Monday, April 4, 2016

3D printing, molding and casting!

A few weeks ago (as of posting this, not writting) I received an e-mail from my student project director saying the Department of Electrical and Computer Engineering were planning on buying a few 3D printers, and wanted our opinion on the matter. They had received many sponsorship request to buy 3D printers, and, due to the demand, wanted to make one/some available to the whole Science and Engineering Faculty. They also had made a pre-selection of printers: The Form 2, which would be primarily used for research purposes, and a Stratasys uPrint SE.

The Forms 2 is a GREAT idea! it's not too expensive for research, it's high quality, and it's..."fairly" simple to use.

The uPrint came out in 2010. Just to compare; you know what else came out in 2010? The first Ultimaker. Oh, and the very FIRST Makerbot came out in 2009. Thingiverse started in 2008. Heck, the reprap project started in 2005! The uPrint SE is closer in time to the creation of the RepRap project than today! It's minimum layer height is 0.254 mm (oh, look at that, 10 thou, not even metric), a far cry of today's 0.1 and 0.2mm, (or even 0.02 if you actually believe ultimaker's specs) Not only that, but it costs 17 000$ canadian pesos. Well, ok, 12 000 for the printer, some for the wavewash...thing, and some for taxes, duties, formation, and so on. Still, for a printer not really better than the Printrbot simple, it's quite appalling.

So, I've tried to steer the department away from that printer, towards cheaper alternatives; Rostock max v2, Ultimaker, Makerbot, Printrbot simple, Lulzbot Taz5, Markforged, etc. For that 17 000$, you could almost buy all of them! It would serve the community better, and allow for unhindered growth instead of being stuck with 1 big and expensive printer for a while, until the next grant comes in...maybe. The main problem being that you also have to include time for set-up, calibration, and maintenance. On that point, the uPrint should be more more or less "Set and forget" While, for some other printers, the process can be...a lot more complicated. Finding the right tool-chain: Cura by itself? Cura + Pronterface? Slic3r? and so on. Then finding the right settings for every printers, then printing, maybe, and finally, well, maintenance is another thing you have to consider when you have to pay technicians to maintain these things.

All right, enough text, let's go to more interesting stuff! return season has passed, and I have some money to do stuff...humm, what can I do...humm, looking at all these 3d printers for actual research makes me mighty tempted. Uh? Monoprice has a printer? Uh? the old version is on sale and has better steppers than the new one? Oh? it's based on one of the newer reprap (The last I had heard of reprap before that, the Mendel just came out...2009) What's that? only $300?...welp, looks like I now have a 3d printer! (which, after a few mods, will still be better than that uPrint SE...) Delivery is expected this week! I already got the plasteeq too!

The next post will be an adventure in 3d printer calibration.

Mold Making and casting
Since I didn't buy the HTC Vive (because I think it would be worth 1000$, not the 1400 canadian pesos they're asking for right now) I finally bought all the smooth-on products required to do a mold of that part on dark repulsor that makes the whole build so hard.

ALL the smooth-on products, +Punished Props  would be proud

I've been watching Bill's (+Punished Props ) videos forever now. So I used what I learned to do a one part mold. Measuring cups are so usefull! And since they're flexible, if you mix your stuff well, you can just pull it off once it's cured.

I ran into a small problem casting the mold. I used contact cement to hold down my master on the floor. Thing is, contact cement is somewhat flexible...and the silicone got under the master and lift it up. I'll have to sand the bottom of both my finished pieces. Oh well, now I know not to use contact cement to glue down a master, and to be careful so the bottom of the master is somewhat water-tight.

Guesstimating the correct quantity of...well, everything, is so hard! I made double the urethane I needed. Oops =( Should've filled the mold with water first to see how much i'd need.

In any case! I got 2 pieces I can use out of it! I've wasted some material, and i'll have to do some sanding so the pieces sit flat, but for a first time, i'd say it's pretty good. I've failed at some thing, but then, success is built upon failure! As long as you learn from those failure!

I know I'm getting late on the Robot Combat rule translation. The construction specs are taking a longer time than planned to translate as they are way more technical than everything else. I've also missed a nice opportunity with the Montreal's Festival de Robotique being the past weekend. Oh well, it's coming soon (tm)

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