Hi everybody, I’m assembling the wonderfull Mostly Printed CNC (Today I finished to print all pieces and in the week i will assemble the CNC). and I have a question for you:
I have a CNC shield (like in the picture) with 4 A4988 deiver modules that I would use with Arduino UNO, is it compatible with Mostly Printed CNC? if yes can you help me with the firmware and how I must connect with the motor and with the softaeìware?
Thanks and bye bye
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Absolutely compatible just remember going this route you are going to be using more for cnc work not for 3d printing
Firmware https://github.com/grbl/grbl GRBL
other then setting your settings shouldn’t be too hard.
lots of info for setting up grbl
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Hi Pietro,
did you get your MPCNC to work with Arduino Uno + CNC shield?
Any advice to share?
Thanks
Marco
Why would anyone use the CNC shield instead of a Ramps?
The price difference is negligible, and with the ramps you have the possiblility to use the screen and the SD card reader.
I don’t really see the point, is there any advantage I’m missing?
- If you plan to use MPCNC only through Estlcam, the display will be unusable as well as the SD card. So I don't see any reason to use the Mega instead of the Uno.
- Arduino Uno can run GRBL which is designed for CNC use - while Marlin makes you feel like you are using a 3d printer software to drive a CNC mill.
- For me, the reason was that I had completed the mechanical setup of the MPCNC and my arduino mega was still shipping, while I had an Uno with a CNC shield in a drawer, so I gave it a try! :-)
- I love to see such a small chip driving such a big machine!
I use GRBL on an Arduino Uno equipped with a CNC Shield V3 because my Mega2560 Marlin board did not work. I finally figured out the end stop pins needed jumpers.
“The more you over-tech the plumbing, the easier it is to stop up the drain.” --Scotty
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I have ordered a Mega+Ramps, but it is coming from China and won’t be here for a month or so.
I have an Uno+CNC Shield V3. How did you handle MPCNC’s 2 x-axis+2 y-axis+1 z-axis with the CNC Shield V2, which only supports 4 stepper motors, and not 5 stepper motors?
Hi Fred,
please note that using GRBL software, you will be able to use only 3 of the CNC shield 4 channels. The good news is that 3 channels are enough to drive the 5 motors: to handle the two X motors, you will just use a single channel on the CNC shield and connect the two motors either in series or in parallel. Same for the 2 Y motors.
The choice between series and parallel connection is though. With series connection you will share the voltage between the 2 motors. You might need to increase CNC shield input voltage to get as much juice as you can from both driver and motors Drivers will not suffer more with higher voltage (as long as you stay below 24V o 36V depending on which drivers you have chosen between A4988 and DRV8825). With parallel connection, both motors will receive the full voltage but they will share the current, thus increasing drivers load. I’m not really sure which solution in better but I’ve tested series connection and it works well.
Be sure you understand how to calibrate the drivers current to achieve best results and avoid damaging something. You’ll find plenty info on youtube on this.
Ciao
m
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I run a uno and use tb6600 drivers. Running grbl and i use vetric vcarve desk top. Works flawless. Very easy to adjust steppers etc, too. I started with the rabo mini but quickly knew i wanted grbl.
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Personally the cnc sheild is useful if you wanted to add dual extruders to a ramps 1.4 extruder setup.
https://reprap.org/wiki/Adding_more_extruders
This still starts with the ramps 1.4 base, but adds a few more steppers.
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On the topic of only using three stepper drivers for the uno CNC should with grbl; can you not clone an axid with the jumpers to use the 4th driver for the extra y axis motor? This will reduce the voltage requirement by keeping the y axis on separate drivers . The z doesn’t really need much more than holding voltage if your doing 2.5d projects right?
Drivers control current, not voltage. This is possible as Nema 17 require around 3-4 Volt to allow nominal working current (about 1.75 A). So, with 12V power supply, drivers have plenty room to drive not only 1 but even 2 motors connected in series to the nominal current. Anyway you can use 24 V instead of 12V if you want to give them more room without overloading drivers, which cannot provide more than 2A according to specs. Parallel connection will not ensure you are providing the same current to both motors.
Ciao
m
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So, if I’m using the power supply Ryan is selling and I’m cloning the y axis to the A stepper driver and the z is wired in series, I should have plenty of power right? I think my grbl configuration is wrong. My steppers are making kind of a grinding/jerking noise while moving very slowly (not Smooth at all). The z axis is jerking back and forth but not actually moving up. I’m a bit stumped…
Thanks,
Brian
Yes, by a huge margin.
Step rate, and speed are the two biggest settings to look into.
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also check wiring, grinding noise could depend on swapped or uncoonected motors wires.
m
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Sorry to be so ignorant on the whole GRBL setup. I’m on vacation right now, so my exact settings are unavailable. I have the full step at the moment on all steppers because I read that it is easier to set up that way, and just change later. I think i’ll go to a 1/16th step to get a smoother drive with no power issues. I’m running the A4988 steppers on all four drivers with the Y axis cloned to it using the jumpers. All steppers are set to .975 for the current. my steps are set to 6.25 steps/mm for x/y (200 steps/rotation w/ 16 tooth puller, so 32 mm per rotation). Screw pitch is 2 mm, so I’m at 100 steps/mm. I’ve played with the feed rate, but have no clue what to set them too.
Also, the current in series question for the z axis. I left the current alone on the stepper drivers. Since the z movement isn’t extreme in comparison to the x/y, I thought nothing would be required. I’m understanding that correctly right? without a option to really increase the current, should I leave the Y axis cloned on the A driver, or should I wire that in series as well. Would paralell be better considering that I can control the current with the stepper driver?
Sorry for all of the questions. I appreciate the help!
Thanks,
Brian
Hi Brian. I recently put an Arduino Uno (genuine) and a CNC shield V3 on my MPCNC so I could try out Estlcam and all of its features directly. I will attach a photo of my Estlcam settings to this post for your interest. I have been using it just for hardwood milling so far, primarily oak and hard maple with 1/4” and 1/8” Upcut two flute router bits in my router without any problems. 3 to 4 mm doc for the 1/4” bit only to 20mm depth since I want to leave my dust collector attached. The router handles cross cutting of both woods well. I am not trying for speed records, I just want to cut out so 2.5D designs. Speed usually 15mm/sec. I put 3 DVR8825 drivers on the shield since they handle more juice. I am running a 12 volt power supply. The Z axis is by itself and the XY are in series as with the Rambo wiring. I have the steppers set at 1/32 microsteps and 0.7 amps. I tried 0.75 but I felt the motors were running a little too hot. I added a Microsoft Game controller and Microsoft framework as Christian describes in Estlcam and it is slick. I milled a 4” square touch plate from MDF and put aluminum tale on the XY edges as well as the top corner all touching with a screw to connect one of the probe leads to. You have to wire to the correct pins for the Z probe as Input 8 - SEL plus GND in the top corner of the board. The ‘Auto edge and deviation angle’ finding works really well. Just remember to Zero the XY axes Before starting the auto zero or the machine will go looking for them. I had XY endstops wired via a cat 5 cable as NO but I had so much noise they always seemed to be triggered on the control panel. I just disconnected them and it all works fine now. As Ryan has often said in the past, you don’t really need endstops when first starting out (Dual Endstops are a different precision story). I hope this is of help to you. I’m no expert and am still learning myself. I may switch to a 24V power supply later and will likely play more with speed settings. It is nice to be able to skip the Repetier step and machine directly from Estlcam once the tool paths are decided. Meanwhile I will use Rambo for printing and Lasering since I have that wired. I just swap the stepper motor plugs between the controllers.
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Congratulations and thanks for sharing. I’ve published estlcam configuration screenshots for the same setup in my personal page here Link
It is in italian but screenshots are from the english version of estlcam.
Ciao
m
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Thanks Marcob. I visited your site and with the help of Google Translate I could read your construction experience. Ryan may be interested to know that you’ve translated the Marlin comments into Italian. I like using Marlin/Rambo and have adjusted it from Ryan’s initial settings a little.
For it’s simplicity for milling, I really like Estlcam which is why I set up an Uno/CNC Shield. Both components are so cheap I couldn’t resist. I don’t mind having a computer in my shop at all. I found I didn’t use the SD port of the LCD screen all that much anyway. It is interesting that our Estlcam settings are similar. I have had the speed as high as 190mm/sec but that was way too fast for moving with a gamepad. Too hard to control. I am still finding the speeds I prefer.
Cheers, Jeff
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It works! Thank you guys the help. After reading your post I have flashing the estlcam firmware another shot. It worked perfectly, and I’m up and running . I’m not sure what resolved my z axis power issues though. I took my series harness apart and resoldered and continuity tested every pie which I hadn’t done before, so maybe that was it. I never got my GRBL setup to work, but that’s ok. I was a bit afraid of being tied to estlcam controller and cam because if some limitations, but actually it’s very capable. I’m trying to learn to flip mill now so that I can get my first guitar body done. I have to learn to changed as well, but it takes everything from AutoCAD perfectly so I’m happy. I have an MR1.3a coming from China and a RAMPS 1.4 board coming today. I’m going to test all 3 and compare GRBL and Marlin for ease of use.
So In short no technical hold ups anymore. Now I’m just behind the learning curve! That’s an exciting place to be. Sooooo many new possibilities. My kid is obsessed with airplanes (2yr old) so it’s of to build a 3w laser rig next .
Thanks so much for the help.
Brian