Industry Glossary Oven Forming Acrylic
ACRYLIC GENERAL DESCRIPTION
Acrylic (Polymethyl-Methacrylate or PMMA) is an amorphous thermoplastic which is optically transparent, unaffected by moisture, and offers a high strength-to-weight ratio.
GENERAL PROPERTIES OF ACRYLIC
Acrylic offers high light transmittance with a Refractive Index of 1.49 and can be easily heat-formed without loss of optical clarity. Prolonged exposure to moisture, or even total immersion in water, does not significantly effect the mechanical or optical properties of acrylic. Most commercial acrylics have been UV stabilized for good weatherability and resistance to prolonged sunlight exposure.
Acrylics are unaffected by aqueous solutions of most laboratory chemicals, by detergents, cleaners, dilute inorganic acids, alkalies, and aliphatic hydrocarbons -- however, acrylics are NOT recommended for use with chlorinated or aromatic hydrocarbons, esters, or ketones.
Acrylics are easily sawed, drilled, milled, engraved, and finished with sharp carbide tools. Cut surfaces may be sanded and polished. The main drawback to acrylic , including Oven Forming Acrylic, is its low notch strength which means that it cracks easily, especially around drilled holes. Special care is required. Acrylics are also readily bent or thermoformed at low temperature and solvent bonding of properly fitting parts produces a strong, invisible joint. Acrylics are available in colorless clear as well as a wide variety of colors and tints. They are available in extruded and/or cast material in sheet, rod and tube forms as well as custom profiles.
Oven Forming Acrylic
Acrylic is an economical, general purpose material used in a wide variety of applications, including: store fixtures and displays, lenses and lighting fixtures, light pipes, windows and skylights, sight gauges, furniture, outdoor signs and sculpture.
Acrylics are often known by their register trademark names:
- Plexiglas® is marketed by Altuglas in North America
- Lucite® is marketed by Lucite International
- Acrylite® is marketed by Cyro Industries, a Degussa company
POLYETHYLENE GENERAL DESCRIPTION
Polyethylenes are semi-crystalline materials with excellent chemical resistance, good fatigue and wear resistance, and a wide range of properties (due to differences in length of the polymer chain.)
GENERAL PROPERTIES OF POLYETHYLENES
Polyethylenes provide good resistance to organic solvents, degreasing agents and electrolytic attack. They have a higher impact strength, but lower working temperatures and tensile strengths than polypropylene. They are light in weight, resistant to staining, and have low moisture absorption rates.
Low Density Polyethylene (LDPE)
This extruded material offers good for Oven Forming Acrylic corrosion resistance and low moisture permeability. It can be used in applications where corrosion resistance is important, but stiffness, high temperatures, and structural strength are not. A highly flexible product, LDPE is used widely in orthopedic products, or where mobility without stress fatigue is desired. LDPE is also frequently used in consumer packaging, bags, bottles, and liners.
High Density Polyethylene (HDPE)
Representing the largest portion of the polyethylene applications, HDPE offers excellent impact resistance, light weight, low moisture absorption, and high tensile strength. HDPE is also non-toxic and non-staining and meets FDA and USDA certification for food processing.
Ultra High Molecular Weight Polyethylene (UHMW PE)
Light weight (1/8 the weight of mild steel), high in tensile strength, and as simple to machine as wood, UHMW PE Oven Forming Acrylic is ideal for many wear parts in machinery and equipment as well as an excellent lining in material handling systems and storage containers. UHMW PE is self-lubricating, shatter resistant, long-wearing, abrasion and corrosion resistant. It meets FDA and USDA acceptance for food and pharmaceutical equipment and is a good performer in applications up to 180 °F (82 °C) or when periodically cleaned with live steam or boiling water to sterilize.
Polyethylene sheet manufacturers:
POLYPROPYLENE GENERAL DESCRIPTION
Polypropylene is an economical material that offers a combination of outstanding physical, chemical, mechanical, thermal and electrical properties not found in any other thermoplastic. Compared to low or high density polyethylene, it has a lower impact strength, but superior working temperature and tensile strength.
GENERAL PROPERTIES OF POLYPROPYLENE
Polypropylene provides excellent resistance to organic solvents, degreasing agents and electrolytic attack. It has a lower impact strength, but its working temperature range and tensile strength are superior to low or high density polyethylene. It is light in weight, resistant to staining, and has a low moisture absorption rate. This is a tough, heat-resistant, semi-rigid material, ideal for the transfer of hot liquids or gases. It has excellent resistance to acids and alkalines, but poor resistance to aromatic, aliphatic and chlorinated solvents. Polypropylene has excellent dielectric properties, resists stress cracking.
FABRICATION TECHNIQUES FOR POLYPROPYLENE
Polypropylene can be joined by hot gas welding, fusion & butt welding and can be readily machined with wood or metal working tools.
TYPICAL APPLICATIONS FOR POLYPROPYLENE
Polypropylene is frequently used for chemical resistant tanks & linings, laboratory consoles, sinks & ducts, plating barrels & tanks, lavatory partitions, clean room walls, floors & ceilings, and marine fresh water and wastewater tanks.
Depending on thickness, available in natural, white, black, blue and European gray.
Polypropylene sheet manufacturers:
GENERAL DESCRIPTION FOR POLYCARBONATE
Unfilled polycarbonate is a tough, transparent engineering thermoplastic which offers very high impact strength and high modulus of elasticity. It also has a high heat deflection temperature and absorbs very little moisture. These properties, plus good low frequency and high voltage insulating characteristics, make polycarbonate a prime material for electrical and electronic components. Its strength, impact resistance and transparency (unfilled grades only) also make it an ideal material for certain transparent structural applications.
GENERAL PROPERTIES FOR POLYCARBONATE
Compared to other plastics, polycarbonate has high impact strength with excellent strength retention at elevated temperatures, high tensile, shear, and flexural strength and a high modulus of elasticity. Over time it has excellent creep and cold flow resistance and a low coefficient of thermal expansion It has good electrical insulation properties and is easy to fabricate & machine.
TYPICAL APPLICATIONS FOR POLYCARBONATE
The range of applications for Polycarbonate is very broad. See the manufacturers’ web sites for the possibilities.
Brands of polycarbonate:
- Lexan® manufactured by GE Plastics
- Zelux® manufactured by Westlake Plastics Company
- Makrolon® manufactured by Bayer MaterialScience
POLYVINYL CHLORIDE (PVC)
Polyvinyl Chloride, or PVC, is usually an amorphous thermoplastic material with excellent chemical resistance and dielectric properties, good tensile, flexural and mechanical strength, low moisture absorption, exceptional dimensional stability and good flammability characteristics.
There are two main classifications of polyvinyl chloride materials:
- Rigid Polyvinyl Chloride (PVC)
- Chlorinated Polyvinyl Chloride (CPVC)
Rigid Polyvinyl Chloride:
Rigid PVC is the most common type of PVC used in the manufacture of pipe, fittings, valves, machining shapes, sheet and duct. Rigid PVC offers advantages for piping and related applications due to its low cost, high strength to weight ratio, pressure bearing capability, corrosion and chemical resistance and low friction loss characteristics.
PVC sheet manufacturers:
PVC Foam is a foamed polyvinyl chloride. Much like standard PVC, PVC Foam will not absorb water and is corrosion and weather resistant. The expanded PVC includes several other advantages – the material is very light weight and easily fabricated. PVC Foam is durable indoors and out and is available in a wide range of colors. It is also easily painted or silk-screened to allow for use in signage and display applications.
- Easily Fabricated without special tools
- Durable – Indoors or Out
- Wide Range of Colors
- Easily Painted or Silk-Screened
- Low Moisture Absorption
Typical Market Applications:
- POP Displays
- Photo mounting
- Machine Guards
- Game boards
- Stage Settings
Suppliers of PVC foam sheets:
Each plastic has unique physical properties. In addition to the manufacturers themselves, a couple of sources for this information are:
POLYVINYLIDENE FLUORIDE (PVDF)
GENERAL PROPERTIES OF PVDF
PVDF is manufactured from Kynar® polyvinylidene fluoride resin. For Fabricators it is available in sheet, rod and tube forms. This material offers excellent corrosion and chemical resistance at both ambient and elevated temperatures. PVDF is also inherently UV stable, mechanically tough, abrasion and flame resistant. It is also one of the more expensive plastics.
TYPICAL APPLICATIONS FOR PVDF
PVDF is frequently used for chemical process and storage including ozonation processes, fluid handling, semiconductor equipment, fire-safe components, and DI water systems.
The advantages of PVDF include:
high purity, flame resistant, easy to machine, and excellent weatherability. The resin meets the requirements of FDA, USDA, USPXX Class VI, 3A, UL, V-0, FM 4910
KYNAR® is a registered trademark of Elf Atochem North America, Inc.
Manufacturers of PVDF sheets:
- Westlake Plastics
- CPG- Vycom
More on Oven Formed Acrylic
Oven forming acrylic is one of the most useful techniques for creating beautiful shapes from sheet material. The first requirement for oven forming acrylic is an oven with accurate temperature controls. Hot air convection ovens are preferred for thicker sheets. Acrylic is an excellent choice when optical clarity is important. It can be manufactured in a wide array of colors and finishes. It is also FDA approved for food applications. The easiest shapes for oven forming acrylic are simple bends that do not require stretching the material. If you can wrap piece of paper on the finished part fitting perfectly without wrinkles you have an excellent candidate for drape forming acrylic. Shapes which require stretching can also be achieved by oven forming acrylic. The fabricator just has to figure out how to apply the force to the hot soft acrylic to stretch the material to the mold. The most common technique for oven forming acrylic in more complex shapes is vacuum forming, but good results for partial domes and deformed cylinders can be had with mechanical force to pull the sheet onto the mold.
Polyfab has a convection oven 14 feet long by 4’-4” wide inside which means we can oven form acrylic pieces up to those dimensions. We can make much larger pieces by forming components and then cementing them, or if your design allows it, joining the pieces with fasteners. The acrylic is heated to a forming temperature of about The most common shapes for oven forming acrylic are cylinders. We prefer to have vertical seams if the cylinder is upright because they are less noticeable than seams going around the cylinder. Polyfab has manufactured cylinders 4 feet in diameter and eight feet tall, and much larger diameter cylinders that are shorter than eight feet tall. Please call us with your requirements and we will discuss what we can do to meet your requirements.
Other common shapes for oven forming acrylic are cones. Polyfab has made cones of many shapes and sizes from 4 inches in diameter by 4 inches high to 3 feet in diameter by 4 feet high. Since our cones are made from bent sheet stock, they do not go to a point. If you require and oven formed acrylic cone that goes to a point, we machine and polish a point that is cemented to the hollow cone. We have made cones with walls as thick as 1 inch when required.
Category: Oven Forming Acrylic