California remains one of the largest and most diverse manufacturing markets in the United States, with plastic injection molding companies supporting industries ranging from medical devices and aerospace to electronics, automotive, defense, consumer products, packaging, and industrial equipment.
For OEMs and purchasing professionals searching for the top rated plastic injection molding companies in California in 2026, choosing a supplier involves much more than comparing molding prices. Certifications, engineering capabilities, tooling support, cleanroom manufacturing, material expertise, production capacity, secondary operations, quality systems, and industry experience can all influence the success of a manufacturing program.
This guide compares 10 established injection molding manufacturers with operations in California. The companies are not presented as an independently audited numerical ranking. Instead, they represent notable California injection molding resources that buyers may consider based on publicly available capabilities, certifications, experience, and manufacturing services.
10 Plastic Injection Molding Companies in California to Consider in 2026
| Company | California Location | Years / Founded* | Employees* | Key Certifications / Registrations* | Manufacturing Highlights |
|---|---|---|---|---|---|
| Hi-Rel Plastics & Molding Corp | Riverside | 40+ years / 1985 | Approx. 50–99 | ISO 9001:2015, ISO 13485:2016, AS9100D | Injection molding, LSR, cleanroom manufacturing, tooling, engineering, secondary operations, assembly |
| JG Plastics Group | Costa Mesa | Since 1975 | Not publicly disclosed | ISO 9001:2015, ISO 13485:2016, AS9100D, ITAR | Precision molding, thermoplastic and thermoset molding, mold making, cleanroom molding, assembly |
| Westec Plastics | Livermore | Since 1969 | 51–200 publicly listed range | ISO 13485:2016 | Precision molding, two-shot molding, tooling, insert molding, overmolding, cleanroom manufacturing |
| JATCO Incorporated | Modesto | Since 1976 | Public estimates vary | ISO 9001:2015 / ANAB-accredited certification | Injection molding, engineering, tooling, assembly, decorating, packaging, warehousing |
| Plastikon Industries | Hayward | 40+ years | 1,000+ company-wide range reported by industry directories | ISO 9001 / ISO 13485 at applicable facilities | Injection molding, tooling, product development, automation, healthcare manufacturing |
| Distinctive Plastics | Vista | 40+ years | Not publicly disclosed | ISO 9001:2015, ISO 13485:2016; FDA registered, UL listed | Multi-shot molding, insert molding, in-mold decoration, cleanroom manufacturing, assembly |
| Aprios Custom MFG | Vista | Established manufacturer | Not publicly disclosed | ISO 9001:2015, ISO 13485:2016 | Precision molding, DFM, tooling, medical manufacturing, ISO Class 8 cleanroom |
| Canyon Graphics | San Diego | Since 1981 | Not publicly disclosed | ISO 9001 | Injection molding, multi-shot overmolding, insert molding, IMD, printing, thermoforming |
| Fabricated | Stanislaus | Established | Not publicly | Verify | Injection molding, large-part |
| Extrusion Company / FABEXCO | County | manufacturer | disclosed | certification requirements directly | molding, engineered resins, automation, extrusion, tooling, engineering |
| Universal Plastic Mold | Baldwin Park | 64 years / 1962 | Not publicly disclosed | ISO 9001 | Injection molding, large-part molding, engineered resins, assembly, packaging |
*Company size, certifications, locations, and years in business are based on publicly available manufacturer information and industry directory data available in 2026. Employee counts for privately held companies are generally estimates or published ranges and may change. Buyers should verify certifications and capabilities directly before supplier qualification.
1. Hi-Rel Plastics & Molding Corp. — Riverside, California
Hi-Rel Plastics & Molding Corp. is a Southern California custom plastics manufacturer offering a broad range of molding, engineering, tooling, assembly, and contract manufacturing capabilities.
Established in approximately 1985, Hi-Rel brings 40+ years of plastics manufacturing experience and supports customers throughout California and across the United States. Industry directory information estimates approximately 50–99 employees at its Riverside operation.
One of Hi-Rel’s major differentiators is its combination of quality certifications. The company supports programs under ISO 9001:2015, ISO 13485:2016, and AS9100 Rev D, positioning it to serve demanding medical, aerospace, defense, electronics, automotive, and other quality-critical markets.
Key capabilities
- Custom plastic injection molding
- Precision and tight-tolerance molding
- Liquid Silicone Rubber (LSR) molding
- Insert molding and overmolding
- Cleanroom injection molding and assembly
- Engineering and DFM support
- Mold design and manufacturing
- Mold flow analysis
- Prototype through high-volume production
- Secondary operations and decorating
- Product assembly and contract manufacturing
- Engineering-grade and high-performance resin processing
- Packaging and turnkey manufacturing support
Hi-Rel works with commodity, engineering and high-performance thermoplastics including materials such as PEEK, PEI/ULTEM, PPS, PPSU, PES, PVDF, LCP, PBT, polycarbonate, ABS, acetal, nylon, glass-filled nylon, TPU, TPE, PP, HDPE and other specialty materials. Industry listings also identify capabilities for tight-tolerance components and a broad range of secondary manufacturing operations.
Industries served
Hi-Rel’s capabilities make it particularly relevant to OEMs operating in:
Medical devices • Aerospace • Defense • Automotive • EV • Electronics • Communications • Industrial equipment • Consumer products • Cosmetics & personal care • Construction • Agriculture
This combination of three major quality certifications, broad material knowledge, multiple plastics manufacturing processes, cleanroom capabilities and turnkey manufacturing support makes Hi-Rel a strong candidate for companies seeking a California injection molding partner rather than simply a molding job shop.
2. JG Plastics Group — Costa Mesa, California
JG Plastics Group has provided plastic manufacturing solutions since 1975 and serves medical, aerospace, defense, electronic/connector and consumer markets.
JG maintains an especially strong certification portfolio with ISO 9001:2015, ISO 13485:2016 and AS9100D, along with ITAR registration. Its capabilities include thermoplastic and thermoset molding, precision mold making, insert molding, overmolding, medical mesh overmolding, assembly and secondary operations.
The company also operates ISO Class 7 cleanroom environments for medical injection molding, assembly and packaging.
Best suited for: medical, aerospace, defense and other highly engineered precision components.
3. Westec Plastics — Livermore, California
Westec Plastics was founded in 1969 and operates from Livermore in the San Francisco Bay Area. The company specializes in high-precision custom injection molding, particularly for medical and biotech applications.
Its manufacturing capabilities include 23 injection molding machines ranging from approximately 28 to 610 tons, two-shot molding, insert molding, overmolding, tooling, cleanroom manufacturing, secondary operations, advanced metrology and CMM inspection.
Westec is ISO 13485:2016 certified and has more than 50 years of injection molding experience. Public company profiles place its employee range at approximately 51–200 employees.
Best suited for: medical devices, biotech, electronics and precision components requiring strong tooling and process-control capabilities.
4. JATCO Incorporated — Modesto, California
JATCO Incorporated has manufactured injection molded plastic components since 1976 and operates a major California facility in Modesto.
JATCO offers a broad one-stop manufacturing model covering product design, engineering, tooling, injection molding, secondary operations, assembly, packaging, warehousing and distribution.
The company reports more than 50 injection molding machines, including two-component molding capability, and significant production and warehouse capacity.
JATCO identifies itself as an ISO 9001:2015 registered company and highlights ANAB-accredited certification.
Best suited for: OEMs seeking molding plus large-scale assembly, packaging, warehousing and distribution support.
5. Plastikon Industries — Hayward, California
Plastikon Industries is a global manufacturing organization headquartered in Hayward, California, with more than 40 years of manufacturing experience.
The company provides plastic injection molding, injection mold design and tooling, prototyping, engineering, automation and specialized healthcare and pharmaceutical manufacturing capabilities.
Public industry databases categorize Plastikon as a significantly larger organization than many regional California molders, with a company-wide employee range reported in the 1,000+ category, although the number associated specifically with California operations should be verified directly.
Best suited for: large OEM and healthcare programs requiring global manufacturing resources and extensive automation.
6. Distinctive Plastics — Vista, California
Distinctive Plastics is a specialized Southern California injection molder based in Vista.
The company has approximately 40 years of experience and specializes in technical molding processes such as multi-shot molding, in-mold assembly, in-mold decorating, in-mold labeling, insert molding and medical manufacturing.
Distinctive Plastics identifies itself as ISO 9001:2015 and ISO 13485:2016 certified, FDA registered and UL listed.
Best suited for: technically complex multi-material components, medical devices and products requiring advanced decoration or multi-shot processes.
7. Aprios Custom MFG — Vista, California
Aprios Custom MFG operates a California manufacturing location in Vista and provides precision injection molding, tooling, DFM and contract manufacturing services.
Its California facility is listed as ISO 9001:2015 and ISO 13485:2016 certified.
In 2025, Aprios announced additional ISO Class 8 cleanroom injection molding capacity in Vista using electric molding presses, expanding its ability to support medical-device manufacturing programs.
Best suited for: medical-device programs, product development, tooling and precision molding.
8. Canyon Graphics — San Diego, California
Canyon Graphics was founded in 1981 in San Diego and has developed a distinctive combination of injection molding and product-decoration technologies.
Capabilities include single-shot molding, insert molding, multi-shot overmolding, film insert molding, automated part handling, printing, thermoforming, precision cutting and lamination.
Canyon Graphics reports ISO 9001 certification and has particularly strong expertise in In-Mold Decoration (IMD).
Best suited for: consumer, electronics and specialty components requiring molding combined with sophisticated graphics or decoration.
9. Fabricated Extrusion Company / FABEXCO — Modesto, California
FABEXCO operates manufacturing facilities including a location in Modesto, California and combines injection molding with extrusion, engineering and tooling capabilities.
Its injection molding operations include 400-to-660-ton presses, multi-cavity molding, automated molding, robotics, large-part molding and processing of commodity, engineering, recycled and biodegradable polymers.
FABEXCO’s broader manufacturing capabilities also include profile extrusion, sheet extrusion, engineering, prototyping, material selection, die development, finishing and packaging.
Best suited for: larger molded components, industrial applications and customers needing both injection molding and extrusion capabilities.
10. Universal Plastic Mold — Baldwin Park, California
Universal Plastic Mold (UPM) was founded in 1962 in Baldwin Park, California and has grown into a large-scale custom injection molding manufacturer with extensive high-tonnage production capabilities.
Capabilities include custom injection molding, large-part molding, gas-assist and water-assist molding, engineering and DFM support, tooling, assembly, finishing, kitting, packaging and distribution. UPM operates injection molding presses ranging from approximately 150 to 2,000 tons.
UPM reports ISO 9001:2015 certification and IATF 16949 compliance, with particular strength in large-part and high-volume injection molding.
Best suited for: automotive, consumer, industrial and other applications requiring large components, high-tonnage molding or high-volume production.
California Injection Molding Company Comparison
The right injection molding company depends heavily on the application.
For a medical device, ISO 13485 certification and cleanroom capabilities may be critical. Aerospace and defense customers may prioritize AS9100 certification, traceability and tight-tolerance manufacturing. Consumer-product companies may place greater emphasis on high-volume automation, decoration and cost efficiency.
A useful supplier comparison should therefore examine more than company size.
| Selection Factor | Why It Matters |
|---|---|
| ISO 9001 | Demonstrates a structured quality management system |
| ISO 13485 | Particularly important for medical-device manufacturing |
| AS9100 | Important for aerospace and defense supply chains |
| Cleanroom Manufacturing | Supports contamination-sensitive medical, pharmaceutical and electronics applications |
| Engineering & DFM | Helps identify manufacturing problems before tooling is built |
| Mold Flow Analysis | Can help optimize filling, cooling, gate locations and potential molding risks |
| In-House / Managed Tooling | Simplifies mold development, modification and maintenance |
| Engineering-Grade Resin Experience | Important for demanding thermal, chemical and structural applications |
| Secondary Operations | Reduces the number of outside suppliers required |
| Assembly | Allows the molder to deliver higher-level finished products |
| Multiple Molding Technologies | Provides more manufacturing options as product requirements evolve |
| Prototype-to-Production Support | Allows one supplier to support a program throughout its lifecycle |
Why Hi-Rel Plastics & Molding Is a Strong Candidate in 2026
California has many capable injection molding companies, and no single manufacturer is the best choice for every application.
However, Hi-Rel Plastics & Molding Corp. offers an unusually broad combination of capabilities for OEMs looking for a turnkey California plastics manufacturing partner.
1. Three Major Quality Certifications
Hi-Rel operates under:
ISO 9001:2015
ISO 13485:2016
AS9100 Rev D
That combination allows one manufacturing organization to support quality-sensitive programs across medical, aerospace, defense and general industrial markets.
2. More Than Injection Molding
A major advantage is the ability to support customers beyond conventional thermoplastic injection molding.
Hi-Rel’s broader plastics manufacturing capabilities include injection molding, LSR molding, blow molding, thermoforming/vacuum forming, rotational molding, mold manufacturing, prototyping, secondary operations and assembly.
For OEMs with multiple plastic components or manufacturing processes, consolidating work with a broader supplier can simplify purchasing, engineering communication and supply-chain management.
3. Engineering-Grade Material Experience
Not every injection molding project uses ABS or polypropylene.
Hi-Rel supports advanced engineering and high-performance materials used for demanding applications, including PEEK, ULTEM/PEI, PPS, PPSU, PES, PVDF, LCP, PBT, glass-filled nylon, polycarbonate and other specialty thermoplastics.
This can be particularly valuable for medical, aerospace, defense, electronics and industrial applications requiring elevated temperature resistance, strength, dimensional stability or chemical resistance.
4. Medical and Cleanroom Manufacturing
Medical manufacturing requires more than an injection molding machine.
Hi-Rel combines ISO 13485 certification with cleanroom injection molding and assembly capabilities, allowing the company to support medical devices, diagnostics, laboratory products and other contamination-sensitive components.
5. Aerospace and Defense Capabilities
AS9100D certification gives Hi-Rel another important differentiator when compared with California molders focused primarily on general commercial applications.
This makes the company a potential manufacturing partner for aerospace, defense and other programs requiring rigorous documentation, quality management and process control.
6. Tooling Through Finished Assembly
Hi-Rel can support projects through multiple stages of development:
Concept → DFM → Mold Flow Analysis → Prototype → Mold Manufacturing → Injection Molding → Inspection → Secondary Operations → Assembly → Packaging → Production
For purchasing managers, this type of vertically integrated manufacturing approach can reduce the administrative burden associated with managing separate engineering, tooling, molding and assembly suppliers.
Which California Injection Molding Company Is Right for Your Project?
Rather than simply searching for the “largest injection molding company in California” or the “cheapest injection molding company near me,” OEMs should evaluate suppliers according to the actual requirements of the program.
Before requesting a quote, consider providing potential manufacturers with:
- 3D CAD files
- 2D drawings and tolerances
- Expected annual quantities
- Target material or performance requirements
- Part weight and dimensions
- Cosmetic requirements
- Existing tooling information
- Required certifications
- Cleanroom requirements
- Assembly requirements
- Packaging specifications
- Expected production life
- Target production date
Providing this information allows injection molders to evaluate tooling, machine requirements, materials, cycle time, automation and secondary operations more accurately.
Looking for a Plastic Injection Molding Company in California?
If your company is evaluating plastic injection molding companies in California, Hi-Rel Plastics & Molding Corp. can review your project from initial design through production.
With 40+ years of plastics manufacturing experience, a Riverside, California manufacturing operation, and ISO 9001:2015, ISO 13485:2016 and AS9100 Rev D certifications, Hi-Rel supports customers in Southern California, Northern California and throughout the United States.
Whether your project requires a simple injection molded component or a complete turnkey manufacturing program involving engineering, mold manufacturing, injection molding, LSR molding, cleanroom manufacturing, secondary operations, assembly and packaging, Hi-Rel can evaluate the requirements and develop a manufacturing solution.
Request a Quote from Hi-Rel Plastics & Molding Corp.
Frequently Asked Questions
What are some top rated plastic injection molding companies in California in 2026?
California has numerous established injection molders, including Hi-Rel Plastics & Molding, JG Plastics, Westec Plastics, JATCO, Plastikon Industries, Seaway Plastics Engineering, Distinctive Plastics, Aprios, Canyon Graphics and FABEXCO. The best supplier depends on the project’s material, volume, certifications, tooling, tolerance and secondary-operation requirements.
What should I look for when selecting an injection molding company?
Important considerations include quality certifications, years of experience, engineering support, tooling capabilities, available press sizes, material expertise, cleanroom availability, inspection technology, production capacity, secondary operations, assembly capabilities and experience within your industry.
Which certifications are important for plastic injection molding?
ISO 9001 is widely used for quality-management systems. Medical-device manufacturers frequently look for ISO 13485-certified suppliers, while aerospace and defense customers commonly seek manufacturers operating under AS9100 quality systems.
Are there ISO 13485 injection molding companies in California?
Yes. Several California manufacturers support medical injection molding under ISO 13485 quality systems, including Hi-Rel Plastics & Molding, JG Plastics, Westec Plastics, Distinctive Plastics, Aprios and other specialized medical manufacturers.
Are there AS9100-certified injection molding companies in California?
Yes. Hi-Rel Plastics & Molding and JG Plastics are examples of California injection molding manufacturers that publicly identify AS9100D certification among their quality credentials.
Does Hi-Rel Plastics & Molding offer more than injection molding?
Yes. Hi-Rel provides a broader range of plastics manufacturing and contract manufacturing services, allowing customers to consolidate engineering, tooling, molding, secondary operations and assembly requirements with a single manufacturing partner.
Where is Hi-Rel Plastics & Molding located?
Hi-Rel Plastics & Molding is located in Riverside, California, serving OEMs throughout Southern California, Northern California and across the United States. Industry directories identify the company as an established Southern California custom plastics manufacturer dating to approximately 1985.