|
|
MikeNCR
Joined: 05 Jan 2012
Posts: 54
Location: Norcross, GA USA
|
I'd have to see a bit more on the design to be sure, but a few general thoughts-
Vac Forming PC is a pain, to do it properly you have to dry the material, which is a good deal more involved than it sounds.
quote:
Thermoforming: Polycarbonate sheet can be thermoformed on standard equipment, with vacuum forming, free-blown forming and line bending the most extensively used processes. While most standard forming techniques can be used, critical process modifications specific to polycarbonate sheet are necessary.
Polycarbonate sheet must be pre-dried prior to thermoforming and heating cycles need to be accurately controlled for uniform product quality. The thermoforming machine should be capable of generating and maintaining sufficient vacuum pressure throughout the thermoforming cycle. A minimum vacuum of 20 inch Hg throughout the entire vacuum cycle is necessary to retain part integrity.
Most commonly used vacuum forming machines with infrared heating elements perform well for polycarbonate sheet forming. Rotary and shuttle designs with automatic or semi-automatic controls are the most suitable because of their timer control accuracy, uniform heating sources and sufficient vacuum power. Single-sided heating has proven effective for polycarbonate sheet gauges up to 0.177 inches. For thicker gauges however, it is recommended that dual-sided heating ovens be used for effective radiation penetration.
That said, doing a simple bowl shape would be fairly doable. If you were trying to get the same sort of pocketing that you see with the 3D printed bots or thin stiffening ribs you'll have to spend a good amount of time tweaking the mold to make sure the vacuum is pulling on the right areas without tearing the plastic. Having some sort of draft angle to the sides will make removing the finished parts from the mold much easier.
|
Sun Mar 11, 2012 4:37 pm |
|
|
|
kato
Joined: 11 Dec 2010
Posts: 92
Location: 4505
|
I was looking at a
Snow Peak
or
Lifeventure
dinner plate as the weapon - Titanium, 190mm diameter, already formed into a beautifully balanced circle, 63 g. All that would be needed would be to add or carve some teeth, and maybe a bit of drillium to keep the weight below the limit.
Put on the polycarbonate chassis a couple of servos, a RX, a brushless and ESC, and away you go - rocketproof from above and (hopefully) below. Of course, there's bound to be more to it than that.
For the Vacuum Forming, I was going to use a very basic rig like
this instructable
|
Sun Mar 11, 2012 5:20 pm |
|
|
|
|
|
|
|
|