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CBN grinding wheel in DMU50 Ecoline

johnnski

Plastic
Joined
Sep 19, 2023
Hi all, i have been looking at DMG Mori Seiki DMU50 Ecoline 5-Axis CNC Milling Machine with a view to having a CBN grinding wheel mounted on the spindle to grind 600 x 45 degree splines on the surface of a 500 diameter disc.
I have not been able to find anyone who is willing to tell me if this can or cannot be done, this is why I am reaching out to a world wide community for any information.

Look forward to any and all help.

Thanks,
Johnnski
 
You will find you get more input, sooner, if you have a more descriptive title. Your title means nothing to most people here and being busy, people won't bother to read further. Include an abbreviated description of what you seek or even what machine you seek it on. Then people that have experience with that will be more inclined to read further.
 
It's certainly possible if the machine is in good condition, i.e. low runout and vibration. The required wheel RPM would be well under the the max RPM of the spindle, and this isn't a high hp, high rigidity application.

The consideration of grit in a machining center is always there, although any superabrasive like CBN generally loses much less grit than a typical friable wheel.

That said, when a superabrasive wheel loads up, rather than hitting it with a diamond dresser, you hit it with an aluminum oxide "white stick". The sacrificial white stick breaks down extremely quickly, and that frees up a ton of grit that you won't want inside your machine, so do it offline, like in a manual lathe @ 1000 RPM, or whatever's appropriate for your CBN wheel diameter. 1000 is sufficient for a 4 or 5 inch wheel.

Truing the wheel is a different story. That requires spinning a green wheel against the CBN wheel. You could outsource this. Or you could not do it all. Depends on the tolerances you're after. Some arbor + wheel combinations runout a couple tenths straight out of the box. Some runout a few thou. Either way, the corners of the wheel will round out over time. If you need sharp corners on the wheel, you'll need to true it.

As for the thread title, yes get that edited asap to prevent the thread from getting locked. E.g., "CBN grinding wheel in DMU50 Ecoline?".
 
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Hi, thanks for your input on the thread title. I am lead to believe that you can run a light mineral oil when cutting this should prevent the wheel from clogging up thus reducing the need to dress with the white stick. there may need to be a change in the filtration system to remove the very small particles form the oil.
What you have written is very positive and thank you as this will drive me on to get a resolution.
 
If you use a DMG that is setup with the "Ultrasonic" package it will have everything required to handle the abrasives as the ultrasonic process is like a grinding process and it can handle machining carbides and ceramics. The one unit I have has a centrifuge built into the coolant tank for this type of use.
 
The machine will handle it fine, but it is protected for metal chips, not for grinding fines. I assume the wheel will spray the grinding fines everywhere so protecting the machine for what it was never ment to be exposed to will be a challenge. I would also assume you would want/need sub-micron filtering, which will narrow down what you can use for coolant. Then there is getting the coolant exactly where it needs to be, at high pressure.
 
Please excuse response times and things that i have set out in my thread, I am new to any type of forum and have no complaints on any advise good or bad.
It is great that people take time out to help others so Thank You Alll.
 
What type of wheels are you thinking of, resin bond or plated? Have you asked DMG if they have a grinding package for said machine?

I machined stone, quartz, and ceramics for 18 years on a VMC so have some experience. Grinding is certainly different with a lot more cutting forces. Getting the most coolant directed exactly where you need it is critical to increasing feeds and reducing wheel wear.
 
Thanks for all your input, it is a resin bond wheel of 200 diameter x 15mm wide on a 45 degree outer section cutting on the hypotenuse face(2.61mm(O/D 500mm) at the deepest running smaller to the centre to 1mm of depth) and probably running around 3000 to 3500rpm. See Image attached.
 

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