G0678 CNC Conversion Build Log

This forum is dedicated to those Hobbyists Interested in CNC machining in their home shops. (Digital Read Outs are also topical, as is CAD/CAM as it relates to CNC)

Moderator: Harold_V

User avatar
Dave_C
Posts: 943
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.
Attachments
1226171853.jpg
I learn something new every day! Problem is I forget two.

User avatar
Dave_C
Posts: 943
Joined: Mon Apr 21, 2008 10:34 am
Location: Springfield. MO.

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.
Attachments
0110181459.jpg
0110181459a.jpg
I learn something new every day! Problem is I forget two.

User avatar
Dave_C
Posts: 943
Joined: Mon Apr 21, 2008 10:34 am
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.

User avatar
ctwo
Posts: 2653
Joined: Tue Mar 27, 2012 12:37 pm
Location: Silly Cone Valley

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...

User avatar
Dave_C
Posts: 943
Joined: Mon Apr 21, 2008 10:34 am
Location: Springfield. MO.

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.

User avatar
Dave_C
Posts: 943
Joined: Mon Apr 21, 2008 10:34 am
Location: Springfield. MO.

Re: G0678 CNC Conversion Build Log

Post by Dave_C » Wed Jan 24, 2018 9:14 pm

Progress Report:

I got the saddle mounted tonight and the X axis ball nut mount attached as well. The pocket for the X axis ball nut is .236" deep and this puts the ball screw right back to the original center line height.

The front plate needs the bolts put in and I'll do that tomorrow!

So far so good!
0124181954 (2).jpg
0124181954a (2).jpg
Next will be to cut the X axis ball screw to length, turn the end and re-work the table ends for the bearing mounts. Then I'll be readuy for some teknic Clearpath servos.

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

User avatar
Dave_C
Posts: 943
Joined: Mon Apr 21, 2008 10:34 am
Location: Springfield. MO.

Re: G0678 CNC Conversion Build Log

Post by Dave_C » Thu Jan 25, 2018 12:13 pm

A couple of short videos showing some of the detail involved in getting the X and Y ball nut carriers installed:

https://youtu.be/rzBCprsDj10

https://youtu.be/kHi-lq5O2fE

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

User avatar
Dave_C
Posts: 943
Joined: Mon Apr 21, 2008 10:34 am
Location: Springfield. MO.

Re: G0678 CNC Conversion Build Log

Post by Dave_C » Mon Jan 29, 2018 4:33 pm

Progress Report:

I worked on my X and Y home switches today. I was able to make a "t-nut" type bar that fit in the original Y axis stop bracket. Since this was a nice sturdy bracket I just made a 4" long bar that fit in the slot, put a 1/4-20 set screw on one end and mounted the limit switch on the other end. The set screw lets me make fine adjustments if I need to move the switch. The down rod was already there as it was part of the original stop setup.

The X axis is not in the picture but I got it done later. Real simple, just a Honeywell Micro limit switch, not the cheap one, and it indexes off of the end bell on the table. It is mounted under the saddle but accessible if I need to replace it.

Motors are on order from Teknic along with some other minor stuff like the timing belt and pulleys for the Y axis, motor couplings and spider, X axis motor mount, and I think that will get me finished on the X and Y axis.

So no play until the stuff comes in!
0129181020 (2).jpg
Dave C.
I learn something new every day! Problem is I forget two.

User avatar
Dave_C
Posts: 943
Joined: Mon Apr 21, 2008 10:34 am
Location: Springfield. MO.

Re: G0678 CNC Conversion Build Log

Post by Dave_C » Wed Jan 31, 2018 7:01 pm

Someone asked about the X Axis motor mount. I made short video to show how it mounts over the end of the Thrust bearing.

https://youtu.be/kqLqRvMuCDI

I also have a picture:
0131181401 (2).jpg
Motors are on the way!

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

WJH
Posts: 1375
Joined: Sat Jan 16, 2010 9:29 pm
Location: Florida

Re: G0678 CNC Conversion Build Log

Post by WJH » Mon Feb 05, 2018 6:35 pm

Looking good

User avatar
Dave_C
Posts: 943
Joined: Mon Apr 21, 2008 10:34 am
Location: Springfield. MO.

Re: G0678 CNC Conversion Build Log

Post by Dave_C » Tue Feb 06, 2018 11:31 am

Progress Report:

The Clearpath motors came in yesterday and I got two of them mounted. I still need the trim washers under the bolts but this is how it mounts. Today I will start the tuning process on the Y axis. The X axis will have to wait until I get the right coupler. I had ordered a 30 size coupler and it is too short. I ordered the next larger size last night. (40 MM size)

You'll notice the green chip catcher pan looks like it will hit the Y axis motor if I lower the knee all the way down. Well yes it would but the front part of that green tray comes out. It was made that way by Grizzly but Grizzly installed it with the removable part at the back. I just turned it around!


I cropped the pictured to fit on this siteso you may not be able to see the green pan.

Dave C.
Attachments
0206180924.jpg
X axis Motor
0206180925 (2).jpg
I learn something new every day! Problem is I forget two.

User avatar
Dave_C
Posts: 943
Joined: Mon Apr 21, 2008 10:34 am
Location: Springfield. MO.

Re: G0678 CNC Conversion Build Log

Post by Dave_C » Sun Feb 11, 2018 12:47 pm

Progress Report:

I know before I even start to post this it is going to draw some criticism! That's OK because this is just a temporary way to operate the Spindle so I can move on to the Spindle Encoder.

The backlash is .025" and I can overcome that by putting a little pressure on the down feed handle if I need to.

I'm rethinking the Z axis permanent solution and I may put a ball screw under the knee and just lock the spindle in place. That would give me 20" of Z instead of the 4" I have with the spindle now. There is plenty of room under the stand to place the servo!

We will see!

Dave C.
Attachments
0211181110a (2).jpg
I learn something new every day! Problem is I forget two.

Post Reply