Plastic Molding Processes

Rotomolded Products – Fibertech, Inc.Plastic processes differ greatly in both the way they form plastic products and in the shape and structural integrity of the products they manufacture. Blow molding, for example, is nearly the sole method by which plastic bottles for beverages, household cleaners and cosmetic products are made, as well as a range of low-cost toys and parts with low to medium performance. The extrusion process creates linear profiles, strips and sheets with high structural integrity useful in many construction siding, trim and furniture applications. Vacuum forming, or thermoforming, forms trays, linings and thin plastic packaging from heated plastic sheets, while dip molding forms a variety of soft molds and plastic coatings. Other plastic molding processes use casts, or dies; injection molding squeezes melted (or “plasticized”) plastic resin into a closed mold, forming a solid plastic object, while rotational molding uses a type of gyroscope to evenly coat the inside of a mold, creating hollow parts with high impact resistance.

Plastic molding processes vary greatly in cost. High end plastic molding processes, such as rotational molding and injection molding, provide precision three dimensional plastic parts with structural integrity and impact resistance few other processes or materials can provide. On the other end of the spectrum, blow molding and dip molding processes offer very affordable options for long runs and mass production of containers and household commodity items. A wide range of plastic materials are molded through these processes, although some processes are more effective with certain polymers than others.

Injection Molded Plastics Manufacturers

Injection Molded Plastics – ICOMoldThis is one of the most common forms of plastic molding, and the process can range widely in cost, depending on the complexity of the part being molded and the materials which are used. Injection molding produces three dimensional, solid parts with mid to high strength and is unique in plastic molding processes, as it can produce relatively complex shapes. Advanced injection molding techniques include insert molding and reaction injection molding (RIM); insert molding dies contain a solid object, such as an electric coil, around which the molten plastic is injected, creating an encapsulated object. Reaction injection molding combines a liquid resin thermoset polymer (typically polyurethane) with liquid polyisocyanate, which acts as a reagent within the mold, causing the polymers to expand and form bubbles (either open or closed cell foam), filling the mold.

Injection molding machines consist of three main sections: the hopper, where plastic resin pellets are fed into the machines; the extruding barrel, containing a small screw conveyor which simultaneously “plasticizes”, or melts, the plastic resin while moving it towards the die; and the die, or closed mold, into which the melted plastic is injected under pressure. The plasticizing of the resin is often assisted by electric band heaters and cartridge heaters wrapped around the extruding barrel.

business Leading Injection Molded Plastics Manufacturers

GSH Industries, Inc.
Cleveland, OH | 440-238-3009

Holland, OH | 419-867-3900

MSI Mold
Shelby Township, MI | 248-275-1978

Britech Industries
Stuart, FL | 772-286-9278

Molded Devices, Inc.
Riverside, CA | 951-509-6918

View a full list of Injection Molded Plastics Manufacturers

Plastic Extrusion Manufacturers

Plastic Strips – Creative Extrusion & Technology, Inc.Plastic extrusions are formed similarly to the way injection molded plastics are formed, although extrusions are formed through an open die. Plastic resins such as PVC, acrylic, polypropylene or ABS are fed through a hopper into the extruding barrel, which shears and melts the resin, pushing it through the open die to form a profile or shape. This profile is immediately immersed in cold water to set the plastic; the profile is extruded continuously, passing through the die, through cold water tanks and onto a sawing table, where pre-specified lengths are cut.

Extruded plastics may be manufactured to meet the specifications for a broad range of niche applications, including but not limited to building trim, window and door sealants, vinyl siding, PVC pipe and surgical tubing. Plastic sheets and flexible plastic sheet rolls are also formed through extrusion, being pulled and stretched instead of cooled after the melted plastic exits the die; flexible plastic sheets are rolled through a series of large calenders before being rolled onto a tube.

business Leading Plastic Extrusion Manufacturers

Preferred Plastics, Inc.
Plainwell, MI | 269-783-4068

Polytec Plastics, Inc.
St. Charles, IL | 800-739-9066

SFR Industries Inc.
Cadott, WI | 800-369-9410

Absolute Custom Extrusions, Inc.
Stuart, FL | 772-286-9278

Britech Extrusions
Stuart, FL | 772-286-9278

View a full list of Plastic Extrusion Manufacturers

Plastic Blow Molding Manufacturers

Plastic Blow Molding – R&D Molders, Inc.Numerous products are made from blow molding. Any consumer item that has a three-dimensional shape and is hollow, such as tanks and CD cases, is manufactured using the blow molding process. Blow molded products are capable of holding a variety of substances such as herbicides, pesticides, cosmetics, and automotive oil. The plastic utilized for these processes are all thermoplastic resins. They include acetal, polysulfone, polyamide, polystyrene, butadiene styrene, Barex, polyvinyl chrloride (PVC), and high and low density polycarbonate.

Plastic blow molding can be categorized into three types: injection blow molding, extrusion blow molding, and stretch blow molding. All of these processes consist of two steps, which vary the most in the early stages. The ultimate shape of the blow molded plastic depends on the shape of the mold cavity. While blow molded products come in an assortment of standard shapes and sizes, there are some products that can be made using custom blow molding, and are thus used for special applications.

business Leading Plastic Blow Molding Manufacturers

Custom-Pak, Inc.
Clinton, IA | 563-242-1801

Iceberg Molding
Sturgis, MI | 269-651-9488

Western Case, Inc.
Riverside, CA | 951-214-6380

Western Industries, Inc.
Winfield, KS | 620-221-9464

Apex Plastics
Brookfield, MO | 800-467-4640

View a full list of Plastic Blow Molding Manufacturers

Plastic Dip Molding Manufacturing

PVC Coatings – Precision Dip Coating LLCDip molding plastic is one of the simplest means of molding plastic and, like blow molding, is capable of producing a large number of parts or products at low cost. The dip molding process serves in one of two manufacturing capacities: to create whole flexible or rigid products such as rubber gloves, condoms and plastic caps; or to coat pre-manufactured products such as wire racks, wire cable and plastic coated handles.

Both manufacturing methods use the same basic process: a large volume of glass or metal molds are surface prepped, so that the final product may be easily stripped from the mold when dry. Objects which are to be coated in plastic are buffed and prepped so that the plastic coating stays firmly on. The molds are then dipped into a vat of molten polymer or elastomer resin; depending on the desired thickness and the consistency of the polymer material being used, molds are often dipped multiple times, sometimes alternating between cold water or another solidifying reagent and the molten polymer vat. Flexible products with complex layers, such as kitchen gloves, may have other layers, such as a fabric layer, applied in between polymer coats. Once the molten plastic has set, the plastic product is ready to be removed from the mold, trimmed, cleaned and finished.

business Leading Plastic Dip Molding Manufacturers

U.S. Plastic Coatings Corporation
Sellersville, PA | 800-398-2520

Precision Dip Coating LLC
Waterbury, CT | 203-805-4564

Carlisle Plastics Company, Inc.
New Carlisle, OH | 888-777-8320

Rubber & Plastic Company
Auburn Hills, MI | 800-482-1842

Plastic Dip Moldings, Inc.
Quakertown, PA | 800-262-2111

View a full list of Plastic Dip Molding Manufacturers

Polyurethane Molding Manufacturers

Polyurethane Molders – American Urethane, Inc.Polyurethane is a material that is valued for its uses in “memory foam” products due to its flexibility and rigidity. Polyurethane is also a valuable material for products such as solid plastic forms, polyurethane rods, urethane wheels, urethane brushings, and urethane sheets. Polyurethane moldings have an excellent reputation for their high performance. Their longevity is greater than that of plastic, and are more impact-resistant than rubber. It also has elastic memory, reduces noise, and is resistant to heat and chemicals. It possesses many of the good qualities of metal, rubber, and plastics, and is capable of forming strong adhesive bonds with most plastics and metals.

Polyurethane molded parts require little to no additional finishing. This process is used by manufacturers to fabricate a wide array of moldings, parts, bowling balls, urethane bumpers, polyurethane belts, conveyor bushings, electrical potting compounds, press tool blocks, and pneumatic seals. Polyurethane products are used extensively in industries such as athletic equipment, engineering, manufacturing, industrial, food processing, automotive, and construction.

business Leading Polyurethane Molding Manufacturers

American Urethane, Inc.
Odenton, MD | 800-394-7883

Unicast Inc.
Easton, PA | 800-275-0818

Argonics, Inc.
Gwinn, MI | 800-991-2746

FallLine Corporation
Reno, NV | 800-325-5463

Weaver Industries, Inc.
HDenver, PA | 717-336-7507

View a full list of Polyurethane Molding Manufacturers

Rotational Molding Manufacturers

Rotationally Molded Inserts and Fittings – Roto Dynamics Inc.Rotational plastic molding is capable of achieving plastic parts with more strength and structural complexity than any other plastic molding processes. Unlike other plastic molding methods, rotational molding produces a relatively low volume of parts in what are typically short runs, due to the amount of time and equipment required for rotational molding. Rotationally molded plastics may not be mass produced like blow molded, dip molded or thermoformed parts, and this process is typically reserved for complex or high-performance parts such as plastic figurines and military-spec rackmount carrying cases.

The rotational molding process is unique among plastic molding techniques. A molten polymer – often polyethylene or polycarbonate – is poured into a closed three dimensional mold; the mold is then placed within a gyroscope-like structure which slowly spins, evenly coating the entire interior of the mold with the polymer to form a hollow shape. This process is not only more effective at creating complex three dimensional structures, but it also creates parts with uniform material consistency and, consequently, very high strength.

business Leading Rotational Molding Manufacturers

Sterling Technologies, Inc.
Lake City, PA | 814-774-2500

Sherman Roto Tank
Pearland, TX | 281-648-0909

Fibertech, Inc.
Elberfield, IN | 800-304-4600

Innovative Rotational Molding
Madera, CA | 559-673-4764

Assmann Corporation of America
Garrett, IN | Marshall, TX | 888-357-3181

View a full list of Rotational Molding Manufacturers

Vacuum Forming

Clamshells – Valk Industries, Inc.Vacuum formed plastics are used as faceplates and semi-flat components in a wide range of industries, particularly in electronic equipment such as fax machines, keyboards, phones and home appliances. Also known as thermoforming, or pressure forming, the vacuum forming process begins with stock plastic sheets rather than polymer resin pellets; these sheets are heated until the polymer reaches a flexible temperature, then they are vacuumed into an open mold, causing the heated sheets to “thermoform” to the exact shape of the die mold beneath. Twin sheet thermoforming is commonly used to create large and precision application parts such as hot tubs and interior wall panels for aerospace, but thermoforming is also a highly cost-effective means of producing three-dimensional plastic packaging. Blister packs, clamshells, plastic covers, plastic trays and other plastic packaging can be produced for low costs at high runs by vacuum forming.

business Leading Vacuum Forming Manufacturers

Valk Industries, Inc
Greeneville, TN | 423-638-1284

Profile Plastics, Inc.
Lake Bluff, IL | 847-604-5100

Conlet Plastics, Inc.
New Milford, CT | 860-354-0885

MARC, Inc.
Grand Hendersonville, NC | 828-595-2995

Engineered Plastic Products, Inc.
Stirling, NJ | 800-304-3774

View a full list of Vacuum Forming Manufacturers

Fiberglass Fabricators

Fiberglass Enclosures – Fiberdome, Inc.In the creation of fiberglass-reinforced plastic products, fiberglass molding is the most frequently used process. Fiberglass is made when molten glass is extruded through very fine openings in a tool. This extrusion process produces threadlike formations in the glass that are later put through heat treatment or pressing and mixed with plastic resin.

Fiberglass molding is used to fabricate a multitude of products such as machinery support products, electric circuit boards, shells of racing cars, and panels. This process is used extensively because fiberglass does not shrink or expand with changes in temperature. Furthermore, it does not absorb water, is resistant to chemicals, has high strength-to-weight ratio, is not flammable, and can function as an insulator from electricity.

business Leading Fiberglass Fabricators Manufacturers

All Plastics and Fiberglass, Inc.
Mobile, AL | 800-226-1134

Fiberdome Inc.
Lake Mills, WI | 800-359-4416

McNichols Company
Tampa, FL | 877-884-4653

Fiber-Tech, Inc.
Franksville, WI | 262-835-1300

Hood Manufacturing Inc.
Santa Ana, CA | 714-979-7681

View a full list of Fiberglass Fabricator Manufacturers