Wednesday, October 31, 2012

Vacuum Forming Part 1

My re-worked Vac Form Rig is up and running and working as well as can be expected from a DIY unit.  Since my first attempt, I have added halogen lamps for heating, variable aperture plates for different jobs and a rising frame with enough travel to allow bucks as tall as 150mm to be used.

The New Vac Forming Rig

I am still using the same Platen and in the coming weeks, I will make a few different sized units to be interchanged with this rig.  

Custom Sized Plates

When I first got into Vac Forimg, I wasted allot of plastic Vac Forming small parts.  I was using the full 600mm  x 600mm sheets to make parts just 70mm on any one edge.  I then learned that I could make aperture plates for smaller jobs.  I now have several different size plates that I can interchange for the different size parts I am working on.   

The Heating Units 

When I first made this, I was using traditional heating elements and I could not get uniform heat across the plastic.  I've had an Easy Cooker in my kitchen since 1997.  Whilst the original units used coiled heaters [stove elements], the new versions use Halogen lights.  The air in these new units is super heated and once the preset temp is reached, the lights turn off, so the unit is quite power efficient as well.  After running some experiments, I decided that Halogens would be the best answer to my heating issues for this Vac Form as well.  

Material pending, these lights will heat the plastic to the point of it releasing vapor in as little as 2mn 30sec.  The thicker the plastic, the more time and different plastics require more time and heat than others.  I've successfully Vac Formed 3mm ABS and PVC on this unit.  One of the best points about using Halogen lights is that they don't burn the plastic like traditional heaters can.  You also have lots of light on the job! 

New Vac Chamber

Whilst a shop vacuum cleaner works to evacuate most of the air, there is no substitute for true vacuum and my Vac Chamber is set up to act as a surge tank.  This unit can pull 30 inches of mercury.  

I will also be rebuilding the platen and riser.  Images to come soon.    



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