Cast acrylic

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Cast Acrylic is a form of poly(methyl methacrylate) (PMMA). It is formed by casting the monomer, methyl methacrylate, mixed with initiators and possibly other additives into a form or mold. Sheet and rod stock are generated by casting into static forms, while tubing is done in rotational molds.

It has better thermal stability, higher resistance to crazing when exposed to solvents, wider thermoforming range than extruded acrylic. Cast acrylic has a better ability to be reworked hot and it is known for its superior surface finish and optical properties. Also cast acrylic is more scratch resistant than extruded acrylic. Cast acrylic is also preferred over extruded in applications that require machinings, such as turning on Engine Lathe or milling/drilling. Extruded acrylic, with far less thermal stability, tends to melt and clog cutting tools. Even with slow speeds and much coolant, extruded acrylic does not produce the surface finish and tight tolerances achievable with cast acrylic.

Advantages of Acrylic (PMMA):

• Excellent optical clarity and transparency
• Highly resistant to variations in temperature
• Up to 17 times the impact resistance of ordinary glass
• Half the weight of glass and ideal for precision machining
• Highly resistant to many different chemicals
• Has certain properties making it an ideal material for use in a wide range of applications, including medical, life sciences and food/beverage testing.

PMMA – PolyMethyl MethAcrylate. Crylux, Plexiglas, Acrylite, Lucite, and Perspex are trade names for Acrylic.

General Properties:

• Relative Density 1.19 g/cm3
• Rockwell Hardness M 102
• Water Absorption 0.2%
• Flammability Class 3 (BS 476 pt 7), UL94 HB

Mechanical:

• Tensile Strength 75 MPa
• Flexural Strength 115 MPa

Thermal Properties:

• Minimum Service Temperature -40°C
• Maximum Service Temperature 80°C
• Softening Point >110°C
• Linear Expansion 7.7×10-5

Optical Properties:

• Light Transmission >92%
• Refractive Index 1.49

This type of acrylic is often used for aquariums, awards, financial tombstones, trophies, corporate gifts, and other products that require shaping or machining. It tends to be more clear and made to a higher quality standard, but in doing so makes it more expensive than extruded acrylic.

• Financial tombstone
• Acrylic embedment