Reply with QuoteWell done on the detailed description. I'm sure someone will find it very useful.
(Solution) if you own a cnc 3018 and the spindle mount has play in it
i bought one of these machines and after a couple of weeks my spindle mount (Z axis) had over 3mm of play in it. here's how i solved it.
First take the motor out, followed by the whole z axis mount complete (easiest to leave the lead screw in it as it won't get in the way)
ok with the whole z axis on your bench undo the z axis lead screw collar that attaches the servo to the lead screw and remove it followed by the four machine screws on the z axis servo and carefully lift it off.
now look on the bottom of the mount and you will see two small cross head machine screws holding the 8mm slide rails, take out the two screws.
now look under the four cream coloured spacers where the servo attached and you will see four recessed pozi head machine screws (to make life easier i bent at right angle an old slim pozi screwdriver to make undo these easier)
you only need to unscrew three of these as the servo mount can be turned so that you can slide the 8mm rails out, now unscrew the z axis lead screw if not done already.
you should now be able to remove the separate spindle/motor housing which has two cheap and nasty linear bearings in each side (8MM x 15MM x 24MM) these are way too short and allows for rapid wear due to the stress they take. now the depth of the holes where the linear bearings are located are actually 35MM.
carefully tap or press out the old linear bearings.
now with two plain holes waiting for new linear bearings you will want to get hold of 4 of this size 8MM x 15MM x 17MM (two for each side =34MM.
once you have your nice new 17MM long linear bearings go ahead and tap one in each end of the motor housing rail holes.
once the new bearings are fitted have a look on the top where the z axis lead screw would pass through and you will notice a circular recess 8MM X 15MM
I put three M8 steel washers in one at a time and super glued each one in while periodically inserting a piece of 8MM bar to keep the washers central until the superglue set. you will notice that the last washer you put in is perfectly flush with the mount surface and to make sure the washers never came out i screwed down a M5 steel washer so the it overlapped the M8 washer keeping it covered and secure..
now that's all done go ahead and put back the motor housing and slide the 8MM rails back in and secure with the screws you removed, then line up the servo mount and tighten the recessed pozi screws and check the cream pillars to make sure they don't spin and is tight, attach the servo motor and tighten the 4 machine screws.
put the z axis lead screw back in only far enough so you can attach the servo to lead screw aluminium collar and secure it via the tiny grub screws.
now go ahead and put the whole axis back on the machine and re align those rails. once all the rails are aligned and both X and Z axis are working ok go ahead and grab hold of the mount and see if there is any play in it....i guarantee you it will be solid with zero movement ........happy days
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Re: (Solution) if you own a cnc 3018 and the spindle mount has play in it
Well done on the detailed description. I'm sure someone will find it very useful.
Re: (Solution) if you own a cnc 3018 and the spindle mount has play in it
What exactly does the insertion of the three M8 steel washers into the Z axis where the lead screw passes through achieve? Surely the lead screw is held centrally by the stepper coupling?
Not quite sure why this has been mentioned. Anyone else curious as well?
I have ordered the bearings as mentioned above, mainly to reduce excessive vibration through the Z axis while actually cutting, play is not an issue on mine at all!
All good info though - and I am also going to replace the Y axis bearings with the Igus equivalent as well.
Re: (Solution) if you own a cnc 3018 and the spindle mount has play in it
OK guys, I have now replaced all the bearings including those on the Y axis as well as the Z. The transformation is almost startling!. The whole machine is far quieter than it has ever been - and movement is as smooth as silk.
Play anywhere on the Y and Z axes is just non-existent now, and my next job is to replace the Y axis bearings as well (I did order enough to replace all of them at the time).
Very successful update - but I still fail to see the purpose of glueing in the washers as suggested by the original poster, and I can't really see the resoning behind the suggestion?
Anyone have any ideas why this was done?
Re: (Solution) if you own a cnc 3018 and the spindle mount has play in it
the purpose of the M8 washers are to eliminate any movement from the lead screw which passes through as the bearing and shaft collar alone is simply not strong enough to stop any movement, plus the lead screw shaft collar has socket set screws holding it on they sometimes will screw into the internal pitch of the lead screw resulting in poor alignment. hope that clears it up for everyone.
Originally Posted by willower
Re: (Solution) if you own a cnc 3018 and the spindle mount has play in it
Being an owner of the same machine, I was looking into ways of improving it and I came across this thread... so why not do a little necro.
This whole upgrade seems interesting, but I'm curious as to what bearings did you guys use? Looking around the shops in my area, I feel there's a high chance of ordering the same bearings as the machine originally came with.
On top of that, I was looking into the whole M8 washer idea and I noticed there's a second hole in the bottom of the X axis carriage, through which the Z axis lead screw goes through. I think we could fit another bearing in there which would improve things.
However, looking at it now, my biggest problem is flex on the Z axis due to elasticity in the guiding rails and X axis lead screw. I can easily push the whole spindle holder up 2-3mm and I see the rails flex. Any ideas on fixing this?
