Here's my latest vacuum forming machine

[Charles (Upstate NY)]

Click the link below to view pics of my latest vacuum forming machine. I made a few design changes to this one and performance is outstanding. The key things to note are the use of the giant silicone o-ring (20.5 inches) for the seal, the use of a solid slab of 1 inch thick polyeth to ensure an air tight table, and the addition of a second 6cfm pump. This thing gets to 29 inches of vac in about 1 second.



Pics of the vacuum forming machine

[Charles (Upstate NY)]

A pic of the first shell off the new vac machine - 8.5 inch spider coil

I'm making this spider coil for my Explorer to pick through the rusty nail infested areas.

[Reg]

Re: A pic of the first shell off the new vac machine - 8.5 inch spider coil

Hi Charles,

Interesting design. What size housings are you going to make in the future?

Also, the ears appear to be made differently. Are they cut from other material? If so, then the coil housing could be universal and ears changed to fit other lower rods, correct?

Reg

[Charles (Upstate NY)]

Re: A pic of the first shell off the new vac machine - 8.5 inch spider coil

Next up a 12 inch spider, a 6 inch spider, then a big mother of a double D probably 16 inches. If the 12 inch spider is not too noisy I may try a 15 inch spider also.

Yes I decided not to vacuum form the ears and so a shell could be adapted to various sized lower rods but thats not really why I designed it that way.

Vacuum forming the ears is problematic, I have done it but its annoying and prone to "oops" events. This method is nearly as fast and much easier to drill since I just toss them on the drill press and presto its done.

I created a master set of ear out of lexan, the base and two ears. I glued these together then created a mold of this part using liquid silicone. Now when I need a set of ears I just pour in some urethane resin and poof 10 minutes later I have a set ready to go. Since nothing sticks to the silicone and its flexible I can do deep draft parts with no taper.

[Carl-NC]

Re: A pic of the first shell off the new vac machine - 8.5 inch spider coil

Obvious question, how are you trimming off the excess?

My prior question on Findmall, concerned the platen. Are you placing a positive mold directly on the platen, and pulling the plastic down to to the o-ring? Doesn't seem to be enough depth in the platen for this.

- Carl

[Charles (Upstate NY)]

Re: A pic of the first shell off the new vac machine - 8.5 inch spider coil

I'm using a positive mold (see pic below) and you are correct there is scant depth between the platen and the o-ring seal, about .110 inch in fact. This keeps the volume of air to evacuate to an absolute minimum which was my goal. Note some vacuum table designs out there don't even bother with a rubber seal, they just stretch the hot plastic over the edge of the platen.

In any case it works wonderfully, its even faster with a hot plastic sheet than when I tested with a cold sheet, I hit 29 inches in no more than 1 second. The sheet is very rubbery when heated and stretches over and down the sides of the table, the seal is instant.

Trimming the part, thats the next big challenge. I can trim with hand tools but thats time consuming. I think its going to require a custom tool and a vacuum jig to hold the shell.

[Allan Westersten]

Re: Here's my latest vacuum forming machine

Hi Charles,

Do you sell your shells? I'm working on a prototype machine and need 12" shells.

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