On 3D Printing - Part 1

Earlier this week, a wild package arrived on my front porch. Inside of it was another box. Inside of that box was another box (seriously). Inside of that box, was a Monoprice Select Mini 3D Printer.

It was an exciting day for us.

We eagerly unboxed the printer (no photos, sorry, I'm feeling lazy) and and set about printing our first object, this cat, which was the test object on the included SD card. It came out well. There was a little bit of z-banding, but no more than I expected for the printer's resolution and more importantly, its $199 price point. Everything looked great!

So then we started printing dungeon tiles for D&D (because we're neeeeerds). All in all, the little MP Select Mini ran for about 12 hours yesterday, doing a total of 4 print runs.

We had some issues with the thin tiles not adhering to the bed in a couple of places, but that was easily fixable by adding a brim and bumping up the bed temp by 20 degrees (it had been a bit on the cool side to start with).

All in all, it was a good, successful day of printing and I fell asleep last night to the musical tones of the printer doing its thing.

Then, Tragedy Struck!

The next day, I decided to begin realizing my dream of building a reasonably accurate replica of a PPG from Babylon 5... and things kind of fell apart.

The hot end, when returning to the home position, suddenly would not stop lowering and the nozzle would push into the bed so hard that it actually damaged the aluminum slightly.


No amount of tinkering with bed leveling would fix this, and in fact, you could level the bed perfectly and it would be fine during the level test, but as soon as you started to return the printer to its home position, wham!.

I Googled until my Googlers were bruised, found a few videos and one wonderful document that someone had generously curated on common issues and their solution with this particular printer (among other things).

It really seemed like the issue lay with the z-axis limit switch, which reportedly could be mounted rather loosely from the factory. Sure enough, taking a look at my printer, when the arm descended, it didn't appear to be hitting the switch evenly.

In the hopes that this was the issue, we popped the cover off intending to fix the switch alignment, only to discover that it wasn't nearly as misaligned as it had looked when we tried to peer into the inner workings of the printer with the cover on. Yes, the arm was only hitting one side of the switch, but it only needed to.

So we plugged it back in, started lowering the print head and manually depressed the limit switch, which should have stopped any downward movement.


It just kept right on going.

So either the switch is bad or something on the control board is bad.

And you know, maybe it could be fixed, maybe even easily fixed... but the thing's 24 hours old and I just shouldn't need to be taking apart things that are 24 hours old in order to fix them.

So what now?

Back to Amazon it goes! I'll let them give me a refund and I won't be replacing it with another MP Select Mini. The UPS guy should be here to pick it up sometime today.

But I don't consider this whole endeavor a failure. Buying this little Monoprice printer was a great way to get a taste of 3D printing without a huge investment. We had some specific use-cases in mind for it when we bought it and during the time it worked, we were able to test those use cases to see whether or not a 3D printer would really fit our needs.

In that, our time with this little printer was a success.

To that end, once we'd processed the RMA, we ordered another printer. It doesn't have a ton of reviews, but the ones it has are good, and it looks like another nice, budget option that will give us a bigger build surface and 2x the resolution of the mini.

I would have been very happy with the MP Select Mini for a long time had it worked, but since we were returning it, it seemed like a good opportunity to upgrade.

While it's twice the price, assuming it works as advertised, it's also an upgrade. If it doesn't, I'll box it up and ship it back to Amazon, save my pennies, and get an Ultimaker 3 in a few months.