MaxNC-10 conversion

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geclevenger
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Joined: Sun Oct 15, 2017 4:27 pm

MaxNC-10 conversion

Post by geclevenger » Sun Oct 15, 2017 9:59 pm

Hi all,

I just finished converting an older MaxNC-10 benchtop milling machine to use a Protoneer v3.0 shield, GRBL and GRBL Controller 3.6.1. The first MaxNC I started on had five wire motors on each axis so I switched them out to some six wire Japan Servo motors that I got from HobbyCNC many years ago. First question - the six wire steppers can be wired in series to give 10 ohms / 43mH or just use half the coil and wire them for 5 ohms / 9mH. I'm currently wired with the 10 ohm arrangement but wondering if there be an advantage to going to the 5 ohm setup? I'm using the TI DRV8825 drivers and have the current set to about 1.4 amps. It is working but I have had to back off the speed a little more than I would like (maybe 10-12ipm?, I can't recall). Leadscrews are original MaxNC-10 1/4-20.

The tech high school that my son is attending has three of these MaxNC-10 mills and two of the older (non encoder) T2 lathes collecting dust and I'd like to get them all up and running without having to go down the path of expensive hardware and software. MaxNC / Ximotion is right around the corner from us but they have been completely unresponsive. Thankfully Taig Tools was helpful in supplying us with some collets that we needed.

All of the mills have the original MaxNC electronics but the software is long gone and the cables/connectors are in disrepair. Two of the mills have the optional 4th axis. I've seen some discussions and projects towards 4 axis GRBL control but nothing really formalized. I am not capable of pioneering this effort so I'd like to know if there is anything in the works that would steer us towards one board or the other. I like the look of the Protoneer Raspberry Pi shield but with the integrated nano on it I would think that this board will always be limited to 3 axes. So I'm wondering if the Raspberry Pi solutions should be ignored and I should just be looking at a PC solution with the v3.51 shield?

BTW, the school has two Haas machines, a VF-2 and a TM-1. The hope would be to get these three MaxNC-10 mills running (with a very small budget) and use them as trainers before turning the kids loose on the expensive Haas equipment. I wonder if anyone with familiarity with Haas controls could comment on which GRBL interface has at least some similarity. bCNC looks interesting but I haven't tried it yet.

Thanks for any input and direction you can provide!
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Bertus Kruger
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Re: MaxNC-10 conversion

Post by Bertus Kruger » Tue Oct 17, 2017 5:57 pm

geclevenger wrote:
Sun Oct 15, 2017 9:59 pm
First question - the six wire steppers can be wired in series to give 10 ohms / 43mH or just use half the coil and wire them for 5 ohms / 9mH. I'm currently wired with the 10 ohm arrangement but wondering if there be an advantage to going to the 5 ohm setup?
My thoughts would be that the two setups would be very similar in performance as the energy(Watts) going into the system would be the same. The main advantage would be that steppers can be used in bi-polar and uni-polar systems.

Bertus Kruger
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Re: MaxNC-10 conversion

Post by Bertus Kruger » Tue Oct 17, 2017 6:01 pm

geclevenger wrote:
Sun Oct 15, 2017 9:59 pm
All of the mills have the original MaxNC electronics but the software is long gone and the cables/connectors are in disrepair. Two of the mills have the optional 4th axis. I've seen some discussions and projects towards 4 axis GRBL control but nothing really formalized. I am not capable of pioneering this effort so I'd like to know if there is anything in the works that would steer us towards one board or the other. I like the look of the Protoneer Raspberry Pi shield but with the integrated nano on it I would think that this board will always be limited to 3 axes. So I'm wondering if the Raspberry Pi solutions should be ignored and I should just be looking at a PC solution with the v3.51 shield?
GRBL is the main limitation with the 4th axis needs and affects both the Shield and Hat versions of our boards. SmoothieBoard is another option to consider if you are looking for more axes...

Bertus Kruger
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Posts: 1404
Joined: Wed Feb 03, 2016 10:26 pm
Location: Wellington , New Zealand
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Re: MaxNC-10 conversion

Post by Bertus Kruger » Tue Oct 17, 2017 6:02 pm

geclevenger wrote:
Sun Oct 15, 2017 9:59 pm
BTW, the school has two Haas machines, a VF-2 and a TM-1. The hope would be to get these three MaxNC-10 mills running (with a very small budget) and use them as trainers before turning the kids loose on the expensive Haas equipment. I wonder if anyone with familiarity with Haas controls could comment on which GRBL interface has at least some similarity. bCNC looks interesting but I haven't tried it yet.
bCNC and Universal G-Code sender is a good start. bCNC being more advanced....

animal
Posts: 22
Joined: Sat May 06, 2017 11:03 pm

Re: MaxNC-10 conversion

Post by animal » Fri Oct 20, 2017 2:59 am

looking at your pic , I don't see any limit switches . are you not using any , or are they mounted on the back of the machine ? I have a old MAXNC10 with the Powermaxx11 steppers that I am working on getting set up on a 3.0 CNC shield. If you use them & don't mind posting more pic's I would be interested on seeing your LS mounting
tks
animal?

geclevenger
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Joined: Sun Oct 15, 2017 4:27 pm

Re: MaxNC-10 conversion

Post by geclevenger » Fri Oct 20, 2017 5:06 am

Bertus, thank you for all of your feedback. Very much appreciated.

Animal, I don't have any limit switches yet. I realized just recently that I'll need to back down from GRBL 1.1 to 0.8 in order to do that with the v3.0 shield. The other two mills the school has are also open loop but have the Powermax II eight wire motors. I will be tackling those next. Since they have the 4th axis and GRBL isn't really there yet, I may back up and go with either Mach3 or UCCNC - not sure yet. I guess it depends on what funding we can get from the administration. If you find a good limit switch and mounting method please post pics back here. I will do so as well if and when I get to that point.

One thing I would add is to be sure and shield everything. When I first did this it would work great until I turned the spindle on. Then it was hit and miss (mostly miss) with it executing the gcode. Not sure if it was a usb issue or an Arduino / GRBL issue but switching to shielded cables and a metal enclosure for the Arduino fixed it. The cable shields are grounded at the motor mounts and to the Arduino enclosure.

animal
Posts: 22
Joined: Sat May 06, 2017 11:03 pm

Re: MaxNC-10 conversion

Post by animal » Fri Oct 27, 2017 2:16 am

thanks for the info , it will be a bit til I get back to the MAX , waiting for my kid to visit , he is the Arduino pro . I was figuring on using one of the old electronic's enclosure for the uno & cnc shield . so you have the shield connected on both ends ? reason I ask is for some reason I seem to recall that we used to only connect it on one end , but that don't mean we were doing it right back in the day. will post back when we get some progress on this end
tks
animal

geclevenger
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Joined: Sun Oct 15, 2017 4:27 pm

Re: MaxNC-10 conversion

Post by geclevenger » Sat Oct 28, 2017 3:33 am

You may be right about grounding on one end only - I probably have a ground loop the way I have it. What I probably should have done was not ground them at the motor end, and add a single ground from the Arduino case to the MaxNC structure. This is working for now so I'm going to leave it be.

If you retain the original speed control the Arduino might not like being in the same box as it is. Perhaps you could put in a divider? I just went to the thrift store and picked up a small tin for 50c and mounted the Arduino in that. The lid contacts the heat sinks and seems to help dissipate some of the heat.

animal
Posts: 22
Joined: Sat May 06, 2017 11:03 pm

Re: MaxNC-10 conversion

Post by animal » Tue Nov 07, 2017 1:15 am

My speed controller was a cludge of components & solder snott. I thought I would use a speed control I have for a Dremel for the initial testing & I will prob replace the motor at some stage to get rid of the noise & fire issue.
tks
animal

mpicco
Posts: 2
Joined: Thu Mar 29, 2018 10:43 pm

Re: MaxNC-10 conversion

Post by mpicco » Thu Mar 29, 2018 11:22 pm

I've been given a MaxNC-10 by a company that tried to upgrade it with new steppers, G-540 & 5i25 I/O board. The computer that came with it runs what appears to be the latest version of LinuxCNC. I saw it running in its original form with a DOS computer and what was probably the original software. That computer was junked by the company, so I've tried to get the MaxNC-10 running with LinuxCNC.

The problem I'm having is that the new motors aren't always responding to the change of direction and they will occasionally run nicely in one direction, but 'growl' while moving in the other.

It would be nice to put this to use for some minor engraving and small plastic and wood work. It appears that it needs some tweaking, but I'm too new at this to know how/where to start!

Any suggestions would be most welcomed!

Thanks!
Michael
K6MLE
CM98pr

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