Sajar Plastics Inc: The Remarkable History and Manufacturing Expertise of an Ohio Plastics Pioneer

Sajar Plastics Inc at a GlanceSajar Plastics Inc. is an American plastics manufacturer specializing in large, complex injection-molded components and advanced production technologies. Founded in 1949 in Middlefield, Ohio, the company developed expertise in producing custom plastic parts for original equipment manufacturers (OEMs), including businesses in medical equipment, laboratory systems, manufacturing and retail technology.

The company became particularly recognized for its involvement in gas-assist injection molding, a technique that lets manufacturers produce large plastic components with complex shapes and demanding surface requirements.

Sajar’s history also includes a significant ownership change. In 2017, Universal Plastics acquired the business, bringing its manufacturing capabilities into a wider group offering several plastic-forming technologies.

Today, the Middlefield operation remains identified within Universal Plastics Group’s manufacturing network.

Understanding Sajar requires more than looking at its company history. Its significance lies in how specialized production methods help manufacturers address problems with product dimensions, appearance, material consumption, and assembly.

Sajar Plastics Inc at a Glance

Detail	Information
Company name	Sajar Plastics Inc
Founded	1949
Original location	Middlefield, Ohio, United States
Industry	Plastics manufacturing
Specialisation	Custom injection-moulded plastic components
Main processes	Gas-assist, structural foam and conventional injection moulding
Parent group	Universal Plastics Group
Acquisition year	2017
Primary customers	Original equipment manufacturers
Industries served	Medical, laboratory, diagnostic, industrial and retail equipment
Manufacturing facility	Approximately 150,000 square feet, according to company information
Quality certification	Listed by the parent group as ISO 9001 registered

The History and Development of Sajar Plastics Inc

Early Beginnings in Middlefield, Ohio

The company’s history began in 1949, when its original manufacturing operation was established in Middlefield. According to historical information published by Universal Plastics Group, Sajar initially operated three injection molding machines to produce conventional plastic parts.

Its development reflected a growing industrial need for manufactured plastic components that could replace or complement products made from other materials.

Rather than focusing on consumer retail products under its own brand, Sajar focused on custom manufacturing. This business model involved producing components according to customers’ technical designs, functional requirements and production specifications.

As customer needs grew more complex, the company expanded its equipment, manufacturing space, and processing expertise.

Over time, its Middlefield facility grew into a substantial industrial operation capable of handling larger molded components and more demanding production assignments.

Development of Gas-Assist Injection Molding

A major chapter in Sajar’s history emerged during the early 1980s.

Universal Plastics Group identifies the Middlefield operation as one of three companies involved in the original development of gas-assisted injection molding technology.

This involvement became an important part of the company’s industrial identity.

Traditional injection molding was already widely established, but producing large plastic components with complex internal structures could create difficulties with shrinkage, surface defects, and molding pressure.

Gas-assisted processes offered an alternative approach by introducing controlled gas pressure during molding.

The technology expanded the types of plastic parts manufacturers could produce through injection molding.

According to the parent company’s published historical information, the operation has commercialized more than 500 gas-assisted plastic components. This figure describes its accumulated manufacturing history rather than a current annual production volume.

Three Major Manufacturing Technologies

The Middlefield facility uses three main injection molding processes. Although they share some equipment and principles, they serve different design requirements.

1. Conventional Injection Molding

Conventional injection molding heats a thermoplastic material to a processable state, then injects it into a specially manufactured mould.

The plastic cools and solidifies into the required component shape.

This method works well for repeatable production, especially when precise component geometry and consistent dimensions matter.

However, large sections or significant wall-thickness variations can pose challenges. Engineers must consider how the material flows into the mould, cools, and contracts.

Poor design may lead to surface imperfections, distortion or unnecessary manufacturing costs.

Conventional injection molding remains useful when component geometry, production quantities and tooling economics suit the process.

2. Gas-Assist Injection Molding

Gas-assist injection molding is the technology most closely associated with Sajar’s specialist reputation.

During production, controlled gas pressure is introduced during molding. Depending on the technique, gas can create hollow channels inside thicker sections or apply pressure against a surface while the plastic cools.

Internal gas assistance can reduce the amount of resin required in selected thicker sections while maintaining the intended component geometry.

External gas assistance uses controlled gas pressure to help the plastic reproduce the mould surface more consistently.

These methods can be particularly useful for large handles, equipment covers, cabinet components, and other parts where structural design and visible appearance matter.

Potential advantages include improved dimensional consistency, reduced sink marks, lower material consumption in suitable designs, and the ability to combine several components into one molded part.

However, the benefits are not automatic. Gas-channel design, material selection, tooling and process control all influence the final result.

3. Structural Foam Injection Molding

Structural foam molding offers another manufacturing option for large plastic components.

In this process, a blowing agent creates a cellular structure within the molded material. The resulting component typically has a denser outer region and a foamed interior.

This approach can be useful when a part needs substantial thickness or stiffness without the material consumption of a fully solid section of equivalent dimensions.

Structural foam molding is commonly used for industrial panels, equipment housings, and structural components.

One limitation is surface appearance. The process can produce visible swirls or other cosmetic characteristics that may require finishing.

As a result, it is not necessarily the preferred choice for every customer-facing component.

The most suitable technique depends on the product’s mechanical requirements, visible finish, dimensions, and production economics.

What Products Does Sajar Plastics Manufacture?

Sajar’s manufacturing business focuses on custom components rather than a fixed catalog of mass-market consumer products.

Its capabilities are particularly relevant to manufacturers requiring larger plastic parts with carefully controlled shapes and finishes.

Medical and Laboratory Equipment

Medical and laboratory equipment frequently requires protective housings, equipment panels and externally visible components.

For example, a diagnostic machine may need an enclosure that accommodates internal electronics, supports, ventilation openings, and access panels.

The plastic parts must fit the overall equipment design while remaining practical to manufacture and assemble.

The manufacturer’s experience with large custom components makes this sector a natural application for its documented processes.

Any application-specific requirements, including cleaning compatibility, biocompatibility or regulatory obligations, would still need separate verification.

Retail and Transaction Equipment

Self-service kiosks, dispensing machines, and transaction equipment often incorporate molded housings, doors, handles, and bezels.

These components may need to accommodate display screens, payment equipment, service access points and internal structures.

A consistent external finish can also matter because customers interact directly with the equipment.

Gas-assisted injection molding may offer useful design options for selected parts that combine demanding appearance requirements with substantial dimensions.

Industrial Machinery

Manufacturing equipment can require plastic covers, control enclosures, machinery panels and protective housings.

In suitable applications, molded plastic can offer advantages in product integration, component weight, and design flexibility.

For example, an enclosure might incorporate mounting features that would otherwise need separate attachment operations.

Whether plastic is appropriate depends on operating temperatures, mechanical loads, chemical exposure, and other conditions.

Material selection and engineering validation remain essential.

Why Sajar’s Manufacturing Approach Matters

One major challenge in custom manufacturing is selecting the right process before investing heavily in tooling.

Two parts that look similar may require very different production methods because of their intended quantities, structural loads, surface finishes, or assembly requirements.

Consider a large equipment enclosure.

A conventional injection-molded version might offer detailed integrated features, while a structural foam version might provide a practical alternative for a thick industrial component.

Gas-assisted molding could offer another approach when hollow sections or improved surface control are needed.

Alternatively, thermoforming may be worth considering for certain large covers, especially when lower tooling investment matters more than integrating intricate molded features.

The best manufacturing method isn’t necessarily the most technically advanced. It is the method that meets the project’s requirements at a defensible total cost.

That distinction matters to product designers, purchasing managers and businesses developing new industrial equipment.

Acquisition by Universal Plastics in 2017

In June 2017, Sajar Plastics was acquired by Universal Plastics, a Massachusetts-based plastics manufacturing business.

The acquisition expanded the group’s capabilities into specialist large-part injection molding.

Before this expansion, Universal Plastics was best known for heavy-gauge thermoforming.

Adding Sajar allowed the wider organization to take on projects that require different manufacturing techniques.

For example, a customer might initially manufacture a product through thermoforming, but a later redesign or production increase could make injection molding worth evaluating.

Having different processes available within a wider manufacturing group can support such discussions.

The acquisition announcement also said Sajar would retain its manufacturing facilities, employees, and established procedures.

Today, Universal Plastics Group continues to identify Sajar as its Middlefield-based specialist in large, complex injection-molded parts.

It is important to distinguish the Ohio operation from the wider group’s other facilities. Thermoforming and blow-molding capabilities available elsewhere in the group should not automatically be described as machinery installed at the Sajar plant.

Manufacturing Capacity and Technical Capabilities

Published information from Universal Plastics describes the Middlefield manufacturing operation as having approximately 150,000 square feet of facility space.

The company also identifies injection molding presses with clamping forces ranging from approximately 85 to 1,500 tons.

These specifications illustrate the breadth of projects the facility is designed to accommodate.

For gas-assist and structural foam applications, the manufacturer’s technical material lists potential component dimensions up to approximately 80 inches in length and 70 inches in width.

These figures should be understood as published capability information rather than a guarantee that every material, geometry or production program can use the maximum dimensions.

In-house painting, secondary operations and assembly are also identified among the facility’s available services.

These capabilities can be valuable when a customer needs more than an unfinished molded part.

For example, a finished enclosure might require surface treatment, printed markings, joining operations and packaging before delivery.

Combining these stages under one supplier can simplify coordination, but buyers should confirm which operations they handle internally for their project.

Quality Standards and Production Considerations

Manufacturing quality involves more than producing a part with the correct outward appearance.

Components must satisfy the agreed requirements for dimensions, materials, fit, finish, and function.

Universal Plastics Group identifies Sajar as ISO 9001 registered, indicating a documented quality-management framework.

Nevertheless, buyers should request a current certificate and confirm its scope, issuing body, and expiration or validity details.

A quality-management certification does not automatically establish that a component meets every industry-specific technical or regulatory requirement.

Customers commissioning custom plastic parts should also establish how the manufacturer handles design changes, material traceability, inspection results, and nonconforming components.

For equipment with demanding dimensions, the inspection approach can be as important as the molding technique itself.

What Businesses Should Check Before Choosing a Plastics Manufacturer

Companies considering a manufacturing partnership should begin by defining what they need from the finished product.

A supplier’s reputation or equipment list provides only part of the picture.

The following questions help make the selection process more useful.

Evaluation area	What the buyer should confirm
Component dimensions	Whether the proposed part fits the available machinery and tooling limits
Material requirements	Suitability for heat, chemicals, strength, appearance and intended use
Surface finish	Whether painting, texturing or other finishing processes are necessary
Production quantity	Expected annual demand, batch sizes and capacity
Tooling	Design responsibility, ownership, maintenance and replacement arrangements
Quality control	Inspection methods, tolerances and documentation
Commercial terms	Tooling charges, unit costs, delivery arrangements and payment terms
Project changes	Procedures for engineering revisions and design approvals

An effective quotation should cover the full manufacturing program rather than just the price of each plastic part.

Tooling, assembly, transportation, inspection and future design changes can all affect the final cost.

This becomes especially relevant when a product is expected to remain in production for several years.

Challenges and Limitations of Custom Injection Molding

Although advanced molding technologies offer valuable possibilities, they also have limitations.

Injection mould tooling can require substantial initial investment. Complex components may require specialized equipment, careful processing, and several rounds of engineering review.

Gas-assisted designs add considerations for gas channels, resin behavior, and mould construction.

Structural foam components may need additional finishing when surface appearance is critical.

Material performance also varies. Not every thermoplastic offers suitable resistance to temperature, impact, chemicals or outdoor exposure.

Production quantity also influences the economics of each process.

A design that makes financial sense at one annual volume may not be the most economical choice at another.

Businesses should therefore compare manufacturing alternatives using actual project specifications and supplier quotations, not general claims that one technique is always cheaper or better.

Is Sajar Plastics Inc Still Operating?

Current corporate information continues to identify Sajar Plastics within the Universal Plastics Group manufacturing network.

The group describes the Middlefield site as an injection molding facility serving medical, laboratory, industrial, and retail-equipment customers.

An Ohio Environmental Protection Agency industrial permit listing, published in October 2026, also identifies Universal Plastics–Sajar Molding Services Inc. at 15285 South State Street, Middlefield, Ohio.

This is useful evidence of the facility’s continuing presence in public industrial records.

However, a permit listing alone does not establish daily production levels, employment numbers, financial performance, or available machine capacity.

For the most accurate information about a current manufacturing project, customers should verify operating details directly with Universal Plastics.

Conclusion

Sajar Plastics Inc. has a manufacturing history dating back to 1949 and played an important role in developing gas-assisted injection molding.

Its experience producing large, complex plastic components makes it relevant to original equipment manufacturers in the medical, laboratory, retail, and industrial markets.

The 2017 acquisition by Universal Plastics connected the Middlefield operation with a wider manufacturing group offering additional processing capabilities.

For potential customers, Sajar’s practical value lies in its documented technological specialization, large-part manufacturing experience, and ability to support projects with demanding component geometry.

Choosing the right manufacturing partner still requires a clear understanding of material performance, tooling, production quantities, quality requirements and commercial terms.

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FAQs

1. What is Sajar Plastics Inc?

Sajar Plastics Inc. is an American custom plastics manufacturer that has historically been based in Middlefield, Ohio. It specializes in large injection-molded components, including parts made using gas-assist and structural foam processes.

2. When was Sajar Plastics founded?

The company was founded in 1949. Its early operations used conventional injection molding equipment before it expanded into more specialized manufacturing technologies.

3. Who owns Sajar Plastics today?

Sajar Plastics was acquired by Universal Plastics in 2017 and is identified within Universal Plastics Group’s manufacturing operations.

4. Where is the Sajar Plastics manufacturing facility?

The facility is located in Middlefield, Ohio, United States. Public industrial records identify the operation at 15285 South State Street, Middlefield, OH 44062.

5. What is Sajar Plastics best known for?

Sajar is particularly known for its early involvement in gas-assisted injection molding and its experience manufacturing large, complex plastic components for original equipment manufacturers.