https://www.bbc.co.uk/news/uk-25613828

Maybe I can get my custom freewheel cogs after all!!!

My youngest son has a 3D printer in his Technology/Intro to Engineering class in high school.

He has a couple of ideas for projects that sound interesting as well.

Looks like a promising way to create "new" old parts.

Yes...but.... "with some parts costing less than £100".....to get the strength and quality.....it will still cost. There is hope in the future, costs will come down and quality will go up.

Member rhm has some experience with 3D printing of saddle badges if I recall. It will be a while before highly stressed parts can be printed with dimensional accuracy and functional strength.

I agree. I was thinking about headbadges, clamps, stops and the like. I don't know enough about the technology or which materials the printer can work with.

Think models, not functional parts. My knowledge may need calibration but, the mechanical properties of the "parts" produced are enough to support the model and the handling of it, not the intended use. Over time, this will change as material properties and the process is improved and developed to produce parts for intended use.

It is difficult for some people to visualize a 3D part in their head. Creating a physical model helps overcome the communication challenge. It also helps the designer to check his model in a physical world.

There appears to be some investigation of reheating the finished part to better fuse it into a stronger whole, but dimensional stability suffers, my guess with careful design and post heat treat machining things will get closer to useable.

Here's a saddle I recovered with help from 3D printing:




I designed the graphics in CorelDraw, had the skirt stamps printed in white plastic, and used the stamps to form the leather. The badge on the back was also 3D printed in " aluminide" which is a plastic with aluminum dust in the mix.

I wish they offered the option of printing in aluminum or magnesium! Not an option now, though. Which brings me to the next question: if you have a good model 3D printed in plastic and want to have it manufactured in aluminum or magnesium (or titanium ) how would you go about that?

For a limited run you could have soft tooling done. Use the model to create a rubber mold (-) which is used to create another mold (+) that used to create the final soft tooling for the limited run. May be good for a couple of hundred castings. Key here is taking shrink into account for all the materials used. This has to be done in the 3D model for the printing so it will be "transferred" to the final mold and base. Keep in mind that draft should be taken into account too. Straight walls cause the part to "stick" to the mold and not come out. The other option is using a Lost Wax process where wax is used to creat the mold. It is destroyed for each part but the material can be recovered for new molds. In addition, sprues need to be designed in for the material flow along with vents to ensure the matieral flows into all the cavities. And we thought castings were straightforward!

"Lost foam" casting was used and might still be used in the automotive industry. (Saturn was proud of their efforts)
I have seen ti investment cast. Steel of course is.
Part of the problem is to find a foundry interested in doing prototype qty. parts for an acceptable cost.
When I saw the results that rhm did on that vintage saddle replicant I immediately thought of headbadges.

I'm not certain of this, but I think I read somewhere that the file format that defines the 3D printed object is the same one used for CNC milling, even though the processes themselves are sort of inversions of one another. I'd contact someone who does CNC milling and ask, since that would seem to be the best way to get something like this made from aluminum.

Kind of. A vector based digital file will get you closer to what you want, for basic 2D with uniform depth cutting. A stl. file will get you closer but will still require a dedicated cutter path file to be created, and you can create an object for a 3D model that may not be machinable.

Is magnesium typically cast to final form? I believe that is the case. Wax can be 3D printed so perhaps magnesium parts could be made through a combination of 3D printing and lost wax casting, but it seems a complicated and (prohibitively) expensive way to go about it.

I really don't think cast aluminum would have the strength needed. The parts of want made in aluminum would have to be stamped or forged.

I've recently got my hands on a CNC engraver and could see cutting rhm's badge and stamp with it. It's basically a light duty 3 axis mill.

I'm having a ball with it.

.stl is for 3D printing.

Native Solidworks, native ProE, .stp and .igs for machining. Although that gets converted to cam data depending on what type of mill used.

3D printing is not ready for prime time. Maybe in 5-10 years.

https://mashable.com/2013/11/11/3d-printed-metal-gun/

I don't think durability is an issue......just a matter of costs...

There's a youtube video out there of an aviation company using 3d printing to do titanium parts. It exists. I bet it's not cheap though.

And time. And finish.

If you think that polish was printed, you would be mistaken.

This.

OP: I was in a 3D printing workshop from my uni last month, I'll post the link to my project once they put it online. I specifically asked the industry people what use current gen 3D printing has in the restoration world, and they confirmed the suspisions we had on this forum in an earlier thread that you can't really replicate the structure of the materials you try to reproduce, meaning you can't print reliable replacements yet.

This gives an idea of what can be done currently.
https://www.youtube.com/watch?v=tkwd2...e_gdata_player

Or, as we like to say around these parts, "microfussione"

Magnesium is an interesting metal to cast as it likes to burn. As Mercedes found out long ago at La Mans.

It seems that Kirk, of Kirk Precision frame, found out as well when the factory went through a fierce fire caused by a magnesium dust explosion. Temperamental stuff. https://www.kirk-bicycles.co.uk/Kirk-History.htm

little known item, the pedal bodies of Merck's Hour bike are Magnesium, and perhaps the hubs too. Long ago there was a 32° low flange pista hub body on ebay auction and it was magnesium, claimed as such and the dull finish gave it away. Pino also liked the stuff for seat posts.