The difference between cast acrylic and extruded acrylic a comprehensive comparison guide of the two processes
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The difference between cast acrylic and extruded acrylic - a comprehensive comparison guide of the two processes
The most commonly asked question in the selection of acrylic (PMMA, polymethyl methacrylate) sheets is "What is the difference between cast acrylic and extruded acrylic. These two seemingly identical transparent materials have fundamentally different "personalities" in terms of molecular structure, physical properties, and processing performance due to fundamental differences in manufacturing processes.
Acrylic casting adopts liquid monomer casting molding technology, which slowly polymerizes and solidifies like baking a cake; And extruded acrylic is produced through continuous extrusion technology, which is rapidly molded like "squeezing toothpaste". These two different production methods endow materials with distinct characteristics and are suitable for completely different application scenarios. A thorough understanding of the difference between cast acrylic and extruded acrylic is a crucial step in avoiding the risk of "buying the wrong board and ruining the project" when selecting materials.
Product feature comparison
Core characteristics of cast acrylic:
Cast acrylic has a higher molecular weight (up to 2000000 g/mol or more), longer and more tightly entangled molecular chains, which makes the material perform excellently in multiple dimensions. Specifically, the surface of cast acrylic is harder and denser, with excellent scratch resistance; Has stronger impact resistance and cracking resistance; Excellent chemical resistance, with better tolerance to solvents such as alcohol and cleaning agents; The transmittance is over 92%, and the optical clarity is excellent. The internal stress of the board produced by casting process is extremely low, and it is not easy to deform after long-term use.
Core characteristics of extruded acrylic:
Acrylic extrusion is produced using continuous extrusion molding technology, with a relatively low molecular weight and slightly weaker mechanical properties than cast products. But this feature also brings unique advantages: the thickness tolerance of the sheet is extremely small (about ± 5%, while the casting sheet can reach ± 10%~15%), and the dimensional consistency is excellent; Low softening point, stable and reliable hot bending and hot forming performance; After laser cutting, natural smooth flame polished edges can be obtained, with excellent cutting effects.
The following table summarizes the specific performance of the differences between cast acrylic and extruded acrylic in various indicators:
Characteristic indicators: Cast acrylic, extruded acrylic
High molecular weight (≥ 2M g/mol) and low
Thickness tolerance ± 10%~15% ± 5%
Light transmittance of 92%~98%, around 92%
Excellent scratch resistance, average
Excellent chemical resistance but low
Laser engraving effect is frosted white, high contrast gray, not obvious
Hot bending forming is less predictable, stable, and reliable
Material usage
The main application areas of cast acrylic are:
Cast acrylic, with its excellent optical performance and durability, is widely used in high-end signage and lightbox panels, trophies, medals, and carved artworks, aquariums and large observation windows, medical equipment and optical instrument components, building skylights and display windows. Especially in aquarium applications, cast acrylic is the only safe choice - extruded acrylic is extremely unsafe to use in aquariums due to its insufficient strength and susceptibility to cracking.
The main application areas of extruded acrylic are:
Extruded acrylic is known for its cost advantage and excellent thermoforming performance, and is commonly used in retail display racks and shelves, machine protective covers and safety partitions, greenhouse glass and skylights, lighting diffusers, advertising display boards and signage. For projects that require large-scale production and high requirements for thickness consistency, extruding acrylic is a more efficient and economical choice.
production process
Production process of casting acrylic:
The casting process is similar to traditional glass casting methods. Firstly, mix liquid methyl methacrylate (MMA) monomer with catalyst, coloring agent and other raw materials in precise proportions; Then inject the mixture into a sealed mold composed of two glass plates; Slowly heat in a constant temperature oven to gradually polymerize and solidify MMA monomers, which usually takes several hours or even longer; Finally, slow cooling is performed to eliminate residual stress inside the material and prevent cracking during subsequent use.
Casting process is an intermittent production method with limited single batch output, long production cycle, and high cost, but it can produce high-quality sheets with high molecular weight and low internal stress.
Production process of extruded acrylic:
The extrusion process adopts a continuous production mode. Feed high-purity acrylic particles (PMMA resin) into the extruder hopper; Melting particles into a viscous flow state at high temperatures; The molten material is uniformly extruded through a specific shaped die under the push of a screw; The extruded sheet is cooled and shaped by a cooling roller; Finally, cut and package according to standard dimensions.
The extrusion process can operate continuously with extremely high production efficiency, suitable for large-scale production. The cost of extruding acrylic is 10% to 25% lower than casting acrylic, which is the core reason why extruding acrylic is cheaper.
Common specifications and sizes
Cast acrylic: The thickness range is usually 1.5mm to 100mm, and commonly used sizes include 1220 × 1830mm, 1220 × 2440mm, 2050 × 3050mm, etc. Other special sizes can be customized.
Extruded acrylic: The thickness range is usually 0.8mm to 12mm, and commonly used sizes include 1250 × 2500mm, 1200 × 2400mm, 1220 × 2440mm, etc.
The thickness of the two types of boards varies from 1mm to over 50mm, with common thicknesses including 1mm, 2mm, 3mm, 4mm, 5mm, 8mm, 10mm, 12mm, 15mm, 20mm, 25mm, 30mm, etc.
Frequently Asked Questions
How to quickly distinguish between cast acrylic and extruded acrylic?
A simple on-site identification method is to carefully heat the edges of the sheet with a lighter. Cast acrylic will melt or burn more thoroughly when heated, without producing wire drawing phenomenon; After being heated, extruded acrylic will become like a strand, with obvious stretching filaments. In addition, observing the edges of the board can also help determine that the edges of the cast board are transparent and free of blemishes, while the edges of the extruded board may have blemishes or slight blackening.
Is extruding acrylic of poor quality?
and be not so. The difference between cast acrylic and extruded acrylic is not in their quality, but in their suitability. Extruded acrylic has significant advantages in thickness uniformity, hot bending stability, and cost-effectiveness, making it highly suitable for large-scale production and budget sensitive projects. The key to choosing which type of acrylic is to match specific application needs - there is no "best" material, only the "most suitable" material.
Why do aquariums have to use cast acrylic?
The aquarium can withstand water pressure for a long time, requiring extremely high material strength, crack resistance, and water resistance. Cast acrylic has higher molecular weight and uniform molecular structure, and stronger impact resistance; However, there are residual stresses inside the extruded acrylic, which can easily cause stress cracking or even overall rupture under continuous water pressure, posing a serious safety hazard.
What are the common quality issues with acrylic sheets?
Whether casting or extruding acrylic, the following problems may be encountered during use: surface scratches (can be repaired with professional polishing agents), yellowing (caused by long-term UV exposure, it is recommended to use UV resistant sheets), cracking (caused by internal stress or large temperature changes during processing), and deformation (softening deformation in high temperature environments). It is recommended to perform standardized annealing treatment after processing, and avoid scratching with hard objects and contact with chemicals during use to extend the service life of the material.
The difference between cast acrylic and extruded acrylic lies in the fundamental differences in manufacturing processes, which determine their different positioning in terms of performance, cost, and applicable scenarios. Cast acrylic is known for its excellent optical properties, high strength, and outstanding chemical resistance, making it an ideal choice for high-end displays, precision machining, and aquarium applications; Extruded acrylic has the advantages of uniform thickness, stable hot bending, and low cost, making it very suitable for large-scale production and budget sensitive projects. When purchasing, a scientific choice should be made between the two based on specific application requirements.
| product type | pet、ps、acrylic、acrylic mirror、pvc sheet,acrylic sheet |
| thickness | 0.35-300mm |
| Styles | 1220*2440,1220*1830,500*900,50*60,960*1950,700*900/Customization of various specifications and sizes |
| delivery time | 5-8day |
| manufacture | Yifang |
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