Compression Molding at Onit:

Compression molding is an affordable, high-volume method for producing rubber and silicone parts with medium complexity. From O-rings and seals in consumer products and machinery, to rubber boots, shoe soles, and more, this process excels at forming flexible, durable components. Also referred to as vulcanization, compression molding works by heating and compressing thermoset materials until they cure, creating the final parts.

What sets compression molding apart? Simple tooling and shorter build times compared to injection molding mean you can scale production faster and at a lower upfront cost. Many of our clients invest in multicavity tools to further boost productivity and reduce part costs.

How the Compression Molding Process Works

1. Material Placement
   A measured “slug” of rubber, silicone, or other thermoset material is placed into a heated mold.
2. Mold Closure & Compression
   The mold closes under pressure, forcing the material to flow into the cavity and fill all details. Excess gets squeezed out in this step.
3. Cooling & Part Removal
   After the machine’s cycle completes, the mold opens and ejects the part (often multiple parts in a single run).
4. Flash Trimming
   Finally, any excess material (flash) is removed, leaving the desired shape and surface.

(Think of it like making waffles—just with rubber or silicone, and a bit more pressure!)

Materials We Work With

Onit focuses on soft durometer thermoset materials, including:

• Rubber (SBR, EPDM, Viton)
• Urethanes
• Specific Silicones

These materials offer a balance of durability, flexibility, and chemical resistance, making them ideal for seals, gaskets, and more.

Engineering Specs

• Dimensional Accuracy: Good enough for most medium-complexity parts; perfectly suited for soft components that conform to mating parts.
• Simple Geometry: Undercuts are not recommended, and thicker parts may require longer cure times.
• Consistent Thickness: Maintaining uniform thickness helps ensure reliability and quality across runs.

Applications

• Seals & O-Rings
• Rubber Pads
• Shoe Soles
• Overmolded Handles & Grips
• Boots & Wearable Components

Frequently Asked Questions

What Are the Benefits?

• Cost-Effective at High Volumes: Lower per-part cost once tooling is created.
• Quick Tool Build Times: Compared to injection molding, compression molds are simpler and faster to produce.

Are There Any Disadvantages?

• Limited Geometry: No undercuts, and it’s difficult to achieve sharp edges with soft materials.
• More Labor: Trimming flash and manual handling can add labor compared to injection molding.

What Features Can I Expect?

• Soft, Flexible Parts: Best for sealing, cushioning, and wear applications.
• Simple Geometries: Smooth shapes without complex undercuts or intricate details.

How Long Does Tooling Take?

• Around Two Weeks: Typically faster than injection molding, making it ideal for quick-turn projects.

Why Choose Compression Molding vs. Injection Molding or Urethane Casting?

• Cheaper & Faster Tooling: Excellent for larger volumes and tighter budgets.
• Unique Thermoset Materials: Rubber and silicone are well-suited for sealing, shock absorption, and other applications requiring flexibility.
• Scalability: While urethane casting is great for smaller runs (10–200 parts), compression molding is more economical at higher volumes.

UR-2180 (DPI)

UPX-5210 (AXSON)

UP-5690 (AXSON)

T-0387 (Hei-cast)

PX-223HT (Axson)

T-8400 (Hei-Cast)

T-8263 (Hei-Cast) – ABS-like FR V0

T-8150 (Hei-Cast)

ABS-LIKE

MATERIAL PROPERTIES

Hardness: 75-85 Shore D

Tensile Strength (Mpa): 42-73

Elongation %: 16-21

Impact Strength: 12kJ/m2 0.58 - 2ft lb/in

URETHANE MATERIAL GRADE (OVERSEAS)

Onit Mfg 12009

URETHANE MATERIAL GRADE (DOMESTIC)

Rampf TP 4056

COLOR

Natural, Yellow, Purple, Color Match

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Blow Molding at Onit

Blow molding is our top choice when you need hollow plastic parts in large quantities. Most commonly used to manufacture bottles, jars, and other containers, this versatile process also enables the creation of more complex shapes for specialized applications. By heating and shaping molten plastic within a mold, blow molding delivers lightweight, cost-effective products that can’t be made using standard injection molding.

Two Main Types of Blow Molding

Alright, let's dive into resins! This section is extra credit for those who want to understand the deeper workings of production methods and their materials.

• Begins by extruding a molten tube of resin between two mold halves.
• Less refined surface finish and less detail for threads/bottle necks.
• Classic milk jugs are an everyday example.

• Starts with a preform created by an injection tool, enabling sharper necks, threads, and a more polished finish.
• Commonly used for cosmetic or fancy lotion bottles where quality presentation is key.

Our Blow Molding Process

Urethane casting often serves as a steppingstone toward high-volume production. Injection molding resins have some key differences when it comes to the raw material chemistry used.

Injection Molding involves melting pellets of the chosen resin and injecting them at high pressure into a metal mold/tool. Once the resin cools, the part is ready to be removed. The resins used here are thermoplastics—they are "one-part" resins that can melt, solidify, and be remelted multiple times. Chocolate, everyone’s favorite treat, acts in a similar way to thermoplastics.

Urethane Casting on the other hand is a bit different. It uses a 2-part mixture of resin and catalyst. This mixture is combined in small batches and poured into a soft mold at low pressure. No added heat is needed, and once cured, these parts are “set” permanently—they can't be melted down or separated again.

1. Preparation – Depending on the method (extrusion or injection), we form either a molten tube or a preform of your chosen resin.
2. Mold Closure – The heated material is then placed into a mold that defines the product’s exterior features.
3. Air Injection – Air is blown into the tube or preform, expanding it against the mold walls.
4. Cooling & Removal – The mold opens, and your hollow part is removed once the resin has cooled.
5. Finishing – Injection blow molded parts typically need no post-processing, while extrusion blow molded parts may require trimming to remove flash or excess material.

Materials We Use

We can work with a wide range of thermoplastics, including:

• LDPE
• HDPE
• PET
• PP
• PS
• PVC
• Nylon
• TPE

This flexibility allows us to find the perfect balance of durability, weight, and cost for your specific application.

Engineering Specs

• Varied Surface Finish: Injection blow molding offers a more refined finish, while extrusion blow molding can be slightly rougher.
• Hollow Features: Ideal for containers, ducts, and shapes that are difficult or impossible to create via simple extrusion or injection molding.
• Wall Thickness Variations: Parts may have uneven wall thickness depending on how the plastic stretches to fit the mold contours.

Applications

• Bottles & Jars
• Ducts and Tubing with intricate internal features
• Any Hollow Items that would be impossible or impractical to form with injection molding

Frequently Asked Questions

What Are the Benefits?

• Affordable Production: Blow molding is cost-effective when you need large quantities of hollow items.
• Unique Geometry: You simply can’t make true hollow parts with standard injection molding.
• Lightweight Parts: Great for saving on shipping costs or for handheld products where weight matters.

Are There Any Downsides?

• No Undercuts: Blow molding can’t handle deep undercuts or intricate internal structures.
• Wall Thickness Variations: Parts may have uneven thickness, especially in complex designs.
• Surface Finish: Extrusion blow molding may require additional cleanup or finishing if a high-end appearance is desired.

What Features Can I Expect?

• Hollow Parts with Narrow Openings: Perfect for bottles, enclosures, and similar designs.
• No Undercuts: Keep designs straightforward for the best results.

How Long Does Tooling Take?

• 2–4 Weeks: Depending on whether extrusion blow molding or injection blow molding is used, the total lead time can vary.

Why Choose Blow Molding Over Injection Molding?

• True Hollow Shapes: Standard injection molding can’t create fully hollow parts without secondary operations.
• Process Simplicity: For bottles, jars, and similar containers, blow molding streamlines production, reducing costs and complexity.

Die Casting at Onit

Die casting is our go-to solution for high-volume production of both complex and simple metal parts. This repeatable, accurate process is ideal for everyday products—from engine blocks and electric motor covers to nearly any high-volume, high-strength metal component.

Why Die Casting?

At Onit, we frequently start with CNC-machined aluminum for smaller batches or prototypes—giving our clients that high-quality appearance and user experience. As demand grows, die casting becomes an excellent alternative thanks to significantly lower per-piece costs, with the trade-off of tooling investment up front.

Materials We Use

• Aluminum, Magnesium & Zinc Alloys

These materials give you the flexibility to balance strength, weight, and cost, depending on your product’s needs.

Our Die Casting Process

• Mold Setup – We set up a high-volume production mold in our die casting machine.
• Metal Injection – Molten metal is injected under pressure into the mold.
• Cooling – The metal solidifies quickly, capturing intricate details.
• Ejection – The part is then ejected.
• Trimming – Finally, we remove runners, vents, and any excess material, revealing the finished part.

Engineering Specs

• High Strength, Low Weight: Achieve robust parts that won’t weigh customers down.
• Surface Finish: Typically 1–25µm, which can be rougher than CNC or MIM. If a sleek, cosmetic finish is essential, post-processing (e.g., anodizing or machining) is highly effective.
• Max Part Weight: Up to 70 pounds—ideal for larger components like engine blocks or housings.

Applications

• High-Volume Aluminum Parts
• Commercial Motors & Equipment
• Covers and Enclosures for handheld and electronic devices
• Rigid Components in high-heat environments

Frequently Asked Questions

What Are the Benefits of Die Casting?

• Lightweight & Strong Parts – Great for products needing durability without added bulk.
• Cost-Effective at High Volumes – Once the mold is made, unit prices drop significantly.

What Features Can I Get?

• Complex Geometries – Varying wall thicknesses make engine blocks, transmissions, and other intricate designs feasible.
• Refined Details – Features can be post-machined, tapped, or otherwise finished as needed.

How Long Does Tooling Take?

• 4–6 Weeks – After we finalize your design, tooling typically takes about a month or more to complete.

Why Die Cast vs. MIM (Metal Injection Molding)?

• General Use vs. Precision Small Parts – Die casting excels at bigger, more general components, while MIM is best for small, intricate geometries.
• Lower Setup Complexity – Die casting tends to be simpler and more economical to set up.
• Minimal Secondary Processing – Most die cast parts are ready after molding, whereas MIM parts often need extra steps like debinding and sintering.

Thermoforming at Onit

Thermoforming, sometimes referred to as vacuum forming, is a versatile production process that heats thermoplastic sheets until they’re soft and then uses vacuum pressure to shape them into 3D forms. From protective packaging trays for action figures to clamshell food containers and even fun, lightweight party hats, thermoforming opens up a world of cost-effective possibilities—especially for larger or simpler parts where injection molding might be overkill.

One way we love to use this method at Onit is in creating custom trays for our other production projects, helping to keep parts organized and damage-free between manufacturing steps. If you need rapid, budget-friendly solutions for packaging, covers, or organizers, thermoforming might be the perfect fit.

Why Thermoforming?

• Affordable & Flexible: Tooling is relatively cheap and easy to produce, even using a 3D-printed “buck” (mold).
• Large Parts, Low Cost: Big plastic sheets are straightforward to scale up, without exponential cost increases.
• Lightweight Protection: Ideal for packaging that shields products while keeping shipping weights low.
• Quick Turnaround: We can produce molded parts in just a few days when timelines are tight.

Our Thermoforming Process

1. Heat the Sheet
   A thermoplastic sheet (e.g., PS, PP, PET-G, ABS, PVC, etc.) is placed in a heater to soften.
2. Form Over the Mold
   Once pliable, the sheet is pulled down over the mold or “buck.”
3. Vacuum Assist
   Air is extracted from beneath the sheet, causing it to conform tightly to every contour of the mold.
4. Removal & Trimming
   After cooling, the formed sheet is removed from the mold. Excess material around the edges is trimmed, either by hand for small runs or with a trim tool for higher volumes.

Mold (or “Buck”) Creation

We often 3D print our molds using FDM technology, because the slight porosity of FDM prints naturally aids vacuum pull, enhancing the forming process. It’s fast, cost-effective, and easily modified if you need design tweaks.

Materials We Work With

• PS (Polystyrene)
• PP (Polypropylene)
• PET-G
• ABS
• PVC
• And more…

Choosing the right material depends on your project’s need for durability, clarity, flexibility, and cost.

Engineering Specs

• No Undercuts: The final part must be removable from a one-sided mold.
• Soft or Rounded Features: Sharp edges and precise corners aren’t typical due to the low pressure process.
• Varying Sheet Thickness: Areas of higher stretch will be thinner, so keep this in mind for strength and design.
• Edge Trimming: Discuss your quality requirements for trimming in advance—manual or tool-based trimming can affect final appearance and cost.

Applications

• Packaging Trays: Ideal for display and protection of consumer goods.
• Clamshell Packaging: From food service to retail blister packs.
• Party Hats & Novelty Items: Lightweight, colorful, and easy to produce in bulk.
• Toolbox & Drawer Organizers: Custom trays that ensure everything stays in place.

Frequently Asked Questions

What Are the Benefits?

• Budget-Friendly: Lower tooling and equipment costs compared to injection molding.
• Large Parts Possible: Scaling up is relatively simple—just use bigger sheets.
• Lightweight: Perfect for cost-conscious shipping and handling.
• Nestable/Stackable: Thermoformed parts often stack neatly, reducing storage and shipping bulk.

What Features Can I Get?

• 3D Shapes Without Undercuts: Perfect for trays, covers, and shallow, contoured enclosures.
• Rounded Corners: Sharp edges aren’t feasible under typical vacuum pressures.

How Fast Is the Turnaround?

• Very Quick: We can form parts in just a few days for urgent projects.

Why Thermoform Instead of Injection Molding?

• Tooling Cost: It’s significantly cheaper to develop and modify a thermoforming mold.
• Large or Simple Parts: Bigger pieces are far more economical compared to injection molding, which requires heavier molds.
• Faster Setup: Ideal for packaging or prototypes where speed is essential.

Metal Injection Molding at Onit

Metal Injection Molding, or MIM, is an advanced manufacturing process that’s ideal for producing small, intricate metal parts—often with high cosmetic standards and precise tolerances. From consumer electronics to industrial components, MIM offers a unique combination of design flexibility, strength, and dimensional accuracy. If you need high-volume production of metal parts under 200 grams, look no further than Onit’s MIM capabilities.

Why Choose MIM?

• Intricate Geometries: Unlike many other metal processes, MIM excels at producing complex, high-precision parts.
• Small Part Specialty: Perfect for components often less than 200 grams.
• Scalable: Once tooling is set, you can produce tens of thousands of identical parts cost-effectively.
• High Cosmetic & Tolerance: Get both the look and the fit your products demand.

Our MIM Process

1. Feedstock Preparation
   Fine metal powder is blended with a thermoplastic binder, making it workable at temperatures much lower than metal’s typical melting point.
2. Injection Molding
   This metal-plastic mix is injected into a mold—similar to plastic injection molding—to form a “green” part.
3. Binder Removal
   The “green” part still contains the binder. We remove it through heat and solvents, leaving behind a structure of fine metal particles.
4. Sintering
   The part is then sintered (heated to very high temperatures), causing the metal particles to fuse into a solid, robust component. During sintering, the part shrinks 15–30%, a factor carefully calculated by our tooling engineers to reach your final dimension.
5. Optional Finishing
   If you need further cosmetic or functional processing—such as polishing, plating, or coatings—we can handle that, too.

Materials We Work With

MIM is compatible with a variety of ferrous and non-ferrous alloys, including:

• Stainless Steels (e.g., 316L, 17-4PH)
• Low-Alloy Steels
• Tool Steels
• Titanium Alloys
• Specialty Alloys based on project requirements

Have a specific alloy in mind? Just let us know!

Engineering Specs

• High Precision: Achieve complex part geometries with tight tolerances.
• Excellent Mechanical Properties: Parts are sintered metal, offering strength and durability close to wrought metals.
• Size & Weight Range: Best suited for small components, typically under 200 grams.
• Cosmetic Flexibility: Final parts can be finished in various ways—polished, plated, or coated—to match your aesthetic and performance needs.

Applications

• Small Machinery Components (e.g., gears, levers, specialized connectors)
• Medical Devices requiring precision and biocompatibility
• Electrical Connectors with intricate form factors
• Heat Sinks for electronics
• Cosmetic Enclosures where metal aesthetics matter
• Wearable Electronics requiring lightweight, high-strength parts

Frequently Asked Questions

What Are the Benefits?

• High Precision & Intricacy: Ideal for detailed parts that might be impossible or too costly with other metal processes.
• Excellent Surface Quality: MIM often rivals or surpasses other methods for cosmetic finishes and tight tolerances.
• Material Efficiency: Minimizes waste and can reduce secondary operations.

What Features Can I Get?

• Complex Internal Geometries: MIM can produce fine details, threads, and design features directly in the mold.
• Post-Mold Finishes: If you want a polished look, coated surface, or additional machining, we can handle it.

How Long Does It Take?

• Tooling & Process: Initial mold creation and process setup can take a few weeks. Once that’s ready, high-volume runs are quick and repeatable.

Why MIM vs. Die Casting?

• Intricate & Small: MIM is particularly suited for highly complex parts under 200 grams.
• Higher Precision: Tighter tolerances and finer detail than die casting.
• Efficient at High Volumes: Lower per-part cost once tooling is established.

Reaction Injection Molding at Onit

Reaction Injection Molding, or RIM, is a specialized process for creating lightweight, foamed polyurethane parts in a variety of shapes and sizes. Unlike traditional injection molding that relies on heating thermoplastic pellets, RIM mixes two fast-reacting components and injects them into a mold to chemically cure. Thanks to this low-pressure, low-heat method, RIM is perfect for large, sink-mark-free parts often used in medical devices, enclosures, and other applications where weight reduction and robust design are critical.

Why Choose RIM?

• Large, Complex Parts: Produce parts up to 6 ft+ without worrying about sink marks.
• Lower Pressure & Heat: Ideal for foams that expand to fill the mold, ensuring a lightweight result.
• Comparable Cycle Times: Similar efficiency to injection molding, but with added benefits for certain geometries.
• Cost-Effective Tooling: Molds can be made from aluminum instead of steel, reducing upfront investment.
• Thermoset Resins: Create durable, high-performance parts with excellent surface finish.

Our RIM Process

1. Chemical Mixing
   Two reactive chemical components are precisely metered and mixed. This mixture begins reacting immediately, so timing is crucial.
2. Injection
   The combined materials are injected into the mold under lower pressure than traditional injection molding.
3. Expansion & Curing
   The foam expands to fill the mold’s cavities, and the part cures (solidifies) due to the chemical reaction.
4. Part Removal
   The mold opens, and the finished part is removed. RIM parts typically feature uniform, sink-mark-free surfaces.
5. Finishing
   If needed, secondary operations like trimming or painting can be performed for specific cosmetic or functional requirements.

Specific Material We Work With

Baydur VP. PU 60 IK20 – A polyole formulation reacting with various Desmodur® types to produce foamed moldings in the 500–700 kg/m³ density range.

• Flame-retardant variants (Baydur 66FR, Baydur 66FR-1, Baydur 60 FRS) are available.
• No fillers or CFCs in our ready-to-use formulation.

This specialty foam enables lightweight parts with excellent strength and thick geometry options, all while meeting fire safety or regulatory requirements when needed.

Engineering Specs

• Surface Finish: Comparable to injection molding; easily painted or coated.
• No Sink Marks: Great for designs with varying wall thicknesses.
• Part Size: Can be very large (6 ft+).
• Tolerance & Precision: Adequate for enclosures and housings; final accuracy depends on material choice and part geometry.
• Tooling: Typically made from aluminum, reducing cost and lead time.

Applications

• Medical Enclosures: Lightweight, robust casings for imaging devices, monitors, etc.
• Equipment Covers & Panels: Ideal for industrial machinery.
• Large, Lightweight Packaging: Protective foam structures that won’t add excessive weight.
• Consumer Products: Where large, sink-mark-free surfaces are crucial (e.g., furniture components).

Frequently Asked Questions

What Are the Benefits?

1. Comparable Cycle Times: Enjoy production speeds similar to injection molding.
2. No Worry of Sink Marks: Vary wall thickness freely without aesthetic or structural concerns.
3. Lightweight Parts: Perfect for portability and reduced shipping costs.
4. Thermoset Resins: Ensures high strength and durability.
5. Huge Part Possibilities: Scale up to 6 ft+ with ease.
6. Cost-Effective Tooling: Aluminum molds reduce initial investment.

What are the Downsides to RIM Molding?

• Expensive Raw Materials: Polyurethane systems can be pricier than standard thermoplastics, so factor that into production budgeting.

What Features Can I Get?

• Similar to Injection Molding but thicker walls, so design freedom is broad.
• High-Quality Finishes often comparable to molded plastic housings.

How Long Is the Turnaround?

• 30 Days for Tooling: Once your design is locked in, we can often have molds ready in about a month.

Why Use RIM vs. Injection Molding?

• Large, Complex Parts: Injection molding struggles with big or sink-mark-prone shapes.
• Foamed & Lightweight: RIM significantly reduces part weight.
• Lower Mold Costs: Aluminum molds are more budget-friendly than steel tooling for large parts.