Ultraviolet

Manual mechanical assemblies, such as mirror mounts and lens positioners, have relatively simple standards to meet UV requirements.  Un-anodized aluminum or stainless steel are preferred base materials, and aluminum is the best choice for cost effective manufacturing processes.  Within these assemblies, brass bushings and stainless steel adjustment screws require the use of low vapor pressure (LVP) lubricants.  For their adjustment screws and sliding surfaces, Siskiyou usually recommends the use of
Krytox®  LVP or Tribolube®-15.  Both of these lubricants are industry standards for UV or high vacuum applications.  Depending on the application and mechanical design, and unless otherwise specified by the customer, we will recommend the best choice of lubricant for long term performance of the specific mechanical assembly.

Motorized mechanical assemblies for UV applications differ from manual assemblies only in the electronic wiring and motor requirements, but they are similar in other aspects.  Therefore, LVP lubricants are required for motor gear heads, lead screws and bearing ways.  Our standard DC servo motor gear heads use a lubricant with a vapor pressure of less than 0.1 mbar at 20°C (0.075 Torr, .00145 psi or 9.9x10-5 atm).  This is not an extreme high vacuum lubricant, but it does perform well at ambient temperatures under atmospheric pressures with no risk of out-gassing.

The ability to use our stock motor for UV applications saves time and money. There is no longer a need to purchase motors with special lubricants.  For lead screws and bearing ways we use Krytox® LVP or Tribolube®-15 depending on the application and performance requirements.  The use of plastics is generally not accepted in UV environments, and, for motorized assemblies, there are few exceptions.  Plastic components are acceptable in standard wiring, but only where the wires or electronic components are shielded from the UV light.  For our Motorized drives, we use plastic micro-switches that are housed within a light-tight area of the drive.  For all external wiring, Kapton® coated wire is used.

Vacuum

Mechanical assemblies used in vacuum chambers or launched out of the atmosphere require unique materials and finishes if they are to survive this harsh working environment.  When these devices are used in closed-loop environments, such as a vacuum chamber, the materials must not contaminate the atmosphere or optics in the system.

Manual mechanical assemblies, such as mirror mounts and lens positioners, have relatively simple standards to meet vacuum compatibility (VC) requirements.  Un-anodized aluminum or stainless steel are preferred base materials, and aluminum is the best choice for cost effective manufacturing processes.  Within these assemblies, the use of brass or plastic is not acceptable due to their oxidization, their source of virtual leaks and high temperature instability in which a system bake-out of 350°C is required.  All blind holes must be vented to ensure maximum flow during pump-down of the vacuum system.  To achieve this, tapped holes are drilled through and ball pockets are drilled from the opposite side.

Depending on the pressure of the system, low vapor pressure lubricants must be used on adjustment screws, bearings and sliding surfaces.  For systems at or around 1x10-6 Torr, Apiezon® or Krytox® LVP are both acceptable lubricants.  For high or ultrahigh vacuum systems reaching 1x10-12 Torr or better we recommend Tribolube®-15.

Motorized mechanical assemblies for vacuum applications differ from manual assemblies only in the electronic wiring and motor requirements, but are similar in other aspects.  Therefore, LVP lubricants are required for motor gear heads, lead screws, and bearing ways.  Our standard DC servo motor gear heads use a lubricant with a vapor pressure of less than 0.1 mbar at 20°C.  However, this lubricant is not acceptable at pressure ratings below 1x10-3 Torr.

Per special order, Siskiyou can supply motor drives with vacuum compatible prepped motors which will operate at 1x10-6 Torr.  These motor drives are manufactured with low vapor pressure lubricant in the gear head and a Teflon® ribbon cable for the electronic interface to the chamber feed through.  Vacuum compatible stepper motors are also available on request.