PLA Shrinks Too

October 27th, 2019 by Keith Neufeld

Everybody all, “ABS bad, it shrink when you print it,” and I’m, “Yo, dog, PLA shrink too.”

3D-printed PLA box

That’s a box with 2-mm walls and a 2-mm base. Hatchbox PLA. The layers of the base that are not stuck down to the hot build platform shrank right up.

Don’t be up in my grill about PLA being nature’s perfect filament. I need me an enclosure.

Calibrating Filament Diameter, Nozzle Temperature, and Extrusion Multiplier

October 27th, 2019 by Keith Neufeld

With several filaments I’ve used lately, I get a rough surface on the top of my prints that makes me think the printer is depositing too much filament. I took a bit of time today to learn how to calibrate that; and one of the same tutorials gave a nice reference for nozzle temperature calibration, so I did that, too.

3D printer extrusion multiplier calibration cubes

These notes are as much for me as for thee, as I expect to run through this again with more filaments in the future.

Read the rest of this entry »

So I Bought a Prusa i3 MK3S 3D Printer

August 15th, 2019 by Keith Neufeld

Yup, went ahead and did it. I’d been holding off because I really want to fix the printer I have and I was afraid that getting a new printer would remove my interest in doing that. But I’m happy to say that my insight into my own psyche after I’d given it more thought turned out to be correct — having a working 3D printer makes me feel more motivated to get my CupCake working, not less.

Prusa i3 MK3S 3D printer

While shopping and looking at pictures and videos, I had a hard time envisioning exactly what the Prusa’s build capacity was. Some pictures looked like the build platform was huge; some looked like it was scarcely larger than the CupCake’s. I think there’s a lot of wide-angle lensing going on in the world of 3D printing videos. So here’s a shot for you with a reference standard, for your size-interpreting convenience.

I might even write posts about it from time to time.

Reason #1 to Love OpenSCAD’s 2D Subsystem: Fillets

June 12th, 2019 by Keith Neufeld

I just designed and printed a battery holder and I’m shamelessly reusing this image from the blog post about it to illustrate fillets in 3D design:

3D-printed holder for Makeblock mBot robot LiPo battery

You might notice that the holder’s mounting bosses have nice roundy fillets that are standard in professional CAD packages and have been a wee bit difficult to achieve in OpenSCAD until fairly recently. The ability to design them now is one of two observations in the last week that have really driven my interest in OpenScad’s 2D subsystem. If you’re not interested in OpenSCAD, you’ll probably want to stop reading now. (Who am I kidding — I’m sure that the two of you still reading are interested in OpenSCAD.)

Read the rest of this entry »

3D-Printed Makeblock mBot LiPo Battery Holder

June 12th, 2019 by Keith Neufeld

I’ve assembled a couple of Makeblock mBot robots I picked up a few years back and intend to start programming soon. They come with a 4xAA battery holder, but I’m not a fan of single-use batteries and Makeblock’s LiPo is only $10 on Amazon [no affiliation and not an affiliate link, just a happy customer], so I ordered a couple.

The LiPo batteries came in clear plastic cases with tabs that looked like they should latch into the slots on the robot chassis, but the spacing was off. The robot kit came with hook-and-loop tape to fasten down the battery holder, but yuck. So I designed this holder, which is good enough to use after a single pass of dimensional refinement.

Makeblock mBot robot with 3D-printed LiPo battery holder

Many thanks to my student employee Kip for printing the battery holder on his Prusa I3 MK2s. The quality is outstanding.

I’ll upload the design to Thingiverse after a bit of code cleanup.

Read the rest of this entry »

Chewing ABS to Make New Filament

August 16th, 2018 by Keith Neufeld

Like many other 3D printer owners, I’ve long dreamed of processing post-consumer plastic into new filament for printing. I’ve now taken a couple of steps in that direction.

ABS plastic pelletized with sheet-metal nibbler tool

Read the rest of this entry »

Booting the MakerBot CupCake after Five Years Part 3: Heated Build Platform and First Print

July 9th, 2018 by Keith Neufeld

Friday evening I left off with the extruder working again. Saturday I focused on the heated build platform.

I’ve always had astoundingly good luck with kapton tape since nophead’s serendipitous discovery, probably because I (still) prefer to print in ABS. When the build platform is warm, my prints stick to it absolutely with no raft or mouse ears and once it has cooled, they release easily. That’s a pretty compelling combination.

kapton tape for MakerBot CupCake heated build platform

So my first step was replacing the scraped-up kapton that I gouged the last time the printer was on. I bought a 4″ roll way back when and I keep a strip of unsticky tucked under the end so I don’t have to peel it up with fingernails and get fingerprints on the stickum.

In the past I’ve always replaced the tape by sticking down the end and using a credit card to “squeegee” it onto the surface, and it can be tough to avoid getting bubbles. Yesterday I unrolled enough tape to cover the platform and when I had it stretched out, it was easy to align the front edge of the tape with the front edge of the platform, at which point I squeegeed it down with my thumb with no bubbles at all. Huh, well, I guess I’ll remember that.

Read the rest of this entry »

Booting the MakerBot CupCake after Five Years Part 2: Installing Software

July 7th, 2018 by Keith Neufeld

The next step in running the CupCake 3D printer is reinstalling the software and connecting to the machine.

ReplicatorG 0026 main screen

It went surprisingly well, with the only real snag being my misremembering the installation process, leaving me stuck in NotConnectedLand for a while.

Read the rest of this entry »

Booting the MakerBot CupCake after Five Years Part 1: Powering Up

July 6th, 2018 by Keith Neufeld

I devoted Wednesday, my Independence Day holiday, to getting my CupCake 3D printer running again.

MakerBot CupCake

Foreshadowing: It turned out as a pessimist might suspect rather than as an optimist might plan.

Read the rest of this entry »

Why I Haven’t Touched the MakerBot CupCake for Four and a Half Years

July 4th, 2018 by Keith Neufeld

After making the filament de-duster five years ago about which I posted recently, I was finally getting consistent, reliable, beautiful 3D prints for the first time ever. For a month.

Then I was trying to print a draft of a pocket holder for a tube of moustache wax and comb and when I came back, I found that something had gone wrong after about 40 minutes of printing. I forget the order in which these occurred, but through the original attempt and two retries it:

  • kept running the filament while printing so the model snagged and the X-Y build platform skipped steps and lost its place; then when the print finished, kept the extruder on forever, creating a thumb-sized fungal growth of plastic
  • kept moving the X-Y build platform but stopped extruding
  • kept moving the X-Y build platform but shut off the nozzle heater, chewing a divot through the filament

failed MakerBot CupCake 3D print

The second try, I ran another print of the same model; the third try, I made a tiny dimensional change to the model or Skeinforge settings in case the extruder controller was glitching on some particular G code; but that doesn’t seem to have been the case. I got different bad behaviors and it seemed as though the extruder controller stopped taking instructions and kept doing exactly what it was doing at that moment.

I don’t know whether it’s a firmware bug, a power supply problem, a wiring problem, an extruder board problem, or something I haven’t thought of yet. I have (recently) found reference to a few of the DC extruder motor windings shorting, reducing the coil resistance and increasing the load, to the point that the extruder controller FETs burn out. But these weren’t burned out — they worked again immediately (for another 40 minutes).

And then before I could muster the motivation to troubleshoot it, both my laptop SSD and my workstation motherboard crashed, leaving me no working computer with 3D-printing software installed and no working computer with my CupCake’s calibration settings on it. And then time passed; OSes were upgraded; ReplicatorG versions increased; the barrier to reentry increased substantially; and I simply have not touched it since early 2014.

This shall change.