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Special Feature: PMI Linear Bearing Units – Part 2


The MSA Series is a category of linear guideways manufactured by PMI Linear Motion Systems (previously AMT-PMI Linear Bearings).  These particular linear guideways are renowned for achieving a balanced pre-load which helps increase their rigidity in four directions while crucially maintaining a low frictional resistance.

The MSA Series such as the models described in greater detail below are particularly suited to operations requiring high precision and high rigidity.

PMI Linear Guideway: MSA15SSSFCN 

These particular models in the MSA Series feature a square flange, which has a smaller width than some of the other flange types that provides the option of it being installed at the top of the carriage. This linear ball bearing unit also features three seal types: one bi-directional seal, a bottom seal and an inner seal. As the smallest of the MSA Series of linear guideways, the MSA15SSSFCN is the lightest of the group, while all of these PMI bearing units use a rolling motion that produces very low amounts of friction. Thanks to the extremely low amounts of friction, the problem of ‘stick-slipping’ is no longer an issue even when being fed submicron loads.

Technical Specifications:

  • Model No. MSA15SSSFCN 
  • Outer Diameter: 47mm
  • Width: 24mm
  • Weight: 180g (0.40lbs)

PMI Linear Guideway: MSA20SSSFCN 

The MSA20SSSFCN is the second smallest of the MSA Series, weighing just 0.3kg while still being able to handle a light preload. Again, the three seals are present (bi-directional, bottom and inner), while the square flange gives its potential positioning some versatility. The low frictional resistance experienced by the MSA Series of PMI-AMT linear guideways means each of the models described here enjoy a high positioning accuracy as well as high repeatability.

Technical Specifications:

  • Model No. MSA20SSSFCN 
  • Outer Diameter: 44mm
  • Width: 30mm
  • Weight: 300g (0.66lbs)

PMI Linear Guideway: MSA25SSSFCN 

As well as the square flange and three seals which afford these linear bearing units positional versatility and operational reliability, the MSA25SSSFCN and its fellow MSA Series guideways are primed for extended periods of constant operation. They can be utilised for long periods without the need for any downtime, in part thanks to the grease nipple on the carriage which enables industrial machinery lubrication to be added either manually or automatically without shutting the operation down.

Technical Specifications:

  • Model No. MSA25SSSFCN 
  • Outer Diameter: 48mm
  • Width: 40mm
  • Weight: 520g (1.15lbs)

PMI Linear Guideway: MSA30SSSFCN 

As the largest of the MSA Series, the MSA30SSSFCN can handle the heaviest loads, while its own weight still comes in at well under a kilogram. It features the same versatile square flange that the smaller PMI-AMT linear guideways benefit from, as well as the bi-directional seal, bottom seal and inner seal which help keep it all in good working order even during constant operation.

Technical Specifications:

  • Model No. MSA30SSSFCN 
  • Outer Diameter: 60mm
  • Width: 45mm
  • Weight: 860g (1.9lbs)

If you require any PMI linear bearing units such as the MSA15SSSFCN, MSA20SSSFCN , MSA25SSSFCN  or the MSA30SSSFCN , then contact YB Components who are the UK’s leading linear guideway suppliers who can ship these parts all over the world.