Spindle Encoder Mechanical Connection

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DLAM
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Spindle Encoder Mechanical Connection

Post by DLAM »

I am wanting to add a spindle encoder to my Vectrax Knee mill. The mill is a 3 axis mill with a Allin1DC Board running CNC11. The previous owners that did the install never added a spindle encoder or have the spindle motor control by Centroid. I am looking for a method to add the encoder so that I can have the spindle motor controlled by Centroid.
I can easily add the encoder to the bottom end of the motor shaft. This would be the easiest way, but have a couple concerns. The motor pulley is 6” and the spindle pulley is 4”, so the spindle RPM and Motor RPM are different. Is there a place in the software to accommodate for this? Is there any concern about belt slipping? I have been taught that the Encoder should be driven at 1:1 from the spindle.
I thought about adding the encoder deep in the head but have concerns about space. The pulley that would have to go on the spindle would have to large to fit on the end of spindle. This would mean the pulley on the Encoder would have to be large as well to maintain a 1:1 ratio. Also getting everything in there.
I eventually want to upgrade to CNC12 with rigid tapping, nut getting the spindle encoder installed and spindle under Centroid control is the first step.
I am looking for any feedback and options from any one that has been across this bridge in the past.
Thank you on Advance
tblough
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Re: Spindle Encoder Mechanical Connection

Post by tblough »

Here's how I did it: viewtopic.php?f=64&t=1944&hilit=bridgep ... le+encoder

It's not an easy job, but it works in direct drive and back gear.

Just to clarify, a spindle encoder is not needed for spindle control. Spindle speed control requires a VFD that will accept a 0-10V input for speed. The encoder DOES NOT provide speed feedback, it is only used to coordinate movement between the spindle snd Z axis.

If the encoder is not connected 1:1 with the spindle, you'll still be able to implement tapping, but you will not be able to peck tap.
Cheers,

Tom
Confidence is the feeling you have before you fully understand the situation.
I have CDO. It's like OCD, but the letters are where they should be.
DLAM
Posts: 128
Joined: Thu Nov 22, 2018 6:27 pm
Acorn CNC Controller: Yes
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CNC12: Yes
CNC11: Yes
CPU10 or CPU7: No
CNC Control System Serial Number: none

Re: Spindle Encoder Mechanical Connection

Post by DLAM »

Tom, Thanks for link on how you did things. I dont know if I want to go that deep into the head to add an encoder. I have more room in that VECTRAX Head than I do in my Bridgeport head. I was hoping to add the encoder into the housing where the pulley is. But I do have other option if that is not feasible. Thanks again.
martyscncgarage
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Re: Spindle Encoder Mechanical Connection

Post by martyscncgarage »

The only thing the encoder will get you is Rigid Tapping. Is that what you are after? Or just having the control manage spindle speed? (Tom provided the same observation)
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ
martyscncgarage
Posts: 9140
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Re: Spindle Encoder Mechanical Connection

Post by martyscncgarage »

Also Google search Elrod rigid tapping. While it is no longer sold, might give you some ideas.
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ
DLAM
Posts: 128
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Re: Spindle Encoder Mechanical Connection

Post by DLAM »

Thank you for the information. I figured since I was going to have the spindle motor controlled by Centroid I might as well add rigid tapping. I am starting to think just have centroid control spindle speed and not worry about an encoder and rigid tapping. A Tapping head on the drill press can save a lot of down time for the upgrade and aggravation.
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