Lubrication

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Lubrication is important aspect of every CNC machine and the RepRap is no exception. Proper lubrication will make your machine run smoothly, will suppress or even remove ugly noises and reduce wear and tear of your components.

Lubrication

The main parts of the RepRap machine that need to be lubricated are:

  • Threaded Rod + Nut
  • Bearings
  • Sliders

Threaded Rod + Nut

Both Darwin and Mendel RepRap models have multiple Z-stage drives constructed using threaded rod and a nut, though some experimental or RepStrap machines use only one. There are RepRap clones that have X and Y also made with threaded rod and a nut. Friction between nut and threaded rod, especially under the load of the Z platform in Darwin based models is huge and if not lubricated the Z-Stage will produce ugly squeaking sounds and rub off metal powder, and soon your threaded rods will show signs of wear and tear (especially if you use a lot of Z-Motion). Properly lubricating the rods will reduce the wear and tear on the rods (not to mention reducing the ugly sounds). So far, high viscosity PTFE filled oil (super-lube for example) shown best results here.

Bearings

There are two major types of bearings found in RepRap machines.

  • Roller bearings
  • Linear bearings

Roll bearings

These bearings are usually closed and have their own lubrication, so no additional lubrication is needed.

Linear bearings

Linear Bearings come in open and close package. The closed ones have their own lubrication and no additional lubrication is needed while open ones need additional lubrication. high-viscosity PTFE filled oil (super-lube) for example shown best results here. Synthetic Gear Oil also shown very good results.

Sliders

Depending on the type of a slider (PLA on Chrome, PTFE on Chrome, ABS on Chrome ..) you will need to find appropriate lubricant. Note that some oils do not interact well with some plastics. In most cases when using PTFE on Chrome no lubrication is needed but some PTFE filled oil will help a bit especially if you use PTFE inserts for X or Y movement. Multipurpose grease also shown nice results.

Less Successful Lubricants

  • WD40 is possibly the worst lubricant, tested on a Darwin based RepRap rapman. It "ate up" the Z threaded rods and produced huge amounts of ugly black gunk that was impossible to remove while not improving Z movement at all.
  • Light oil reduced the sqeeking sound but did not really help with friction and on the sliders it even increased friction (by attracting dust and creating sticky surface on the slider rod). CupCakeStrap has used light machine oil for the linear rails, which are aluminum rod and brass tube "brushings." The oil worked very very well, but over a one-month period the oil formed some black gunk, and much of it leaked down from the rails onto the acrylic X stage, lightly discoloring it. The gunk is easily removed, but doing so dries out the rail.
  • Silicone grease that is often used with RepRap is actually meant to be used with rubber gaskets, o-rings and similar equipment. It is not "bad" and some users report good results with it. There is also silicone grease with PTFE that is reported to work well.