basic example calculations provided, these are helpful to more experienced designers as well as to students
The following subjects form the main body of the course:
- Design for Stiffness
- Controlling Degrees of Freedom
- Flexure Mechanisms
- Hysteresis and Microslip
- Bearings, Rollers and Webs
- Dynamics and Energy Management
After the course the student comprehends the principles of conceptual design of precision mechanisms and is able to recognize problem areas, to generate design alternatives and to make adequate choices.