Anyone tore into a MSY live tool drive motor?

[Skubeesnak]

I recently had the splined drive shaft on a 250 MSY live tool motor snap in half. As long as I have worked on this machine the live tooling rattled way more than on other live tool lathes I have ran. My dilemma at the moment is replacing the whole motor drive at a price of about 6gs, or tearing down and replacing the splined shaft at about 2gs. Keep in mind this cost is just for parts. I cannot imagine this repair to be as complicated as a main lathe or mill spindle but idk? Any thoughts? I appreciate any input given.

 

[noname777]

just shaft, and few bearings around it. U can do it yourself. a day work. I can show u on the pictures what u need to replace to rebuild it. An also tell u why they rattle. Save money. Spend them on beautiful women, buy them pizza and white wine . They deserve it =)

 

[noname777]

to do it properly is to replace all bearings. They dont cost a lot but at least you know that they are new. Positions 1,2,3 probably you gonna have to replace in any case.

and there is one funny spacer that needs to be replaced as well, as it gets damaged a lot. Position 6.

Now, what is important here is what I marked as number 4. That is a wrong way to preload this set of bearings as once you assemble everything and start to align mill drive shaft ( moving it in and out) , you will definitely loose bearings preload, as under 4 way of preloading, inner runners create preload.

If you swap them around and assemble the way I circled as number 5, than they will be preloaded with two outter runners. That is how I done it few times and all is okay, mill drives still going good.

any ways, not a big job, make sure you position turret at the position where u have access from behind and also u can remove milling drive from the front of it.

 

[Skubeesnak]

Those pics look like the previous generation drive motor, Where the motor is driven with a shaft thru the turret with belt. The drive on this is a direct drive.

 

[noname777]

that is new. Never seen this one before. I know DMG uses direct drive motors. Sure there must be a way to replace the shaft only. How does drawing look like?

 

[Skubeesnak]

Pretty similar. i don't have in pdf but can take a pic on Monday and show you then.

 

[noname777]

ok

 

[Skubeesnak]

Here are a couple of snaps of parts book. Im probably wrong because the parts look pretty close. I was going by what service guy told me.

 

[Skubeesnak]

 

[cnctoolcat]

Direct drive in this Mazak sense is different from the DMGMori direct drive. The DMG has the motor actually inside the rotating part of the turret, with no 90-degree coupling.

Mazak's direct drive has the main turret shaft as the motor shaft as shown (not belt driven), with the motor still inside the turret box and parallel to the lathe's Z axis, so the live tool-drive must have the 90 degree coupling.

It's not that bad to take apart, I would tackle it myself if you're handy with a wrench...

ToolCat

 

[noname777]

this is not a DIRECT drive, you still have similar design and mill drive is driven by outside motor through belt connection. And it has exactly the same issue with bearings preload as I mentioned before. Just replace the shaft the way I was trying to explain before.

in your case u have a separate servo motor to rotate a turret and mill drive for milling. I guess it was easier for Mazaky to separate tool change and mill drive functions and stop using MDS-B-J ( or whatever they were using ) to switch in between spindle and servo controls. God only knows what and why they do in Japan. I guess they are trying hard to build as robust as possible machines, later in a day wondering why people still using QT with T1 and T2 control. Wonderland indeed.

O yea... I think I know why they changed the design. There was and is an issue on older SQT when mill drive goes into tool change mode, if gears dont mesh properly, MDS drive will report Servo Overload. There is a special way to assemble mill drive on SQT machine and avoid this kind of drama.

 

[Skubeesnak]

Thank you to both of you for your response. I have so much lathe work right now that I have not had a chance to tear it apart. to be honest it has been not the biggest inconvenience for the recent past in the fact that other than additional setup, I can plow through cuts on a mill vs the un-rigid wanna be a real mill live tools. I believe cnctoolcat is correct as well as 777 is less the drive belt yet still the 90 deg shaft through the center of the turret. I have left the decision up to the owner of which way to pursue this. I will let you know what happens. Personally i'm confident I could repair the whole thing including remaking the broken shaft for thousands less.