routercnc_MK3

[routercnc]

One of the ballscrews that I sent away to be straightened was returned some time ago but I've not had much time recently to put it back together (started a post on that subject and will update at some point!). So last weekend I had another session on the machine and took the opportunity whilst refitting the ballscrew to shim both X axis AC bearings and pack in some grease. I also corrected one of the AC bearing pairs which were not face-to-face, but line-astern.

Before the shims were fitted I could grab the ballscrew and move it back and forth ever so slightly, possibly 0.1mm or so, but now it is nice and solid.

I also noticed that the cap head bolts holding the X axis stepper motors on were hard against the laminations of the motor body, preventing the bolts sitting centrally in the mounting hole. This was preventing me from inserting all 4 bolts fully, and putting a twist/offset in the coupling, so I end up drilling out the thread in the mounting bracket to a large clearance hole and using a nut and bolt to secure the motor. The Y axis motor is a different model (but similar spec) and seems to have more clearance for the cap heads and went on without a problem.

After all this work the X axis is now running much more smoothly - a bit more adjustment should have it just right.

With everything looking good I decided to lightly skim the bed frame - see photos below. As my spindle is a 1.5kW model with a maximum collet size of around 6mm it took some time but it's done now.






I've also managed to re-mount the cooling system off the side of the gantry rather than on the Z axis. This was mainly for cosmetic reasons but whilst doing this I had difficulty filling the system and eventually realised that the spindle was blocked. A quick blast of compressed air and all was well. It must have been running like this for some time but I didn't notice the spindle getting warm so I'm clearly not stressing the machine for the little jobs I throw at it. I was going to buy one of those computer water cooling flow indicators (small vaned disc which rotates with the water flow) but noticed that a thin strand of the PTFE tape on the outlet of the spindle connection fluttered about when the pump was started so decided to just look at that instead!

I don't have a detailed photo story of the cooling system relocation but you can see the initial Vs the almost finished layout in these 2 photos:

vs


Now I'm working on replacing the last 2 wooden parts on the machine (Y axis ballnut mounting plate and the Z axis stepper motor plate). The first one should improve Y axis stiffness, and the second one will just make it look nicer.

The other improvement parts in the pipeline are:
Much better Z plate with pockets for the Z ballscrew etc.
Buying one of those SMA50 GUU linear bearings (from Zapp) to convert to an 80mm spindle mount
Long awaited upgrade of the control system to seperate drivers on 60V (from an all-in-one at 27V)

I hope I can stop myself from further upgrades at that point since the machine already cuts through wood, liteply, and balsa with more speed and accuracy than I could ever need. And yet I find myself sketching mk 4 . . . . worrying.

[EddyCurrent]

I also corrected one of the AC bearing pairs which were not face-to-face, but line-astern.

Are you sure you don't mean back-to-back ? see here http://www.mycncuk.com/forums/gantry...html#post56132

Those bearings really do need attention, all the ones I bought had to have the bearings turned, shimmed, and greased.

The cooling system looks far better on the side of the gantry and I like the sound of the cheapo flow indicator.