Category Archives: FAIL

Printing With Steel on the Printrbot Simple

printrbot

One of the most popular pages on this blog is Calibrating the Printrbot Simple. To be honest I haven’t been using my Simple much lately, what with the hullabaloo surrounding my Barbie-Compatible 3D printed armor Kickstarter. Just don’t have the time.

My mental juice can’t be occupied by all Kickstarter, all the time, so I took a few hours to mess around with Mr. Simple, and I decided to try an experiment that’s long been tugging at my frontal lobes. Can I print something recognizable, in metal, using my Printrbot simple and some clever engineering?

There are hobbyist metal printers on the way. I saw Vader Systems’ prototype at Maker Faire NYC, and can’t wait to get one of these bad boys into the basement at Zheng Labs.

But! Enough wishful thinking. Let’s get down to brass tacks.

I’m using baling wire for this project. You can get this stuff at any hardware store. Just make sure it’s not galvanized, because that can give off some nasty zinc fumes when it’s heated up. Also, I highly advise wearing protective gear.

wire

warning Attempt this project at your own risk! There is an excellent chance that you’ll completely junk your Printrbot, or at least melt the plastic collar at the top of the extruder nozzle. Have a fire extinguisher handy, just in case. Goggles, gloves, the whole nine yards. Be smarter than I was: under no circumstances should you down three mimosas before trying this, no matter how much fun you were having at brunch.

As a precaution, you’ll also want to cover the print bed in fire-retardant tape, unless you’re willing to deal with a flaming Printrbot.

I’m planning on doing this repeatedly, so I replaced the Printrbot Simple’s print bed with a piece of asbestos tile instead. Yay for Open Source!

I just redid the kids’ room with asbestos tile and had some left over. It’s cheap and durable and I can’t believe people just throw this stuff away. Watch this space for a blog post about turning old asbestos tile into cutting boards; I’ll be putting them on Etsy once I’ve cut a dozen of them or so.

Temperature is everything here and you’ll have to move quickly once you start, so be sure to have your gCode pre-generated. Don’t waste time slicing the model before you print.

Preheat the extruder as high as you can get it. I managed to get mine up to 275°C by disabling the firmware safeties and working under heat lamps in the basement. (Printrbot firmware hacking is a topic for another day.)

Even 275°C is way too low for melting steel, so you’ve got to help the Simple across the finish line by heating your baling wire up with a propane torch. Depending on the alloy of your wire that means somewhere around 1400°C, which should be within the range of a hardware store torch.

tip

Start the print and gently feed the hot wire into the Simple’s extruder. I epoxied a steel washer onto the collar of the extruder nozzle to protect it from the hot wire. Don’t lick the glowy part!

The print was a miserable failure, just your typical tangle of filament touched by His Noodly Appendage, ramen. This is what happens when you leave steel prints unattended:

print failure

The second time through I stayed with the print, keeping the propane flame focused on the wire as extruder pulled it in.

feed

With just a little filing and polishing the nose ring looks way better than I expected it to. Not bad for a printer kit that retails for $300, even if I did have to babysit the print the entire time.

yurenjiekuaile

Permit me a brief foray into my other hobby, studying Mandarin Chinese. It’s a remarkably concise language, so cramming the entire One Ring poem (to find them, bind them, yadda yadda yadda) onto the side of the ring is easy peasy lemon squeezy.

You can compress the whole poem into five characters, 愚人节快乐. Way fewer than required in the Black Speech of Mordor.

Flagrant stagecraft alert: I printed the ring and nose separately and welded them together afterwards; I haven’t tried printing anything with support yet.

You can download the STL files for the nose ring in the Baubles section of The Forge, or if you’re impatient or don’t have a 3D printer just grab one from Shapeways.

Pro tip: I found that copying my gCode into OpenOffice, coloring it pure red (#FF0000), and then re-pasting it back into Repetier-Host helped me get the extruder nozzle up to 282°C the second time around.

On Wonky Geometry

The Faire Play Kickstarter is doing great: 17 days and 8% to go! Go give it some love if you’d be interested in seeing Barbie don some 3D printed medieval armor.

The Athena Makeover Kit’s been out in the wild for twelve days now and there are several photos of prints floating around the internet. I’ve collected two of them here.

First: Bill Owens’ print of the AMK with a cut-down spear to fit his printer’s bed, with tunic hand and machine-sewn by Maddy. Nice job, Bill and Maddy!

Bill has made some suggestions for improving the boots, which I’ll be taking into account when I release the final STL files to backers at the end of the Kickstarter.

owens large

Second, Josh Ajima’s hot-pink Aegis print, shown here with a Percy Jackson figure. Love this one.

percy jackson

Josh also made a modification to the aegis clip that will help it fit other Barbie dolls with inflexible wrists. You can download it from Thingiverse. Creative Commons licensing roolz.

5mm clip

Mr. Ajima blogs at DesignMakeTeach.com, and has all kinds of great resources for STEM educators over there.

If you’ve printed an Athena Makeover Kit, Send it my way with as much info about yourself as you care to reveal, and I’ll get the photo up on the blog toot sweet.

Early printers of the AMK might have noticed some fugliness at the intersection of the shield and medusa. To wit:

aegis fail

I’ll fall on my sword for this oversight; my initial prints handled this intersecting geometry just fine, but other folks using different slicing software have had some problems with this. Here’s what it used to look like in wireframe:

bad geometry

See how the medusa is just kind of jammed into the shield face and creates some intersecting geometry? That’ll print, sure, but it’s a less-than-optimal solution to the problem. We here at Zheng Labs prefer to minimize less-than-optimal solutions.

So! Here’s what it looks like now. I’ve welded the vertices together and now the mesh is watertight as the proverbial frog’s ass.

joined geometry

The final print result is now much improved. Go on over to The Forge and Download the latest and greatest model.

aegis better

Can’t wait to see your prints.

Plunger Fail

Lately there’s been a proliferation of 3d printing failure blog posts percolating around the twitterverse. I’ve got plenty of these on the blog already, so I’m dropping another one in the spirit of mutual commiseration.

Plunger Fail

I’ve been printing dozens of bloxen in preparation for Maker Faire NYC lately, and finally managed to wear out one of my delrin plungers. I had two or three days of intermittently failing prints before I figured out the problem.

I printed a new one, but printing a replacement plunger while using a faulty plunger leads to interesting results.

Ultimately I held my filament in place manually while the replacement plunger printed. It’s a quick print, about five minutes, so it was a good time to put a little dent in my Netflix queue.

Quality Control

I recently released a Magic: The Gathering Snake Token into the wild, but many iterations of the model got left on the scrap heap before the final slithered off the build platform.

Here’s one that made it all the way to the light tent before I realized the many problems it had. Sometimes you don’t see all the problems until you really dig into a macro photograph.

Snake QC fail

  • overhang: violations of the 45° rule. Not terrible on this one.
  • scrubbing: the model’s too thin here. ABS or a cooling fan might help.
  • nickeling: not enough geometry to make a smooth curve in the body
  • schmutz: really should have filed this off before painting.
  • I can forgive a little bit of overhang on a model. Sooner or later some 3d printer manufacturer’s going to lick that problem for us. Scrubbing is a technical issue too, and schmutz removal is a time-honored pre-photography process that I was just too lazy or preoccupied to do on this model.

    It is the nickeling that I shan’t abide.

    I come to 3D modelling from a video games background, where realtime constraints force model efficiency. When I was a lad with an onion tied to my belt, which was the style at the time, we designed characters with 150 triangles and we liked it that way.

    So every now and then I forget that I’m not living in 1997 anymore and I can be a little more luxurious with the poly count. It still feels dirty though.

    So Ms. Cobra went back into the Forge, got subdivided again, re-posed, edited, tweaked, and was reborn as the final product you saw a day or two ago.

Penny Ballista Fail


download Still using the demo spool of recycled ABS supplied to me by Filabot. When this print doesn’t fail it creates a Penny Ballista that’ll easily launch Abe across the Oval Office.

I left my Replicator1 unattended for a few minutes and came back to this. This fail isn’t due to any flaw in the filament– if you look closely you can see that the texture of the filament’s very even. Unfortunately, robots don’t do what we want them to do, they do what we tell them to do, and the slicing step of this print went to Wallyworld at some point.

I’ve been having this problem with some models sliced in MakerWare lately; it doesn’t seem to want to add a solid bottom layer to some prints. So I hopped back to ReplicatorG and it sliced just fine; see my previous post.

Annals of Seemed Like a Good Idea at the Time

Nozzle Fail

When cleaning a clogged extruder nozzle with a power drill, do not, I repeat, not have Pussycat Dolls videos playing on YouTube in the background.

For that matter, you probably shouldn’t try to clear a clogged extruder nozzle with a power drill under any circumstances.

Usually I leave my nozzles in a shot glass full of acetone for twenty minutes, then use the drill bit by hand to snake out a bit of cruft. Then back to acetone to soften up the newly exposed plastic, then drill, then acetone, then drill, then acetone yada yada yada until the cows come home.

This time I said to myself, “Zheng, old chap, this is awfully slow. You should apply a tremendous amount of torque to this expensive part while not paying attention. That will resolve this problem with minimal downtime.”