How to Select Plastic Molding Services

Image Credit: Ohio Precision Molding, Inc. | STACI | Inudstrial Molding Corporation

Plastic molding services are companies which have the capability to produce custom plastic parts on either a small or large scale using various molding processes. Services with low-volume production runs typically have run times of less than one week, while high-volume production runs require more time.

Molding Techniques

Plastic molding services use a number of different molding techniques to produce thermoplastic and thermoset components.

• Plastic injection molding is the most widely used of all plastic processing methods. It offers the lowest piece prices available, the but tooling costs are generally higher than other methods.
• Blow molding (includes injection blow molding) is similar to injection molding, used typically to create jars, bottles, containers, and other similar products.
• Rotational molding services usually have low tooling costs and high piece prices, with cycle times averaging around 40-45 minutes.
• Thermoforming services, either vacuum or pressure, usually have low tooling costs and piece prices which vary depending on machinery.
• Structural foam molding is used for parts that require thicker walls than standard injection molding.
• Compression molding provides services at both moderate tooling and part prices.
• Resin transfer molding (RTM) is a liquid molding process commonly used for the aerospace and automotive industries.

Additional Services

Additional services offered by plastic molding companies include assembly operations, machining, micro-molding, mold prototyping, and two-shot injection.

• Assembly operations include ultrasonic and heat welding, printing, painting, bonding, and machining operations.
• Machining involves the removal of material through milling, drilling, turning, or other processes.
• Micro-molding services use special, miniaturized molding machines to produce very small parts that typically weigh less than two grams.
• Mold prototyping involves the creation of plastic prototypes to investigate true manufacturing costs or develop design ideas and plans.
• Two-shot injection molding services produce parts from two different raw materials or colors in a single operation.

Materials

In terms of material capabilities, plastic molding services address considerations such as impact strength, high and low temperature characteristics, warping, and resistance to ultraviolet (UV) light. Commodity grade resins are more widely used than other graded resins and include polyethylene, polypropylene, polystyrene and polyvinyl chloride (PVC). Engineering grade resins are more difficult to process than other graded resins, but have characteristics that make them desirable for specialized use. Widely used engineering grade thermoplastics include acetal, acrylonitrile butadiene styrene (ABS), nylon, noryl and polycarbonate.

Certifications

Plastic molding services are located across the United States and around the world. Some services are designated to meet various certification and quality requirements to ensure certain standards are met. These include ISO 9001:2000, ISO 14001, and QS-9000.

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