Creating a Plastic case for a Monimotor bicycle tracker

This is the main reason I joined this maker space, to create a plastic case for my bike to house a Monimoto tracking device. Print-it-Yourself Plastic Bracket for Monimoto 9

I split the design into two halves, top and bottom and sent them into different prints files.

My first few attempts failed as I selected the wrong plate type and plastic, first TPU then ABS.

You can see the failed prints of the top half of the covers below as it moved out of place after the first 5 layers. There was warping very early on. In some of the cases, the actual base moved completely out of place.

Thanks to the advice of John and Leia I’ve made a few changes:

  • Switch to use PC material to print.
  • Set the design to the correct plate that’s actually in the machine :man_facepalming:
  • Baking the PC for 2 hours at 90 degrees C before the print.

I am just now starting the print with the new settings and will update this thread with my progress

Out of curiosity, is there any reason you’ve not tried printing it with just PLA or PETG first?

They’re obviously less durable, particularly outdoors, but I have PETG parts last for years without any issues. It would give you a chance to make sure you’ve got things like splitting the design right much more quickly. You could then come back to more exotic and expensive materials once you’re confident with that.

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Hi Hugo,

Thanks for this. I’ll likely switch materials if I don’t have any joy with PC

The first two attempts to print the top half of the case failed after the 3rd layer.

The machine (Robert) seemed to struggle with a loose filaments and get stuck in a loop, moving the printer head to areas of the plate that are not in my design.

In order to ascertain if this a problem with the printer or my design, I have started to print the bottom half of the case, which is in a different file


Unfortunately the print of the bottom half failed too and took the printer out of action

will be down the space in a bit, about 45 mins. Can have a quick look at your file. I have some ideas of what going on.

MM9 case 3D print.zip (2.6 MB)

Here are the attached files in a zip @scday94

I have to leave around 17:30 today but I’m in the area this evening, so I could pop back after 19:20 if you are around Sam?

Bambu printers will from time to time move to a corner or closer to the camera, its a self check - totally normal.

Just checked your files, look fine though I would use normal support on items like this instead of trees (everyone loves trees). How old is the filament?

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I’m not sure how old the spool is. I’m fairly new member.

So I made changes to the print as Sam recommended; reducing shell layers back to the presets, using a simplified filling pattern for the interior and most importantly, slowing the filling time to 50% which did doubled the print time.

This was a big improvement so the first 15 layers works very well, with no warping.

However unnoticed to me early on, the print somehow became offset to the left by 5mm. This might have happen when I paused the print to remove filament that was building up in the wrong place on the build.

Twice the front cover of the printer head dropped off which I had to replace.

The second time this happened the print went very wrong and it started to print a layer in the air about 10cm offset from the previous layers. At this point I abandoned the print and called it a day.

I’ll have to come back another day to see what more I can do. I believe slowing the print might help avoid the build up of plastics in the wrong place


Yesterday I successfully printed out the top shell of the case in PC, on the printer Robert

I slowed the speed of wall construction to 40% of the preset and use Adaptive Cubic as the infill.

Design File attached
MM9 case 3D print top.gcode 1.gcode.zip (921.6 KB)

There were a few hiccups, the Toolhead front cover came off twice, which I replaced.

This time I didn’t cut away stray fillaments that looked like there were going to cause the print to fail. The machine overwrote these blobs and the walls formed correctly.

There where a few flaws in the print where the side wall along one axis printed a few millimetres off. However this shouldn’t be a problem in my case.


PC is very tough material. I have the top half of a weather proof case for my bike part. Next stage is to print the bottom half of the shell to complete the project!

Thanks to those who helped me in the Maker space, not gonna lie, Tuesday was a long & frustrating day with failed prints, but yesterday everything came together :grin:

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Lower section of the case is completed, on the first attempt!

I slowed the speed of the print to 40% again, which meant there were no errors.

File attached for anyone interested:

MM9 case 3D print bottom 1.gcode.zip (1.6 MB)

The joined sections fit well and house the tracker snugly. I’m pleased how it came out in the end

:smiley:

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