Going crazy with Arduino CNC control!

I’m just building my first MPCNC.
Printing, assembling, all of that was a lot of fun. But now I’m going crazy with this CNC control!!!
At first everything worked fine, the stepper could be driven with UGS jogs. It passed the crown test.
Then (after installing drag chains) I had a problem with the Z axis, it only went in one direction.
If I plugged the Z connector into y, it worked.
I checked the wiring but ended up ordering a new CNC shield.
This worked fine… for about 5 minutes. So I ordered a new one, plus an Arduino to be on the safe side.
The Arduino shows an error message: “See https://support.arduino.cc/hc/en-us/sections/360003198300 for suggestions”
I’m new on Arduino, but I’ve been trying by google search to solve it for a long time, but I can’t fix it!
I will send it back!
When I put the new CNC shield on the Arduino I used first, the drivers get so hot that the heatsinks come off and the motors make weird noises. This wasn’t before. There is no way to get connection to UGS software.
I have another Arduino where the CNC shield behaves the same way. Unfortunately I tried to do a firmware update. It was shown when I pluged it in and opend Arduino app, but to be honest, Ididn’t know what I did!
I’m a Mac user and not used things can go wrong by clicking the wrong button, usual this is blocked by Apple. But not on the Arduino, it is no longer shown in the dropdown list, there is a number only, no way to upload anything.

I’m so confused now that I don’t know what to do anymore!
Is the new CNC shield faulty too? Or the stepper drivers? Or is the Arduino the source of errors? Or is the installed GRBL firmware faulty?

You are listing multiple boards and multiple failures, so it is a bit hard to figure out where to start in helping you. And, I feel your frustration, especially since you were so close to a working machine.

The first step is being able to communicate with your UNO board. Being unable to connect to the UNO probably means you’ve damaged the board. Unless you have experience with electronics, it is easier to just replace the board(s) than try and fix it/them. Note the UNO board can be programmed before it is plugged into the CNC shield, and you also test the UGS connection to just the UNO board. That is where I would start…just working with the UNO board with no CNC shield.

Did you set the vref voltage on your stepper drivers? I assume you are using either A4988 or DRV8825 drivers. Both need to have their current calculated and set manually. If it is set too high, your driver and your steppers will overheat. Set too low, and they won’t have the torque to do the job.

Z axis, it only went in one direction.

Did it go down but not up? If you did not set the vref on your drivers, this could also be a symptom of that issue, since the motor current setting could be too low to lift the router. Another possibility. I saw a similar issue (one direction movement) on the forum recently. It turned out to be a bad connection to the direction pin on the stepper driver.

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Thank you for the swift reply!
Here all data of my hardware: Arduino UNO with CNC shield, GRBL, UGS (Mac), Nema 17 +DRV8825

I was just able to fix 2 of my Arduino, I was able to load “blink”!
Driver: They are between 6V and 7V, which is correct I think!

Regarding Z: It worked with the shield which gave up after 5 minutes, so I guess it was the shield.
Do you think I had bad luck with all the CNC shields and simply should order new?

It might be a typo, but you are looking for 0.6V to 0.7V. For DRV8825 I think the calculation is half the max current, so the starting values should be 0.6V to 0.7V range for most steppers we see on this forum. You need to look at the specs for your steppers.

Do you think I had bad luck with all the CNC shields and simply should order new?

If you really set the current on the stepper drivers to 7V rather than 0.7V, then it is possible you pulled too much current through the CNC shield. These boards do have a fuse, but it requires you desoldering the old one and soldering in a new one. It is also possible that you damaged your stepper drivers. Again, this assumes you set the voltage to 7V not 0.7V.

Edit: Did a quick search. I’m just a hobbyist when it comes to electronics, but if it were me, I’d spend a bit of time analyzing the current CNC shields before ordering new ones. First, I’d pull all the stepper drivers. Then looking at a pinout diagram (or the labels on the steppers), I find the VMOT and GROUND pins for one in one of the stepper sockets. I’d apply power to the board and see if I had power at these two pins. If I did not have power, I’d check the fuse on the board. It is located between the X stepper driver and the Z stepper driver.

image

If you find the fuse is dead, you may still want to replace the board, but you will have a cause of why things are not working.

Also, I’m glad you are able to communicate with your old UNO boards. The only open question is whether you burned out a pin or a voltage regulator. Plugged into a computer, the board is powered over USB.

Thank you for sharing all this information, much appreciated! I checked the fuses on both shields I have, and the old one has a blown fuse!
Now I can check voltage on the other shield, but first I have to reload GRBL. Unfortunately I Installed new Arduino app (2.0) and it is not possible toe upload the GRBL version I have.
But I will get it and come back!

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Is there a way to see if GRBL upload to Arduino board worked or failed?

I checked the drivers, two had 0V, one 0.67, so I used 2 I still had and tuned them to 6-7V.
But I’m still not able to connect it to my macbook, and it is still hot, not as it was, but hot. And motors do a high frequency piep sound.

A couple of things here. First, all your drivers should be in the 0.6 to 0.7 range. Anything else and you risk damaging your board or the drivers. With that said, drivers do run hotter than expected, and they pull current even when you are not moving the steppers, so maybe they are working correctly. Or, you may have already damaged your drivers pulling too much current earlier.

Second, as mentioned above, you can test UGS without having the CNC shield installed. I don’t know this for a fact, but I understand how things fit together and am 95% sure that is true. Before hooking up your CNC shield, get your communication working. I don’t use UGS nor a Mac, but when I connect to my GRBL machine, I get back an acknowledgement including a version of the GRBL I’m running. I also get an acknowledgement when I send a command. So, you should be able to use your UNO board and UGS to establish that you have GRBL installed and working. After that, you can move on to connecting to the CNC shield.

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Ok, thank you! I will see if I can get it so far!

At the end I bought a new shield and now it is running!
But now, the next issue is, the machine has interruptions when it makes its tracks!
Every tip appreciated…

did you ever check the voltage?? Many people have pointed you there, but you never responded. It is CRITICAL to get that right.

Edit, apologies, I see you did check, but again you say 6-7volt, that is way to high, are you mistyping every time? it is .7

Ok, I’ll check again…

mistyping, about 0.65V

Since you mention this is your first CNC, I want to repeat a warning that you must completely power down the system before working on any of the stepper motor wiring. The drivers can blow invisibly if a motor is connected or disconnected while the driver has power.

What size power supply are you using to power the screw terminals of the CNC shield? Mine is marked as being good up to 35V dc.

If the stepper drivers get too hot, they protect themselves by limiting the current they try to pass, which can result in hesitation of the stepper motors. You mentioned the heat sinks came off - have you put them back on? I would also suggest running a fan across them until you get the amperage tuned.

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Thank you! I guess that was the mistake I did with the last set. I will take care in future!

That was with the set before, the new set is hot, but not as hot as the last one. I can touch it.

That was my thought too. I use this https://www.roboter-bausatz.de/p/mean-well-steckernetzteil-12v-5a-gst60a12-p1j It is 12V and 5A.
But I thought amp is the important size!? The shield takes 12 Volt, and as far as I understand, more Volt would destroy the shield!? Please correct me if I am wrong.
Do you think a more powerful power supply is required, does that cause the interruptions error?

EDIT:
Now I tried the shield I used before, but replaced the drivers with new one and this works with very minor interruptions. It seems interruptions started after driver are heat up.
I have not used a housing for the tests, I have not found a good one for GX16 Aviation Connectors at thingiverse.
I just have a fan above the shield.
Is the heat the reason for the minor interruptions?

if you have new drivers, please make sure to set voltage on them as well!

Sure, they are about 0.65V :upside_down_face:

My CNC shield screw terminals have printing stating they’re good up to 35v dc. I’m using an old 19v laptop power supply on mine. Your 12V 5amp supply should be fine. It is common for folks to use 24v supplies - I have one on a different CNC that uses a different controller.

Overall power (voltage multiplied by amperage) will determine things like the maximum acceleration and velocity your stepper motors will be able to achieve. The stepper drivers manage the current delivered to the steppers so as long as the supply isn’t higher than the voltage the components on the shield can handle, there shouldn’t be any problems.

As I stated above, if the drivers get too hot they’ll protect themselves by cutting power until they cool down. This happens fast, so can appear as hesitation. I’d try blowing air across the heat sinks. If that stops the hesitation then that’s a good indicator that heat is the problem.

This would have been my next question, thank you for answering before I asked! I have set feed rate to 8000, and it is such a kind of slow. So I need more power to get more speed?

I found this on thingiverse MPCNC - CNC-Box - Steuerungsbox by open_mind_interest - Thingiverse, it is still printing. This should solve the issue.

The other alternative to increase velocity and acceleration is to cut down on friction in the system. Generally, 12v 5amp should get you pretty good performance unless there’s something mechanically off within the machine.

Once any mechanical issues are addressed, you can look into tweaking the motion settings. I fine tune acceleration first (at a known safe, slow velocity setting) by increasing acceleration one one axis at a time until I lose steps, then back off the setting 5-10%. I then tune velocity using the same approach, increasing until losing steps, then leaving a little safety margin.

Ok, thank you! But what is a “good” friction? I can move it with my pinkies… is that good enough?