G0678 CNC Conversion Build Log

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Dave_C
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Joined: Mon Apr 21, 2008 10:34 am
Location: Springfield. MO.

Re: G0678 CNC Conversion Build Log

Post by Dave_C » Tue Dec 26, 2017 9:08 pm

k, control panel is just about finished. Acorn is installed, power supplies are all in and almost all wired. I will wire up the last of them as I go through my startup and test procedure.

I got the calibration cable in for the closed loop steppers so the first thing I will do is change the Enable state of the drive enables and the alarm states so they match the acorn board "drive Ok" circuit. I need it to all be normally closed circuits on the alarm states.

Then I will reprogram the drive since I added a braking resistor. I'll need faster accel and de-cell times plus I need to set the drive reset input.

All in all it is going pretty well. Once this is all checked out I will order my ball screws and start making the mounting blocks and some motor plates.

I spend more time waiting on parts to arrive than I do working, but hey, what else is there to do when it is cold outside?

Dave C.
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I learn something new every day! Problem is I forget two.

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Dave_C
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Re: G0678 CNC Conversion Build Log

Post by Dave_C » Wed Jan 10, 2018 4:18 pm

Y axis ball screw came in today so I had to make sure everything was going to fit.

It does! With a .040" gauge block on top of the knee elevation screw, it centers on the existing hole just about perfect. There will be a 1" face plate to attache the thrust bearing and to mount the Teknic clearpath servo below out of the way.

This is the largest ball screw and nut that will fit into this machine, there just isn't any room for anything larger!

So metal is ordered to make the face plate and the ball nut mount. The ball nut mount will attach in the same fashion as the Grizzly lead screw nut did originally. The .749" attaching hole is around 1.000" deep through the middle of the web so that should be study enough to hold this thing in place.

Ball nut mount is drawn, just waiting on the delivery!

Dave C.

P.S. I changed from closed loop steppers to Teknic Clearpath Servos! I had some trouble with a bad motor and I sent them back for a refund.
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0110181459a.jpg
I learn something new every day! Problem is I forget two.

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Dave_C
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Location: Springfield. MO.

Re: G0678 CNC Conversion Build Log

Post by Dave_C » Wed Jan 17, 2018 11:20 am

Progress Report:

It was -5 here yesterday so I spent the day making the ball nut carrier for the Y axis. It doesn't look like all that much but there are three clearance issues. Width of the slot in the table verses the width of the ball nut itself, the knee elevation screw head which ends up being about .040" below the bottom of this nut and then the knee elevation crank assembly itself. The 45 degree chamfers are for clearance on the left side. Right side is just matched for looks!

Three Pics.

First one is the Original Grizzly Lead Screw and Split nut.
0117180948 (2).jpg
The second is the Ball Nut Carrier that I made out of 1018 and it will mount just like the original.
0117180948a (2).jpg
The third pic is of the new ball screw and the carrier (less the mounting screws)
0117180949 (2).jpg
Next is to make the front plate that mounts the thrust bearing and the servo motor.

Dave C.
I learn something new every day! Problem is I forget two.

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ctwo
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Re: G0678 CNC Conversion Build Log

Post by ctwo » Wed Jan 17, 2018 4:39 pm

Oh, there's a page two!
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...

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Dave_C
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Re: G0678 CNC Conversion Build Log

Post by Dave_C » Fri Jan 19, 2018 11:09 am

More work:

I've been working on the front plate making a recess for the NEMA 34 Servo to mount on the backside. .600" deep pocket, 4 motor bolt slots, one motor shaft slot and a pocket for the nose of the motor "pilot" to fit into.

Then some cuts on top to match the contour of the mill knee and a pocket .325" deep for the thrust bearing to sit down in. This give me a better shot at alignment with the servo motor pulley. If you've never done one of these that may not make any sense, but once you see it finished you'll get the idea.

I still have some bolt holes to drill for the plate to mount to the knee but that will come later once I make the final alignment of the ball screw setup.
0119180933 (2).jpg
Front Plate
0119180933a (2).jpg
Showing bearing pocket
Dave C.
I learn something new every day! Problem is I forget two.

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