Annealing of Acrylic Sheet Mirror and Painting Acrylic Sheets
Acrylic is a transparent thermoplastic and is classified as a type of glass. There are different types of acrylic sheets available like tinted, mirror, fluorescent, prismatic and more. To make parts from acrylic sheets the processes followed are fabricating, finishing, cementing and annealing.
Acrylic is lightweight and shatter-resistant therefore it can be used as an alternative to glass. The acrylic sheet mirror can be used in applications where glass mirrors can be too heavy to use. These sheets help to enhance the look and the safety of an application.
The sheets are scratch-resistant and easy to fabricate. It is also a cost-effective option compared to glass. It is used in POP displays, signage, salt walls, children’s toys and cosmetic displays.
Acrylic Sheet Mirror
Annealing
When the acrylic sheet is fabricated or thermoformed it causes internal stress and the sheet can be improved by relieving this stress. Annealing is one of the most important measures taken to improve the performance of the parts. It also helps to improve the strength of the cemented joints.
In the annealing process, the acrylic sheet is uniformly heated to a temperature that is below the forming temperature followed by cooling. Internal stresses that are set up due to the fabrication of the part are reduced or eliminated. It results in greater dimensional stability and resistance to crazing. It helps to lessen the effects of solvent sears which result from errors in cementing.
If stresses exist on the surface of the parts then only the surface should be heated. Drilled holes are considered a special case and such parts should be placed in an oven so the air flows through the hole passage.
When the sheet is cooled the rate of cooling of the thicker parts will be slower than that of the thin parts.
Painting of acrylic sheets
Acrylic sheets can be easily decorated using commercially available paints which are produced for acrylic and vinyl. Before painting the dust and the masking should be removed. If you are painting a surface that will be exposed to the weather then you will have to apply a protective coating.
Before painting a liquid maskant can be applied to the sheet to provide a protective layer. The maskant should be allowed to dry for 24 hours. The design should be made on the film without scratching the sheet. Paint the sheet and do not remove the film until the paint has dried completely.
The different methods that can be used are spray painting, screen printing, powder coating, stamping and in-mould painting.
Spray painting should be done by automating the spray gun to distribute the paint uniformly. Screen printing can be used for patterns, logos and more. In stamping pre-dried inks and foils are transferred to the surface at high temperatures.