Category Archives: tinkering

Finding Sparky’s Voice

In early February I debated whether to make a promotional video for my Kickstarter. The 3D modeling was done, the armor was printing reliably, and I figured the concept of 3D printed medieval armor for Barbie dolls would just about sell itself to the right crowd of people. Did I really need to invest the time in making a video?

SPOILER: I ended up making the video.

I dithered and hemmed and hawed for a day or two while I weighed the pros and cons of investing even more time in the Kickstarter. Eventually the creative itch won out over the practical hurdles of lighting, shooting, and editing with less-than-professional tools (my vendetta against Apple Motion 5 continues unabated) and after much gnashing of teeth and rending of garments I released this to the world:

I’m glad I did because people really seem to enjoy it. It’s also on Youtube and Vimeo now, BTW.

Acquiring scenery and minifigs for the video wasn’t a problem, but I clearly needed a Big Bad. I rooted though every bookshelf and toybox in the house and came up empty. The Zhengspawn are growing up quickly, and are more interested in playing with software than they are with plastic. Clutter is the enemy, so only the most cherished or useful toys remain in the house.

Candy Crush is also the enemy, but no matter how many stakes, silver bullets, DDT, UV, and Slim Whitman Indian Love Calls I use, I can’t seem to rid Zheng Labs of that particular infestation.

Last year’s purge resulted in an unfortunate paucity of plastic dinosaurs in the storage tubs, just when I needed one the most.

Ever supportive, the Lovely and Talented Mrs. Zheng3 dropped by the local thrift store, popped some tags, and returned with Sparky. She found him in the discount bin for a dollar, on account of his non-functional pushbutton speaker.

Sparky is a generic-looking therapod carnivore with very broad feet. Artistic compromises were clearly made during his design, but I think the size of his forearms pegs him as a reasonable attempt at an Allosaurus, with a little pre-1990’s tail anatomy thrown in for stability’s sake.

sparky full

I’ve spent a lot of time with Sparky, and now I’m curious about his origins. Somewhere on the Internets there’s an expert on cheap plastic dinosaurs who can take one look at Sparky and identify him immediately. Until that person surfaces, our only clue is a “MADE IN CHINA” stamp between his legs, which narrows his origin not at all.

The wear patterns on Sparky’s maw, brow, and toes suggest that he was extensively played with in the past. He’s definitely attacked his fair share of villages. Sparky, at some point in his life, was loved. The discount bin would be too ignominious an end for such a loyal toy.

wear pattern

To the workbench with you, my Jurassic friend.

Whoever sculpted Sparky did some nice work, especially with the reticulated scale patterns on his skin, but the person or people who inserted his speaker botched the job a bit; I think a hole saw was used to access his chest cavity but the opening was messily enlarged with a knife at some point before the speaker was jammed inside.

sparky hole

With some prying and pulling I’m able to extract the speaker assembly, hopelessly mangling it in the process. It uses two LR41 batteries, which are easy enough to come by, if redonkulously expensive when purchased as singletons.

Sparky’s noisemaker is a simple affair. A speaker is connected to a small circuit board, activated by a (gray) plastic plunger that completes the circuit by touching that solder squiggle in the middle.

But wait, you say? How does nonconductive plastic complete a circuit? There’s a circular swatch of black, conductive somethingorother glued to the bottom of the plunger. Any EE’s who swing by, please tell me what this stuff is called, for curiosity’s sake.

If you squint and turn up the contrast on your monitor you can see a dark circle in the southwest corner of the circuit board. That’s where the recording of Sparky’s voice is stored underneath a blob of epoxy. A little more on that later.

speaker

Two fresh batteries later, here’s what Sparky sounded like straight from the factory. Turn your speakers down, it’s a bit unpleasant.

Hmm. That roar sounds familiar. Here’s Godzilla, king of monsters:

Here’s the two of them, side-by-side with a little bit of audio cleanup in Audacity. Sparky is first, followed by Godzilla. Big G is sped up by 90% with an accompanying change in pitch to make Sparky.

waveforms

It appears to me, at least, that someone just ripped off Godzilla when Sparky was made. I’m offended.

A little research tells me that I won’t be able to hack Sparky’s audio chip and record my own roars. Apparently the audio is burned onto an IC at the factory and then covered with a little black blob of epoxy. “Flip-chip” technology, this sorcery is called, and working with it is beyond any magic I possess at Zheng Labs.

I’d love to be able to hack these chips because they show up everywhere, especially in Happy Meal toys.

I do have a toolbox full of electronics, and I might be able to cobble together a replacement roar for Sparky after the Kickstarter is finished. At the very least, I can print him a new bezel for his speaker today.

sparky fixed

Guy can’t be walking around with a nasty hole in his chest, now can he?

Also. All the time I’ve spent on TVTropes? It actually paid off: see how many tropes I managed to cram into one video, and post in the comments below:

I’ll give you the second one for free: Action Girl. Or is it Badass Princess? Reasonable people can disagree.

Home is Where the Art Is, Part II

2404

Casa de Zheng is getting some work done lately. Her old house numbers, milled from wood, had to come off so the underlying fascia could be painted. Brittle with age were the numbers, and unable to survive the removal process. Upon reflection we (by which I mean the lovely and talented Mrs. Zheng3 and I) didn’t care much for the early 80’s Facts of Life typography anyway, so replacements were in order.

broken wood

If one has a 3d printer every broken household object’s an opportunity to recoup another few bucks on one’s ridiculously impractical investment.

After choosing font that’s apropos for the house’s character, I plucked some newly ripened heirloom vertices from the south side garden boxes and set to work forging them into house numbers. A quick extrusion, a nip, a tuck, and some geometry welds later and I have some digits ready for printing.

the story of 0

There’s more sculpting here than meets the eye– Maya 2008’s text beveling tools are the very definition of execrable. This oversight was inexcusable in 2008 and even more grating in this day and age, but I’m stuck using M2008 on OSX 10.6.8 in a 32-bit update cycle until I can swing a huge hardware/software upgrade. We go to war with the army we have, not the army we might want or wish to have at a later time.

The numbers don’t have a lot of detail and won’t receive close scrutiny since they’re about 10 feet off the ground, so I print them at .3 layer height to save some time. They are going to have to be sturdy enough to withstand a bit of weather, so I add a second shell to my usual print settings. Infill at 10%.

printing 0

Most of the digits aren’t anything special, except for a couple of pilot holes baked into the 3d model. The number four is an exception; I’ve added a hollow compartment in the back of the model and printed a watertight lid, turning the otherwise innocuous digit into a potential time capsule.

capsule

Discussion with the family yields a few paragraphs about ourselves, the house, the painter, our pet, the neighborhood, and the current state of 3d printing. I print it out, roll up the paper, and put it into a Zheng3 Scroll Tube, which is in turn sealed within the printed number four for posterity. I hit the seams with some all-weather caulk because I’m a belt-and-suspenders kind of guy.

Our house painter gets the numbers primed and painted and nailed to the house in short order. I hope whoever finds the note fifty? a hundred? years hence has a good chuckle at the primitive technology involved in its creation, what with the dumb toner, 英文, and thermoplastics.

open me

Previous home improvement post: Home is Where the Art Is

ComposiMold: First Impressions

The friendly team at ComposiMold recently sent me a sample of their product for review. Like many experimenters I’m mostly unacquainted with mold-making and casting but I’m willing to get messy and give it a go. Let’s dive right in and see how this stuff works.

TL;DR Summary: ComposiMold is easy to use, reuse, and reuse again, even for a casting n00b. It’d make a great gift for a Maker kid. Highly recommended.

Composimold: The Unboxening

open container

Opening the 10-ounce container releases the faintest waft of lemon. It’s not unpleasant or pronounced; only bloodhounds and those accustomed to huffing day-old mimeographs will have the chemoreceptors to detect the scent.

It’s firmer than I expected. I was thinking I’d have something a little gooier, but when ComposiMold is cool it’s got the consistency of a flexed bicep. At 10 ounces the sample container feels satisfyingly dense in the hand. I feel like I could make stuff with this.

Virgin ComposiMold looks surprisingly like honey. So much so that the lovely and talented Mrs. Zheng3, slightly less talented than usual at 5:30am, nearly dropped a heaping spoonful of ComposiMold into her oatmeal. I probably shouldn’t have left the container on top of the microwave last night.

In theory, the mold making process is simple and straightforward: heat ComposiMold, pour it over the object you want to reproduce, allow to cool, and then extract your object.

Naturally I screwed it up.

Jumping into this project like an enthusiastic idiot I naturally made a a rookie mistake right off the bat. I forgot to coat my mold container with a release agent. So I restarted the project. What you’re seeing here is actually take two on my quest to replicate a Seej bloxen.

So! Into the microwave with you, ComposiMold.

in the microwave

Another brief installment of Zheng’s household hints: before photographing the inside of a microwave you’ll want to clean it so the Internet doesn’t think you’re a gavone. Put a cup full of vinegar in the microwave and nuke the bejeezus out of it. The steam will soften the Hot Pockets splatter off the inside of your microwave so that you can wipe it clean with a rag. The healing brush in Photoshop will take care of any pastacules you might have missed.

Thirty seconds in my microwave and I’ve got a golfball-sized nugget of ComposiMold suspended in honey-like goo. Stir with a craft stick (always, always, always have craft sticks around any maker project), give it another 20 seconds of non-ionizing radiation and we’re good to go. During the melt the lemony scent is a little more pronounced but doesn’t stink up the kitchen.

bloxen, masonry
I’ve decided to try and cast a Seej Bloxen for my first project. I’ve made sidewalk chalk bloxen using a 3d printed mold, but I’m interested to see how ComposiMold picks up the detail in the 3D modeled grout and stones of something I’ve already printed. This particular bloxen was produced during my review of Filabot’s recycled ABS filament.

Composimold: Making A Mold

I give the bloxen a rub with some vegetable oil and put it into an old laundry scoop. Here’s where I run into my first unknown unknown in the mold-making process.

pouring

unforeseen problemThe plastic object I’m trying to copy is less dense than ComposiMold, so it wants to float. I try holding it down with a craft stick, but I’m unwilling to wait half an hour for the ComposiMold to solidify at room temperature. I throw the whole thing in the freezer to cool and abort the first try at mold-making.

It’s 9AM on a Sunday morning so I take a break and have some cheese danish before the kids get up and eat it all. After twenty minutes and a cuppa joe I cut open the mold to see how well it captured the details. Click to embiggen.

detail

The detail’s quite fine here. ComposiMold even picked up the layer artifacts left by the 3d printing process. Each of those parallel lines is about 100 microns wide. I can’t use this failed mold for casting, but it provides an excellent chance to test ComposiMold’s reusability.

Forty-five seconds in the microwave and I’m back to pouring a new mold. Easy peasy George and Weezy. So far ComposiMold is living up to its promises.

This time I’ll try suspending the bloxen from a stiff piece of hookup wire before I pour. I drill a small hole in the side of the bloxen, superglue in a wire scrap, and wrap it around a craft stick. (See previous admonition about having craft sticks around.) I’ll use a plastic cup for my mold container this time, because I can just cut it away without having to worry about pre-treating it with mold release. The vegetable oil gets everywhere and I don’t want it schmeered all over my camera and light box.

suspended

The bloxen remains submerged this time, if a little off-kilter as the unsecured bottom of the plastic tries to float upwards. The newly-poured mold goes back to the freezer for fifteen minutes or so before I cut away the plastic cup.

The mold resists my hobby knife with the strength of an overcooked ham, but splits easily and the bloxen pops right out. A little vegetable oil on the inside of the mold and it’s ready to be filled with Plaster of Paris.

ready

Composimold: Casting

ComposiMold’s produced a perfectly usable mold. The process has been simple even for a mold-making novice, but today I’m wishing I paid more attention on casting day in sculpture class.

In all fairness, I was trying to get the lovely and talented not-yet-Mrs. Zheng3 to notice me at the time.

plaster

Notice that almost all the bubble artifacts on this plaster bloxen faces inwards; this isn’t ComposiMold’s fault, it’s mine. Either I didn’t get the plaster/water ratio correct or I didn’t agitate the mold enough after pouring, or my plaster’s old, or something else. I’d love to see what ComposiMold can do in the hands of someone with more casting experience. ComposiMold also sells a bubble buster that will assist in the casting process that wasn’t included in my review sample.

A couple hours of playing with this product has given me all kinds of great ideas for where to go next with this. Traditional casting and 3D-printing are a powerful combination, so #staytuned for another casting attempt, this time with cement. The younger Zhengspawn and I have a project in mind that’s perfect for ComposiMold. We’ll see how an 8-year old does with this stuff under lax supervision.

If you’d like me to put your Maker-related gizmo, material, tool, or software through its paces at Zheng3.com, email me and I’ll give it a shot.

ABS Printing, First Layer


It’s possible to get a mirror finish on your first layer when printing with ABS on kapton tape. Make sure your bed is level and give the kapton tape a quick wipe with ABSynthe; dampen a paper towel with acetone, rub it a few times across a failed print, and then wipe your kapton tape with the residue.

Look closely and you can see the little folds left in the print from bumps and bubbles in the kapton. I’ve given up trying to get my kapton to be perfectly smooth, because I have enough things in my life that give me agita. A few little wrinkles aren’t going to make your print fail if your bed’s level and you’ve got an ABSynthe wipe on your kapton.

If the bottom of your print looks like this, you might have a little trouble getting it off the build platform. I’ve had my best results giving the side of the print a little tap with a hammer while holding my build platform in place. It helps if the platform’s still warm from the print.

This print of a Masonry Bloxen uses Filabot’s recycled ABS at 250°C on a 110° heated bed, on a Replicator1.

Zheng3’s Household Hints


Organize stray pushpins by sticking them into a super bouncy ball.

This is a great way to occupy a child for fifteen minutes so that you can get just an iota of work done because could you just stop asking me for stuff every five minutes on summer vacation and go read a book or something wait here’s some pushpins do this.

Also: is a proto-morningstar. Just add #2 pencil haft. SHUT YO MOUTH!

I’m just talkin’ about haft.

Printrbot Simple: First Impressions


Lao Zheng's Printrbot Simple

In mid-May I got all hopped up on endorphins from 6AM yoga and BAM! right there in my Twitter feed was an offer. The first N users who bought a Printrbot Simple would save $50 off the already low, low price of $300. My impulse control weakened by the flush of healthy qi, I had one in my shopping cart within two minutes, or roughly the time it takes me to huff and puff four sun salutations.

Two-fiddy plus shipping isn’t a budget breaker for a 3d printed squirrel magnate, and the gnomes at Interdimensional Bank of Zheng say we haven’t skimmed anything off the upgrades fund in a while, so why not, indeed.

A quick note for anyone thinking they might purchase this printer once it’s out of beta in June and available to folks other than the lucky N.

if (eval(‘yourTime’)>=eval(‘yourMoney’)):
     buyADifferent3DPrinter()
else:
     thisIsThePrinterForYou()


If you’re a high school student with a few hundred bucks and a weekend to burn, grabbing the Printrbot Simple is a no-brainer. If you own a complete set of matching stemware, look elsewhere for your first 3D printer. Especially if your only exposure to 3D printing so far has been the SkyMall catalog.

Make no mistake, even more so than the Replicator1, this is a hacker’s 3D printer. You’re like two steps up from a homebrew RepRap when you get into the Printrbot Simple. If tweaking and calibration and watching prints fail while you dial in gCode ain’t your thing, purchase a different printer.

On the other hand: right after I made my first successful print on the Simple I was mobbed by Brazilian bikini models. Your mileage may vary.

On the gripping hand: as an instructional tool, the impact of the Printrbot Simple can’t be overstated. Anyone who assembles, calibrates, and prints with this bot is going to learn buckets about the ins and outs of 3D printing at a granular level.

Best of all, at $299, it’s relatively inexpensive. I’d be disappointed if hundreds of these bots don’t find their way into high school STEM clubs.

Well-to-do techie parents looking to build a 3D printer with their tweens might be the sweet spot for this bot, but Mom or Dad should be prepared to sneak back to the basement after bedtime to put in an hour or two of extra build time.

The Build

warning The Simple is a beta, so there are guaranteed to be some bumps along the road. It ships as a kit, so you’ve got to put it together yourself. You’re also paying someone else for the privilege of beta testing their hardware, which is a genius business model if ever there was one. Fortunately Printrbot is up front about that fact; “BETA” is laser-etched onto the build platform. You buys your ticket, you takes your chances.

Printrbot describes the build difficulty as “moderate.”

I am reminded of the time I went to the Thai place across town that isn’t my usual Thai place and I ordered the larb with a 7 on the 1 to 10 spicy scale which is where I like it but they use a different hotness scale and hoo doggies that’ll burn tomorrow on the way out but I could still mostly finish it. Ach, mein ass.

So maybe Printrbot’s definition of moderate is different than mine.

I’m not a complete idiot. I can read English and make logical deductions, I’ve got a well-stocked toolbox, I have an amateur’s burgeoning knowledge of electronics, and I’m not afraid to jimmy-jim-jim a part to get it to work. Surprisingly, given my pyrotechnic proclivities as a pup, I still have all ten fingers. I have a SparkFun wish list, for the love of Pete.

Even with my bona fides, I still find Printrbot’s estimate of one to two hours for assembly of the Printrbot Simple wildly optimistic. I’m sure there are wizards from the Printrbot community who can wham-bam-thank-you-ma’am this printer into a finished state in that time, but coming at this build cold I’ve probably got 8 hours put in over the course of three days. Keep build time in mind while you’re salivating over that $300 price tag.

Printrbot’s marketing claims that you can put this together with only a screwdriver. Maybe, if you’re the Last Son of Krypton or you have vise grips for hands. There are a few tools that will make this process much easier:

  • you’ll need super glue.
  • it amazes me that my kit didn’t include an Allen wrench. Maybe Printrbot figures that IKEA has acheived such market penetration that the probability of an Allen wrench being within reach is approaching 1.0 for a given location in the Western hemisphere.
  • a cordless drill with an Allen bit will speed up the assembly considerably.
  • a metric/Imperial ruler so you can tell the different bolts and screws apart
  • scissors or a hobby knife– you’ll be cutting fishing line.
  • an adjustable wrench, and maybe an M3 socket.
  • needlenose pliers
  • zip ties. You’re going to need a lot more zip ties than are included with the beta to manage all those cables.
  • painters’ tape for the print bed. No sense in marring that nice birch any more than you have to.

Most people willing to tackle this process are going to have this stuff in the toolbox anyway, I just include the list because I’m a huge fan of deflating marketing hype by emptoring my caveats.

There’s a point during assembly where one must gently fit two steel rods through laser cut plywood holes; these are the rods that stabilize the extruder arm as it traverses the lead screw. The holes are cut to very fine tolerances, so much so that it can be difficult to push the rods through.

I recommend that you put your steel rods in the freezer maybe an hour before you get started on the build. Thermal contraction will temporarily shrink them just enough to get them through the plywood. Once they warm up again they’ll be nice and snug.


rods in the freezer

Be prepared to slightly modify some of the parts that came with the kit to get them to fit. The laser cut plywood all fit together perfectly, but I had to file down the plastic edges of my hot end so that it fit into the extruder assembly. I accidentally stripped the wood around an M3 nut and had to super glue the nut in.

Not a big deal for your average maker geek, but someone expecting a snap-together 3D printer is going to be sorely disappointed around hour three. You can see where my file chewed up the top of the hot end in the closeup below.


hot end

Suggestions for Printrbot

I’d like Printrbot to etch more directions onto the wooden parts of the printer. Etched labels like “this side faces out” would be very helpful in determining orientation during the build. I got turned around a few times and ended up dismantling and reassembling the previous two steps of my build.

At the end of each step, a photo of the entire printer from multiple angles could help a lot. I kept getting disoriented and had to backtrack or skip ahead to find out what part went where.

Once you get the bot together the first print is very satisfying, but along the way there is likely to be some gnashing of teeth and rending of garments. Here’s a test print of a small cylinder that I did, just to make sure everything was put together properly.


first print

Calibrating the Printrbot Simple so that your prints are the right scale is a whole other can of worms. I’ll get into that in a subsequent post sometime in the next few days. Watch this space.

Printing a Replacement Technic Axle


Zhengspawn the Younger has begun to dabble in LEGO Mindstorms, and since our kit has been floating around the house for the better part of three years, naturally a piece or two has gone to the great scrapyard in the sky.

The bot couldn’t be completed according to instructions in this excellent book without a 9L axle. The axle is a cross-shaped piece of plastic about 70mm long and maybe 5mm in diameter. (I’m ballparking here.)

I’ve got a 3D printer and some modeling software, so a replacement part isn’t too hard to hack together, although I did have to go through a couple iterations before I got a snug but not too snug fit with my homebrew axle.

Note to LEGO, not that they need my help in dominating this particular toy niche: I’d pay for a LEGO-certified chunk of gCode for printing my own replacement parts instead of futzing with calipers and test prints and acetone.

The axle’s cruciform profile means I can’t lay it on its side for printing; it’s got to go straight up. But it’s a really narrow print which means it’s likely to topple if I print it as-is.

So I made a little base for the axle and printed with 100% infill. The model prints in about half an hour, and after a quick wipe of the axle with some acetone to smoove out the printing ridges, Zhengspawn’s Mindstorms bot is off to the races.

Now. Usually I boolean join my multi-part models together so that ReplicatorG doesn’t make a hole at the intersection of two separate pieces of geometry.

If the shaft and base were booleaned together, they’d need to be cut apart with a hobby knife. This can be a little tough when printed at 100% infill.

See how the edges on the top of the base connect to the bottom of the shaft here? This model is watertight– as far as ReplicatorG is concerned this is one contiguous mesh.


But. If one just kinda jams the two pieces together without actually joining the geometry, ReplicatorG will create a very delicate connection, easy to snap off after printing.


Usually this self-intersecting geometry is a problem in 3d printing, like it was with my Gingerzombie cookie cutters, but here it’s actually an advantage in creating the final product.

Repairing a Canon G11 Dial

I take most of the photos for my blog with a beat-up Canon PowerShot G11. It’s an older prosumer camera with a known hardware issue: the control dial for the manual settings will gradually fail, and setting exposure, shutter speed, and manual focus becomes progressively more difficult and eventually impossible.

The fix is pretty simple if you’ve got a small Phillips screwdriver, an electronics cleaning solvent, and some patience. I followed the steps on this forum, and took pictures with my phone as I went along.

Apparently the latest in the PowerShot line doesn’t have this problem, but I’m not one to skip a chance to vivisect a gadget. Also, the discretionary budget for electronics in Casa de Zheng is tapped out.

WARNING: This will void your warranty, might destroy your camera, yadda yadda yadda. Proceed at your own risk. Take the battery out first, so an errant slip of your screwdriver doesn’t short something in the camera.

Tinkering 101 tip: Have an ice cube tray, egg carton, or other segmented container handy to separate the screws for each step.

Also, never, ever work near a floor register. Trust me on this.

Step 1: Remove the screw next to the preview button.

Step 2: Remove the screws on the bottom of the camera.

Step 3: Remove the screws on the left side of the camera. The strap harness is a separate piece and will come off easily.

Step 4: Remove the screw on the right side of the camera, next to the AV door.

Step 5: Open the AV door and remove the screw inside.

Step 6: Gently pry open the case with a flat tool and pull the case straight back. Some fiddling may be required to get things apart. There’s a ribbon cable holding things together, so don’t yank too hard.

Step 7: Flip the little tab holding the ribbon cable in place upwards. Be gentle.

Step 8: Remove the clear plastic covering these screws, and then remove the screws. Gently pry the metal piece off, making sure to save the small L-shaped bracket on the lower left.

Here’s the the dial assembly.

Step 9: This is where the magic happens. Lift the front of the dial away from its contact pad a little bit. Don’t try to pop it off, just create some space between the two pieces. Spray your solvent into this space. I just dribbled some isopropyl alcohol in there and then rotated the dial around a bunch of times to clean out the mystery gunk that was causing my dial to fail.

Follow these steps in reverse order to reassemble. I used some packing tape to replace the plastic removed in step 8.

Getting the ribbon cable back into its socket can be a little tricky, but the rest of the case snaps back together in less than a minute.

What should my first layer look like?

Your 3D printer just arrived. The nearest hackerspace is 100 miles away. You’re all ready to start printing, but all you really know about the technology is what you’ve seen on YouTube videos and breathless reports on Wired, or the Colbert Report.

They never show you the bottom of the print in any of those venues. It’s always Stanford bunny this or Colbert head that, and that’s all well and good but there’s no one around to tell you you’re doing it wrong.

first layer

I was happily printing failbottom models for months before I went to Maker Faire in Detroit and saw a proper print done by some experts.

The stringy bottom on the first two prints is mostly caused by having an off-kilter heated build platform. Make sure your heated build platform is as level as possible before you start printing.

MakerBot Replicator 1
ABS, 240° C
HBP 110° C, with painters’ tape

(These are prints of my Magic: The Gathering Fungus Tokens, available for free download in The Forge.)

MakerBot’s leveling script never seems to work perfectly for me, but since I’m printing small objects anyway I just make sure the HBP is locally level in my printing footprint. There’s no need for the corners of the platform to be 100% level if the center’s good enough.

I often start a print and let it run for a single layer to let the print heads get to their destination. Then I abort the print, remove any plastic from the HBP, and use ReplicatorG’s homing function to home the Z-axis to minimum.

(In ReplicatorG, go to Machine->Control Panel and select the Homing menu to do this.)

Then it’s a matter of twiddling the thumbscrews on the HBP until the nozzle passes MakerBot’s business card test. When you slide a business card between the nozzle and the HBP and the surface of the card just catches on the nozzle, you’ve got it.

It takes some time to get a knack for it, so don’t despair. I find it works best when the nozzle makes an indented scratch along the card’s face.

The first company to ship an auto-leveling build platform gets a fistful of cash from me.

It’s possible to get a mirror-smooth base when printing on kapton, but I’m mostly printing with ABS on painters’ tape right now. More on that in a subsequent post.