Views:0 Author:Site Editor Publish Time: 2021-11-09 Origin:Site
Heat-resistant conveyor belts are widely used in the aluminum extrusion industry. As you may know, the temperatures keep changing during the process in the aluminum line. We always use conveyor belts with different materials based on the temperatures. (PBO, Kevlar, Nomex, Polyester)
PBO stands for Polybenzobisoxazole, a synthetic polymer invented by SRI International and is currently manufactured by Toyobo Corporation in Japan. The trademark name for PBO is Zylon. Zylon is 1.6 times stronger than Kevlar and can also withstand higher temperatures.
For aluminum extrusion, PBO usually can withstand temperatures up to 1200℉/600℃.
Kevlar is the trademark name for an aramid fiber made by Dupont. Kevlar is made by a solution of monomers 1,4 phenylene-diamine and terephthaloyl chloride in a condensation reaction.
For aluminum extrusion, Kevlar can generally withstand temperatures up to 950℉/500℃.
Nomex is a trademark for a flame-resistant meta-aramid developed by Dupont. Nomex has good thermal, chemical, and radiation resistance for a polymer material. For example, the firefighters’ suits are made of Nomex because of their resistance to fire and chemicals. But this also causes Nomex to have a poorer strength and a lower resistance to heat than Kevlar.
For aluminum extrusion, Nomex can withstand temperatures up to 450℉/500℃.
Polyester is a synthetic polymer made of purified terephthalic acid(PTA) or dimethyl ester dimethyl terephthalate(DMT) and ethylene glycol. It doesn’t have high resistance to heat, so it is usually used at the very end of the progress, where the profile is cooler.
For aluminum extrusion, Polyester can withstand temperatures up to 300℉/150℃.
The aluminum billet gets heated up and then pressed through a die to give it the desired shape.
After being extruded, the profile falls into rollers that convey it further down the line. The first rollers have to hold the most heat, so we use PBO; then, we use Kevlar rollers as the profile cools down.
The profile goes to a cooling table, where it moves back and forth to cool down. We usually use Kevlar for this table.
If there are 2 or 3 cooling tables, we can start using less costly materials like Nomex or Polyester as the profile gets colder.
Generally, at the end of the process, there is the saw that cuts the profile. Here it is much cooler, so we can use Polyester.