Palram PALSU - Manual (Page 32)

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3. Installation
a. Cold bent polycarbonate is more sensitive to mechanical or chemical abuse in the vicinity of the bend. Therefore, Palram
recommends a design that offers better protection for bent areas from any detrimental influence.
b. Avoid putting additional strain on bent parts, like forcing a bent angle in or out to fit into an existing framework.
Thermoforming
Pre-Drying
General Guidelines
ƒ Nearly all types of PALSUN sheets are suitable for various thermoforming (TF) procedures. However, due to a native small moisture
content absorbed after manufacture, they demand a thorough pre-drying process prior to most thermoforming techniques.
During this process, the sheet’s temperature will be raised to over 160°C (320°F). Avoiding this preliminary treatment may result in
moisture blisters, marring the appearance of the finished product, and/or reduce its properties.
ƒ Higher thicknesses require longer periods in the drying oven.
Typical Pre-Drying Time in Oven for Various Thicknesses*
Sheet Thickness Drying Time at 125°C (260°F)
mm Inch Hours
1 0.04 1.5
2 0.08 4
3 0.12 7
4 0.15 12
5 0.2 18
6 0.24 26
8 0.32 45
Notes: Time for thicker sheets can be calculated through interpolation.
ƒ The sheets are put into an oven, with the protective film removed from both sides, and arranged 20-30mm (3/4”-1”) apart, to
enable free air circulation. They can be stacked horizontally (on stays or suspended) or vertically- just so they will not be distorted
or twisted.
ƒ The pre-drying process should be performed as close as possible to the actual forming. Fully dried sheets taken out of the oven
and cooled down to room temperature may be workable within 1 to 10 hours (depending on relative humidity and temperature
in the workshop).
ƒ Longer delay may necessitate repeated pre-drying session. A recommended practice, if possible, is leaving the pre-dried sheets
in the switched-off oven until the actual thermoforming process. This method saves energy and time on the thermoforming
apparatus.