Monthly Archives: August 2012

Seej Pillar

My Seej fortifications have been looking a little mundane lately so I designed this seven-piece fluted column to add a little bit of architectural elegance to my battles. It handily interlocks with existing Seej bloxen, and collapses spectacularly when hit with a penny from a Seej engine.

It’s pictured here with a Riveted Bloxen for scale.

This post was originally going to be about how to adjust your gCode by hand-tweaking it to get a good raftless PLA print, but then I went ahead and downloaded ReplicatorG 037. Editing gCode wasn’t necessary, except to set the HBP temperature to 65°.

Perfect print the first time out, even with a relatively complicated model like this one. No hocus-pocus required.

1.75mm Blue PLA (available at Amazon)
Infill 10%
Layer Height .20mm
Shells: 1
Feedrate 25mm/s
Travel Feedrate 55mm/s
Print Temperature 190°
HBP Temperature: 65°

Download it here.

Blazing fail.

This is a failure of a Seej Masonry Bloxen.

I stuck an LED inside it to highlight the software-generated infill pattern.

ReplicatorG does this cool thing when preparing the model for printing, generating a honeycomb pattern for large solid volumes. Presumably this feature was designed to save plastic and printing time.

It’s like magic the first time you see it in action.

This is a PLA print at 10% infill. One hundred percent infill would print a solid block of plastic.

Chinese is puzzling.

My Chinese teacher is on vacation this month, so while my spoken proficiency withers on the vine I thought I’d brush up on my geography. Laoshi is visiting Xinjiang, which as I understand it is like going to Wyoming but with spicier food and fewer AK-47’s.

I don’t expect this to be one of my more popular models; the last time I tried combining my hobbies I wound up with the Happy Family Chopstick Rest Set, which is bumping along the bottom of the lake with 23 downloads as of today.

Seej models are much preferred by Thingiversians. The Seej Starter Set is at 431 and the Penny Ballista is well over 1200 (!) downloads by now.

A 3D map of China is a pretty nichey thing, but the design and printing process has been a really valuable educational experience for me, so time well spent.

The first approach to this model was the straightforward one– find a public domain SVG China Map, download, and extrude.

Any map you find online is going to be a crapshoot– either too much data, not enough data, or poorly organized data. My rule of thumb is if I can’t find what I need in seven minutes, it’s probably a better use of my time to just put in the work and do it myself.

So, to Illustrator it is, remaking each province control point by control point with the pen tool, letting the names and forms seep into my subconscious.

At this point, about six hours in, I can feel the names and shapes starting to gel. Mnemonics arrive unbidden: Gansu is kind of long-necked like a goose, and ganso is goose in Spanish, so there’s a connection there. Heilongjiang resembles Bill Peet’s Droofus the Dragon looking out of his cave — Heilong literally means Black Dragon in Chinese so I’ve got that one down.

Whoops, missed the border between Jiangsu Jiangxi and Fujian. Easy fix. Jiangsu and Fujian don’t share a border. Remember that for later. And the border between Hebei and Shaanxi (or is it Shanxi? Crap, it’s Shanxi) isn’t going to work when it’s printed in 3D. Tweak, tweak, tweak, learn. Part of Xizang’s south is disputed by India. Ok, two models for Xizang. We can probably ignore the disputed western border and chalk it up to the puzzle’s resolution.

It should be easy enough to remember there are four municipalities– Beijing, Shanghai, Tianjin and the sprawling megacity of Chongqing. The first three are too small to print, so I’ll just have to remember that they exist.

The islands. Hainan, Macao, and Hong Kong are easy to remember, although the latter two are too small to include at any reasonable printing scale. Which brings me to Taiwan.

Is Taiwan part of China? That really depends on who you ask. If you ask the People’s Republic, they’ll tell you absolutely, Taiwan’s a part of China and it always has been. If you ask the Taiwanese, you’ll get a hell no.

The United States is emphatically wishy-washy on the matter. Our official position is that we’d like Taiwan’s relationship to remain the status quo, without ever defining what the status quo actually is. This is why we invented diplomats, I suppose.

Taiwan’s in the model and users can choose for themselves whether or not to print it. I think it’s better to include it with the caveat that its diplomatic status is in dispute: that’s a much more interesting and instructive answer than yes or no.

Printing tip: ABS seemed to shrink too much post-print to ensure a good fit between pieces. I printed a second version in PLA, which is a lot more malleable.

I put the whole map (minus the islands) on a cast-iron griddle, heated it up, and then gently pressed the pieces together. Now every province is nice and snug with its neighbors.

I’d have used a wok, but I didn’t want a concave map. This time.

You can Download the .zip of this puzzle for free from Thingiverse. Includes PDF maps in English, pinyin, and Simplified characters for your educational convenience.

Replicator Maintenance

This morning my Replicator wouldn’t accept a new filament. I’d get the filament a few centimeters into the extruder and then it’d just stop moving and start clicking rhythmically.

MakerBot tech support (great tech support, by the way) suggested I follow their maintenance video and clean out the extruder.

Here’s the culprit. Earlier I’d clipped a filament without doing a proper unload procedure and it got stuck. Don’t do this.

Naturally, it broke off when I heated the extruder and tried to pull it out, so there was nothing to do but force it through with one of the many poking tools around the Replicator’s eyrie.

As long as I had the thing taken apart I cleaned the crufty buildup of filament particles off the stepper.


And now I’m back in business with some red ABS. New model coming soon.

Raftless Printing with PLA

I’m no expert at 3D printing, but through a lot of trial and error I’ve discovered a few nuggets of information that I wish I’d known a few months ago.

A few weeks ago I said I was chasing a raftless print. I’ve finally got it, at least with PLA and ABS, printing Seej bloxen.

This comparison isn’t entirely fair, since the bloxen are sourced from different models, but the difference between a hot, rafted print on the left and a cool, raftless print on the right should be pretty clear. Both of these are printed from the same roll of 1.75mm PLA.


Here’s what I’ve learned.

PLA likes a cool build platform, somewhere around 45° C: My MakerBot Replicator ships with a heated build platform, and ABS plastic seems to stick nicely around 115°.

When I first started printing with PLA I just assumed it was more or less like ABS. When prints started shifting off the platform I kept cranking up the temperature on the HBP, eventually resorting to elaborate raft structures with painters’ tape.

It never occurred to me that lowering the HBP platform temperature was the solution.

Changing the build temperature in gCode is easy: just find a line that looks like:

M109 S100 T0 (set HBP temperature)

And change S100 to S45. This assumes that you’re using ReplicatorG to generate your gCode.

There’s one other change that seems to be helping: print a nice, gooey first layer of PLA, and then back off the printing temperature to maintain the model’s integrity through the rest of the print. The gCode for this isn’t much more complicated, but you have to get it in the right place. First, set the extruder temperature at the beginning of the print, close to the top of the gCode:

M104 S240 T0 (set extruder temperature)

Change 240 (or whatever it is in your gCode) to 210.

The last step is to find the point in the gCode where the first layer stops and the second layer begins, and back off the temperature a bit.

In the other two instances there are existing M codes that tell the machine to wait for the extruder or bed to reach the specified temperature before proceeding. You’ll have to put those codes in yourself for this line.

Find the first example of:

M73 P1 (display progress)

and add these lines after the next <layer> tag:

(*custom gCode here*)
M104 S190 T1 (set extruder temperature)
M6 T1 (wait for toolhead, and HBP to reach temperature)
(*end custom gCode*)

That should drop the extruder temperature down to 190° and then resume printing. The delay can be a little unexpected the first time your Replicator just seems to stop printing abruptly, but then your forebrain will kick in and you’ll realize it’s just doing what you told it to do.

The usual warnings about bricking your Replicator or burning down your apartment building apply. Use this code at your own risk, and you should probably own couple of fire extinguishers anyways.

To arms.


Cocktails.

I’ve been interested in melee weapons ever since I was a kid, but my interest in cocktails really didn’t develop until I had kids.

Never liked martinis, or or gin and tonics, the blue stuff the barber keeps his scissors in, or anything else that tastes like witch hazel.

I want my daiquiri frilly, bartender, and I want it now.

We use The Ultimate Book of Cocktails around here for day-to-day mixology, but my go-to, it’s Friday-night-at-eight-o-clock-and-it’s-time-to-get-my-Downton-Abbey-on cocktail is a Long Island Iced Tea prepared by the lovely and talented Mrs. Zheng3. Here’s her recipe:

Mrs. Zheng3’s Long Island Iced Tea

Contains 3.25 shots of booze. Be careful.

3/4 shot Triple Sec
3/4 shot vodka
3/4 shot white rum
1/2 shot gin
1/2 shot tequila
2 tablespoons frozen lemonade concentrate
1 shot sours mix
1/4 freshly squeezed lemon
splash of non-diet Coca-Cola

Mix in a cocktail shaker with lots of ice. Garnish with a lemon wedge and serve.

 

This Long Island Iced Tea recipe is distributed under a Creative Commons Attribution 3.0 Unported License. You are free to share and remix (especially remix) this work, but you must attribute it to the lovely and talented Mrs. Zheng3, but not in any way that suggests that the lovely and talented Mrs. Zheng3 endorses you or your use of the work.)

Warning: the consumption of this beverage limits your capacity to avoid responding to idiots on Facebook, Twitter, and other forms of social media.

Download the Zheng3 Cocktail Arsenal if you have a 3D printer, or you can have Ponoko print you a set if you don’t.

The Virtuous Cycle of Fail

This is a failure of an Seej Tournament Bloxen print. Seej is an open source tabletop wargame based around 3D printing.

After a minor success with custom gCode yesterday I started experimenting with altering printing temperatures on the fly.

I tried cooling off the raft a bit and lowering the extrusion temperature; the raft worked great, but the rest of the print didn’t want to stick to the raft anymore.

PLA can be a little fussy, and tends to lose its shape if it’s printed too hot. The next thing I’ll try is feathering off the extrusion temperature layer by layer; hot and sticky at the raft layer, and then successively cooler until I get to a minimum print temperature.

Filament gets gummed up in the extruder at 170° C.

Experimenting leads to failure. Failure leads to knowledge. Knowledge leads to experimenting.

And here’s a Seej Ourobouros Guardian fail. Plenty of tries on this one before I got something that printed correctly.

ouroboros_fail_2