3D printing (plastic) projector parts?

[Mathew Bailey]

Has anyone ever thought of 3d printing plastic projection equipment parts? I do know in some instances there are people 3d printing things with other materials besides plastic,but what about plastic parts such as for example Christie film rollers? (I have some of these rollers myself,but not 3D printed) I f I'm correct, you fist scan or photograph all sides of the part & then convert the images to the correct formats & files for 3D printing.

[Marcel Birgelen]

The problem with your average additive 3D printer is that the resolution isn't really sufficient to print rollers, you'll end up sanding the hell out of those.

We've got a resin based 3D printer, which exposes one layer via UV light and can achieve quite a resolution, but the thing is dead slow and considering the cost of the resin, it ain't that cheap either.

Also, just 3D scanning and printing a part won't be enough for fine applications, you will still need to manually polish those files.

Another problem with plastics is strength. Most 3D prints aren't sufficiently durable to replace many parts with a high-wear potential. A more realistic approach for metal parts is CNC, but a professional CNC machine is both extremely bulky and expensive (and loud).

[Mark Gulbrandsen]

I just assembled a tiny NAS out of a Raspberry Pi 4B and a couple of 1 TB SSD. Many of the "Pi" cases available are 3-D printed. The one I bought is a piece of crap, and the printed parts are kind of brittle. Not sure that all 3-D printed stuff is like this, but these parts are. Next time I'll buy a metal case for these sorts of projects.

[Randy Stankey]

3-D printing is fine for prototyping or for making household gewgaws but it isn't the best way to make things that will be used in the real world.

At minimum, the printed object will need to be finished by machining, grinding, filing or sanding. Most 3-D printing plastics aren't strong enough to stand up to use in a machine like a projector. They'll wear out or fall apart, pretty quickly.

In my opinion, the best thing to do is to make the part in the 3-D printer then use it as a pattern to cast the final version out of metal. It's possible to cast items out of aluminum at home. Just melt down a bunch of empty beer cans. Zinc is good for casting at home and, if you want to be industrious, copper or bronze is doable. You will have to clean up the cast part by machining, though. Soft metals like aluminum or zinc can be finished fairly easily in a home workshop.

Years ago, I made a campfire pie iron by melting down empty cans. It wasn't hard to do. I still have it and use it at family picnics.

In order to create the design for a part, you don't just scan an object. You have to model it using some sort of CAD software like AutoCAD. The part is modeled then exported to machine code that your 3-D printer can use. The file is uploaded to the printer then you run the machine.

I have tinkered with 3-D printing but I don't have my own. Maybe someday...
The process is fairly easy, once you learn, but don't expect to just spit out finished parts on the first try. Even experienced people often have to make a couple of test runs before they get workable parts.

The place where I work has a 3-D printer about the size of a refrigerator. It can make parts as large as 12 inches cubed but it can take ten hours or more.
They print the part, take it back to the machine shop to be finished then test fit the result. Some things are used as-is but many of them have to be sent out to be professionally machined or made from metal.

I don't know the brand of the machine they use. It's not part of my department. I have gone over to check it out when it's running and have BS'ed with the engineers. They told me that this particular machine operates on a version of G-Code which can be converted to a form that an NC mill can use. Basically, they just print the prototype in-house, finish it, test it then send the file(s) to the machine shop. The final part comes back in a few days or a week.

For making something like a plastic pad roller, I'm sure that 3-D printing can make a workable part but, to be honest, I would only consider it temporary until a permanent replacement can be found.

[Mark Gulbrandsen]

I somewhat disagree Randy. It's cheaper for these companies to buy lots of 3-D printers than it is just to have one mold made at 50K a pop.

[Randy Stankey]

I don't understand. Maybe I'm being dense?

Yes that's, pretty much, what the machine is being used for. Mostly, it is used either use it for prototyping or for making a sample part before ordering parts to be machined or molds to be made.

They also use it to make things for daily use, such as part holders and racks but these are non-critical uses.

Plastic just doesn't stand up to daily use in a shop environment.

[Mark Gulbrandsen]

Well, you can have 20 printers spitting out computer parts for a fraction the cost of the same custom molding die that would normally be used. I have a friend that does die jobs and some approach 100K a piece.

[Randy Stankey]

Yeah, I agree with that.

I guess it depends on what the part is going to be used for.

A lot of things that they make with 3-D end up being used as fixtures and jigs that are meant to be used in production.

Plastic is good for testing things like that but will wear out quickly or break. A good wire forming jig needs to be made out of metal.