obligatory obscure reference

Something got trashed in my WordPress configs, so I’m re-installing it from scratch. No malware/hackers/whatever, a simple case of my web editing software deciding to delete any file it didn’t think I actually needed.

The build is almost finished, all I need to do is build the extruder and get host software running on my Mac or Wintel box.

Instead of doing the build (like I planned) I’m spending a lot of time sitting after knee surgery. I do a lot of my hacking/tinkering either standing or sitting on the floor, neither of which has been much of an option for the past few weeks. Deep knee bends (aka “catcher bends”) caused my knee to make a bad noise, the doctor agreed it was bad and to stop making that noise until surgery. Surgery probably fixed it, but now I have ~3 weeks of sitting and taking it easy on my knee.

I’m posting photos to flickr as I make progress.

We’ll cover:

— How EL-wire works
— How to solder the wire and assemble controllers
— Using EL-wire in clothing, signage and other projects
— Safety and design considerations

Each student will receive a starter kit with 2 meters of wire, an EL-wire controller, batteries and additional components. Additional lengths of EL-wire in a variety of colors will be available for purchase at the class.

More details, pictures, and video are on Hack Pittsburgh’s web site.

Well, not open source as much as legal clone.

I’m not naming names until I test it, but for less than half of the cost of replacing the cartridges for my Epson R2400, aka “the big ass printer”, I got:

• A new set of “never empty” cartridges that never go to %0 and can’t be re-used
• An insultingly huge amount of UV dye. I got less hair dye than this in a bottle of Manic Panic, and now I have nine bottles of dye.
• Refill syringes so I can not make a huge mess refilling things

The problem we R2400 owners have is tiny cartridges that cost $20 each and that dry out, die, or get eaten by grues when they’re not used. I’ve spent over $80 on ink in the past month and made only a couple dozen prints. My studio is too dry or my printer is broken or I dunno, but I’m ready to jump ship if this ebay purchase works out.

I think it’s been 10, maybe 15 years since I’ve actually worked on open source software as an author. I’ve helped fix bugs in things like Arduino and ReplicatorG, but I haven’t done anything major on my own.

Until Friday, when my frustration with a certain class of software got the perspective and skill of my being a professional engineer. Instead of complaining, instead of getting frustrated with how someone else managers their project, instead of not being able to pull rank and make them do it my way, I can just go write my own and hand it out.

It’s a nice feeling. I don’t think I’d have gotten here without writing it-cannot-fail code for security and privacy projects as a day job. That sort of rigor is like daily exercise for the brain, like daily exercise or workouts only for the brain.

Soon after I started testing the Mk7 head it stopped moving plastic, period. I had a working Mk6 handy and a Mini MakerFaire to attend, so I fell back to the Mk6 and decided to let other people debug the Mk7.

However, nobody on the MakerBot list really had a reason or a fix I liked, so I took it apart to fix on my own.

The first thing I discovered was that the pressure mechanism for pushing the plastic against the stepstruder was not pushing hard enough, due in part to scratches on the head’s surface.

The second — and more important — thing was that the stepstruder gear was filled with shreds of plastic. It came off easily, so like the Mk6, just pushing the plastic harder would clear the junk out of the motor.

But how to do that?

Like this.

It’s really that simple. Grab a spare M4 bolt from your parts kit, buy a wingnut at the local hardware store and glue/Loctite the wingnut to the end of the bolt.

I set it up, dialed in a temp of 240C (see earlier posts about temperature), and it forced plastic through with no problem at all. Even a 5 minute run ran without any problems at all.

Now to print some test models….

I had the Mk.7 on the “needs help” bench while doing the previous set of temp tests. I took it apart and discovered the problem with it not pushing plastic was the tensioner against the drive. It had scratches and the drive pulley was clogged with plastic. After fixing that — see the next post for my cheap and adjustable tensioner — I put it on the Cupcake and did another set of temperature tests.

Like the previous set of tests, for temperature reads I used:

• built-in sensor that ReplicatorG software reads
• Fluke 88V temp sensor with temperature probe. Not a cheap device but the readout is 0.1C and it’s fast
• $20 BBQ grill cooking thermometer. Cheap, easy to use, but I think their goal is to make sure I don’t kill someone with undercooked poultry.

As with the Mk.6, the temperatures are lower on Replicator than on the other two sensors, so I need to run with much hotter temps than are required by the instructions. At this point I’m considering adding an offset/calibration value in the software so that the read temp is adjusted properly.

(The images are hosted on flickr for easier commentary)

Mk.7 with software 0033

Part of switching over to Gen 4 was improving daily operation by locking down the extruder and the build environment. Going to the Mk.6 Stepstruder was already in progress but I really needed to ditch the difficult-to-use but trendy Automatic Build Platform for the Heated Build Platform (HBP). It was great for making kid’s favors at a Maker Faire but a real PITA for complex or experimental objects.

After some decent experiments with the Mk.7 (more on that later), I decided to try the 0.3mm head and 1.8mm plastic on the Mk.6 after the success with the 0.4mm head and 3mm ABS.

It works, but not well enough to actually print. The drop from 3mm to 1.8mm plastic, almost %50, should have worked well with the drop from 0.4 to 0.3 but the extruder doesn’t want to extrude. There was some talk on the makerbot list that black 1.8mm plastic required higher temps, those were red-lined by the software, so I did some measuring on my own.

Back in the early days, getting your print temperature correct was one step from ritual magic. That seemed likely, so I decided to repeat some early tests and wire up second and third sensors to run in parallel with the default sensors.

With these, I collected some data and made some graphs. The sensor tips were put as close to the MakerBot sensors as possible and I waited as long as seemed reasonable for the temperature adjustments to stabilize after a change.

• built-in sensor that ReplicatorG software reads
• Fluke 88V temp sensor with temperature probe. Not a cheap device but the readout is 0.1C and it’s fast
• $20 BBQ grill cooking thermometer. Cheap, easy to use, but I think their goal is to make sure I don’t kill someone with undercooked poultry.

The short answer is this — the replicator is reading at least 10C lower than anything else, so I need to run with much hotter temps than are required by the instructions.

(The images are hosted on flickr for easier commentary)

Mk.6 tests:

Mk.6 with software 0033 (recent tree build)

Mk.6 with software 0029 (distributed)

HBP tests:

HBP with software 0033

HBP with software 0029

The past few months have been an unexpected “learning event”. In early December I had a nasty fall and got a concussion, a couple of weeks in the hospital, and almost 2 months off work recovering at home. Lots of physical and speech therapy, lots of rebuilding muscles, and a lot of “you know, I think I’m pretty damn lucky”.

My thinking is doing fine, I’m passing all my medical tests, and I can write code and talk on the phone and drive around town. I was wanting to go back to work a month before they let me, but I think I needed the time off for the physical work.

Physical stuff is a little slower — concussion recovery is nothing to joke about. I’m not allowed to do all sorts of “dangerous” exercises like riding my bicycle, running, or even running on a treadmill or standing on a chair to change a lightbulb. I’m actually proud that I can go for a mile or two walk, do a dozen situps, lift weights, and go back to music lessons.

More importantly for you, I suspect, I am back to soldering-and-coding. I’m finishing up some existing projects like finishing the Cupcake Upgrade docs, working on Lasersaur #4, and starting some new software for digifab. I’ll update things about hacking here and talk design stuff on allartburns.

Well, it’s working, and quite nicely. I don’t have the print range of a TOM, but I have quality, and that’s what I was after.

The trick to getting it all working was replacing the Z stepper that shipped with Cupcake #235 and replacing it with a more powerful one from Lin Engineering (which required a new metric pulley from SDPSI). The Z-table is now quite zippy and does not stall like the old one did.

Photos and parts lists to be posted everything’s a scattered mess in the aftermath of Pittsburgh MiniMaker Faire, the lasersaur build, fixing my mom’s laptop, and a thousand other papercuts.