What is the greatest thickness you can have vacuum formed?
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What is the greatest thickness you can have vacuum formed?
do you mean the thickness of the plastic material or the thickness of the item you are forming?
plastic material
I once used a piece of vinyl siding as an experiment - heated ok but tore on pull - may have cooled a bit from oven to vacuum table and may have had too much vac. Did have some 8 and 10 mm polycarbonate bent - but not vacuumed. They were heated in a large propane (lpg) open oven then put on formers. If you tried to vacumm them I'd expect the material could get too thin as it pulled, unless you get the vacuum right. Too much it might pull to thin and too little - not to shape. Hope that helps.
:cheers: Jim
There are many variables that effect the question you ask. I have formed 1/2" acrylic (FF and GP) and ABS sheet on simple low profile molds with no problem at all. If you have a deep draw mold or a detailed part requiring high forming definition there are several forming techniques that can be implied depending on your equipment. If you have some more detailed information I would be glad to share what I can.
I have formed .500" ABS with a DR cap for a tilt front end on a piece of agricultural equipment.
High temp epoxy mold, 38" depth of draw.
Sheet size was 78" x 49".
Predraw took over 28 seconds to stretch the sheet prior to driving the mold in from the top.
How thick the plastic can be depends on several variables:
1. How evenly you can heat it
2. How forgiving it is of uneven heat
3. The general shape of the part---is it gently curved, or a more difficult shape?
4. The "hot strength" of the plastic---how resistant it is to stretching and bending when it's at thermoforming temperature
6. How hard your vacuum source or surge tank can pull, to overcome the plastic's resistance and pull it tight around the details you need.
A very inexpensive homemade vacuum former that's reasonably well-designed can usually handle plastics up to an eighth of an inch or so, with a cheap vacuum source such as a good vacuum cleaner. (A lot of people use shop vacs, but many regular vacuum cleaners are equally good these days, with high-amp motors that suck hard. My 8-amp Euro Shark hand vac can pull as hard as my 12-amp, 5.5 HP Shop-Vac(TM).)
A somewhat more expensive machine with a high-vac system should be able to handle plastics up to about a quarter of an inch thick. (Depending on all those variables, of course. Your mileage will definitely vary.)
If you can use thin polystyrene or PETG, and don't need very fine detail, life's usuallly pretty easy. Almost any half-assed vacuum former should do the job. (For example, a board with a hole in it, and a weatherstripping gasket around the edge, hooked up to a vacuum cleaner. Heat the plastic in your kitchen oven and you're good to go.)
For instructions on such a lowball approach, check out the vacuum forming pages at http://www.studiocreations.com. For more capable but still inexpensive machines---a very few hundred dollars---check out the articles and the discussion board at http://www.tk560.com.
You might also get Doug Walsh's book "Do It Yourself Vacuum Forming for the Hobbyist," or even buy his higher-end plans on build-stuff.com if you're willing to pay money for plans. I haven't used them, but my impression is that they're well-thought-out. (But a bit pricier to build than Thurston James design as filtered through tk560.com.)