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Prusa MINI+ 3D Printer

This is not really a review of the Prusa MINI+ 3D Printer. There are plenty of full reviews out there. What this is though is a post about my own experience with the Prusa MINI+, at least the first week with it.

First, some background. I am not new to 3D printing. My first post about 3D printing was in 2011. (See them all!) I got my first RepRap working in 2012, and helped start the Milwaukee 3D Printing Meetup the same year. I was using printers at Milwaukee Makerspace, UWM, and other places around town (including at work) and in 2017 I replaced my ageing RepRap with a Monoprice Maker Select Plus. So I went about five years between printers, which is fitting, because it’s five years later and I just got another printer. (I’m not counting the Creality machine I gave to my daughter or the Maker Select v2 I just gave away to someone I know.) So yeah, I get 3D printing. ;)

So while the Maker Select Plus served me well (after a few upgrades) I wanted something a bit better in the quality department. Years ago I spec’d a Prusa i3 at work to replace an ageing (and often broken) MakerBot and I loved that machine. I basically told everyone I knew to get a Prusa if they could. (They got a whole bunch of them at Milwaukee Makerspace.) The experience was top notch for someone coming from the old RepRap/Pronterface world. Alas, I left that job and left the Prusa behind.

Print quality from the Maker Select Plus was pretty good, but I’m hoping for much better quality from the MINI. One important thing to note is that while the MINI has a smaller bed, it can probably print more reliably across the entire bed. I’ve found that cheap printer with large beds don’t always excel at using the entire bed. Part of this is probably leveling. While I’ve been a gruff old veteran who says “Argh! All ya need is a sheet of paper and some patience to level things!” the probing and leveling system of the Prusa is great. (Yes, I know I could add it to the MSP, and upgrade the firmware to support it and… at this point I really just need to print.

In 2021 I started having to print more quality items that were for sale, and sometimes it was difficult to keep up and get good quality prints. I started eyeing the Prusa MINI again. I finally decided to grab one (after selling some other equipment I didn’t need) and it arrived in less than four weeks, which sounds like a long time but I was expecting 6+ weeks. So that’s a win.

As for the actual experience, here we go. Assembling it was a bit of a pain. I’ve put together two Ender 3 printers and it was very simple. The MINI assembly (while not many steps) kind of sucks. Maybe because I expect a certain level of Prusa experience. Luckily you should only have to do it once. (To be clear, I got the assembled model, so it was just bolting the two halves together, plugging in and routing all the wires, and that was it. Still a painful experience.) Remember how I said “you should only have to do it once”? Well…

After assembly the setup and calibration was great. Excellent experience! The machine walks you through the process very smoothly. I then did a test print found on the included USB drive and it looked good. (I used some Hatchbox filament, not the included Prusament.) So yeah, cool! From opening the box to getting a first print was a little over an hour in my freezing cold basement. I called it a night.

The next night I went down with a file I sliced with PrusaSlicer (which is a really nice piece of software) and get ready to print it but… ERROR! It showed an error on the screen. You can then look up the error code online or scan the QR code with your mobile. Seems the hotend thermistor was having issues. I checked on it, including opening up the enclosure to check the wiring, thinking maybe I didn’t secure things. Again, the wiring is a pain. Ugh. Painful. But at least I was getting used to it. So here’s the deal… It was cold in my basement, and this printer is so smart (ha!) it thought the thermistor had failed because, well… if the reading is that low, something is wrong. The only thing wrong was that I have a basement in Wisconsin. I ended up pointing a space heater at the printer until the thermistor read warm enough to pass the check. (It was honestly just a few degrees, but still.)

Okay, that was the second night. Not great, but a little annoying. I get why they do it, but hey, it’s winter in Wisconsin. I know how cold my basement is. And yes, the cold may affect the print quality. I know that.

Right so time to print! I put in the included USB drive and… nothing. It doesn’t see the thumb drive. Oh hell, now what!? I go upstairs to my computer, insert the drive, and… it’s corrupted itself. Damn. My old printer used SD cards and they always worked. Is this going to be a normal occurrence? I hope not! I reformat the drive, then copy files to it again, and I print. All good. (Note: The drive had been fine since then, as is the other one I use for printing.)

A bit of a rough start, but overall I am really pleased with the machine itself, the experience of using it (apart from the few hiccups at the beginning) and that printing plate is awesome. I was at first worried about the “bubbles” that appeared on the surface, because the (cheap) plates I’ve used with the MSP wear out, but I’ve been told these will last… and they sort of “self heal” after a bit of time. Sweet.

Now of course the real test is when things go wrong. With the Prusa i3 I used at work, it was amazing, but once we had to tear down the extruder to deal with a nasty clog and that was a nightmare. So time will tell as far as how things go when things go wrong. Right now I can pull apart the extruder to remove a clog on my MSP or an Ender 3 in less than ten minutes. For the MINI, well… I don’t know yet. Maybe it won’t clog. (Ha! Just kidding! It will. It’s a 3D printer after all.)

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Creality Ender 3 V2

Hey, this is not my printer! I’m still mainly rocking my Monoprice Maker Select Plus with a number of upgrades over the years. It’s printing well enough, though I tune-up is probably in order one of these days… And yes, my RepRap 6000 is still in progress.

But this Creality Ender 3 V2 is what we’ve got at work now. As we’ve been making more 3D files (and parts) the old Monoprice MP Select Mini was showing its age and… it’s loud. The Ender is much quieter, which is nice.

We’ve already done a few upgrades, including adding OctoPrint and a Pi with a touchscreen, new PEI flexible sheet, and metal pars for the extruder. We had a bunch of issues extruding filament at first but I swapped the nozzle and all was good. It’s only been a few days but so far I’m impressed with quality the way I was when I replaced my 2011 printer with a new one in 2017. I’m still not a huge fan of Bowden extruders, but I can see the appeal and reasons for them.

Oh, I will note that I assembled this using the printed instruction book that came with it, then later realized the included SD card had a video that was ten time better at showing how to assemble it. This isn’t the first time I’ve found printed directions lacking in comparison to video. This doesn’t mean video is always better, it means people are bad at making printed directions.

Oh, I forgot to mention my other other printer. A Creality3D CR-20, which I picked up from MatterHackers at a discount after a giveaway win last year. I gave it to my daughter and her boyfriend to babysit for me until I get room in my shop. Yeah, I expect to have room for it by 2024 or so. Happy Printing!

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RepRap Y Carriage

acrylic-bed

Contrary to what the photo above may suggest, I am not using a laser cut acrylic piece for the Y carriage of my RepRap… What I am using it for is a template to make sure things work properly, and once I’m sure I’ll use it as a drilling template to mount things on the Aluminum Y carriage I have. (Which Frankie gave to me, oh, maybe six years ago!?)

y-plate-metal

Here’s the Aluminum Y carriage. The photo looks weird because it’s from my flatbed scanner. I often scan objects so I can bring them into Inkscape and trace them to get a vector drawing I can work with. (And I had to scan it in two passes and stitch it into one image.)

y-plate-drawing

Here’s the SVG file created in Inkscape by tracing things. Notice I added more holes, which will be used to hold the bearing blocks.

acrylic-fake-bed

It seems to slide pretty smoothly. I mentioned in a previous post, the igus drylin slide bearings want to be under some pressure to work properly, so I adjusted them just right with the blocks I printed and did some slide tests. So far I’m pleased!

Next up will be the holes in the Aluminum. I’m not sure if I should drill and tap for 3mm bolts, or drill for pass-through of 3mm bolts and hold in place with nuts. My thought on the first method is that my alignment via drilling has to be perfect, while with the second method I can adjust just a bit with some slop. Thoughts?

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Rapid RepRap Disassembly

reprap-disassembly-01

Part of the process of [re]building my new RepRap 3D Printer involved disassembly of my old RepRap 3D Printer. It felt strange at first taking it apart, probably because of all the hours I spent putting it together, but it also felt sort of exhilarating.

reprap-disassembly-02

Wow! I forgot how many nuts and bolts went into building a Prusa Mendel. The BOM calls for nearly 90 M8 nuts. The good news is, I can reuse all of these components. I don’t think I’ll have to buy any M8 nuts or washers for quite some time, and the threaded rod should come in useful in the future.

reprap-disassembly-03

Here are all the components I reclaimed. I disposed of all the printed plastic parts, though I will admit that inspecting them before disposal gave me a few ideas for how parts should be designed.

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RepRap (More) Printed Pieces…

x-carriage-00

I’ve put a lot of time into the x-axis left side recently. It’s one of the more complex pieces and I really don’t know if I’m doing it right but I can’t wait to find out if it works. Since I’m starting with some existing parts, I need to design it to fit those parts. (I originally thought about using other existing designs that are available, but it would have meant purchasing the exact parts to fit, so here we are.)

x-carriage-model

Here’s my model. I’ve hidden the motor, rods, star nut thing, bearings, etc. This is just the part I printed. It seems to do all the things I need/want it to do, but it’s not on the machine yet, so who knows?

x-carriage-02

Here’s the print, with the pieces attached. Seems to look okay, that’s a good sign, right?

x-carriage-01

One of the interesting things about this project is that when I started designing my own pieces I also started to pay more attention to other designs out there, and that’s caused me to think about the decisions people made. Often decisions are made based on print orientation of FDM printers, or amount of material, etc.

support-blockers

I also learned that Cura has a feature called “Support Blocker”, which allows you to set areas where support will not apply. (Here’s an explanation, since I can’t find official docs on it.)

bearing-holder

I also got some 12mm igus drylin slide bearings for the y axis, and printed a holder for them that allows them to be put under pressure for a solid fit. Things are moving along now!