What should my first layer look like?

February 24, 2013

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.)

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.

Repairing a Toy with 3D Printing

November 19, 2012

My daughter bought an inexpensive headlamp recently, and like many inexpensive toys, it broke within hours of purchase. She can’t wear it anymore because part of the buckle assembly snapped off and we managed to lose the broken piece before she could glue it back together.

Here’s the damage.

This is a perfect opportunity to fire up the MakerBot Replicator.

If you look carefully in the back of the photo you’ll see an AppleCore earbud wrap, which I highly recommend if you’ve got a bazillion small cables in your life. AppleCores are great stocking stuffers for geeks, BTW, and the holiday shopping season is nigh.

Moving on: let’s test one of my expectations about Living In The Future: in The Future, one will be able to repair broken household items quickly and easily using a 3D printer.

TL;DR version: we don’t live in The Future yet. But we’re getting there. This whole process took about an hour and a half of human-time.

The first step is to get a scan of the broken part. Scanning it with 123DCatch is probably too much hassle for what’s basically a flat object, so I put the headlamp down on a flatbed scanner and covered it with a few sheets of office paper and a black piece of cloth to keep too much light from getting in.

And then a little levels adjustment in Photoshop to bring out the contour I need for tracing. I’m going to add an entirely new backing to the headlamp instead of trying to replace just the broken bit.

I brought the photo into Maya, and traced the edges with NURBS curves. Next, extruded the poly surface, made sure the dimensions were correct, and exported to ReplicatorG. After 45 minutes of vertex wrangling I had this shape:

The slice and print went quickly. I glued the 3D printed part to the original with JB Weld.

(JB Weld also makes a great stocking stuffer for geeks. I once owned a ’92 Toyota Corolla [R.I.P. Felipe] that was 30% JB Weld by weight, not including the zip ties and the fuel door I machined out of an old PC case.)

Wait 24 hours to cure, and we’re done.

Totally functional, if not the most beautiful repair ever. I debated putting the STL for this up on Thingiverse, but this model is useful to exactly one person in the world so there’s not a lot of point in sharing it. If you must have one, email me or DM me.

Why We Don’t Live in The Future Just Yet: The barrier to entry on doing this at home is still pretty high for most people– computers and software are cheap, but the 3D printer required to do this hasn’t hit the sub-$300 range yet. Five years, maybe?

The technical skills for working in 3D aren’t too common yet either, but the easy availability of apps like SketchUp and TinkerCAD will take care of that in time.

BUT. I could see a service like this being offered at your local hardware store in The Future. Bring in your busted genechtagazoink and an eager nerdling will drop the part in a yellow, overbuilt scanner made by DeWalt, flop the geometry around in some yet-to-be-announced Autodesk product, and then print you a replacement part while you wait, sort of like the way house keys are copied now.

(If you ever meet me in person and want to start a good rant about legacy technology, ask me how I feel about house keys.)

Naturally, I found the broken-off piece this morning. Next to the fridge. Feh.

His nibs.

October 19, 2012

I started using a Wacom Intuos 2 tablet in 1999 after struggling with a mouse-induced repetitive stress injury. I’ve been holding the same stylus pretty much every day, for hours a day, for the last twelve years.

Over time, the nibs eventually wear out, and I’m left wondering where I left that tiny bag of replacement nibs I bought from Wacom three years ago to replace the tiny bag of replacement nibs I lost six years ago.

Now I have a Replicator, and I can print my own highly precise pieces of plastic. I’m a big believer in Taking It Just A Little Too Far, so I’ve designed a nib based on the slicing end of a Shaolin spade.

The Shaolin spade (月牙铲, or yuèyáchǎn for my fellow xuésheng) was the favored weapon of drunken monk Lu Zhishen, made famous to those without an interest in classical Chinese literature by Max Brooks’ Zombie Survival Guide and the fine Kurt Russell vehicle Big Trouble in Little China.

The nib should work for any Wacom stylus. Here it’s pictured in my Bamboo, which I use for work when I’m traveling.

My original plan was to include the Shaolin spade in the Zheng3 Cocktail Arsenal, but the tip is too wide to be thrusting through maraschino cherries. It should make a dandy calligraphic nib for those so inclined.

If you’re the kind of person who cares enough about the quality of a digital brush stroke to 3D print custom nibs for a Wacom tablet, you deserve a step-by-step tutorial on how to do it.

This is a really precise, but very simple print. The nib’s shaft needs to be sized so that it fits the bore of the Wacom pen and can be removed with the tiniest effort, but not so loose that it falls out when one begins to draw with the stylus.

I did a lot of trial and error to get the nib diameter correct, because my four-dollar hardware store calipers produced a measurement that was way, way too thick to fit into the pen. A radius of .065 cm seems to do it when printing with the following method. I’m assuming there’s some contraction/expansion/plastic real-world-weirdness that doesn’t show up when the design isn’t all vertices and electrons.

Note that I’m printing with PLA.

ReplicatorG Settings:
HBP: 45° C
100% infill
Layer Height: .2
Number of shells: 1
Feedrate: 25 mm/sec
Travel Feedrate: 55

This print is so small and delicate that any extruder-induced jiggling of the Replicator is likely to shift the plastic off your platform. I got good results by slowing the print heads down. Here’s how I did it:

Generate your gCode from within ReplicatorG using the above settings. Then do a couple of find/replaces in your favorite text editor:

Replace F750.0 with F100.0
also replace F1500.0 with F100.0

There’s probably a way to do this from the GUI but for some reason I’m more comfortable mucking around in the ASCII.

Run the print. Your instinct will be to pull that new nib off the build platform and jam it into your stylus ASAP. Don’t. Give it a few minutes to cool so it doesn’t warp upon removal.

It’s easy to remove a fresh nib from a Wacom stylus. Just grab it with some pliers and pull gently. Scissors are useful for removing a worn nib; cut slightly into the plastic of the nib with the blades and then pull it out.

Download it from Thingiverse.

MakerWare Beta: First Impressions

September 21, 2012

TL;DR summary: I’m avoiding this software for now. It’s borked my USB port and made my Replicator shake violently using MakerWare’s default settings for PLA printing.

I can still print from the SD card, so I’m not completely dead in the water.

Frustrating and kludgetastic, but I’m sure I’ll get to learn something about the inner workings of USB drivers by the time all this is done.

On the plus side, MakerWare has some nice usability improvements over existing software, even if it needs a little UI love. Miracle Grue is insanely speedy slicing software.

My goal is to evaluate this software as a 3D printing hobbyist who’s big on ease of use and good UI design. Also keep in mind that MakerWare’s still in beta, so I wasn’t expecting a flawless performance.

Ok, on to my experience. I’m using a MacBook Pro running 10.6.8.

Startup: Launches quickly and automatically recognizes that I have a Dual Extrusion Replicator connected. Nice.

Navigating around the virtual build platform is easy. Wacom tablet support would be nice: a middle-click and drag to zoom in and out would replace the scroll wheel functionality that I don’t have.

(After 12 years of exclusive Wacom tablet use I find it amazing that anyone can or would make art with a mouse.)

I’d prefer to see the MakerBot branding moved to the title bar rather than taking up screen real estate, but that’s a quibble.

I’ve decided to use one of my Seej models as a test. I chose the Rubble Bloxen because I know the mesh is pretty dense: I sculpted it out of banana bread and then scanned it with Autodesk’s 123DCatch. Lots of polygons for the software to chew on here.

I import the bloxen and click “Make It.” This creates the slicing dropdown.

I choose “High Quality” settings and then (mostly by instinct) click the Advanced tab. The default settings for PLA seem a bit hot to me, but that’s an easy change: Just drop the extruders to 190° and the HBP to 65°. Easy peasy mac and cheesy.

It’d be nice to be able to save my preferred options as a preset, but I don’t see that functionality yet.

I hit the “Make It” button and I get a Slicing progress bar that hangs at 0% with no apparent way to cancel. The rest of the app seems responsive, though: I can still move the bloxen around the virtual platform, rotate it, etc.

The rubble bloxen is a complicated model, though. Maybe it crashed Skeinforge? Let’s try this with something different.

I quit and reboot, and my slice windoid is still there. This feels buggy. (Keep reading, it isn’t.)

I load up an example STL: Mr. Jaws. Click “Make It” and the Slicing dropdown appears again, with default settings. It’s a little disappointing that the settings I added last time haven’t stuck.

Still, it’s a Beta, so let’s not get too worked up about it.

Now I have a second slicing windoid, that’s also stuck at zero percent. Let’s try this again, one more time.

While I’m poking around doing other things, I notice that one of the windoids has started updating its progress bar! This must be the rubble bloxen finally getting its slice on after five minutes.

The software’s not buggy, it’s actually continued a slice after a quit and restart. Very cool.

I’ve blundered into cancelling a slice. Got to click the Bot’s icon in the lower right corner. This doesn’t make a lot of sense to me. The Bot isn’t doing the slicing, my laptop is! Putting a cancel button on the slicing progress bar would be more intuitive.

Ok, so I cancel everything out and start fresh with a single model, the Rubble Bloxen again.

Import the STL. No problems there. I’ll move it around a bit just for fun.

I disagree with the function names “Move” and “Turn.” It feels a little dumbed-down and non-technical. I’m imagining I’ve just bought a cutting-edge piece of 3d printing hardware, and I want to feel like I’m using some massively powerful software with it. “Move” and “Turn” feels too toylike for a prosumer device. Give me translate, rotate, and scale, please.

I rotate the bloxen just to explore the UI a little. Makes sense, easy to use, no surprises. Free rotation is easy, but it would be nice to constrain the model to 45° rotation increments by shift-dragging.

Same goes for duplicating the bloxen: I’d like to be able to option-drag the block to duplicate it, but that’s Photoshop reflexes talking. Not a major feature requirement, and Copy/Paste does the job.

Being able to reset the SRT values is a nice touch.

I hit “Make It” again, and this time I’m going to use Miracle Grue for slicing. Bre Pettis was pretty stoked about a rapid slicing algorithm in the launch webcast, so let’s see if this is it.

Wow! That progress bar that stalled at zero with Skeinforge goes from zero to printing in less than ten seconds with Miracle Grue.

My first print goes straight to la-la-land and fails. So I click “Make It” again.

I have to re-enter my settings.

I hit “Make” and the second print fails, too. I suspect that my extruder head travel settings are too fast, so I check and sure enough the defaults are set way, way higher than I’ve been used to.

My HBP doesn’t appear to be warming to 65° like I told it to, either. Strange. It’s stuck at 16°.

After six attempts I finally gave up trying to print something. I hop over to ReplicatorG to see if something’s up with my Makerbot. Can I print a rubble bloxen with ReplicatorG?

Uh oh. It looks like MakerWare is hogging the serial port even after a quit. Unplug? Replug? No. Reboot? Still no. Shut down and restart? Uh oh. No.

I can’t use ReplicatorG over USB anymore. This is a problem. I launch MakerWare just to see if it still works. Sure enough, it does. Connects to the Replicator no problem. I try a test print, using the default Medium settings on Mr. Jaws.

It prints. But the print is so violent that I end up canceling it after two minutes, just so I don’t have to recalibrate my HBP. It’s literally shaking the Replicator and tabletop.

This behavior might be OK with a heavily-reinforced Replicator 2, but my little plywood buddy looks like it’s having a seizure. Cancel, cancel, cancel.

I’m done. MakerBot support has been very responsive in the past, so I’ll post an update once they get back to me.