The drawbot, a junkbox project inspired by Bill Paulson, is driven by a couple of $3 steppers from American Science and Surplus, some cheap H bridges and an Arduino clone. Software is free from Makelangelo.com. It does the heavy lifting math to convert from X-Y coordinates to the “inches of string” coordinates the polar geometry imposes on its steppers. In addition to accepting normal X-Y gcode, it can take a jpeg image and use the traveling salesman algorithm to generate a single path reflecting the darkness of different areas in the image as it’s doing in the picture above. Such a path is ideal for a plotter that doesn’t have pen lift capability. Yet.
Our hackerspace had purchased a Kossel Clear Delta Printer. In retrospect, it seemed like it was a forever project getting the printer assembled and operational. For months, it was in the box in the back room with lots of talk about putting it together but no action. One of our senior members, Andrew, had finally had enough. He grabbed the kit and spread it out on the table in the front room of our space.
Well, once the pieces were just laying out there, it was sort of like a jigsaw puzzle just asking to be put together. Like moths drawn to a flame, hackerspace members contributed and we got it assembled over the course of a couple of weeks. Actually, in hindsight, it’s somewhat amusing. We have our open nights on Thursdays and we frequently have guests come in to check out the space. It seems like they couldn’t resist the jigsaw puzzle effect either. Everyone enjoyed the assembly process.
Unfortunately during the timeframe we were assembling the Kossel, there was some major cleaning/rearranging taking place due to renovations in our back room which caused things to be moved around the space. The Kossel was basically done less the extruder which was in a box along with the laser cut outs. The extruder portion of the kit had basically vanished. (We surmised that scrap cutouts from the kit were in its box, so it might have been inadvertently thrown out with the trash).
We debated what to do. Did we actually get the extruder portion with the kit? (Yes. I remember laying hands on the pressure fittings, so it did come with the kit) So do we order a replacement kit? What?! No! We’re hackers/makers! We’ll make a new and better one!
One of workshop 88’s friends, Ryan who periodically visits and has a Kossel Clear, suggested we try out http://www.thingiverse.com/thing:245677
This is actually a very clever design; it uses part of a paper clamp (binder clip) to tension the bearing against a hobbed gear.
There a couple of minor features in this design that I thought could be improved on. I’ve seen Bowden-style extruders where there is a pressure fitting mounted on the input side of the extruder (The Kossel Clear extruder we misplaced had that feature). Having a PTFE tube on the input side offers lots of options on how to route the filament of the extruder. In addition, it seems like the post that supported the bolts to the Misumi 1515 frame could have could have been beefed up a bit as well.
The thingiverse file only included the STL’s, which I loaded into Freecad. Below is the original base as part of assembly. Display properties of the original files where transparent so it was easy to wrap a new solid model with the same proportions over the original model with the new features I wanted.
Here is the base with modifications:
Initially, I had donated a spare MK7 hobbed gear that I had made for my Rockbot printer to the space for use on this printer; but the short length of the MK7 gear caused some problems(which you can sort of see in the assembly drawing) The setscrew I used protruded from the wheel and was contacting the 608ZZ bearing. Another issue was with the wheel itself: it was a not my finest work. The set screw hole overlapped the hobbed portion of the wheel.
I set out to make a new one.
First thing I did was turned down a piece of bar from the scrap bin and sized the hole with a 5 mm reamer.
The blank was then mounted on the stepper motor and basically marked to where it should be hobbed.
Next step was to hobb the blank using a spin indexer. I used a 10-32 tap to do this and Unfortunately, I didn’t have a R8 collet of the correct size to grip the tap… So I put it in a drill chuck and hoped for the best, i.e., that the chuck wouldn’t get sucked out of the morse taper.
The spin indexer really does a nice job of hobbing with a tap and I was very pleased with the result.
After that the cross hole was center drilled, drilled and tapped.
Afterwards, the part was cut off from the bar with a parting tool.
And here is an image of the finished unit assembled.
So far I’ve been exceedingly pleased with the performance of this extruder but there are a few things that need to be addressed before the mod can be considered done.
One issue that annoys me is that changing the filament is more difficult than it needs to be. I was having difficulty getting new filament to feed through the tiny hole in the lever arm. It seems like there is enough room to add some type of tapered pilot hole to help make feeding the filament a little easier. Also, it seems that lever arm has split along the holes of the spring. (This part was printed in our space’s original printer, a Makerbot Cupcake. The Cupcake has seen better days so I’m thinking this separation was more of an issue with extrusion settings vs a design issue) Even so, it should shouldn’t be too difficult to increase the strength around the holes slightly.
The modified design I created needed to have portions ground away with a Dremel tool for clearance. I didn’t take into account how the the filament would push against the bearing. (I was under some time constraints to get the printer ready for a STEM event I was attending, so I wanted to get this project operational vs perfect). The model I had cloned was originally drawn in metric, so was pretty easy to duplicate the nominal dimensions, but I will need to increase the clearance on the stepper motor pilot bore as well.
I’m also currently designing/building a custom Kossel Style Delta printer I’m calling the Wedgie. It’s a fun but slow-to-finish project for me at the moment. It’s uses Kossel Clear proportions and rail arrangement as a starting point. I’m adding some interesting features as well as incorporating the next iteration of the extruder design that was used for this printer.
The calibration of the Kossel Clear seemed like it was more painful that it should have been. This is the first Delta style printer I’ve calibrated and it was a bit of learning experience. I hope to share these insights in a future post.
Dale Dougherty, founder of Make Magazine and creator of the Maker Faire will be stopping by Workshop 88 TONIGHT (March 23rd) at about 9:00 pm. Please feel free to stop by and say hi!
He is in town for an event at the University of St. Francis tomorrow. See the flyer (PDF) that you can download below. Here’s Dale’s TED talk from 2011:
Thanks for visiting us, Dale!
We are thrilled to announce that Workshop 88 has been awarded a “Making the Future” grant from Cognizant, a technology services company based in New Jersey. The grant will allow us to offer a Maker summer camp geared specifically toward 10-12 year old girls. The summer program will be led by Workshop 88 member Rachel Hellenga, who has over 20 years experience planning educational exhibits and programs for museums and libraries.
This pilot program will celebrate girls’ ingenuity and involve them in making flexible circuits by combining LEDs and paper-thin batteries with everything from Legos to paper crafts. Girls will use a circuit printer to produce circuits with conductive ink and work with other flexible materials such as conductive tape and conductive Velcro.
Cognizant’s Making the Future education initiative was created to unleash the passion of young learners—particularly girls and underrepresented minorities—in STEM disciplines by providing fun, hands-on learning opportunities. Two years ago Workshop 88 members teamed up with the DuPage Children’s Museum to lead Sewing Goes High Tech with support from Cognizant, and Rachel invented the name Teknistas to describe the tech-savvy, style-savvy girls in the summer camp. You can see their projects at www.teknistas.com along with updates showing young makers at Workshop 88’s Duct Tape Bling booth (winner of an Editor’s Choice Award 2013 New York Maker Faire!) and Rachel’s Fashion Technology from Chicago showcase at the inaugural Rome Maker Faire. We are involving some of our current Teknistas in planning our next activities and hope to inspire more young makers this summer! If you’d like updates on the upcoming summer camp, drop us a line at email@example.com with the subject line “Making the Future” and you’ll be the first to know when we finalize the dates and program description.
I couldn’t find an empty notebook this morning, so I made threw one together from printer paper and the remnants of the box my Amazon Echo came in.
This one is a quarto with two quires, simply sewn together with waxed linen thread and no glue.
The top stitch on the cover is a bit strange, but topology wouldn’t allow the initial pattern I was planning on. I might use a small ring or a bar to secure the top stitch the next time I try this format so I can avoid the strange fifth hole in the spine.
I’ve always been interested in bookbinding, but haven’t given it a shot until now. I followed these excellent tutorials by Sea Lemon on YouTube, and I think my book came out okay.
I made the case using black Tyvek for the cover, and 1/4″ masonite for the spine and front and back boards. I think it worked pretty well, and I like the way it looks.
I sewed the signatures together using upholstery thread, and the book opens up really well.
This is the view of the cover with the book open on the table. I cut the board for the spine about twice as wide as I should have, and I’m not entirely happy with that. I got a bit impatient once the text block was done, and just charged ahead…
Another issue with rushing ahead was that I used a bit too much glue on the endpapers, and they wrinkled a bit as they dried.
All things considered, I’m very happy with the way the book turned out, and I’ve got some different techniques to try next time.
The Workshop 88 Shapeoko 2 is coming along nicely. It recently cut this 18″ foam sign, taking advantage of the SO2’s “frontless” design that allows working on arbitrarily long pieces, even though its active work area is only about 10″x10″. Some details are here.
The Z axis auto touch-off switch, inspired by the Carvey “Smart Clamp” is now working as well. There’s a little clip of it here.
While it’s machined handles for some of its clamp bolt and even machined the scales for a knife handle replacement, its most ambitious project to date is full 3D machining of the body of a pinewood derby car. That’s still work in progress. Stay tuned!
With the start of the new year, we’re planning to spend some time cleaning up the space. We’ll be out at the space all afternoon on January 2nd, so if you’d like to come out and help clean up, stop by.
This class teaches the basics of using a Linux system, starting with what Linux is, where it came from, and why you might want to use it. Continue reading
Come out and learn basic computer networking skills!
The topics we’ll be covering include:
- Network addresses
- Basic home network design
- Physical interfaces
- Wireless networking
- Debugging basic networking problems