The ongoing miniaturisation of components in several industrial areas is a trend that requires to continuously increase the precision of the production means and of the product itself. In order to obtain the high accuracy needed, it is essential to take particular care to the structure of the mechanisms involved in high-precisions tasks, in particular the guiding principle applied.
It is essential to avoid limiting factors like backlash, friction or low stiffness, which can be hardly overcome by sensors or controllers.
Flexible bearings, relying on elastic properties of matter, can be used as an appropriate alternative to conventional bearings in order to avoid these phenomena. These types of elements have been well known for years, but only recently, along with an increasing demand on high-precision tasks, flexures have gained more and more interest. The range of their applications has grown and many examples of flexure-based devices can be found in hostile or cleanroom environments, in high radiation levels, in space or in ultra-high precision applications where high resolution and accuracy are required.
Characteristic of flexures Flexures are bearings, connecting solid bodies through flexible joints, permitting relative motion in some directions while constraining motion in others.
The guiding principle relies on the elastic properties of material, bringing numerous advantages for high-precision mechanisms:
• Absence of solid friction means no mechanical hysteresis and no ‘stick and slip’ phenomenon limiting the resolution of the movements. Friction is at the origin of wear. Flexures are free from any solid friction.
• Absence of wear • Absence of mechanical play • No need for lubrication
• Immunity to contamination: flexures are perfectly clean and are not affected by dirt.
• Compact and monolithic structures: manufacturing processes such as wire-electrical discharge machining, silicon processes or the new Femtoprint technology for transparent materials allow to produce very complex flexible structures monolithically, thus providing high compactness and precision.
>> Continued on page 10
The ongoing
miniaturisation of components in
several industrial areas is a trend that requires to continuously increase the
precision of the production means and of the
products itself.
<< Figure 2: High dynamic XYZ for micro manufacturing. >>
9| commercial micro manufacturing international Vol 6 No.6
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