Five EIA-564 specified stress levels can be required while the specimens are subjected to oven conditioning using up to four temperature levels.
The polycarbonate specimens are first annealed and placed into strain jigs. The agent or material under consideration is applied or fabricated to make intimate contact with the polycarbonate specimens.
The samples are placed into the oven at a recommended maximum temperature.
Occasionally, specimens are conditioned at room temperature and evaluated before placement into the oven for exposure to heat.
After five days the sets are removed from the oven(s) and all specimens are visually inspected for crazing and cracking in comparison to an unstressed sample using microscopic mapping.
Test specimens are transparent injection molded polycarbonate IZOD bars per ASTM D256.
Clean handling techniques should be observed in the preparation and utilization of the polycarbonate specimens.
Temperature (Ref: EIA 564)
Maintain one set of exposed and strained polycarbonate bars at each temperature being evaluated, namely 730F, 1200F, 158°F and 185°F +/-2°F for five days.
Reapply agents that volatilize in order to maintain continued chemical exposure.
After five days, remove bars from the jigs, wipe clean and inspect visually for crazes and cracks.
Some organizations require testing at the maximum 185°F temperature only for 5 days using the strain jigs 1000, 1700, 2000, 2500 and 3400 psi. This serves as a “worst case” scenario at the 185F temperature level.
The polycarbonate bars (bent at various stress levels) and exposure of supplier's static packaging materials are then subjected to various temperatures for 5 days.
Said speciments are then analyzed for cracks or imperfections.