Vacuum forming press ?

[Tin Falcon]

Ok I am off on an other tangent thinking about other technologies and possibilities.

I a thinking about building a vacuum forming press or maybe purchasing.

The technology seems very simple . Make a box with a perforated top hook up a shop vac place a mold or form on top of the box. place a sheet of hot plastic held in a frame over the form turn on the vac and one has a vacu formed part or candy /food mold. It seems a variety of plastic can be formed on a simple vacuum bed.

I see this as low cost and easy to build . The plastic sheet is the membrane so the plastic used needs to be the size of the table

Then I look at vacuuming Kydex and I see something like the vacuum tables I used years ago in the silk screen printing business. A flat surface a frame with a rubber membrane silicone rubber or latex rubber. And driven by a good vacuum pump like 8cfm . No holes in the table a rope giudes the air flow

So i am thinking advantages and disadvantages of the two designs . And I guess As i write i am answering some of my own questions.

It looks like the membrane type is better for expensive plastics where a rope trail can be cut away and the cheaper simple one is best suited to applications where the materials are cheap and or the whole sheet wiill be kept as in the case of food candy molds .

So now that I wrote this I am interested in input from others. Who out there has a home vacuum forming machine and what do you make with it and what type is it. Also what is a good size to build or buy. Or does one need a couple sizes to allow for larger sizes but eliminate waste and material expense.
Tin

 

[barnesrickw]

Woodworkers have been using it for a while to press veneers, and such. They jostle use a thick bag and a vacuum pump.


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[aonemarine]

Tin, You have gone from 3D printing to vacuum forming to produce ??? There must be something you are looking at making ?

 

[Tin Falcon]

I do have some ideas . The idea that got me going on the vacuum former was small model car bodies. I have been pondering electric dragsters and slot cars.
So the question came to mind is a 3d printed part suitable as a vacuum form mold. the answer is yes. and the second question is how easy is it to build a vacuum former and it appears easy. so while this appears to be a tin is off on another tangent thread. it is actually connected to the Idea of I want a 3-d printer but do i need one what can i use it for and possible how do I get it to pay for itself.

Tin

 

[aonemarine]

I figured it was tied together somehow. I have found that printing parts by themselves can make you a couple of dollars, but nothing to get overly excited about. But when you take the 3d printed parts and investment cast them, well now your onto something. I have also been using the 3d printer and wood filled filament to produce patterns for sand casting. 3d printing IMHO is a starting point for many projects, its just a matter of tieing it all together....

 

[GailInNM]

Almost 50 years ago I built a moderate size vacuum forming machine. Keep in mind that my memory has been clouded with time but here are some details. It had a platen area of about 3 x 4 feet. Used it to form trays of about 12 x 16 inches that were about 5 inches deep out of 3/16 thick sheet but I don't remember what material. Also electronic kit box liners of about 30 mil styrene.

The platen was plywood and had a bunch of about 3/8 inch holes connecting to a plenum chamber, also plywood, with 4 industrial sized vacuum cleaner motor mounted in it. For smaller sheets, we just covered the unused holes with poster board held in place with double stick tape. In the active area we put window screen wire on the platen to give air flow passages so the plastic could not cover up all the holes when it pulled down.

A heater above the sheet carrier heated the plastic. Had the local appliance repair wind ni-chrome coils and they were mounted so they could cover the sheet area and had switches to cut off various coils for smaller sized sheets.

The sheet carrier was just alumnium angle with some clamps to hold the edges of the sheet. It was adjustable to handle different sizedsheets. It was moved vertically with cables hooked to a lever. Rubber weather striping was used to seal the frame to the platen so a vacuum could be formed.

Operation was sheet was loaded, clamped and then raised to about 4 inches under the heater. Heat applied. Because of low thermal conductivity of the thicker sheets, the heating took a couple of minutes. We would just watch for the sheet to sag an inch or so. Thin sheets took less than a minute.

Sheet carrier lowered with lever and the vacuum turned on at the same time. Thick sheets took about a minute to be cool enough to be removed.

Thick sheets rough trimmed on table saw and finished with a router and template. Thin sheets trimmed with swing arm paper cutter.

Gail in NM

 

[Fabrickator]

I built a vacuum box once for a hair brain idea I had to make custom license plates for people. Custom plates were the big thing in the 70-80s and I figured you could put names and sayings on them that the DMV wouldn't let you do. I also figured I could also sell license plate frames to put them in. Great for lovers, friends and pranks, while you wait - in a County Fair setting.

The plan was to create an alphabet out of wood blocks (like type set) that dropped into a rectangle form. I used an old exterior electrical box (Hoffman about 18" X 18") and mounted an old auxiliary 110v heating element in the top cover. I used about .040" poly-styrene or something under vacuum. It didn't really work out as I planned. It melted but didn't form as well as expected, and I got sidetracked and never got back to it.

Maybe you can resurrect this idea Tin. You have my permission.

Rick