3D printer

[Dave Mellor NJ]

Here's another video that was forwarded to me. At various times I've seen references to a 3D printer on these pages. If this is to be believed, they really have one

When you need a five minute break, take a look at this: 3D printer can print functional tools.

[Guest windjamer]

:DSaw this on a gun site, if true I have a few Smiths and a colt or two they can print for me:cool:

[Guest bkazmer]

stereolithography gives an accurate geometry but the properties of the sintered material. So you have a model of the part - so in your example, you have a pistol accurately carved out of soap

[Restorer32]

Neat technology but for the life of me I can't think of a practical use for it in regards to antique car restoration.

[Guest bkazmer]

If the material is thermoplastic instead of thermoset, it could be a way to make a master for lost wax.

[joe_padavano]

Neat technology but for the life of me I can't think of a practical use for it in regards to antique car restoration.

Stereolithography has been around since at least the early 1980s. For some reason (apparently the Jay Leno video), it's been a hot topic lately on nearly every automotive forum. It is not new.

The practical use for car restoration is that you can digitally scan a part, create a plastic replica, then use that replica as a pattern to create a mold to cast a new part. Much more cost effective than whittling a pattern out of wood or metal.

The other practical use is to replicate low-stress parts, particularly trim parts. The electronics industry uses stereolithography to prototype enclosures for parts such as housings. When the plastic part must simulate metal, they vacuum plate the plastic with aluminum or other vacuum deposited metal to simulate a metallic part. One could do the same to replicate die-cast trim pieces. Once the parts have a metallic outer coating, they can be chrome plated.

Finally, the DoD is actually working on adapting this technology to "print" metallic parts. The concept is to use a similar laser system to sinter powdered metal into a 3D part. Now THAT would have extensive applications.

[CarlLaFong]

There has to be more to the scanning process than the video showed, How does the printer "know" what the other side of the wrench looks like, that the thumb wheel turns on an axle, the internal workings and shape of the moveable jaw, etc?

[avantey]

Printers have been in use in enginering for about twenty years and have gotten very refined in methods/types, materials and accuracy. You can print parts in everything from cornstarch to wax to ABS plastics to metal now. Many of the parts are dimensionally functional and have a shortened useable life for initial protoyping of a product.

It is a quick, inexpensive way to explore concepts for an engineering team. It used to be it sort of looked the part, then you held a very real looking part and now we build things that work with them in a rapid sequence of trials. A sintered metal printer with a useful printbed size is about a half million dollars. STL has come down in price and the wax part printers are basically obsolete now. If you are just doing "show and tell" for a marketing presentation technologies like the corn starch are great. They give very fast, very inexpensive parts, multicolored assemblies and even interlocked parts that work(like a gear train sample. Very fun, very mystical to the non-engineer but not useful like newer printer technologies.

This has come a long ways in the recent past and is becoming very affordable for the small shops and even private use if you research it. Look up rapid prototyping technologies and you will get a lot of sites (app 2.4M) to enjoy!

[MochetVelo]

So if I scan a differential housing, for example, and I wish to reproduce the part, how do I make the mold to cast it? I assume you would need a core for the mold, etc. Does the 3-D printer make those things as well?

Phil

[Rusty_OToole]

So if I scan a differential housing, for example, and I wish to reproduce the part, how do I make the mold to cast it? I assume you would need a core for the mold, etc. Does the 3-D printer make those things as well?

Phil

You would have to scan the part to make a virtual part in the computer. Then correct or modify the virtual part ala photoshop. Finally use the 3D printer to make the part, or the mold.

For example if you wanted to make a casting you would have to make the pattern bigger to allow for shrinkage. About one sixteenth inch per foot for aluminum. This would be childs play on a computer, not so easy on the actual part.

Edited July 25, 2011 by Rusty_OToole (see edit history)

[joe_padavano]

So if I scan a differential housing, for example, and I wish to reproduce the part, how do I make the mold to cast it? I assume you would need a core for the mold, etc. Does the 3-D printer make those things as well?

Phil

You would use the "printed" plastic part to make a mold, either a sand mold or silicone, depending on the material you plan to cast. This is the same process as for making any other mold, just the pattern is this stereolithography part, not a wooden master.

[J3Studio]

These things are getting better - if they can't do things that are useful to many of us right now, this might be different in ten years.

[MochetVelo]

My understanding of a mold is that a flat piece, like a door handle, can be cast using a two-part sand mold from the part (in this case, a plastic model from the 3-D printer). However, if you want to cast a "hollow" part, like a cylinder head or a coolant outlet, your mold would need a core for these voids. I assume you must design this on the computer as well, even though there is nothing to scan.

Phil

[MochetVelo]

A member of our Maxwell Forum has produced some 3D patterns for a new differential. Here is a photo of the pattern for the housing and (I think) the core.

Phil

[Restorer32]

Yep, standard foundry pattern work