Over the years, we have conducted numerous tests using many types of materials and laminated combinations. Controlled conditions and data documentation were performed to help us understand how our products are used and what their limitations are. Because we manufacture these Soft Top Rubber coated Pallets for every manual and automatic, I feel that we are in a unique position to state our conclusions with the greatest certainty. Without meaning to sound like a 'know it all', I would like to offer our findings on the subject. This should help explain why the rubber is an advantage when flashing.
Our findings are that solid aluminum by itself will dissipate heat quickly, while the addition of rubber acts to insulate the aluminum, reflect the heat and lengthen the time of heat translation. That is to say...the rubber keeps the heat in and out.
Scenario 1 – Solid Aluminum Only – a Printed Shirt is Loaded and put under the Flash – What happens is that the flash's radiant energy is incident upon the shirt where it is partially absorbed by the fabric and ink and then translated through to the pallet. Aluminum is an excellent heat translator and will absorb heat quickly. A Majority of the initial heat is translated and until the solid aluminum pallet reaches it's own critical point you are spending a majority of the time and energy to heat the pallet up. During this period, the ink is gelling, because it's experiencing incident heat and continuing to take it's own energy at a steady pace. Once the pallet is up to that critical temperature, then the pallet no longer is acting to absorb the heat and absorption is reversed making the solid aluminum pallet radiant itself. Here the energy of the flash is not being absorbed and the ink and shirt increase temperature quickly. When the shirt is indexed past the flash, the aluminum begins to dissipate it's heat very quickly. The next time it's loaded, it will once again take a lengthy period to gel the ink.
Scenario 2 – Solid Aluminum and Soft Top Rubber-– a Shirt is Loaded and put under the Flash – What happens is that the flash's radiant energy is incident upon the shirt where it is partially absorbed by the fabric and ink and then translated through to the rubber. The Rubber makes and excellent thermal reflector/ insulator . Consider that, rubber and plastic are used on many cooking utensils for this same reason. They don't absorb the heat well and allow you to pick up the spatula that you've been stirring your spaghetti with J . So, initially, right out of the gate, most of the energy is being reflected by the rubber and into the fabric/ ink thus effecting much higher heat density. But wait, there's more to the story. Some of the heat does translate through to the pallet. This energy is absorbed, of course slower than before, and acts to increase the temperature of the solid aluminum. If left under the flash for a certain length of time, the solid aluminum will eventually reach that critical temperature where it becomes radiant. In actuality, the gel of the ink is accomplished well before this occurs. If the solid aluminum becomes radiant, you're actually flashing it much more than is necessary and risk burning the rubber. Lastly, the shirt is indexed past the flash and the pallet begins to cool. Because the solid aluminum is now insulated with rubber, the normally radiant heat is partially being absorbed by the rubber and mostly reflected back into the aluminum. This is the reason that the pallets stay hot longer.
We've tested many different materials including all forms of solid aluminum and aluminum laminates. We've tested Dupont Corian and several other exotic plastic materials. They all warped very quickly. We've tested Wood Boards, MDF Boards, all forms. Nothing compares to the aluminum and rubber combination. While we didn't invent this material combination, I believe that we can unequivocally state that for the purposes of screen printing, it's the very best thing available.