What is this kind of machine and technique called?

Simonsig · Dec 30, 2020

Hi,

What am I looking at here? What kind of machinery is this? Youtube link: Horn speaker Oris 150 - our production - YouTube

Thank you,
Simon

sfriedberg · Dec 30, 2020

Looks like standard vacuum forming to me. Sheet of plastic is clamped in a frame, then heated so it's plastic in the mechanical sense. In this machine, it looks like some compressed air is used during heating to pre-stretch the plastic sheet and keep it from sagging. Then a form (male mold) is pushed up from below. (In a lot of manual vacuum forming machines, the heated sheet is lowered down onto the form.) Once the mold is pushed all the way up, vacuum is applied to suck the heated sheet down onto the form. (Actually, to allow atmospheric pressure to press the heated sheet to the form.)

Simonsig · Dec 31, 2020

Dear sfriedberg,

Thank you for your replay. Seeing this video, Do you know how the first mold used in the vacuum forming could be created?

Any information would be great.

Thank you,
Simon

Pattnmaker · Dec 31, 2020

While the vacuum tool could be machined from solid larger tools like the one show are often cast and then polished. They then need the vacuum holes drilled a vacuum chamber built and a cooling system added. Tools for thin low volume parts can be made from wood or Renshape.

Its been a while since I have built an aluminum vacuum tool and I suspect more of them are machined from solid or cast and then machined these days. The fact they're hollowed out in the back and are often fairly big probably keep lots being cast though.

Scottl · Dec 31, 2020

Simonsig said:
Dear sfriedberg,

Thank you for your replay. Seeing this video, Do you know how the first mold used in the vacuum forming could be created?

Any information would be great.

Thank you,
Simon

Could be anything from CNC machined to even something like the old bell casting patterns that were formed out of plaster using a circular screeder that revolved (by hand) a sheet metal form tool around a lump of plaster. The main thing for vacuum forming is lots of small vent holes in the form that connect to the vacuum source.

I don't remember who sold it but more than 50 years ago a classmate got a toy for his birthday that actually was a miniature vacuum forming tool. I think it was called a Vacuform or something like that and it used pre-made forms and thin plastic sheets (about 2 x 2 inches). It was sold as an educational kid's toy. That was back in the day when USA manufacturing was king of the hill.

trevj · Dec 31, 2020

I would guess that the originals for the speaker cones are likely made of laminated wood, turned to shape on a jeesly big wood lathe.

The system in the video is pretty interesting, in that it allows the operator to pressurize the area under the heated sheet plastic, to blow it out a but, then the form is raised up to it's 'working' position before the air is drawn out.

I have done a bit of free form blow molding for light aircraft windshields, and we toured through the Air Canada facility where they made a large quantity of their interior trim panels, and neither was what you could call "High Tech". Some of the Molds at Air Canada's shop were downright crude, and most were cut free from the parent stock by a not very fancy saw blade mounted on a drill press.

gunner312 · Jan 8, 2021

Vacuum Forming.

It appears to me to be a standard vacuum forming process. the master are usually made from almost anything. I've seen wooden, metal and even plaster of paris forms used. I've made masters for a company up on Vashon (?) Island here in Washington a few years ago. Not much to it. His machines were all shop-built and he used
a standard vacuum like you need for a Vacuum Chuck to form the parts once they were heated. Watched it don. Kinda cool.

trevj said:
I would guess that the originals for the speaker cones are likely made of laminated wood, turned to shape on a jeesly big wood lathe.

The system in the video is pretty interesting, in that it allows the operator to pressurize the area under the heated sheet plastic, to blow it out a but, then the form is raised up to it's 'working' position before the air is drawn out.

I have done a bit of free form blow molding for light aircraft windshields, and we toured through the Air Canada facility where they made a large quantity of their interior trim panels, and neither was what you could call "High Tech". Some of the Molds at Air Canada's shop were downright crude, and most were cut free from the parent stock by a not very fancy saw blade mounted on a drill press.

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What is this kind of machine and technique called?

Simonsig

Plastic

sfriedberg

Diamond

Simonsig

Plastic

Pattnmaker

Stainless

Scottl

Diamond

trevj

Titanium

gunner312

Plastic

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