A bit curious

[Flat32]

4 hours ago, Ace-Garageguy said:

Please tell us more about the connecting rods, please...

 

Ford Flathead rods are quite thin and are too weak when printed in plastic or resin even at 1:4 scale so need to make them in metal to make moving parts. Cams as well. The rods also have integral studs, no bolts so not possible to thread them for installing caps.  1/4 scale running engine version that I'd like to see built will need forged rods. I had a 1/4 crankshaft printed in Shapeways stainless steel and it's strong enough to work in a running engine.

[Flat32]

5 hours ago, Ace-Garageguy said:

WHOA...Check this out...

 

I have an older, smaller version of one.  Formlabs has a download white paper on 3D printing molds that get used in the hand operated injection machine.

[peteski]

Ray,

Like you, I am very curious about manufacturing processes.  I would love to hear some "war stories" from kit designers and die/pattern makers who worked in the model kit industry. But unfortunately they don't hang out in model forums.  Well, there are some industry insiders here, but not many. This is more of a builders forum.  Thankfully (as shown in some references in this thread) more and more of this type of info is accessible on the Internet.  But still, I think it would be really cool to have some of the old-timers sharing their experiences on this forum.

[High octane]

Back in 1976 I belonged to a model car club, and through connections we were invited to view the AMT plant. It was very interesting and I wish that I had taken photos, if not on the inside the outside for sure. It was a long time ago and at the time of the tour I also had other issues I was dealing with so I don't remember too much about it.They did give us each a model kit before we left. No I don't recall which kit nor do I still have it.

[Ace-Garageguy]

When Revell released the first issue of Mickey Thompson's Challenger back in the early 1960s, one of the real-car mags did a story on the project, showing the 3D pantograph, and photos of the newly-cut dies. At the time, the R&D and tooling was the most expensive ever done for a model kit...somewhere in the neighborhood of $30k if I remember correctly.

Here's part of the story of Revell's '57 Cadillac Eldo Brougham kit from way back when...

http://hotrodbunny.com/the-history-of-the-revell-57-cadillac-eldorado-brougham-model-kit/

[Ace-Garageguy]

Here's another article on the entire process, start to finish, combining techniques from the digital age and the pre-computer-modeling age. It's more-or-less accurate as far as it goes, but there ARE mistakes and misleading assertions...which once again points out why it's good to have somebody with first-hand experience, or at least an in-depth understanding of an industrial process (things apparently not considered necessary for technical writers today) write stuff like this.

http://www.madehow.com/Volume-6/Toy-Model-Kit.html

[Ace-Garageguy]

On 12/4/2017 at 12:34 AM, Flat32 said:

I have an older, smaller version of one.  Formlabs has a download white paper on 3D printing molds that get used in the hand operated injection machine.

I've begun looking into using some high-temp and high-pressure capable tooling epoxies to make molds for this process.

About 20 years ago, we made matched press-dies for sheetmetal parts from a powdered-steel-filled epoxy tooling material. The company that supplied that is in the metro area where I live.

[Flat32]

I had originally thought to feed PLA plastic into mine, scraps from 3D printing, but I really want metal parts so I'm thinking of feeding it low temp metal instead.  Plan is/was to make plaster molds using silicone master.  Plastic injection requires relatively high pressure primarily because it has a relatively high viscosity in it's molten state.  Low temp metal alloys have a relatively LOW VISCOSITY in their molten state which translates into less pressure needed to fill a mold.  Now RTV silicones have various durometer hardness and temperature resistance so they can be used for mold cavities.  In effect metal die casting without the high temperature  furnaces or kilns investment casting needs.  Why make a resin or plastic scale copy of a metal part and then paint it to look like metal when making a metal scale part can be easily made?  Don't even need a machine to do it.

[Snake45]

On 12/3/2017 at 7:02 PM, Ace-Garageguy said:

WHOA...Check this out...

 

Looks kinda like the Kenner Mold Master I had as a kid, all grown up. 

[Ace-Garageguy]

6 minutes ago, Flat32 said:

I had originally thought to feed PLA plastic into mine, scraps from 3D printing, but I really want metal parts so I'm thinking of feeding it low temp metal instead.  Plan is/was to make plaster molds using silicone master.  Plastic injection requires relatively high pressure primarily because it has a relatively high viscosity in it's molten state.  Low temp metal alloys have a relatively LOW VISCOSITY in their molten state which translates into less pressure needed to fill a mold.  Now RTV silicones have various durometer hardness and temperature resistance so they can be used for mold cavities.  In effect metal die casting without the high temperature  furnaces or kilns investment casting needs.  Why make a resin or plastic scale copy of a metal part and then paint it to look like metal when making a metal scale part can be easily made?  Don't even need a machine to do it.

Fascinating. I'll be extremely interested to hear about your progress as it unfolds.

Just to give you a little idea of what kinds of tooling resins are available though (in case you don't already know...which you very well may) the stuff we used to make the matched dies for aircraft sheetmetal landing gear doors had been used successfully to stamp wheel centers from 1/8" steel sheet, (lotsa pressure) and there are resins that will withstand 450deg F sustained, with short excursions to 500.