A manufacturer of diamond cutting tools for ultra-precision and optical manufacturing applications was having lubrication issues with leads screws in their custom-built cutting machines. The screw drive system controls the device table so a smooth movement is crucial. The competitor grease was not performing well, there was a ‘stick-slip’ issue with the lead screw making it difficult to precisely locate the cutting head.

The competitor grease was not suitable for precision lead screw lubrication and was negatively affecting the cutting tool performance.

The competitor grease would also “gum up” after a few weeks, indicating there was a probably a high level of oil separation which contributed towards a relatively short functional life for the lubricant. The lead screw did not experience any extreme temperatures.

Challenges

The chosen grease needed to ensure precision control of the system via the smooth operation of the lead screw and associated mounting table. Also, the chosen lubricant needed to prevent wear and improve the functional life of the device.

Proposed Solution

  • A light viscosity synthetic grease to ensure smooth movement of the screw drive system.
  • A Polyalphaolefin (PAO) based grease with a clay thickener system to help with shear stability.
  • PTFE fortification of the grease to enhance the lubricity of the formula, helping to ensure a smooth operation.
  • A grease with minimal oil separation characteristics as the lead screw is suspended/not enclosed.

Product Selection

Rheolube 733F

Applying The Grease

A thin coating of the Rheolube 733F is applied along the lead screw. Normal operation of the lead screw system ensured that the grease was well distributed along the thread.

Results

The Rheolube 733F made a huge positive improvement to the overall performance of the cutting units. Replacing the competitor grease with 733F eliminated the ‘stick-slip’ issue so there was a more accurate control of the mounting table. At the time of creating this case study, the 733F had been applied for one year with the screw drive system still operating correctly.

The customer decided that 733F would be applied to all versions of the other cutting/grinding machinery where a lead screw system was used.

Rheolube 733F improved lead screw perFormance, reliability and the positioning accuracy of screw drive system/mounting table.

Related: Our linear guide lubrication overview (vacuum and cleanroom focused and we recommend you view our other case studies.

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