Sunday, March 21, 2010

Prototype #2 printing

Here is Prototype #2 printing. Same speed settings as before:
  • print: 36 mm/s
  • travel: 55 mm/s

Saturday, March 20, 2010

Cutting up

Well, cutting down actually. Yesterday and today I spent several hours in the shop cutting some more trial parts so we could test out our latest round of changes. We reworked the X carriage to make it easier to assemble. We also redesigned the Y carriage bearing supports to reduce both the total number of bearings and the total number of unique parts. I made parts in both the plastic/lumbar (Trex) and some random plastic from the store (chopping block). Here is a short video of our machine hard at work.

Todd and I spent the afternoon trying the new parts. This involved taking the previous machine down to nothing and putting it back together again. This process took us about 6 hours so far (still in progress); but only because we don't have to look at the pictures every 2 minutes :). The good news is that both the x-axis and y-axis changes seem to work well. The bad news is we still have more rotational play where the x motor rides up and down the z axis than we would like. It hasn't affected the print quality at all but we still don't like it. Fortunately I was anticipating this and already have a solution in mind. In the next couple days I expect to have the new parts cut and ready for another trial assembly. Maybe in a few more days we'll even be ready to sell some kits.

Saturday, March 13, 2010

Isaac's First Print Video

Isaac's First Print

Isaac completed its first print today! Brett is stitching the video footage together. In the meantime, here are some photos:

Some more photos

Movement Testing

Here is Isaac flexing its motors:

Monday, March 8, 2010

Some goals of the Isaac-Mendel

The Isaac-Mendel is a derivative of the RepRap Mendel and can be classified as both a RepRap and a RepStrap. We tried to preserve as much of the Mendel's characteristics as possible:
  • All of the machinable parts are printable. An Isaac-Mendel can print its own replacement parts. It can also produce a child Isaac-Mendel.
  • It has roughly the same form factor. It uses the same lengths for stud-frame-side and stud-frame-end. Other stud lengths vary to match the new parts.
  • It's belt-driven.
  • It's GPL. Once we start selling kits we'll post the plans publicly, most likely on the RepRap wiki.
We have some additional goals to support its use as a RepStrap:
  • All of the printable parts are machinable. A 2-1/2-D milling machine or a gantry router can cut out the parts. The only part with cross holes is the frame vertex; the cross holes are easy to drill using a jig.
  • It includes an adapter plate to mount MakerBot's Plastruder MK4. This combination is optional; the Mendel extruder should also fit (untested).
The Isaac-Mendel is a work in progress, but it looks like we're nearing the home stretch. We hope to have it printing sometime this week or next and post videos.

Part 1 (Literally)

Back in November of 2009 Todd started working on printing a Mendel on his CupCake CNC. He brought his work in progress over to a family dinner one night. He hadn't gotten very far at that time because of the hours required to print parts.

As we were all sitting around admiring the Mendel design when discussion turned to the cost of it. The cost of Mendel isn't bad, but you need access to a Reprap type machine like Todd's CupCake, and 60 hours of free time. At that point dad jumped in and said "Why don't you just cut them all out on the CNC?".

Mendel wasn't designed to be cut, it was designed to be printed. We all knew that it wouldn't be an easy endeavor to generate a Mendel design that can be machined. We looked hard at several other pioneers including the wooden mendel, the metal mendel, and others. They weren't very far along at the time enough to know that the idea was reasonable.

Todd got excited about the idea so I helped him finish upgrading his Shirline Mill into a CNC Mill so he could prototype without having to travel to Dad's to use the big one. At that point we were ready, with fresh licenses of Alibre Design in hand we started with one part, the infamous frame-vertex.

Long Winter

It's been a long winter, but first let me introduce myself.

My whole family has been into computers since I was little. Our first family computers consisted of Timex Sinclair 1000's, Vic 20's, Commodore 64's etc. We even had an original Pong. Pretty much had everything up through the first 486's. That was a long time ago, and none of us have left it.

Mom started her own software company in the early 80's selling educational software to school systems all over the US. My father got out of programming but helped mom manage her company. When we moved to Virgina he got re-involved in commercial construction management. My whole life Dad has been an avid woodworker, making everything from Christmas toys to custom cabinetry. My brother Todd went on to Virginia Tech's Computer Engineering school where he got all the way into his PhD program. Now he's doing stuff I'm not allowed to know about :)

Myself, well my name is Brett, and I'm the youngest. I also went to Virginia Tech, and also got into Computer Engineering. I stopped at my Bachelor's and went straight to work. Currently I write avionics software for a small company, and have work on some pretty cool things such as the X-31 control software, X-43C, GlobalHawk, C-130J moving maps, etc.

About 3 years ago dad approached me to help him build a CNC router for his wood shop. He already had a frame from a router duplicator, and so it begun. About 4-5 months later we had a crude CNC machine that would run at 30-40 ipm (inches per minute). We fiddled with it for about a year, constantly tweaking the design trying to resolve issues that crept up.

We started to grow tired of it, and dad decided we should start over from more solid plans. We started with a Joe's CNC design but added provisions for a lathe/rotary axis at one end of the machine. After about a year of working on it, and two rounds of electronics, we finally have a monster on our hands. We can cut almost 4'x6' sized sheets at a time, and turn up to 8"x36" blanks on the lathe, all at up to 200 ipm.

That's where the history ends, and this blog begins.