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How I bulletproofed my Monoprice Select V2 3D Printer

This post is less of a tutorial and more of a list of the modifications I made to my Monoprice Select v2 3D printer. This was my first printer — and I spent dozens and dozens of hours tweaking it to get reliable prints. I can’t recommend this printer highly enough, however, if you want to become familiar with the way 3D printing works on a platform with endless support and documentation online. I highly recommend this website for learning more about this and other 3d printers:

Purchased Parts

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Solid Aluminum Y Carriage Plate Upgrade: The plate included with the Select v2 was the absolute bane of my existence. I was having to re-level on every print. This was probably the most important upgrade I performed, paired with the conversion to 3-point leveling (you can’t do that with the factory plate).

Borosilicate Glass Print Bed: Printing on glass was another game-changer for me. A light misting of purple hair spray every now and then was all it took. Many of my prints would actually pop off of the glass by the time it cooled down. It’s also nice to have multiple glass plates to swap out between prints rather than having a single surface to clean and prep repeatedly. I kept my glass on with small binder clips.

120mm Cooling Fan Upgrade for Control Unit: You’ll need to print a replacement back cover for the controller box, but this fan blows the factory 40mm fan out of the water. A word of warning: depending on your fan choice, this can be loud. The difference now is that you’re hearing air movement vs. the shitty bearings included in the tiny 40mm fan initially. You’ll never worry about overheating the Melzi or MOSFET again, though!

Part cooling and hot end fans upgrade: The factory fans left something to be desired.. and the bearings were NOISY! I replaced both the part cooling and hot end fans with these and never looked back. PS: The parts cooling fan – take out the left side mounting screw and swivel the fan to aim directly at the parts. Free mod for more effective cooling.

Heated bed MOSFET upgrade: The biggest issue with the Select v2 and other i3 clones is that they drive the heated bed directly from the Melzi board. What happens is that eventually, the connectors melt down and you’re left with a repair to make — or a fire. For low cost and relatively low-effort, you can install what equates to an automotive relay– your Melzi board heated bed connectors will only trigger a connection between the power supply and heated bed. Safety third! See the printable mount for this down under the “Printed Parts” section. You’re also going to want some 14AWG stranded silicone wire, spade connectors (I always use heat shrink crimp terminals), and a good ratcheting crimper.

Other mods & printed parts

ZBrace Mod: This tutorial walks you through using printed parts and threaded rods to add rigidity to your i3/select v2. There is a finished kit by Gulfcoast Robotics that can be had for $40 (here). For the price, I’d recommend the kit over going DIY with threaded rods.
Rear Cable Conduit: This was beautiful for cable management and overall appearance, it also kept my harnesses from getting tangled up.
3 Point Leveling Conversion: This eliminated SO much headache. You must have the upgraded aluminum plate that I linked to above. I would recommend printing oversized adjustment knobs to complement this mod.
LED Strip Mounts: Once you’ve done the Z-Brace mod above, you can print and attach these LED strip mounts to the diagonal rods. They look great, and really help if you’re running OctoPrint with a camera for remote print monitoring.
MOSFET Mounting Bracket: The heated bed MOSFET upgrade is super cheap and can save your home (or at least your printer) from a meltdown or fire. This bracket attaches beneath the melzi board in the control box and lets you mount the MOSFET board to it.
40mm Fan Grilles: Fastener-less fan grilles for your parts and hot end fans.
Control Board 120mm Fan Adapter: This replaces your control box’s back cover, allowing you to upgrade from a 40mm fan to a 120mm PC fan for ultimate cooling power.