Encoder Installation on PM-25MV Mill

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martyscncgarage
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Re: Encoder Installation on PM-25MV Mill

Post by martyscncgarage »

Dave_C wrote: Wed Jun 17, 2020 11:12 am
TCandee wrote: Wed Jun 17, 2020 9:38 am Been using it for quite awhile. Really only using the encoder for rigid tapping which is pretty low rpm. Like I said, the very low resistance along with a high coefficient of friction between the aluminum pulleys and the polyurethane belt is working great.
I know most encoder specs say not to side load the encoder bearing and that is why you see most encoders on a mount that has a shaft and some bearings. I can't tell but yours might be a little more robust and can handle the side load. IF not, it won't last very long.

Dave C.
Very true Dave.
Automation Direct.com Medium Duty Differential Encoders:
https://www.automationdirect.com/adc/sh ... 22&start=0
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Re: Encoder Installation on PM-25MV Mill

Post by TCandee »

I also did look into that and did buy a “medium duty” unit. We will see. Wouldn’t be that hard to add some lateral support. Thanks
Dave_C
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Re: Encoder Installation on PM-25MV Mill

Post by Dave_C »

TCandee wrote: Wed Jun 17, 2020 11:26 am I also did look into that and did buy a “medium duty” unit. We will see. Wouldn’t be that hard to add some lateral support. Thanks
Just an FYI: I only mention it so when other DIY guys want to mount an encoder they won't just buy the light duty one and then mount it as you did.

I like the simplicity of your install, I did both of mine with timing pulleys, bearings and shop made mounts. Lots of work but once done it should last the life of the machine.

Dave C.
Grizzly G0678 Mill ,CNC conversion with Acorn. G4004G Lathe, Mach 3 conversion to Acorn.
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Re: Encoder Installation on PM-25MV Mill

Post by nicolasjolliet »

I’m following your thread, as I’m planning to do the same on my taig mill and lathe.
Now I know what type of encoder I need To get and am looking at a medium duty koyo encoder at automationdirect.
Looking at the maximum rpm I see that the medium duty will take 3000 rpm, and the light duty 5000 rpm.
My problem is that my spindle motors goes up to 6500rpm and was hoping to go up to 10000rpm on the spindle.
Can one push these koyo encoders way above 3000rpm?
I can’t seem to find high rpm encoders.
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Re: Encoder Installation on PM-25MV Mill

Post by martyscncgarage »

nicolasjolliet wrote: Sat Jul 11, 2020 4:13 pm I’m following your thread, as I’m planning to do the same on my taig mill and lathe.
Now I know what type of encoder I need To get and am looking at a medium duty koyo encoder at automationdirect.
Looking at the maximum rpm I see that the medium duty will take 3000 rpm, and the light duty 5000 rpm.
My problem is that my spindle motors goes up to 6500rpm and was hoping to go up to 10000rpm on the spindle.
Can one push these koyo encoders way above 3000rpm?
I can’t seem to find high rpm encoders.
Encoders get expensive when you are asking for a high rpm encoder.
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TCandee
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Re: Encoder Installation on PM-25MV Mill

Post by TCandee »

I am not familiar with the reasons for the rpm limitations. Could just be that this is
one way they get the “medium duty” rating. It also could be that the actual sensing part of the different duty encoders is identical and only the bearings are upgraded. Only during rigid tapping. I push mine to 6000 but the acorn isn’t really using the encoder on a mill at those rpms. Only with rigid tapping.

I use the same encoder on my lathe but it Max’s out at 3000. I would look into others that have higher ratings but be prepared to spend 2-4 times as much.
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Re: Encoder Installation on PM-25MV Mill

Post by carbuthn »

Nicolas,
I am using a light duty from Automation Direct that is rated for 4800 rpm, but my mill tops out at 2500 rpm (at least currently).

My guess is that the speed rating is a function of the electronics ability to read the pulses without missing any.

I would suggest that you ask AutomationDirect or see if they can check with the manufacturer of the encoder to see if the limit is the electronics or the bearings and construction materials.

My encoder seems to be working correctly, but have not done any tapping yet. Still running milling and drilling cycles.

Also trying to figure out the inches per minute, depth of cut and depth per tooth that I can use on the PM25 without breaking tools (2 so far, one from not clearing a hold down screw the other not having the set screw tight enough so that it sucked the end mill out of the TTS holder). Live and buy replacements tools. :geek:

Maybe someone that has a high speed spindle can tell you what is on there machine.
Chuck
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Re: Encoder Installation on PM-25MV Mill

Post by martyscncgarage »

Chuck, you are correct about encoder electronics.
Tapping not an issue. You usually Tap under 1krpm.

The encoder provides rpm feedback for constant surface speed and feed per revolution on a lathe and an encoder pulse for threading/tapping

The question is what is hoped to be accomplished with the encoder at high RPM and if it's worth the cost.
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Re: Encoder Installation on PM-25MV Mill

Post by tblough »

US digital has some "light duty" encoders rated to 10K rpm. https://www.usdigital.com/products/encoders Don't know if I'd trust them on a spindle. Their industrial encoders only go to 6K. RS Pro (Allied Electric house brand) has one rated to 10K, but none in stock. https://www.alliedelec.com/product/rs-p ... /70653829/

Hengstler makes some that will go 10K plus:
https://www.hengstler.de/en/s_c100302/R ... _encoders/

Here's one from Newall rated to 12K:
http://www.newall.com/products/?name=Ro ... &catid=131

And then there are the component encoders like RLS makes that are mechanically limited only by your mounting choice. If your spindle is rated to 10K and you can mount the magnetic ring to it somehow, then you are golden.
https://www.rls.si/eng/products/rotary- ... ic-encoder

For any of these encoders, make sure you don't exceed the electrical bandwidth of the encoder or the Acorn at 10K rpm.
Cheers,

Tom
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I have CDO. It's like OCD, but the letters are where they should be.
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Re: Encoder Installation on PM-25MV Mill

Post by carbuthn »

Thanks Tom, electrical bandwidth is the term I could not remember, Old Timers disease, I guess.
Chuck
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