8th Grade MP3DP

I thought I would document my daughter’s MP3DP build here. My daughter is the current 7th Grade Indiana Science and Engineering Fair State Champion. Her research last year was on devising a protocol to “heat treat” PLA. For this years project, she is going in a bit of a different direction in 3D printing but wanted to COMPLETELY understand the ENTIRE process of 3d printing so she decided that she wanted to build her very own 3d printer from “scratch” (or as close to it as reasonably possible for an Honors 8th Grader). The building of the printer is NOT her project! This is very important to understand. Its simply a tool to be used in her experimentation and to provide more background knowledge for her research. More to follow as we proceed.

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More pictures of her build…
Rebecca has been a “maker” from a very early age. Can’t imagine where she got it from;o). LOL!


Rebecca using one of my drill presses as an ARBOR PRESS to insert the bearings. While not completely necessary, she liked the “control” it gave her to make sure they were installed properly. I have to admit, I did too!!!

LIMIT SWITCHES: We were not sure how well zip ties would be for the limit switches. We are using 4in zip ties with 30 lbs of load capacity. Using a pair of very nibble needle nose pliers, we were successfully able to thread each zip tie correctly. She was able to cinch-down the zip zies by grabbing ahold of them at the lock and rotating the pliers in a counter clock wise motion. This created more than enough torque to cinch them down good and tight! The zip ties appear to work perfectly for this use.

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Very cool!

Ah! Are those long screws ones that adjust the limit switch position? I think I remember the holes but didn’t know what they were for. What size and type of screw did she use?

The limit adjustment screws are 3" 10x32

Ran into a a couple of problems last night that really slowed down our progress. First we felt that the RIGHT Z axis lead screw was binding up. While we could still rotate it, it was not as free as the LEFT side. After loosing all nuts and bolts, it was still binding. I replaced the lead screw NUT with a spare (I ordered two sets) and the issue went away. Weird! I think it was just something with the way the nut was seated. As there does not appear to be any issues with the original nut and turned freely in a different lead screw. Once we tightened everything back up, it turned as freely as we expected and equal to the LEFT side. The other issue we have we have not found a solution. We ordered out acrylic kit from TWELVEPRO. The build PLATE appears to be slightly different than the build plate that Ryan originally posted. WE will we have an issue with Y range. Check out the pictures and give us your opinion please… Jon

Looking at the above pics, we feel we have enough -Y range, but as you can see from the pic, we don’t have enough +Y to get to the edge of the build plate.

Is the zip tie hitting the bearing?

No, it is the front bearing (on the double side) that is hitting the front panel that is restricting the build plate from moving far enough. We did a mock up tonight with the heat bed in place. I think we are going to be Ok, but it is really close. Looks like we might be looking a couple of mm of build area. Not gonna worry too much about it for this first printer.

Here is an other question Ryan. We bought heat beds from the link that you referenced. These beds DON’T have the LEDs soldered to the board. We don’t need them, right? I mean, my ROBO doesn’t have anything that tells me the bed is hot so I don’t think Rebecca needs that either. We are going to solder up the heat bed tonight as long as I don’t have to source surface mount LEDs today;o)



Nope no LED’s needed. If you want them any will work really, but it is just an indicator when the power is on to the bed not when it is actually hot.

Hardware assembly is complete! She has moved on to electronics! She received a MAJOR donation yesterday from one of the leading 3D software developers for her research project! We are full steam ahead!!!

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Heat bed silicone is setting up as I type this…

Cool! If you have some, put some kapton tape over the power lead solder points on the bed. You really don’t want that to short!


Can’t we just use the hi temp silicone?

As long as it’s not the copper stuff. I’ve seen that stuff conduct before.

I would slide the extruder over a bit more I clamp on the silver ring closest to the hot end.


Do you think we could use HI TEMP hot glue to protect the heat bed terminals?

Wouldn’t try hot glue. It might work for a while, but the heat will degrade it. Do you guys have a micro center close by?

Protect them from what?

There are 4 holes in the milled bed part so you can cable tie the wires down to stop movement.