Upgrading the MonoPrice Mini Delta Bearings

Introduction: Upgrading the MonoPrice Mini Delta Bearings

About: Slinky Harmonics Engineer by day...


For the following upgrade, you will need the following :

> Socket wrench with a 5.5mm socket

> Phillips screwdriver

> 2.5mm hex screwdriver

> Medium / large spudger

> Hammer

> Extra long 5/8 socket piece (as a base to remove the bearings)

> A large hex screw (to push the bearings out of the carriage)

> Some SuperLube with PTFE grease (transparent)

> a set of Pliers

> a small rag or piece of cloth (to protect the rods)

> 6 x Igus RJ4JP-01-08 self-lubricating plastic bearings

> Some time and the will to finish the job...

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Step 1: Welcome to My Nightmare!

My MonoPrice Mini Delta is only 6 days old and the Z-axis bearings are dead (Great quality MonoPrice!) They get stuck every time and makes the nozzle take a dip onto the lower layers (As you can see in the pictures.) I noticed that the other bearings in the X and Y axis were also "dry." So I decided to find the well recommended "SuperLube with PTFE." It did work wonders for a while but this grease can not fix something that was "broken" or bound to break due to poor manufacturing.

The final answer came in the form of the Igus RJ4JP-01-08 . They are plastic bearings that are self-lubricating (they release what seems to be silicone oil) However, Igus does recommend a light coat of silicone oil / grease to enhance the lifespan of their product.

Step 2: About the MonoPrice Mini Delta

Well, this 3D printer sells between $150 to $280 depending on where you are located.

Even though, it is considered a beginner's 3D Printer, I have to say that it is not for the faint of heart. MANY things were left out from this printer... for example a power button.( No, really, who designs a semi-robotic machine and forgets the power switch!! )

This machine also needs manual coding and other users have been known to change parts under normal use in less than 4 weeks due to poor OEM parts, failures or other things that add up.

If you are not in the USA... good luck trying to find tech / warranty support or parts for this printer...

Step 3: Belts and Cover

So, to start the process we need to gain access to the top of the printer and release the tension on the belts. There are 3 belts regulated by a small 2.5mm hex screw in each top corner. In my case, I want full access to the Z-axis which is located on the back of the printer.

Step 4: Z-Axis , Nuts and Socket Wrench

So, the Z-axis in my case, is located on the back of the printer. The circular ball bearings have stopped working. So, we need to remove the 2 arms that attach the carriage to the nozzle / heater block area.

You'll need a 5.5mm socket wrench to remove 2 nuts, 1 on each side and 4 lock washers. You may also need to move the arms down slowly one by one to gain better access to these nuts. The arms will take a little jiggling to free them from their position.

p.s. - keep an eye on these tiny parts, especially, the lock washers...

Step 5: Removing the Bottom Panel

So, now turn the 3D printer over and remove the bottom panel. HOWEVER, be careful with the small wire for the fan.

Lift the panel a little bit first and locate the connector wire for the fan to the motherboard.

Disconnect the wire and remove to panel out of the way...

Step 6: Removing the Rods...

So, If you have not upgraded the legs of the printer yet, You should be seeing 3 transparent plastic pieces (you do NOT need to remove these) Only remove the legs if you have the extra large enhanced legs.

Remove the screws holding the plastic corners down and pry it up slowly using the spudger.

Once you remove the corners protect the rods with the cloth and pull them out with the pliers.

* Since you are there now also move the belt out of the stepper motor gear.

Step 7: Removing & Replacing the Bearings From the Carriage

Remove the carriage from the 3D printer (you do not need to remove the belt.) However, it is good practice to remove the little wing for the optical sensors (you'll need the 2.5mm hex screwdriver to loosen up the 2 screws.)

Using the 5/8 socket as support, slowly hammer out the bearings from the carriage (a large screw can help you move them out of the way.)

Step 8: Igus Time!

Now, all you have to do is just drop the Igus plastic bearings in place and tap them a little with the hammer to place them in the correct spot.

You are done!...

Reassemble the printer in the reverse order and remember to adjust the belt tension.

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    4 Discussions


    Question 1 year ago

    Thanks so much for the tutorial!
    While this isn't exactly a forum, I'm hoping you might be able to give me a little advice. After replacing the bearings and rebuilding (which seemed to go smoothly enough) the first thing I did was test the Move>Home function, and the printer head rammed into the plate and stayed there.

    Any advice as to what I might have broken?



    Answer 1 year ago

    Hi ,
    Make sure the sensors are it the correct place and that everything is back where it should be. Is the carriage “wing” in the middle , pointing the right way?


    Reply 1 year ago

    Finally found time to look at it again today :D.

    The light sensor was in the wrong orientation in my case, and msutface down (I definitely regret not taking pictures before taking the unit apart, but google images and your guide came to the rescue!).

    How I messed it up is beyond me since I never removed the sensor from the belt when changing the bearings, but alas I managed to do it.

    Thanks again X0n1T3 for taking the time to help me out!


    Reply 1 year ago

    Sorry for the delay, and thank you for the response! Moving house has put me more behind schedule than I'd hoped.

    I did not remove the optical sensors, but they look to be in great condition. I'm not sure if the video will show up, but the printer literally runs straight down into the build plate, never moving up to the optical sensors. I tried to find a video of someone else running the home operation to recall what it looks like but haven't had any luck.

    I'm not 100% sure what you're referring to when you say carriage wing, but I have included a photo of the carriage and optical sensor

    Thank you!