Mach3 upgrade to Acorn CNC12 project

[cnc4me]

I decided to upgrade my Legacy Explorer II CNC router to Acorn. It was running Mach3 with a Warp9 board. The System is about 8 years old. Legacy Woodworking no longer sells this unit – it was their entry level CNC.

• I’ve had mixed results with this set-up, most of the time it runs OK, but every once in a while it will have a mind of it’s own – not good (like tool touch off).
• I will also occasionally receive “ESS” smooth stepper errors for no apparent reason – and I’ll need to recycle everything and mess up my job.
• In general, the motion appears to be a bit ‘jumpy” – I’m hoping Acorn will smooth that out a bit (especially with smoothing functionality once I figure that out)
• Mach3 has always been a bit of a black box for me. This really became apparent when I recently moved to another laptop.

I was thinking about upgrading to Mach4, but after some research I decided to go with Acorn - so far I’m very happy with that decision. Very cool product. Night and day as compared to Mach3 in a good way.

Here're the details of my current system :

• XYZ and A axis. 2 motors for Y to move the gantry which are wired together.
• I may decide to drop the lathe and use that axis for the 2nd Y motor so I can do auto squaring.
• 5 lead shine DB556 drivers with JKONG stepper motors which I don’t think are so great.
• Lenze VFD with 3hp water cooled spindle which I like.

Here’s my progress to date:

• I used the Leadshine “DM driver series” template for configuration and wiring with DB25 connector. My Mach3 configuration had a kernel setting which was set to 75,000 mhz. I didn’t find a corresponding kernel setting in the Acorn Wizard, but did see the DM series driver template had a step rate which was set to 100,000. I went ahead and changed the step rate setting in the XML to 75,000. Question – are these the same (step rate and kernel setting)? According to the Leadshine driver documentation I would need to re-tune the motors if I changed the kernel setting.
• Removed X motor and successfully tested with ACORN board with above modified setting.
• Connected my VFD to 0-10V H8 output (and a relay - see diagram) and was able to successfully run the spindle. This greatly simplified my spindle setup – allowing me to eliminate existing CNC4PC C6 variable speed control board which used a step and direction to control the spindle – which also used another axis.
• Labeled all wires and removed old warp9 board.
• I plan on replacing the conductive tool touch off with touch off with the following recommended by shawnm https://www.amazon.com/BTER-Automatic-N ... 4534&psc=1 - thanks Shawn!

If all goes well, I may consider replacing the motors with closed loop servos like clearpath, but they are a little pricey for my needs – can anyone recommend a less expensive alternative? If I go ahead with the motor upgrade I may switch the x an y axis to from rack and pinion to ball screw (Z already is ball screw) if I can fit it.

This upgrade is mostly a learning exercise for me, and I have learned a lot, but still a long way to go. I have a 5’ x 10’ CNC router in storage which I will be setting up once I find a location for it. It currently has a Wincnc setup but may consider moving it to Acorn if I run into problems.

Bill

[Gary Campbell]

You can install LeadShine CS series closed loop steppers that will get you the same features as the ClearPaths, but with a bit less torque. Your frame may not be able to put the extra torque to use anyway. The CS drives will fit in the same space as the DM series that you have

Set the pulse rate for those drives to 100kHtz Set DIP switches to 3200 (1/16)

Is there mechanical reduction on the X and Y axes? Pinion (spur) gear tooth count?

You can implement hardware paired autosquare and keep your rotary axis

[cnc4me]

Thanks Gary.

I am set to 3200 and will go back to 100kHtz.

Not sure what you mean by mechanical gear reduction. There are about 26 teeth on the gear and which is just about 1" diameter.

Can you point me to directions for auto squaring with XYZ and A?

[jhnmdahl]

Thanks Gary.

I am set to 3200 and will go back to 100kHtz.

Not sure what you mean by mechanical gear reduction. There are about 26 teeth on the gear and which is just about 1" diameter.

Can you point me to directions for auto squaring with XYZ and A?

4Me, check out this PDF for auto squaring options - https://www.centroidcnc.com/centroid_di ... _guide.pdf

Also, it looks like a correct link for the touchoff tool you're looking at is https://a.co/d/gGiosJf

[Gary Campbell]

Not sure what you mean by mechanical gear reduction. There are about 26 teeth on the gear and which is just about 1" diameter.

Mechanical reduction would be either belt or gear reduction between the motor and pinion gear. Which, by the way, you will need to know the exact count. Look this over:

viewtopic.php?f=63&t=8649

[Ken Rychlik]

From your picture, it looks as though your gears are mounted directly to the motors with no gear reduction used. In the CNC Router world that is unusual and pretty outdated. If the machine is rigid enough, auto squaring is not always needed. Some machines are very hard to pull out of square and there is no need to force it out of square and back into square. You be the judge of how rigid or flexible it is and decide from there.

If you do change motors or add gear reduction, you will probably need new pinion gears to match your gearboxes.

Based on the switch settings of your drivers you will see how many steps per motor rev they are set at. You could use that info to set acorn the same in the wizard. Then how many motor revs per inch of movement goes in the setting box below that. 3-5 is fairly common, but yours may be more like .5

[ShawnM]

With that gantry design you'll only be able to use gearboxes for reduction. Looking at your pics you'll have to enlarge that "notch" on the vertical enclosures around the motor because you'll add about 3" to the height of the motor with a gearbox. If you are lucky you can locate a 5:1 gearbox with the same size output shaft as the current motor to be able to reuse the pinion. If not as Ken said, you'll be buying new pinions also.

That machine is small so auto squaring might be a waste of time. It's a steel frame so that is a plus. Auto squaring is really for larger machines with flex like those extruded aluminum frames. Save the 4th axis for rotary if you really want that. You can also hardware pair and auto square with some additional relays if you REALLY want to.

[cnc4me]

Apologies for the delayed response.

Thanks to all for the info - much appreciated! Yes, this machine is a bit outdated - might not be worth the effort to upgrade the motors drivers etc - plus I would probably need to move the new drivers, acorn board etc out of the gantry to a computer enclosure - pretty tight right now. So probably just upgrade the acorn board and software - it's a good hobby learning setup. By the way Acorn is so much better than the Mach 3 / warp9 setup I currently had.

And yes, I've been reading up on the auto squaring for hardware pairing and probably not required.

One question for Shawnm - I did purchase the tool touchoff from amazon you mentioned (link above) to replace the conductive tto I currently have - how did you wire that up? Looks solid especially for $35 - but no instructions included.

Almost done putting everything back together.

Bill

[ShawnM]

One question for Shawnm - I did purchase the tool touchoff from amazon you mentioned (link above) to replace the conductive tto I currently have - how did you wire that up? Looks solid especially for $35 - but no instructions included.

Almost done putting everything back together.

Bill

Hi Bill, I bought two of them for my latest router retrofit, one fixed and one movable, and they both came with a wiring diagram. Unfortunately I won't be back at the shop until Monday but if you can wait I'll post a pic of the diagram. Otherwise if you have a multimeter you can just ring out the wires for the two different switches. There's a touch off switch and an overtravel switch.

They are very robust and work excellent for the cost. Again I use them on a router so plus or minus a few thou isn't noticeable for me.

[silver2row]

Ut oh...nice.

I am watching this build, i.e. as I cannot wait for that "Spindle" to get into orbit! 3HP on that machine may be overkill, to me at least, but I would love to see it expose some clean cuts and quickly.

Seth

P.S. I was reviewing your photos of the machine and the Spindle threw me a curveball of sorts. In any light, good luck with your build and I will stay patient for when you all get some video of the machine in action!