Annealing Acrylic Sheet

Internal stresses in the sheet can cause crazing the appearance of numerous tiny cracks in the material when acrylic comes in contact with solvents such as glass cleaners or paints.

Annealing acrylic sheet.

Annealing is the process of relieving stresses in molded or formed plastics by heating to a predetermined temperature maintaining this temperature for a set period and slowly cooling the parts. Tips for annealing acrylic sheet. Heat one hour per millimeter of thickness for thin sheet at least two hours total. Internal stresses set up during fabrication of the article are reduced or eliminated by this treatment all edges should be cut or machined with as little internal stress as possible.

Cooling times are generally shorter than heating times see the chart below. Sometimes formed parts are placed in jigs to prevent distortion as internal stresses are relieved during annealing. Annealing the acrylic allows fabricators to strengthen the acrylic sheet and reduce or eliminate the fabrication stress through a process of controlled heating and then cooling. It alleviates most of the stress induced by line bending thermoforming screen printing cementing machining buffing flame polishing and other fabrication operations.

Annealing the strengthening of acrylic sheet through controlled heating and then cooling minimizes the effects of fabrication stress. To anneal acrylic sheet heat it to 180 f 80 c just below the deflection temperature and cool slowly.