Introduction to Fabrication

To work with metal, like aluminum, I've used mills and lathes, but those aren't exactly an everyday thing and take a while to learn to use correctly. There are also limitations like making hollow pieces. Also the machines aren't cheap. What you probably want is a CNC machine and those are not cheap at all unless you get really old ones and even then they are massive and require 3-phase power which can be hard to get. :P

More useful than aluminum is plastic. You can easily design things in CAD software and send the pieces off for 3D printing. It can be pricey if you want production quality pieces. (Places like shapeways can print things for dirt cheap using ABS plastic though but the resolution is only like 1 mm).

If you're into plastic fabrication and electronics you can actually build a reprap open source 3D printer or Makerbot, but again quality is a problem.

[Edited by - Sirisian on September 20, 2010 12:31:19 AM]

I don't really know much about this topic, but I've always personally thought RepRap was cool.

3D printing might not be available everywhere and is not always cheap nor fast. I usually for my prototyping work use laser cutting from aluminum, steel or Plexiglas, depending on what i need for a project.
Here is the project i made from a 1 millimeter thick alum, bent the parts and fixed them together with screws.

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For a really quick and small scale prototyping it is also possible to work with aluminum using standard hand tools, like small saw Dremel and file.
http://www.houseofbits.com/index.php?note=2010-03-07

Everything a man needs in life is one of these,
a welding machine,
Drill.

Scrapheap for shafts.

Unless you're willing to unload a crap load of money, I suggest using already mass-produced things...

electric rc cars, and rc airplanes can be tons of fun to robotize without breaking into the multiple thousands of dollar range.


RC plane, gumstix, some cams, direct wire the gumstick to the airplanes servo motors, and a bit of coding, and you have your self a pretty cool autonomous uav for ~$1000

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Original post by BronzeBeard Unless you're willing to unload a crap load of money, I suggest using already mass-produced things... electric rc cars, and rc airplanes can be tons of fun to robotize without breaking into the multiple thousands of dollar range. RC plane, gumstix, some cams, direct wire the gumstick to the airplanes servo motors, and a bit of coding, and you have your self a pretty cool autonomous uav for ~$1000

+ PC power supplies are gold mines. Old CD/DVD drivers, cassette players, all of these use the same standard little motors.

Fiberglass and 2 part epoxy. You can do some amazing one offs with a bit of work. Plasticine to make your rough mock-up. Common plaster to shape and carve out a detailed negative. Pour up and layer out your epoxy and fiberglass sheet, then break away the plaster after everything sets. (Note, do NOT use this method for very large objects, as you're dealing with multiple exothermic reactions, and too large of a mass of curing epoxy is a BAD thing.)


Plastic bread boards from the dollar store can also offer a lot of interesting options for building and carving bodies out.

If you want to get really serious about one off prototype building, then I strongly suggest you invest in a foot pedal controlled rotary tool. (One with a hand safety! I've seen some models that rely only on the foot pedal to turn it on/off and control the speed, which is just an accident waiting to happen when someone steps near your work bench. You should need to hold down a button on the tool itself for the pedal to have any effect.)

You might be interested in Ponoko. You design your parts and then they laser cut them and mail them to you. It's designed for prototyping so it's all centered around doing small runs with quick turnaround times (rather than most other places, where you'll have to order in massive batches).

For general fabrication, the tool of choice for hobbyists is typically a CNC Mill. You can find tons of websites on making your own for a few hundred USD, or you can buy kits for prices started at around $1500 USD and going up from there practically without limit. You can, of course, also buy commercial machines for astronomical prices.

The neat thing about CNC mills is that you can spend a few hundred to build a basic machine, then use that one to make a far better machine while only spending a few hundred more. In general, prices rise faster than linear, while you can incrementally build better machines yourself with the price ratio being linear or sub-linear.

I would not suggest going home made CNC route unless you want to spend all your time making, servicing and tweaking CNC machine, instead of building stuff. In reality home made CNC machines are very limited in possibilities. To do some more or less useful work you will need a small scale CNC router for small parts, Bigger table, for large scale parts, also possibly cnc lathe and other tools, it is just not practical for hobbyist to have. And price can pile up quite fast.

Just find a good workshop near you, or better, get in lab of some engineering university and do all the work there.

How easy is it to handle and mold carbon fiber?

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Original post by Structural How easy is it to handle and mold carbon fiber?

Very hazardous. CF (carbon fiber) is both a skin and lung irritant (specially CF dust).

Yeah, carbon fiber is much worse than regular fiberglass and I've already had some bad experiences with the latter.

Most of the "carbon fiber" car parts they have on eBay are just fiberglass painted to look like carbon fiber, as well.

Not to mention that carbon fiber often doesn't have any real advantage over common class, unless you are doing all the math and engineering to backup the design. (It can often be weaker if poorly designed.)