An engineer(ing student) in serve to the Empire...

LC La Forge · Post by **LC La Forge** » Thu Apr 30, 2009 10:22 pm

As many of you folks know, I am a 3rd year mechanical engineering student IRL. As part of my curriculum, I am required to take a course in manufacturing processes - a course that covers topics in casting metal, among other things and a course in which I am currently enrolled. The primary lab exercise of this course, one that extends several weeks and involves a fair amount of design, is the "Casting Lab" (as we call it). Students are allowed to design a part to be cast, prototype the pattern for the part, and cast that part.

I am pleased to announce that as of this morning I am in possession of a 4 inch diameter Imperial Seal, made out of solid 300-series aluminum. :P

Some pictures for those interested:

The CAD solid model I drew for the part. Each of the features of the Seal itself were generated by taking an image of the Seal on the internet and normalizing the lengths based on pixels and then bringing it back out to the units I was working with in CAD. Took about an hour to draw, including necessary design features such as draft on the sides, etc.

At this point I would put a picture in of the Rapid Prototyped pattern, but my instructor still has it. I'll get it back Monday and put up a picture then.

A picture of the casting after it came out of the mold. We used green sand casting techniques because it is rather easy, inexpensive, fast, and surface finish isn't an issue. And yes, my partner cast the Rebellion's logo. We were rather proud of our nerdiness. :P

Another picture of the post-freezing cast. The flat metal sticking out the side is known as flash and it occurred in this case because the superheat of the casting metal (the temp above solidification temperature) was a bit too high. Not a big deal, though.

A better shot of the casting, this time outside of the sand mold completely. The material in the center of the two medallions is known as a riser and is designed to store liquid metal such that no cavities form in the medallions themselves. I am happy to report that, as far as we can tell, the parts are free from shrinkage cavities. :)

A close up of the Seal. The poor surface finish is partly due to the excessive superheat and partly due to the fact that we cast in sand molds. In fact, if you feel the Seal, it does feel very much like sand. :)

Next steps involve going to the machine shop and removing both medallions from the rest of the casting. I then need to drill a hole in the top of each so they can be hung with ribbon or on a nail or something, and grind off the sides so it looks smoother and cleaner. But all in all, a good casting.

FOR THE GLORY OF THE EMPIRE! 8)

Post by **Jagged Fel** » Thu Apr 30, 2009 10:58 pm

Hooray for SolidWorks! :P

Post by **Vortagh** » Thu Apr 30, 2009 11:17 pm

Looking good! :-)

Since I am lacking the tools to actually turn anything CAD into something usable as a negative for a cast (no heavy CNC machines here :P), I can only cast what I model myself. Thus, so far I have stayed with tabletop figures and parts for model kits. Same goes for non-metal (resin).

I really need to find someone, who works in a big machine shop with access to CNC machinery. :P

LC La Forge · Post by **LC La Forge** » Thu Apr 30, 2009 11:25 pm

Like I said above, I used rapid prototyping methods (or, rather, the rapid prototyping center staff used them :P), so no CNCing for me, either. My pattern is actually thin sheets of paper placed on top of each other in such a manner as to form the shape I modeled up. It works just as well as a CNC'd pattern and is much much easier to produce.

Post by **Vortagh** » Thu Apr 30, 2009 11:56 pm

Far too much work for me, to even consider that :P

Plus, when you want to create something that has details in the sub-mm area, you can't build stuff out of paper for it. :P

LC La Forge · Post by **LC La Forge** » Fri May 01, 2009 1:12 am

Oh, I concur. But for what we were doing, this was the most practical way to go about it. It really did work well. :)

Post by **Jagged Fel** » Fri May 01, 2009 1:58 am

Whenever I get a house I need to get my hands on a Bridgeport, I could have so much fun then... :P

Mike Mar · Post by **Mike Mar** » Fri May 01, 2009 3:52 am

Forge: Start building tons of them. I'll sell them in my store. :p

LCL Fewrfreyut · Post by **LCL Fewrfreyut** » Fri May 01, 2009 11:53 am

first ones free to GE:ER members :P

LC La Forge · Post by **LC La Forge** » Fri May 01, 2009 9:09 pm

MAR: No no, these are limited edition pieces. Of course, by limited, I mean that I made one. :P I will, however, sell it to you for the low, low price of 1,000,000 Imperial Credits. :P

tioneaudrine · Post by **tioneaudrine** » Sat May 02, 2009 7:47 am

Nicely made Commander

CM Jamie · Post by **CM Jamie** » Mon May 04, 2009 5:08 pm

Well done Laforge, good job my young subordinate. :P

Mike Mar · Post by **Mike Mar** » Wed May 06, 2009 2:41 am

/me give a 'fictional' 1,000,000 Imps Creds to LaFo.

Now.... Send me the REAL piece! :p

LC La Forge · Post by **LC La Forge** » Thu May 07, 2009 4:03 am

The real piece still has to be machined, sorry. :P
*runs off with 1 million imperial credits* :P

LCL Fewrfreyut · Post by **LCL Fewrfreyut** » Thu May 07, 2009 12:04 pm

run to the currency exchange!!! quick!!! :P