CR30 – Stepper Motor Upgrade – 3DPrintMill


Hello Everybody and Welcome to another video. Today’s we’ll be installing the Repkord Upgrade kit for the CR-30 since the motors lack proper support. Full disclaimer, this is not a paid sponsorship, I purchased this upgrade kit with my own money and the opinions that you see here are my own. As always, do this mod at your own risk, and I’m in no way responsible if any damages may occur.

Before we begin, I wanted to mention that this video is based on the original Repord installation video and although it was jam packed with useful information, I believe that it would benefit from an instructional over hull. For this reason, I will be including the link to the original video as well as the upgrade kit in the description below.

So there’s a couple of main reason why you may which to undertake this modification, however it is mainly to help prevent issues after long printing sessions. As mentioned in my review for this machine, this printer is better suited for a production setting where it can be expected to run 24/7. For a small business, having a machine go down can cause expensive delays while replacement parts come in. The CR-30 comes initially with two stepper motors, which do not have proper supports and could potentially deform or break over time. Depending on the deformation of the D-shaft, you could also experience extra rigging on your 3d prints if it becomes bent to one side. This modification adds a support across the stepper motor D-shaft where the belt applies constant pressure.

To start things off, we’ll first remove the original stepper motors that came with the machine. These motors are attached with a 4 mm hex screw and have 3 connection points. Making sure to unplug the original motors, we’ll completely remove the screws holding the mounting bracket in place so that only the tensioner remains. The tensioning screws only needs to be loosened enough to remove the stepper motor. Make sure to place these screws in a safe location because we’ll need some of them latter on.

Before we begin installing the new stepper motors, we first need to adjust the timing pulley to ensure that it is roughly the correct height. This will also allow us to adjust the orientation of the stepper motors according to our preferences after we’ve attached the mounting brackets. From the upgrade kit, we’ll remove the T-spring nuts and screw, while making sure to place these in a safe location for later. You’ll then need to loosen the 4 screws which are holding the stepper motor in the mounting bracket with a 2 mm hex key. Take care when lifting the bracket away from the stepper motor so that the screws don’t fall out of place. You can then place the mounting bracket flat on the table while you work on attaching the spring T-nuts to the frame of the machine.

I found that putting my tweezers in the slot was a great way to keep the spring nut from falling down the T-slot. In order to actually put the T-nut in, you can place a hex key through the hole to allow you to tilt into place. The pliers will keep the T-nut from sliding down while you attach the mounting bracket with the provided screw. Make sure that the bracket is just tight enough to keep it into place while still allowing you to move it if necessary. You’ll place the timing belts within the mounting bracket, making sure that they are opened over the hole for the stepper motor shaft.

We can now begin adjusting the timing pulleys by loosening the small hex screws holding them into their position. Using the original motors that came from the machine as a reference, you’ll line these up and set them to the same height. You’ll want to make sure that at least one of the screws is making full contact with the flattened portion. This will mean that the motor with the shorter height will need to be flipped upside down for a better connection. With the height properly set, you can now connect the motor to the mounting bracket while making sure that the connector is either facing up or down and that the timing pulley is within the timing belt. With the screws for the motor tightened, you can then slide the assembly up towards the tensioner screw and begin tightening it just enough to get a small amount of tension. If it doesn’t reach completely, the belt is most likely caught somewhere, so double check that it’s correctly threaded through its entire path. You can now attach the final screw to hold the motor into place and begin adjusting the timing belt tension until both belts are adequately tightened. Make sure to fully tighten the T-nut once it’s installed correctly by using a hex key which has a ball tip. Don’t overtighten the belt, it should have just enough tension that there’s enough resistance when you pinch it together Both motors need to have approximately the same amount of tension to ensure a proper operation of the machine.

The final stage is to adjust the steps per milometer for the new motors. Go to” Advanced settings” + “Configuration” + “Steps/mm” and adjust the steps for both the X and Y motors from 80 to 160steps/mm. With this complete, you can now begin printing once again.

So who is this mod for and when should someone consider doing this? Well, if you’re in a production setting then I would consider this a mandatory upgrade since it prevent issues before it begins. In this case, it would recommend that the user do this upgrade alongside the Bowden tube and tinned wire replacement. If you’re a more casual user of this machine, you could wait until a latter date to upgrade the motors since in most cases you won’t be tied to a specific deadline, however you do risk wasting materials and time should the motor shafts become deformed.


Yasmeen completed both the 2D and 3D animation course at Algonquin College and worked in the animation industry as a freelancer for a number of years before being hired to manage the 3D printing services at ItsYeBoi. While using the Alias of "Jenny" during her services, she was responsible for the testing, maintenance and upgrading of the machine while also filming and developing 3D printable assets for various projects.