Thermo forming

VG Extruded, injection molded, thermo-formed and machined Autoclavable surgical tools, coil forms, pump housings, valves, pipe... 

The chassis is made from a 1/4 in. sheet of either ABS or TPO vacuum formed into a tub and reinforced with reinforced pultruded glass fiber-TS polyester plastic tubing. The hood and other products are being made from a 20 mm thick sandwich of thermo-formed PPO-alloy skins, glass fabric infused with thermosetting vinyl ester, and a urethane foam core. The bumper and front fascia is thermoformed from a polyolefin elastomer sheet with an UV-resistant cap layer of DuPont s Tediar PVF film. The dash and... 

Process used provides different control capabilities. As an example closed molding (injection, compression, etc.) provides fine detail on all surfaces. Open molding (blow molding, thermoforming, spray-up, etc.) provides detail only on the one side in contact with the mold, leaving the second side free-formed. Continuous production (extrusion and pultrusion) yields products of continuous length. Hollow (rotational or blow) produces hollow products. These processes can be used creatively to make different types of products. For example, two molded or thermo-formed components can be bonded together to form a hollow product, or they can be blow molded. 

Part Design Blow Molding Casting Compression Extrusion Filament Winding Injection Matched Die Molding Rotational Thermo- forming Transfer Compression Wet lay-up (Contact Molding)... 

Glazing applications, shatter-resistant glazing, architectural and protective glazing, windows and skylights, sight glasses (e.g. observation windows), transparent thermo-formed products... 

Cast and extruded sheets, cell-cast sheets, stretched sheets, films down to 50 microns laminated protective surfaces on ABS, PVC or other plastic sheets that are thermo-formed into parts requiring resistance to outdoor weathering for residential siding and transformer housings... 

Processing. SAN copolymers may be processed using the conventional fabrication methods of extrusion, blow molding, injection molding, thermo forming, and casting. 

Housewares is another large segment of the use of polystyrenes. Refrigerator door liners and furniture panels are typical thermo formed impact polystyrene applications. Extruded profiles of solid or foamed impact polystyrene are used for mirror or picture frames, and moldings for construction applications. 

An example of a product that has had styrene taint problems over the years has been dairy products such as coffee creamer and condensed milk packed in thermo-formed PS single serve portion pack containers holding 5-10 g of product. The high package mass and surface area ratio to product and high fat content of the product make this package/product system a challenging system to optimize. 

These ASRs are produced either chemically in a reactor or by blending GPPS and rubber in downstream operations. This family of plastics has good toughness and gloss, and very good processability. ASRs can be processed on conventional sheet extrusion and thermo-forming equipment. They are recommended for applications where intermediate... 

Elements Rotational Molding Blow Molding Thermo Forming... 

Kydex [Rohm Haas]. TM for a thermo-formed acrylic polyvinyl chloride alloy plastic sheet. 

L-lactic acid has long been used as a food additive and has recently received great attention because it can be used as an important feedstock for the production of other chemicals such as polylactic acid (PLA), acetaldehyde, polypropylene glycol, acrylic acid, and penta-dione. Among them, PLA is the most important product as it can be used to manufacture thermo-formed containers, packaging, nonwovens, paper-coated articles, and film products. Lactic acid can be produced from sucrose, whey (lactose), and maltose or dextrose from hydrolyzed starch using Lactobacillus strains. 

Polyethylene, polyvinyl chloride and polypropylene are easily worked utilizing ordinary wood or metal working hand and power tools. Being thermoplastic, these materials can be easily thermo-formed as well as cut, sawed, drilled and tapped. In the heat forming process, electric ovens are generally used which can maintain good thermal control. Of the three thermoplastics, polypropylene requires the more finite thermal control. Table III provides approximate time and temperature relationship required for thermoforming these three plastics. 

An important factor with thermoforming is that the polymer should show a pronounced rubbery region on the temperature scale. For this reason, amorphous polymers such as PVC, PS, poly(methyl methacrylate) (PMMA), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), etc. are well suited for thermo forming. With semicrystalline polymers, the rubbery region is largely masked by the crystallinity (Fig. 23.19). With PE and polypropylene (PP), thermoforming is, therefore, a critical operation, in which the processing conditions should be very carefully controlled. 

Heat can be transferred to the sheet in several ways. The most common for thermo-forming is radiation from heater elements. The sheet is moved into or through an oven with radiant heating elements. In some thermoform/fiH/seal equipment, heating is by conduction. In this case, the sheet is pulled up against a heated plate,... 

Part design Blow molding Casting Compression Extrusion Filament winding Injection Matched die molding Rotational Thermo- forming Transfer compression Wet lay-up (contact molding)... 

Acrylonitrile Copolymer A thermoplastic prepared by copolymerization of acrylonitrile with small amounts of other unsaturated monomers. Has good gas barrier properties and chemical resistance. Processed by extrusion, inj ection molding, and thermo forming. Used in food packaging. 

Polybutylene Terepbtbalate Thermoplastic polymer of dimethyl terephthalate and butanediol. Has good tensile strength, dielectric properties, and chemical and water resistance, but poor impact strength and heat resistance. Processed by injection and blow-molding, extrusion, and thermo forming. Used in auto body parts, electrical devices, appliances, and housings. Also called PBT. 

Polyetherlmldes Thermoplastic cyclized polymers of aromatic diether dianhydrides and aromatic diamine. Has good chemical, creep, and heat resistance, and dielectric properties. Processed by extrusion, thermo forming, and compression, injection, and blowmolding. Used in auto parts, jet engines, surgical instruments, industrial apparatus, food packaging, cookware, and computer disks. Also called PEI. 

Semi-finished products (pipe-, film- and sheet-blanks) which must still be turned into a finished product by (thermo-) forming or fabrication... 

Poly(lactic acid)s (PLA)s have been produced for many years. PLAs resemble clear poly(styrene) and have good gloss and clarity for aesthetic appeal, along with physical properties weU suited for use as fibers, films, and thermo-formed packaging. PLA is biocompatible and have been used extensively in medical and surgical applications, i.e. sutures and drug delivery devices (1). 

Blends of styrenic pol5m ers (PS, high impact poly (styrene)) and biodegradable polymers (PLA) can be extruded and thermo-formed to produce very low density food service and consumer foam articles (29,31). The blends are compatibilized with styrene-based copolymers a styrene-maleic anhydride copol5mier, or a styrene methyl methacrylate copolymer. As blowing agent for foaming the compositions z-pentane is used. 

Polyethylene Terephthalate. Crystallization is difficult and slow. Particularly for injection molding, 0.5 percent of 3- im metal oxide, metal salt, pigment, or other minerals, and ionomer are mentioned. For thermo formed food trays, 1 to 3 percent of low-MW polyolefin. 

---