[enyaw]

Hi,

...I see that you are considering using NEMA 34 motors for your conversion in the 800-900 oz-in range for both X and Y and 1200 oz-in for the Z. Good choices to be sure but going 1200 for all three will simlpify your power supply requirements. Unless, of course, you were planning on powering each motor individually.

My thinking on the X&Y axes goes something like this... I think that the 570 oz NEMA 23s should be enough but I don't want to run axes anywhere near the max (to avoid missed steps). At the same time larger motors mean more inertia so accelerating or decelerating too fast becomes an issue. 800-900 oz motors seemed to give me a comfortable margin. The question I guess is (and thank you for adding another item to my list of things to research 8^), "Which is more of an issue, complicating the power supplies, or additional mass on the X & Y axes motors?"

[andrew2085]

As far as the power supply, you might wanna look at this: HP Compaq 226519 001 3000W 48V Hot Plug Power Supply for BL P Class 253232 001 | eBay. I'm using one for my current build. At 57A it should be able to handle anything you throw at it. You will need to supply 240V to it though. You can also make a minor modification to it that lets you adjust the voltage output from 45V - 53V. I think you could probably run several machines off of this if you ever decided to build another.

[109jb]

As far as the power supply, you might wanna look at this: HP Compaq 226519 001 3000W 48V Hot Plug Power Supply for BL P Class 253232 001 | eBay. I'm using one for my current build. At 57A it should be able to handle anything you throw at it. You will need to supply 240V to it though. You can also make a minor modification to it that lets you adjust the voltage output from 45V - 53V. I think you could probably run several machines off of this if you ever decided to build another.

There are also other options that don't require a 220V supply. I am using a Dell server power supply that is a 110V supply and puts out 48V @ 13.5A, and 12V @ 4A. I bought it for $35 and it has performed flawlessly. Not sure if it would fit your voltage or current requirements, but it sure works well. I have been meaning to post pictures of how to jumper it to turn it on in my G0704 build thread but have not gotten around to it yet. Tonight I will get that done and update here and in my thread.

[Poseidon]

You are right to be concerned about acceleration. However it is of utmost concern only if you want your motors to go from zero to max rpm in an instant. With that goal in mind you may be sorely disappointed at the stand you have purchased as a mill perch. Mach3 can tune motors to accelerate at a different rates and this may mitigate the disadvantages of having the larger motors in your X and Y axes.

As for your power supply considerations, the aforementioned PS units that put out 48v may be a little anemic in powering your Z axis stepper. Most 1200 oz-in motors I know of do perform beautifully with a minimum of 60v and purr at about 72v. My motors can receive a max voltage of 75v but 72v does make it run nicely. Mind you these tests were done while bench testing my electronics. I have yet to mount them on my mill for real work testing.

[enyaw]

The mechanical conversion of all 3 axises is done. Many Thanks to Michael at CNC Fusion.

The control/electrical pieces have been purchased. Here's what I've settled on for Rev. 1.0
1. Grizzly G0720R Mill
2. 5mm ball screws (X,Y, & Z)
3. 75 lb Gas Strut (on Z)

4. 70V 2x10A Kelling Power Supply
5. 12V 3A/5V 6A Power Supply

6. 2x570 oz NEMA 23 steppers for X & Y
7. 906 oz NEMA 34 stepper for Z

8. Re-purposed HP 20" TouchSmart Computer (Win 7)
9. Mach3 (Mach 4 if it comes out soon)

10. Ethernet SmoothSpepper
11. Inexpensive Parallel BOB

Hoping it will be done by Christmas (holding off on specifying year)

[wizard]

Pictures, there must be pictures.

[Poseidon]

The last addition to this thread is almost a year old so I may be writing to an empty room. That said, the conversion of my G0720 to CNC has finally been completed. As soon as I figure out how to attach files to these replies pictures will be added to show the completed mill.

[enyaw]

Interested in seeing your build. Still working on the electronics and electrical...

[Poseidon]

PM me with your email addy, the files are too big for CNCZone. Most of the pictures are from last year but I have cleaned up my mill area recently to give you a better idea of the build. An old PowerMac G5 tower is serving as my electronics enclosure. The wiring is messy but it works for now. Until I generate some income from this build it will stay in the G5 tower.

As soon as I get my tripod back I will shoot some air cutting vids.

BTW, Happy Father's Day to all who read this.

Joe

[Poseidon]

Dug up an old camera and set it for the lowest resolution.

[Poseidon]

A few more...

[enyaw]

After two years I can see the end of the tunnel. Yesterday the wiring of the electrical and electronics were completed (mostly... I hope). Additionally initial movement tests were completed.

What I know that still needs to me done:

• Put electronics in a box
• Wire management for motors and limit switches
• Circuit Breaker for main power
• Main power switch
• Replace toggle switch mounted in inverted yogurt cup w/a proper E-Stop switch

More to come.

[Poseidon]

Few have gone down the road that leads to a CNC'd G0720/R/ SX4. I am truly glad that you are well on the way to completion. Only one other machine, an SX4, have I seen operating under complete CNC control. A CNC Fusion kit was used to make the conversion and a high speed spindle was installed on that machine taking the place of the manual quill feed mechanism.

Velocirex, yet another G0720 CNC conversion aficionado, once asked me how I measured the perpendicularity of my mill's column to its base. I made some generous assumptions about the quality of these mills and it is only of late that I have come to terms with the limitations of its manufacturer. My mill table is not perfectly flat and using a spindle square to determine perpendicularity lead me shim the column needlessly. The table is .0055" high up front and it is bowed up to the left by .00035" and up to the right by .00050". After noting all of these discrepancies I have re- squared my column and it is now square to within .0001" over 6.000". Given the 18.500" total travel of my column a vertical dimension can be as much as .0003" out of measurement. Since I am not building anything that will blaze away into the farthest reaches of space I have accepted this limitation and will endeavour to account for it my CAD/ CAM program. I sincerely hope that your mill is far more accurate than my own.

Congratulations on your progress thus far.

[tectonca]

This is a awesome step by step video on using a Cncfusion kit on the Sieg SX4. Really informative and documented video.

https://youtu.be/jppUu-EZcxY

There is also a 2nd part video on his youtube chanel.

https://youtu.be/s53INL8d9L8




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[Poseidon]

After two years I can see the end of the tunnel. Yesterday the wiring of the electrical and electronics were completed (mostly... I hope). Additionally initial movement tests were completed.

What I know that still needs to me done:

• Put electronics in a box
• Wire management for motors and limit switches
• Circuit Breaker for main power
• Main power switch
• Replace toggle switch mounted in inverted yogurt cup w/a proper E-Stop switch

More to come.

Hi Wayne(enyaw)

How is your build progressing? Have you made a mess with flying chips yet?

[tectonca]

There is also a really good 3D CAD model in step format and also edrawings on GrabCad to freely download.

Good quality model really.

https://grabcad.com/library/sieg-sup...ling-machine-1


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