How to change MPCNC over to 3d Printer?

Hi everyone,

   Late last week i put in my order for the mpcnc kit. I bought the electronics kit as well as the printed parts. Ill be using 1" stainless tube and a import 500w spindle. I went with the MPCNC for the same reason im sure a lot of other people have. I love that its a great router/milling machine but can be used for all of the other various tasks on a as needed basis. I am completely new to the diy CNC world. I am not new to computers and im not new to design and fabrication.I have done a lot of machine work on manual mills and lathes. The cnc side is something i have wanted to dive into for a long time. 
   My question is pertaining to the process of swapping the mpcnc over to a 3d printer when i need to. I am seeing all of the mods and cool things for the mpcnc on thingverse that can be printed. I also need a mount for my import spindle, why not get a 3d print head and print the mount first thing? The problem is, i know very little about a 3d printer. 

   I realize that there is an extruder and a hot end, and there is spools of plastic material. I get that a hot bed is nice to have to keep the part nice and use various plastics. I guess i really just need clarification on how i get from a to z with the 3d printer swap over on the MPCNC. Do i need to do something with the firmware, or since the extruder/hotend is sold here is it ready to simply bolt on and plug in? I can obviously buy the extruder and mount from here. This sentence confuses me a bit in the description of the extruder "Firmware edits will be needed to adjust the E steps, thermistor type to #5, and care needs to be taken to set your extruder driver correctly." I see some information about drivers and wiring the extruder/hot end, but again its not super clear to me.

Is there anyone that wouldn't mind to take the time to write up a step by step procedure from start to finish on how to swap the MPCNC over to a 3d printer? It would really be greatly appreciated, and im sure it would help other people new to this that come along. I assume like most things, after you get all of the information you need and apply it, its really no big deal. I'm excited about this machine and can't wait to run some parts. Please help!


Have you done any 3D printing before?

W.r.t. firmware, you’ll need the version with the extruder. I don’t know what Ryan ships, but I’m guessing if you bought it with the extruder, then it will be the right firmware.

I’m not 100% certain on this, but you’ll either need a resistor to fake out the temp or you’ll need to keep your hot end plugged in when not printing

If you haven’t printed anything before, I just want to warn you. The mpcnc is not the easiest way too start. With your background, you’ll be able to do it, but just go in with a lot of patience. I won’t write a guide, there are plenty of generic 3D printing guides (take a look at the rep rap wiki). I will tell you that 90% of printing is getting the first layer right and 9% is getting your slicer setting right. Lucky vicious1 had some decent starting settings. Just go slow, follow one of the calibration guides, and be patient. You can/should post images of your failed prints for help.

Looking forward to see what you mill. I bet you make some great stuff.

Basically, right now, you got a CNC machine, so 3 axis.
For a 3D printer, what you need is to add one more axis: the extruder.

So, you’ll have to purchase:
-An extruder motor, so not only the stepper motor, but the complete extruder assembly.
-a motor driver (pollolu stuff) to give power to this new motor
-Wires, to connect the thing
-A hot end assembly (hot end, thermistor, cooling fans, all the things)
-A glass plate, which will be your bed. No need for a heating bed at firs, you can always puchase that later.

Then, I suggest you to build a new Z axis, dedicated for 3D printing. It is way more practical than having a multi tool support in practice, so you just swap the Z axis from milling to printer and vice versa, whenever you need. Just make sure that you have quick connectors, to disconnect all the things easily.
You can use this hotend support I made, if you want to. It allows you to use a bed sensor later, when you’ll feel confident enough to use it:

Software wise, you’ll need to:
-define the number of steps per mm of your extruder motor. The same way you did it for your other axis motors
-define your thermistor type, the thermistor is the little sensor which tells the arduino what temperature your hotend actually is. Not difficult to do, everything is well explained in Marlin
-I think that is pretty much all, maybe some temperature alerts to disable, I forgot. You can always come back here to ask whenever you have a problem anyways :slight_smile:

Connect your thermistor to the appropriate pins on Ramps, then your heater cartridge, then your extruder motor and you should be good to go, there is nothing really complicated. The difficult part will come later, when you’ll have to dig into the fine tuning to make it print well.

Just get the thing started, you’ll see it’s no rocket science.

1 Like

Did you get the Ramps or the Mini-Rambo?

Thanks guys I really appreciate all of the info! I’m understanding now better how it all functions. Ryan I got the Ramps board. I plan to buy the extruder and hot end and driver from the site here. By what I can tell by the post above (thanks dui!) by buying the extruder/hot end listed on the site and a driver. All I will need is a bed to print on and some spools of PLA. It appears that everything else is included with the purchase. The extruder, the stepper motor, hot end with thermistor, fan, etc…please correct me if I’m wrong! Thanks again for the help…and obviously any additional info software wise, board wise, or suggested start settings will be greatly appreciated.


For the Ramps, yup, an extra driver (you will need to set the voltage), an extruder kit (e3d or MK8 (back in stock soon)), a print fan, extruder mount. Depending on the size of your machine you will probably need to extend all the wires.

The board will need to get flashed with thermistor enabling firmware, I have the MK8 firmware ready to go, but the e3d is just as easy.

A heated bed is highly suggested, and that requires a power supply of at least 20A.

A more fun way to do it is use your mpcnc to cut the frame and make a mp3DP, a standalone printer really is better/faster if you think you will do some printing. The cnc tends to get really dirty, not a good combo with a tiny nozzle.

Ryan, when do you think the MK8 will be back up for sale on the site? I see they are available on amazon. I know that you do some tweaking to them before you sell them so i would rather just buy from you. Also is the firmware available for download somewhere already?




The firmware is here,


I have the extruders here, including the new updates I want to make (high temp, micro swiss throats), but I didn’t buy the stupid little metal fan cover so the screws don’t fit. I just finished milling out a few sets of lowrider parts, let me see if I can come up with a printed fan guard/spacer.

Ok thanks

Have any luck with getting these MK8’s ready?




Oh man, I am so sorry Andy. I have been waiting for those stupid little fan grills to come in, they are needed for the screws to fit. Any other way I try is just too sketchy. I have 3 or so here, I can clean one up for you today. Let me know when a good time is for you and I will put one in the shop for you.

No big deal Ryan…just hold off on getting one ready for me, after some more research I realize I’ll have to go with the e3d in order to run some of the higher temp materials out there. i just decided to deeply research material options and realized the temperature issue. Another probably somewhat newb question. When I flash with the 3D printing capable firmware, it won’t effect how it functions as a cnc router? Meaning I can switch between the two without any issues. I’m assuming it won’t matter, the code just won’t contain any information pertaining to the 3D printing side of things?



I sell the E3d as well, Haven’t found anyone cheaper either.

You can use the exact same firmware for both the only difference is the 3D print firmware enable the thermistors.

So do you just leave the bed and hot end plugged in then?