Plastic laminate size change problem & stress crack



Dimensional change issues: The swellability of plastic laminates has caused many practical problems associated with commercial applications. This includes the problem of mating the panel (made of a plastic laminate) with the substrate sheet. The ideal fit at a certain humidity can be solved by placing a gap between the panels at low humidity or by holding the panel under high humidity. Other problems are stress cracking and warpage. The use of a plastic laminate as a flushing door "lush doors" is a good example of the dimensional stability problem. The laminate on a 2m. 76m flushing door can be subjected to a length of 4. 1 mm when the humidity changes drastically. The dimensional change is 6.1 mm in the width direction. This can be solved by leaving a frame of unpaved substrate around the board at low humidity or extending the laminate beyond the door edge under high humidity. The product is rarely manufactured in extreme humidity. If the laminate panel is used at 50% relative humidity, the maximum expansion can be reduced by half.

Often, the substrate is also subject to dimensional changes, but only a small amount of expansion or shrinkage is considered, so the problem is much less. Plastic laminates are used in the vertical use of siding, and there are similar problems with the connections between the panels. These joints may crack under low humidity, and when the panel may warp under high humidity, so when used as a siding, it is generally or designed to hide the joint behind the strip or T-shaped bead, or use a black scribe line ( Or similar mark), it highlights the joint but makes the naked eye not see some small size changes. Recently, thicker ((4^-12mm) plastic laminated panels for components have also become victims of panel swellability. Whether used as a cover for outdoor buildings or as a secret partition for indoors, All uses require special compensatory support measures and are often special hardware.

Stress cracking: Another problem associated with swellability is stress cracking. This occurs when a hole is cut in a plastic laminate panel, such as a cutting hole in a built-in counter or a window on a vertical panel or a cutting hole O of an electrical switch or an outlet box, which has been observed in a plastic layer when the humidity changes greatly. Cracks are formed around the orifice of the platen. These cracks generally begin at the corner and are about 450. As the crack continues to develop, it turns closer to parallel to the longitudinal direction of the panel. These cracks are the stress concentration points caused by the stress caused by the swelling of the panel, and thus the location of the original crack. Round holes or a relatively stable laminate can prevent such problems from occurring.

  • 05/12/2018
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