To complement the standard range of linear and rotary precision movement systems provided by Feinmess Dresden, UK representative Armstrong Optical of Northampton has now added systems to allow operation in both extreme magnetic fields and ultra-high vacuum down to below 10-7 Torr.
Many of the problems of operating in extreme magnetic fields are associated with the materials used to construct the movement system. Magnetic properties represent an additional specification besides those that are already necessary in standard motion systems. For many applications steel can be considered, but even stainless steel, which is normally seen as 'non-magnetic', may have still enough remaining magnetism to cause trouble in certain applications. In these instances titanium, other alloys and ceramics are utilized to provide optimum performance characteristics.
Alongside material selection, designers also have to deal with possible interference from the external magnetic fields of motors, encoders and other electronic systems used to drive and control the stage. Stages to be used in weak magnetic fields can normally use stainless steel components. For those applications where steel components cannot be used the motors are usually placed outside the direct magnetic field or piezo-ceramics drives are considered.
In order to provide overall control of the motion system optical linear encoders are the only option for position feedback. Limit switches must be based on optical signals since Hall-effect sensors are not usable. There is also the possibility that strong magnetic fields will cause electronic circuitry to fail or malfunction.
Even with all the difficulties associated with high vacuum and extreme magnetic flux Feinmess Dresden has production proven expertise in supplying precision motion systems with demanding specifications in hostile environments that can be custom tailored to meet the most stringent requirements.
