Linear bearing life expentancy

After a print failed with Y slippage I observed that the linear bearings on the carriage had become quite loose and one produced a grinding sound.
The one that seems deteriorated the most is the one that sits alone. Fortunately I capriciously ordered some spare bearings last week so should have it up and running in a few days when they arrive.
I have been running the machine for about a year now and have gone through around 25kg of filament. I was wondering what others had experienced as the general lifetime for linear bearings. I have been using light machine oil for lubrication. Would bronze bushings have a longer life? Or upsizing the linear bearings? Perhaps 4 bearings would work better?

Edited 1 time(s). Last edit at 06/13/2014 03:30PM by Ralph.Hilton.

I swapped the bearings around putting the best one on its own and it is running again.

I ran my sturdy with LM10UU continuously for a couple of years before they wore out.

I estimate my dibond kit model, which has been printing about 1/3 of all the kits we ship must have printed about 100 kg over 18 months. The bearings are still fine and I have only oiled them once or twice.

The problem with bushings is they need to have some clearance or they would seize, so they have some play from day 1. Linear bearings have no play until they wear out because they have pre-load. I.e. the space between the balls is slightly smaller than the rod, so inserting it stretches the outer metal cylinder slightly. The down side is friction and noise.

I can't imagine 4 lasting any more the 4/3 times the time 3 would last and possibly less as it is then over constrained, which may cause more wear.

Edited 1 time(s). Last edit at 06/13/2014 05:47PM by nophead.

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[www.hydraraptor.blogspot.com]

Hi,

I had to change a bearing of my X carriage about 2 months ago. Now one of the Y carriage bearing seems to be damaged (grinding sound).

I have been running my machine for less than a year, and I do not think I printed more than 20kg...

However I do not remember having put oil at any moment... Other than that, is any preventive maintenance advised ?

An occasional drop of oil on the bars and leadscrews. Grease on the extruder gears.

I occasionally have to replace extruder gears and the idler block as they do wear out.

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[www.hydraraptor.blogspot.com]