Sunday, July 22, 2012

Short Update

Workroom, ME 252, is now open Fridays 11 am - 5 pm for anyone who wants to come in and work on their printers. 

We are also working on a few ideas for new, large group projects, and will keep you updated as to what sorts of help we'll need from anyone who is interested.

I also wanted to share with you a 45 sec video of Matt crossing the finish line at the Derby for those who haven't seen it.
Video Courtesy of Lisa Weeks

Tuesday, July 17, 2012

One Week Hiatus

Hey all,

We appreciate all your support.  We had a great time this weekend.  However, we are exhausted so no workshops scheduled this week.  Keep checking back here though, this is where we'll let you all know what our next plans are.

Saturday, July 14, 2012

Seafair and Pictures

Hey all,
We want to see those pictures and videos you took of WOOF at Seafair.  Sadly, we haven't set up a way to upload anything just yet if you aren't a WOOFer.  So feel free to e-mail me files or post as a comment a link to those beautiful images we know you have.

Also until I figure out a better place to collect all of our silly pictures on the website, while maintaining a sense of dignity, you can check out my pictures here:

Thanks again!


Come out and show your support.

We are across from the Radio Disney booth at Greenlake.  Our scheduled race time is 12:30 and again at 1:15.


We did it and had a wonderful time at the Seafair Milk Carton Derby today.
After finishing 2nd  - photo by Alicia
We had some issues at the beginning as the Seafair crew didn't know how to categorize our very unique boat.  However, we worked things out and got to race in the Adult 14+ Racing category and placed an unofficial 2nd!  So way to go WOOF.

I want to thank everyone who came down to see us.  We had a ball.  I also want to personally thank our wonderful WOOF volunteers: Matt, Adam, Brandon B, Brandon P, Mark, Chris, and Morgan for coming down and helping show the public what WOOF is about.

Finally, Thank You Seafair.  We threw you a curveball and we appreciated you working with us and allowing us to go out and play and show the public a new form of recycling.  We hope to see you next year with an even better boat (and hopefully see some great competition in this new field)


Friday, July 13, 2012

Seafair Milk Carton Derby

We did it!  We printed a full-sized boat on Big Red and it floats!  With our trusty President at the helm, we can't lose tomorrow.  Congratulations to you all for your hard work.  We really couldn't have done it without you. A special thanks to: Matt, Adam, Brandon B, Brandon P, Mark H, and Morgan for sucking it up and printing every night this week from 9pm until 6am.  WOOF thanks you guys for your hard hard work.

WOOF would also like to thank Scrapblasters for their assistance in reducing our milk jugs to something that we could actually get down a hopper.
They do fantastic work, check them out:

Tomorrow, we show them all.

The Derby activities are based out of the area around the Seattle Canoe & Kayak Club (the stadium area) at the south end of Greenlake.  We are hoping to set up in a green space slightly to the Northwest of there.  We are going to have a small spot set up with our poster, the Wee WOOF (our test printed boat), and general information about WOOF.    Drop on by, we'd love to see you there.

Tomorrow please wear UW or 3D printing/Fabrication/Hacking related gear tomorrow.

Thursday, July 12, 2012

Calling All WOOFers

Hey all,

We are on our last night of boat printing and NEED HELPERS.  So come on down, ASAP.  Adam, Matt, and myself (Beth) are in ME 252 now and will hopefully be printing soon.
You should come down and help out.  The boat is a thing of beauty.


Wednesday, July 11, 2012

We've Begun

Following the success of Monday night's test print we only had one course of action: begin printing the boat. First we had to prepare for the print. We finalized boat dimensions, modeled the part in SolidWorks, countersunk hundreds of holes in the pegboard, and set up the build surface. We also decided to add a rheostat inline with the drill motor. This would give us the ability to control our extruder without reaching into the machine as it operated. Compared to our track record of hitting every wall imaginable it was a relatively uneventful afternoon.

Our freshly printed base with out test piece to show scale
During the mid-evening we generated stl files and sliced them. Because we were only going to get one shot at the print we needed to make sure the g-code was what it needed to be. After a dry run for final confirmation we broke for dinner. With our bellies filled we fastened the pegboard down and built a rheostat. We were ready to go.

Weeks ago we began joking about how our print would be super long, take a crew of people to make sure all was going well, and likely require working through the night. That joke is no longer a joke; it has become reality. Four of us operated the machine. We began printing at 11:00 pm and didn't finish the first layer until 3:15 am.

Adam, Matt, and Brandon stationed at their
posts making this whole thing work
Our process took a short while to evolve, but we found a great way to make the print turn out beautifully. We ran the printer at 30% speed. Adam sat at the end of the machine and controlled the rheostat so that too much HDPE was not extruded during turns. Brandon stood near the windows to replenish the hopper, screw down the pegboard if it began to buckle, and any other task that needed to be done. Matt and myself sat on either side of the printer and were responsible for "clean up". When the extruder would lay a bead next to a cooled bead it would not fuse to the old one. In more technical terms: the fresh bead did not have enough thermal energy to melt the cooled adjacent one so would not fuse. To overcome this we supplied energy with a heat gun to bring the old bead up to a fuseable temperature. The finished pattern looks great.

Check out these videos of the print:
Big Red minutes after beginning -
Cleaning up the turns -

We learned some valuable lessons during the print. For example, the pegboard will begin to buckle if it is not fastened down with enough screws. We either need to start with more or keep adding them on the fly like we were doing.

Another is how to make turns look beautiful. You can see in the image how some of the turns near the bottom aren't as nice as the later ones. Our clean up process was a little trial and error at first. Though there wasn't much error involved. At least not as much as we've come to expect.

The other big lesson was that we can control the printer manually if the g-code fails, but you end up with a really bad looking print. That's what happened at the tip of the boat in the picture to the right. Of course it didn't help that our HDPE supply had been interrupted by a kink in the feed hose which lead to some bubbles.

We left for the night (more accurately the morning) being exhausted. Exhausted, but elated. We successfully printed our base layer.  The last thing to do is print the walls. Our extruder is so loud that we need to do this sometime at night after the building is cleared. Even with the door closed the extruder can be heard in the mens room around the corner. Any pre-print tests should be done no earlier than 6 (to be courteous to the learning environment) and the actual print probably won't start until 9 at the earliest (because that's when parking is free). It will take several hours and requires a crew of at least 4 again (slightly different jobs but still as much labor as this print). If you'd like to be a part of this last stage get in touch with us and we'd be happy to put you to work. Email, comment, or just show up. We should be in the room after 10:45ish if you just want to drop by but if we're not it's because we are likely making a run to Scrap Blasters for more shredding. If you do lend a hand during the actual print respirators are optional (the fumes irritate some people, but we have decent ventilation). Hearing protection is strongly recommended.

Even if you can't offer several hours late in to the night feel free to come by and oggle if we're in the room. Thanks to everybody who's helped in any capacity at all. It's unlikely we'd be here without your contributions.

A thing of beauty

Tuesday, July 10, 2012

Next Stop: A BOAT!

This is it! Seafair is this Saturday. After yesterday I'm positive we will make it (if only just barely). Yesterday was a "roller coaster day". You know, one of those days filled with emotion: discouragement, hope, despair, and triumph. The best part is that it ended on the triumphant note.

Being unsatisfied with our test pieces up to this point the day started out with us in the process of reconfiguring our extruder. We were encountering problems with what we believe was a back pressure issue. Our paranoia about getting the HDPE to stick to the build surface caused us to mash down on the first layer which would lead to pressure building up in the tip with nowhere to go except backwards. I've lost count of how many times we've had to change that thing but it's near a dozen by now. The good news is I think we got it this time. Making changes to the auger and barrel seems to have made our extrusion reliable which has always been the goal (elusive as that goal has been).

Our new motor mount
The first tragedy of the day struck during a test of the new extruder when the z-axis motor coupling failed. It simply gave up. As disheartening as that was, we got rid of the old coupling assembly and built our own with some aluminum stock, a couple of hacksaws, and the hope that we could make it work. While the new design looks slapped together (it sorta is) it gives us access to the coupling if needed with the added bonus of being extremely quiet.

Using Brandon as a size reference
 With the machine now able to print something, we decided we needed to do a test print. Cubes, buckets, or anything else unboatlike were things of the past. We needed a quick small-scale test to prove to ourselves we could get the machine to do what it needed to do then move on to an actual boat. We pulled out some chalk and started drawing our what our final design would roughly look like. Who says sidewalk chalk is only for little kids?

We quickly modeled a small canoe, set up Big Red, plugged in three ventilation fans, ran a dry run, and prepped the surface. This was it: the moment of truth. Could we press go and let Big Red take over? The answer was no. Of course not. During our print of the base raft the extruder's drill motor began surging so Adam had to sit there with his finger on the trigger the entire time to deliver the appropriate amount of plastic while the computer operator tried to adjust the print speed on the fly. The sudden change in behavior of the drill motor was baffling. It was Adam though that suggested we reconfigure our extension cords so that the motor was not sharing an outlet with the ventilation fans. That did just the trick.

Our test when we finished
Without boring you with the nitty-gritty details, we tested a few variations of the G-code, layer thickness, and overall printing process. Looking at the layers tells a story of the individual lessons we learned as we were testing.

The fruit of our endeavors is a small-scale canoe which shows us that we can go large scale. What we will likely do during the big print is print the raft alone then feed the printer a separate set of G-code for the layers. 

The pretty side
This will be a long print and it will take constant baby-sitting. During our test we had Brandon on the computer, Adam working the extruder, and me cleaning up any slop/refilling the hopper. Theoretically one person could run the print but it should have at least two. This "automated system" is not automated in the least!

The less pretty side
Seafair is in 4 days. We have a verified process and about 70 pounds of HDPE. Stop on in sometime and check out what's going on. If you'd like to help during the printing process even better. Either catch up with us in MEB 252 or leave a reply to this post. We will utilize anyone who wants to lend a hand at this point.

I won't count my proverbial eggs before they hatch, but I think we got this. Let's show Seattle what UW students can accomplish in 2 months worth of free time and some recycled milk jugs.
Brandon thinking about his idea for "concrete skates". Just a little too small.

Thursday, July 5, 2012

Multiple layers and warping solutions...

...Or, one step closer to being able to print a boat!

We've had a lot of issues with the HDPE not sticking to surfaces and peeling away, and a lot of ideas thrown around as a solution. On Wednesday, we tested printing on countersunk pegboard. The thought was that the plastic would get forced into the holes, and get mechanically anchored, thanks to the chamfer of the holes. We screwed the pegboard down to the print bed to try to minimize warping of the bed. Then the 5" test cube was loaded up, respirators put on, extruder and heating activated, and off we went!

To mash the plastic into the holes, we started off with a breakneck clip of 3 inches per minute. This spread our extruded layer out to nearly an inch thick. We modified our GCode to use a very sparse infill (we actually combined two different slicing configs) on the first layer to avoid unnecessary buildup.

Wonderful! Now up to the second layer and infill.

Looks good so far! And a pleasant surprise; HDPE bridges quite well naturally over gaps. But what about the perimeter? That's what everyone's going to see.

So maybe it's not the prettiest in the world, but at least it works, right?
Wrong. We had some issue with the extruder not being very consistent. It's visible both in the perimeter and the infill. But at least it's not a horrible flaw.
Hold on a second, that doesn't look like a cube! We ended up stopping the print here. This little square was almost exactly a thirty minute print. We'll have to try test printing shells of cubes. Solid shapes just take way too much time!
And, unfortunately, we got some warpage. The good news is that when we flipped the board over, the plastic had done exactly what we wanted and was anchored to the holes. We'd like to try printing with a raft included in the base layer, that way all the warping will happen to a part that is trimmed off.

Rumor has it that our layers are also starting to delaminate a little, but I haven't got any pictures of that so far.

Now for some numbers:
Feedrate = 30 in/min (100%)
Perimeter = 60-70% feedrate
Infill = 60-80% feedrate
Base = 10% feedrate

You may notice that these pictures are screenshotted from a video. I have the entire thirty minute print recorded, but I haven't uploaded it anywhere yet. If there is a huge demand for it I will put it up (It's a rather boring video, with a loud whirring sound the entire time), but otherwise we'll just put it in the archives, so to speak.

That's all for now! More updates as they come!