Today's Meeting

Today we had a meeting about bringing all the pieces together and getting our boat printed. Thanks to everybody who showed up to support the project even though it is a vacation week. Here are some of the key things we discussed/accomplished. I'm writing this from memory so if I get some of the details wrong (or forget something entirely) please correct me in the comment section.

We wrote up a calendar to give us a visual idea of what's coming up. We then filled in some dates for deliverables. We settled on an ambitious schedule to allow time for unexpected delays.

Sun	Mon	Tue	Wed	Thur	Fri	Sat
		12 JUN	13 JUN	14 JUN Extruder/Hot End Assembled	15 JUN	16 JUN Obtain milk jugs from Whidby Island
17 JUN	18 JUN Test printing with actual HDPE (hopefully waterproof)	19 JUN	20 JUN	21 JUN Have an idea of warping and how to handle large prints	22 JUN Decide on feasible boat design	23 JUN
24 JUN	25 JUN	26 JUN	27 JUN	28 JUN	29 JUN Print boat	30 JUN
01 JUL	02 JUL	03 JUL	04 JUL	05 JUL	06 JUL	07 JUL
08 JUL	09 JUL	10 JUL	11 JUL	12 JUL	13 JUL	14 JUL Milk Carton Derby!

An extruder design was discussed and should be assembled by this Thursday.

We sorted through 6 garbage bags of milk jugs and separated the clean ones from the ones that needed washing. It was a very unglamorous job but important nonetheless. Keep saving (and washing) your milk jugs because we're going to need them! We also weighed jugs and found that the average is about 67 grams. To put that in perspective if our final design weighs 100 pounds that's about 675 jugs.

We still don't have a final boat design, but that will be highly dependent on how many milk jugs we get and how skilled we become at printing in the first week of the quarter. The simplest design discussed is a flat bottomed boat with vertical walls that seats one paddler. The general consensus is that we will be thrilled with anything as long as it floats.

Lastly we were able to upload and run actual G-code on Big Red. The printer reads dimensions in inches so either our design work needs to be done in inches or we need to adjust scaling factors. We took a video of the print using a sharpie in place of an extruder. The video file is too large to upload here so you can find it at:

http://youtu.be/-vYGF4P9esM

We have overcome several huge hurdles up to this point and only have a few left. Let's keep up the momentum and get this thing together in time for Seafair!

Happy printing.

Matt's add on...

To try ad make up for missing the meeting yesterday, I worked on HDPE printing. I tested various materials plastic cutting board, wood, screen door, tape etc. Wood worked ok but not well enough. So I decided to print directly onto milkjugs. I cut out about 8 squares of milk jug plastic, put a piece of parchment on top and ironed the stack until I had one thick sheet. It was super easy and the plastic fused nicely. I trimmed up the edges and printed on it. As you can see, the HDPE stuck really well. What was surprising is that the print was not completely fused to the build platform. It snapped right off with a good tug. Soon we'll see if this scales well. I'll be in today to work on extruder stuff (6/13).

end Matt's add on