Hi there
I pan to build my own MPCNC. But the choice of the right board/stepper motor/stepper driver gives my a really big headache.
Can you say, that a RAMBO from Ultimachine is the better choice than a combination of Arduino UNO and a CNC shield? And which stepper driver should I go for? A4988, DRV8825 or TMC21xx?
Can I go with this stepper motor http://bit.ly/2tvLKnG or would this be fine at all http://bit.ly/2NdyoFS
/Benjamin
The RAMPS (Arduino Mega with a shield) isn’t recommended anymore because of the inadequate 5v regulator on the cheap Chinese Megas. Mine was good enough to run the LCD, but some aren’t. Mine died when I added the laser TTL connector. I’ve got a beefier regulator to repair it, but I also replaced the whole controller. I used a MKS Gen L which is basically the RAMPS on a single board, so same pin numbers, same firmware, but better 5v regulator and more convenient package. While I have no experience with the RAMBO, I believe it is what Ryan recommends as it is a much higher quality product.
I started with the A4988 drivers, upgraded to the DVR8825 and don’t know that I really notice a difference but don’t think I’ve done anything where I would have noticed a difference anyway. The DVR8825 can deliver slightly higher current than the A4988. Click the links there for the full specs on each.
Those steppers both look fine. Obviously the 84oz/in steppers will be stronger, but the 64oz/in should be plenty strong enough. If I recall correctly, 64oz/in or higher is recommended, but 42oz/in is minimum.
Keep in mind Ryan sells a lot of this stuff in the store. When I was comparison shopping, his prices were right there with Amazon and other places. The prices are competitive and it’s convenient to get it all in one order. And he ships amazingly fast. I highly recommend buying what you can through him. I think the only thing I ended up not buying from him was the RAMPS (and then the MKS Gen L when the RAMPS blew the regulator), nuts and bolts, and other little bits and pieces I already had on hand.
First thanks for all the infos.
The main reason, why I search by myself is, I’m from Switzerland. So shipping cost will be huge. 
Did you ever looked for something like these: http://bit.ly/2SJhDIw - sure the price is way higher than a simple stepper driver with a Ramps, but looks like some nice alternative.
Has anyone taken the time to upgrade the 5V regulator? I have a brand new ramps v1.4 kit ready to use for my machine but after some ready I am afraid of damaging the Arduino if this regulator fails. To me it seems like an easy upgrade, though Im curious if someone has already tried
I understand the shipping issue. Sorry, I don’t know anything about that stepper driver.
If you have decent soldering skills, it shouldn’t be that hard to replace the regulator. I actually have not done it yet, but it doesn’t look all that challenging.
The Stepper Driver you linked to. I believe those are more commonly used with 24 volt setups. Generally I have seen Stepper drivers like that used with NEMA 23 Stepper motors. It would work with the NEMA 17s we use as well but it would be a bit of an overkill.
I will also say my opinion on the MKS boards. They are cheap and easy to use but not as resilient as the RAMBO boards. That is why they are cheaper. I can’t back any of this up with facts but this is what I think I know about the MKS boards. They use the same pins as the Ramps board so firmware is easy. You simply tell the firmware you are using Ramps and it all just works. MKS boards use cheaper Mosfets for the heaters than the Rambo does. These cheaper Mosfets are more likely to have problems with heat. Meaning they could fail sooner or possibly even start a fire. So for a 3D printer you would be better off with a quality Rambo board. For the MPCNC you are mostly just using the Stepper drivers. I haven’t heard any problems with the Stepper drivers on the MKS boards. I don’t know if they are decent quality or not. I would assume they are as good as or slightly better then the Ramps 1.4 drivers but like I said I don’t know.
I personally use an MKS base v1.2 for my MPCNC. I am using 64 oz Nema 17 steppers. I am happy enough with my setup. But I will never use my MKS board to push a heater of any kind.
I believe another difference between the RAMBO and others is in protection from tings like hooking stuff up backwards. They try to think of every way a user will screw up and design to allow that mistake to be made without damage to the board. That’s likely also the bulk of the cost difference between them and others. I doubt the MKS board is much less susceptible to screw ups than the Arduino/RAMPS or Uno/Shield combo.
Heath,
Do you remember what you set your A4988 drivers at, voltage-wise? I have a spare MKS Gen L and A4988’s and after reading here, I think I’m going to try to use it for an MPCNC. I think I can probably figure everything out, but it would be good to have a starting point for the drivers so I’m not always trying to tweak those.
For right now I don’t think I am setting the current levels for my steppers. Just whatever is in the Ramps firmware Ryan has on github. It may be a little low. I skip steps every once in a great while ( very rarely) but that could be my cable management.
I don’t recall the exact vref setting. I just used the formula to set them at 90% of the stepper motor’s max current. And the max current may be different from my steppers than they are for yours. The formula for the A4988 is:
VREF = Current(A) x 8 * Sense_Resistor * 0.9
Current(A) is the max current rating for the stepper motor, in Amps.
Sense_Resistor will be the rating of the current sense resistor on the driver. Most likely 0.068 ohm, but could be 0.05 ohm and I’ve even seen these drivers with 0.1 ohm sense resistors. I’ll assume 0.068 ohm for each of the examples below.
So if your steppers are 1 Amp:
VREF = 1A * 8 * 0.068 *0.9
VREF = 0.4896VDC
If your steppers are 1.5 Amp:
VREF = 1.5A * 8 * 0.068 *0.9
VREF = 0.7344VDC
The DVR8825 stepper drivers have a much more simple vref formula:
VREF = Current(A)/2
Thank you all for the input! 
Can one use the DVR8825 on the any RAMPS 1.4?
I also have the problem not to be US based, so I need to see what I can get.
I see kits with Arduino R3 + CNS Shield (which has only 4 stepper driver slots, not OK for later upgrade for end stops (5 needed as far as i have understood) comes with 4 DVR8825 drivers
or
a different RAMPS 1.4 controller board together with the MEGA2560 R3 (this actually is the one shown on the docu pages), with 5 stepper driver slots. This one however comes with 5 A4988
So what to choose?
Can I replace A4988 by DVR8825 (possibly later on) and why should i dare to do so?
Should one go for the MEGAA2560 or the UNO or what else? Possibly I could get all the parts individually, however at a higher price…
Might be stupid questions, but all this looks quite complicated as a newcomer…
There are good reasons to use the DRV8825 instead of the A4988. Search a bit longer and I’ll bet you can find a bundle that includes the Mega, RAMPS and DRV8825 parts. If you’re going to use the RAMPS, you need the Mega, since the RAMPS will not plug into the UNO board. Do you have access to Amazon, Banggood or Aliexpress?
Yes, you can use DVR8825 stepper drivers on the RAMPS. I started with A4988 and upgraded to DVR8825. I did not do any testing to see if there was actually a benefit to doing so. The firmware V1 Engineering provides assumes DVR8825 drivers. You’ll need to make changes to the steps/mm for each axis to use A4988 drivers, and then change those settings back when you move to the DVR8825 drivers.
Ok, thanks.
I found a package including the MEGA and the DVR8825. The Mega should be compatible, however have mor I/O Ports etc.
I found a kit with MKS Base V1.2 Board+ 5Pcs DRV8825 + LCD 12864 Display . Would that be all I need for the brains, and would this be recommended over a mega/RAMPS setup?
I have had some experience with similar looking drivers and found that there is a time delay upon activation. Perhaps this was my fault as this was my “learning” project but I was unable to get them to work effectively.
If you want to see more, watch my CNC build video from the 3:40 min mark - youtube user Garfish307 “DIY CNC Mill Construction & Testing”