Plastic Injection Molding
Plastic injection molding is an established process melting plastic resin pellets under heat and pressure and injecting it into a precision, hardened-steel tool. Controlled cooling circuits in the tool cool and solidify the molten plastic, where it assumes the shape of the component part designed into the tool. Fielding operates standard hydraulic injection molding presses from 35 to 200 tons to produce high volumes of precision net-shape parts. We process a wide array of plastic resins and offer secondary operations to provide high quality, functional molded plastic parts to meet a variety of applications.
Complex Geometries
Our background in tool and mold-making allows us to design tooling for complex, high performing geometries while still ensuring manufacturability and tool serviceability.
Secondary Operations
We can simplify supply chains with secondary operations on molded parts including ultrasonic welding, hot stamping, pad printing, assembling, kitting, and more. Purchase entire assemblies, not just sub-component parts.
Tight Tolerance
With our experience in precision tooling, we can hold plastic molded part dimensions within +/-.005" tolerance for most resins. We offer high dimensionally stable resin grades to achieve +/-.002" or better on critical features.
Affordability
Where appropriate, we can regrind and re-process runner scrap to reduce overall cost. With experience in tool design and build, molding processing and in-house secondary operations, we can optimize tooling and process to provide the most cost-effective solution.
Variety of Resins
We run a large variety of resins to fit different applications. We mold in all colors, with or without performance additives & fillers, with or without regrind (depending on the application).
Tool Longevity
We have developed an in-house tool preventative maintenance program at no extra cost to extend the lifetime of tooling. We regularly takeover molds that other molders did not properly care for.
Resins Molded
Fielding molds a large variety of standard and engineering grade resins. We work with expert material suppliers and can add performance additives to a base resin such as flame retardants for UL rated products, UV stabilizers for outdoor use, glass fillers for enhance mechanical performance, lubricity additives for bearing surfaces, and more. Almost all resins can be pre-colored by our suppliers or colored in-house using custom color concentrates. We can help spec top performing grades best-suited for any application. Not sure what is best? We can sample different grades at the start of a program to determine the most-suitable material for your application.
Polyamide (PA aka Nylon)
Polyamide (PA) is more commonly referred to by the brand name Nylon. These come in a wide variety of grades with high strength, temperature tolerance and good chemical resistance. Glass fillings (ie. fibers), flame retardant and UV resistance additives can be easily incorporated to improve performance. PA's are often colored black for housings, engineering components, automotive parts, and more. They can form thin-walled features with excellent strength and engineering properties for structural and functional components.
ABS
ABS is a relatively inexpensive resin with high toughness, impact and chemical resistance. It can be prone to visible knit line, sinks ands voids so it is not recommended for cosmetic applications. It is used for a wide variety of consumer and industrial products.
Polymethyl Methacrylate (PMMA aka Acrylic)
Acrylic is a clear resin with good optical properties, high gloss and scratch resistance. Molded acrylic can be too brittle for certain application; PC is a good substitute. Acrylic is typically found in lenses & covers, clear/optical housings, light pipes, decorative pieces and bulletproof glass (typically blended with PC).
Polyvinyl Chloride (PVC)
PVC is the third-most widely produced polymer. It comes in rigid and flexible forms, typically with plasticizer, UV stabilizer, flame retardant and heat stabilizer additives. It can transparent to opaque, clear to colored. It is most commonly used for extruded pipes, tubing, bottles/containers, packaging, textiles. Injection molded PVC parts may be used in medical, consumer, architectural, recreational, electrical applications.
Thermoplastic Polyurethane (TPU)
TPU's are technically a class of thermoplastic elastomers (TPE's) but are typically more rigid to resemble traditional polyurethanes. They are abrasion resistant with high shear strength. TPU's are also resistant to grease and oil. They are used in many applications including automotive panels, footwear, recreational gear, caster wheel, medical and industrial devices.
Polyphenylene Sulfide (PPS)
Polyethylene (PE)
PE is the most commonly produced plastic. This semi-crystalline polymer has a wide range of grades, with low-density (LDPE) grades being "softer" and more flexible/elastic than high-density (HDPE) grades which are generally stronger and stiffer. Compared to other resin types, PE is tough with excellent chemical resistance and good electrical insulation. Due to its semi-crystalline properties, it can easily undergo plastic welding (ie. ultrasonic or heat) to create high-strength joints. As an inexpensive, readily available and decent-performing material for most applications, it is frequently colored and used in consumer products, containers, toys, packaging, tubing.
Polystyrene (PS)
PS is an inexpensive, widely-available plastic that is typically colored for cosmetic applications. Although it is a good electrical insulator, it has poor chemical and UV resistance. It is susceptible to elevated temperatures and should not be used in heat applications. It is commonly used in toys, containers, spacers and household plastic consumer items.
Polycarbonate (PC)
Often referred to as Lexan, which is only a sub-brand of polycarbonate, PC is a strong, impact resistant polymer with good dimensional stability and heat resistance; similar to acrylic but stronger with improved thermal stability. Like acrylic it is optically clear (if not colored) but can easily scratch. To address this, PC can readily be finished with a hard coating. It is found in optical lenses, light pipes, medical and electrical components and bulletproof glass.
Thermoplastic Elastomer (TPE)
TPE's are a broad category of highly elastic, resilient materials that can easily be molded compared to traditional thermoset elastomers. They most closely resembles rubber and are commonly referred to as thermoplastic rubbers (TPR). Grades come with low to high durometers with varying mechanical and engineering properties; all TPE's are characterized by elongation (stretching) under moderate stress with a return to the original shape when the stress is removed. They are commonly used to replace rubber parts, gaskets, seals, and comfort/grip surface or items (ie. handles).
Liquid Crystal Polymer (LCP)
LCP behaves more like a liquid than traditional polymer melt when processing. It has good chemical resistance and is rated for high temperature applications with very low thermal expansion, leading to superior dimensional stability. Due to its high cost, it is primarily used in high end military, aerospace, electrical applications.
Polyphenylene Oxide (PPO)
PPS and PPO are not commonly-used resins as they are more expensive and difficult to process. They offer good dimensional stability with high heat resistance and high impact strength. PPS is known for very good chemical resistance, even at elevated temperatures. They are typically used for structural parts, sterilizable instruments, electronics, automotive components, intakes/pumps/valves and housings that see high heat during regular use.
Polypropylene (PP)
The second-most widely produced plastic, PP is a semi-crystalline polymer available as either a homopolymer (stiffer and stronger) or copolymer (softer with higher impact resistance). PP is inexpensive, flexible, and has good chemical resistance. It has poor UV resistance which is often overcome with performance additives. Due to its performance and availability, PP is found in most consumer products including bottles and packaging.
Polybutylene Terephthalate (PBT)
PBT is a dimensionally stable resin with low creep. Unfilled, it is tough and flexible with moderate to high strength. It is commonly glass-filled to increase strength, but may become prone to warpage. PBT has poor chemical resistance, making Nylon a suitable alternative. PBT is typically found in electrical components, know, gears, cams and other high strength applications.
Acetal (POM aka Delrin)
Polyoxymethylene (POM) is more commonly known as Acetal or the brand name Delrin. It is a strong, tough and hard material with low creep. It has a naturally slippery surface and is used often in gears, impeller, bearing surfaces. It has good dimensional stability and can be easily machined after molding.
Thermoplastic Vulcanizate (TPV)
Part of the thermoplastic elastomer (TPE) family, TPV's most closely match the peroperties of EPDM thermoset rubbers. A common trade name TPV is Santoprene by Celanese. It is mainly used as a replacement for rubber components; seals, grommets, insulation, vibration dampeners, rollers, membranes.
Polyetherimide (PEI or Ultem)
PEI, commonly referred to by the brand Ultem, is a very expensive, but high performance resin. It has good thermal stability, excellent strength, good chemical resistance, dimensional stability and is naturally flame retardant. It is typically used in high end applications including medical, electronics/sensoring, chemical and fluid handling devices, aerospace, military.
Not sure where to start or don't see the resin you had in mind? CONTACT US to select the best material for your application. We've processed most resins over the years and can work with our experienced suppliers to give you the best recommendations. We can even send samples of most materials for you to further evaluate.
Machine Capabilities
Fielding Manufacturing operates standard horizontal hydraulic injection molding machines ranging from 35 to 200 tons with shot sizes from 1 to 35 oz. Our machines are equipped with PLC controllers, advanced process monitoring, individual zone barrel heaters, toggle-style clamping mechanisms, core pulls, robot pickers, vacuum resin loaders, and more. We have a plant-wide water cooling system or individual thermalators at each press to precisely control the mold circuit temperatures. Sprue and hot runner controllers allow us to run molds with hot runner circuits for fast cycles, tight dimensional repeatability, and minimal process material scrap. Depending on the resin, desiccant dryers are used to dry all resin to the proper moisture content prior to molding.
