Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


rjk

#9051

Trays - Conductive vs Anti-Static?? | 11 October, 1999

I am checking out trays for packing of Simms, and I would like to know what are the main differences between Anti-Static and Conductive trays. Anti-static are cheaper, but I would like to know about properties of one against the other, what are various companies using, etc.

reply »

Brian

#9052

Re: Trays - Conductive vs Anti-Static?? | 11 October, 1999

| I am checking out trays for packing of Simms, and I would like to know what are the main differences between Anti-Static and Conductive trays. Anti-static are cheaper, but I would like to know about properties of one against the other, what are various companies using, etc. | | | There is loose terminology in this field. There are three techniques used: a) metallisation of plastics to make the surface conductive. Excellent results, but subject to more wear, as the conductive surface can be scratched away. b) charging the plastic itself with partially conductive particles, usually lampblack (this does not mean that all black plastic is like this: there may be sufficient lampblack to colour the plastic but not to render it conductive, done by c) below). This method is long-lasting and effective. c) charging the plastic with a hygroscopic substance, subdivided into c1) having a long chain hydrophilic molecule within the polymer matrix and c2) spraying on a hydrophilic substance, such as a detergent, so that it is adsorbed into the plastic surface. In both cases, it is possible for the hydrophilic molecule to end up on the PCB, not necessarily improving its electrical performance. The pink plastics for bags and bubble paper belong to this category, as do the ones with a hatched pattern. This is the cheapest type for both wrapping materials and rigid trays, hence popular by those who know no better or cannot argue with the purchasing department.

Brian

reply »

rjk

#9053

Re: Trays - Conductive vs Anti-Static?? | 11 October, 1999

Hello Brian

Thanks for your quick reply. I should explain my situation. We are packing modules in trays for transport. We are currently using Conductive PS as material for the tray base. I am in the process of setting up a new company to manufacture these trays and they have suggested using Anti-Static material as it would be much cheaper. However, I do not know enough of the properties of ANti-Static PS to make a decision. What is the difference between conductive and Anti-Static PS in terms of stress, surface resistance, brittleness etc.? Is conductive PS really necessary for trays - I believe other companies use conductive PS for trays, but it is difficult getting information from them.

Thanks

RJK

reply »

SMT Custom Nozzles

Fluid Dispense Pump Integration