As early as the 1930s, the Swiss company RMB – which changed its name to MPS (Micro Precision Systems AG) in January 2003 – was producing miniature ball bearings for clocks, watches and the measuring instrument industry. In the 1940s, the Swiss-based specialist unveiled its miniature 4-point ball bearings. The company, which today operates within the FAULHABER Group, then went on to supply components for the Apollo Moon missions, thus establishing a strong foundation for its future as leading manufacturer of miniature bearings and actuators. The company‘s expertise is translated into cutting-edge solutions as part of three product lines: 4-point contact bearings and miniature balls, linear bearings and high-precision recirculating ball screws, besides all-embracing customized systems based on brushless miniature DC motors, including control modules.
Precision mounts ...
All microengineering has its origins in the clock and watch industry. Initially, the MPS product portfolio of precision bearings was tailored to the requirements of this industry. The bearings used in clocks and watches have to be extremely accurate, provide a very long service life and feature minimum friction. Furthermore, bearings deployed within this area should be lifetime-lubricated. These requirements also apply to all other sectors of micromechanics. Introduction of the 4-point ball bearing represented a milestone in micro-bearing technology. Based on their
design, these bearings are maintenance-free, feature low backlash and are able to absorb both radial and axial forces. Consequently, the clock and watch industry used them for self-winding mechanisms on automatic watches. This type of bearing quickly found its way into other functional areas, such as adjusting wheels and mounts for Tourbillon cages on high-precision mechanical clocks and watches.
The ability to absorb axial and radial forces is a major advantage in modern actuators. It means that the bearing assembly requires only two identical bearings on motors and gear mechanisms. For extreme applications and in the case of medical implant engineering, MPS manufactures the ball bearings from titanium with balls made of ceramic zirconium oxide. These bearings are biocompatible and feature no lubricants. The titanium bearings are available with an inside diameter of 1 and 1.5 mm, with outside diameters of 4 and 5.5 mm and an overall height of only 1.2 or 2 mm. The standard versions of the bearings made of stainless steel are even smaller. They have an inside diameter of 1.2 mm, with an outside diameter of 1.6 mm and an overall height of 0.4 mm. The axial play of this tiny component is only 6 µm. Of course, the bearing balls are also available individually. The standard range for steel balls is 0.02 to 1.5 mm, while zirconium oxide balls are supplied from 0.7 and 1 mm as standard. The spherical deviation is less than 0.08 µm, with a diameter deviation of 1.3 µm per batch. The hardness of 760 HV in the case of steel and 1150 HV in the case of zirconium oxide provides major wear resistance.
... with perfect guidance
The bearings of the microlinea® range allow linear movements with low friction. Linear bearings, ball cages and recirculating ball screws ensure that the applications “keep on the straight and narrow”. The linear bearings with a shaft diameter of 2 to 6 mm, an outer diameter of 4 to 12 mm and an overall length of 5 to 18 mm, have a load-bearing capacity of 10 to 245 N. With their ultra-compact dimensions, linear bearing cages provide perfect solutions. The range also includes bearings with an inside diameter of 3 to 12 mm. The third linear assembly is the linear recirculating ball screw, suitable for use as a miniature actuator. With its ball nut diameter of between 10 and 28 mm and a shaft diameter of 4.25 to 13.6 mm, it allows precise traverse distances between 70 and 260 mm.
All-in customized systems
The third main pillar of micro-production relates to all-in solutions manufactured precisely to customer spec-ifications. The main fields of activity are prosthetics, implants and medical devices, miniature pumps, positioning actuators and servo-actuators for optical systems, analysis instruments, robotics, precision tools and scanners.
Body-implantable, miniature peristaltic pumps and even dosing micro-pumps for implantation in the eye socket have already been developed in this sector.
The portfolio also includes mechanical “aids”, such as hexapod robots for orthopaedic surgery on the spinal column or compensating probes for optical glass cutting machines. One of the key aspects is maximum precision in each phase of the production process. For this purpose, the individual components with a small cross-section are sorted in pairs into 2 µm classes so as to ensure an optimum press-fit. The bearing play is also monitored 100% and limited to a maximum tolerance of only 8 µm. Among other solutions, MPS deploys company-developed measuring instruments, which are also available for use by customers and suppliers, allowing them to guarantee first-class quality at all times. Decades of experience in development and series production of precision micro-parts pays off, with state-of-the-art materials.
Proprietary measuring systems and special-purpose manufacturing equipment and processes ensure MPS’s technological lead, while also guaranteeing superior product quality. In turn, the high-quality products made possible in this way allow users to take innovative new approaches and provide a source of reliable components. |
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 Components of the miniature 4-point
bearing
Miniature linear recirculating ball screw
with high positioning accuracy
Compensating probe for precision glass
cutting machines
Body-implantable peristaltic pump
Hexapod auxiliary robot for spinal column
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