1971 Amc Matador, A Cheaper Way Of Rapid Prototyping

[choc-ice 2]

To make new bodyshells for my cars I make a master, a silicone mould and then resin casts. Even when you add in some vacformed windows and interior it's still a lot cheaper than the £50,000+ that the major manufacturers use for injection moulds. And with the cars I make, the break even point would be hundreds of years...

 

I now work with a local company to do the silicone moulding and resin casting but the biggest cost has always been making the master for the silicone mould. I've used various types of 3D printing, SLA, and FDM but even though my chassis are made with SLS process (selective laser sintering), I've never tried it for a master bodyshell.

 

However I recently got in touch with a place in London and they said they could make a much higher resolution part than I'd had before. Could this combine the low cost of SLS with the accurate surface finish of the better 3D prints?

 

The next candidate for a bodyshell was the AMC Matador, probably the most common TV and film police car until the 1977 Dodge Monaco came along.

 

I got the 3D surface data for a 1971 model

 

Then got a bureau service to stitch the surfaces together so it could be made. Most 3D models have holes in the surfaces where the edges don't quite meet; it's not a huge problem when the car is used in a computer game but it can't be 3D printed like that, the mesh has to be complete.

 

I uploaded the file, paid about 30% of what an SLA would cost and waited, nervously, for two weeks. Then this arrived!

 

It looked fantastic, the powdery surface was still there but it was much tighter than the SLS usually is, certainly much finer than my SLS chassis. I tried it out for size on a chassis, although I'd done all the checks on the computer before so I wasn't too worried about it fitting properly

 

I then washed it, dried it and put some primer on. Then sanded it down and primered again.

 

It took about 5 coats, sanding down between each one, before I was satisfied that the surface was good. Then I got busy with the silicone mould as usual.

 

Today, the first resin casting came out of the mould and it looks great. The window apertures need a little more cleaning up but the surface quality is excellent.

 

 

It still needs windows, but I'm hoping one of my existing interiors will fit, and the wheel centres are similar to the later Dodge I already have. I see lots of this, in the car's future

 

[Ember 71]

How does the amount of refinishing required compare to the other shells?

[choc-ice 2]

Even the best quality 3D print takes a few coats of paint, sanding back in between. So not much difference, maybe twice as many?

 

The cost of the body is the first advantage, the second is that the SLS process makes a bodyshell that's tough enough to race if you only want to make 1. That's not possible with an SLA or 3D printed part.

[shadow_rusty 41]

Once again, looking great there Choc-Ice...

 

So need to get my butt into gear and get a few of these, and it's partners for Digital 'carnage'...