Consultation: Communicating with OEM customers to understand their specific requirements, including their existing mold design [if any], part design, material specifications, quantity, and delivery timelines.

Analysis: Analyzing the requirements to develop a production plan.

Quote: Paroviding an accurate quote including cost, time line, terms and conditions in a timely manner, typically withing 72 hours.

Molds for plastic injections are expensive though valuable assets and must be designed with absolute precision. Making concessions on your product specifications may result in a change in the quality of produced plastic parts. However, a skilled injection molder can still produce high-quality plastics without compromising on key details. In cases where compromises are necessary, your supplier can offer suitable suggestions to minimize the impact of these changes.

This may involve using alternative resins and making slight adjustments to the design, which can help reduce lead time and cut down on production expenses.

CAD Modeling: Using the client’s detailed CAD models of the plastic parts based on the OEM specifications, or creating such models for the client [on a fee basis].

Prototyping: If needed, producing prototypes to test design accuracy and functionality.

Approval: Seeking approval from the OEM customer on the final design after any necessary modifications.

Common injection molding materials

Material Selection: Choosing the appropriate quality of the plastic material as per OEM specifications unless already specified. Colorants and resin additives as well as different plastic can greatly impact user experience and product value of every plastic product.

Resin standard colors are usually black and natural, with natural colors including white, beige, amber, or other options. Semi-custom colors can be achieved by mixing colorant pellets with natural resins. 

Short glass fibers are utilized to enhance a composite’s strength and minimize creep, particularly at elevated temperatures. They enhance the resin’s durability, rigidity, and fragility. They can lead to distortion because of the varying cooling shrinkage rates between the resin and fibers.

Carbon fibers can also be employed to fortify and/or stiffen a composite, as well as assist in static dissipation. It shares similar limitations as glass fibers. Carbon fiber has the capability to greatly increase the rigidity of plastic.

Minerals like talc and clay are commonly added as fillers to reduce costs or enhance the hardness of final components. Due to their lower shrinkage rate compared to resins during cooling, they can help minimize distortion.

PTFE (Teflon) and molybdenum disulfide are utilized to create self-lubricating parts for bearing applications.

Long glass fibers are employed to reinforce and minimize deformation in resin, increasing its strength and stiffness. However, molding parts with thin walls or long resin flows can prove to be challenging.

Aramid (Kevlar) fibers are similar to glass fibers in terms of being less abrasive but not as strong.

The addition of glass beads and mica flakes can be used to enhance the stiffness of a composite and reduce the likelihood of warping and shrinking. However, injecting them at high concentrations can be difficult.

Stainless steel fibers are used in electronic component housings to manage EMI and RFI, being more conductive than carbon fiber.

UV inhibitors are used for applications exposed to outdoor conditions.

Static treatments enable resins to dissipate static electricity.

The plastic injection process for injection molded plastic parts is intricate and engineers have to consider key tooling aspects before production of plastic parts at scale:

Nozzle selection: Various types of nozzles are utilized in plastic injection molding, each tailored to fulfill a particular need. Factors such as the material being used, design of the part, molding parameters, and specific requirements of the injection molding process all play a role in determining the most suitable type of nozzle to use.

Different types of nozzles include:

1. Open nozzle: An open nozzle is the most basic and commonly used type of nozzle. It consists of a simple channel that connects the barrel to the mold cavity. Open nozzles are typically used for general-purpose applications and materials with low viscosity.
2. Shut-off nozzle: It is designed to provide better control over the material flow. It prevents drooling or stringing. They incorporate a valve or shut-off mechanism at the nozzle tip that closes when the injection process is complete. This leads to sealing off the flow of molten plastic. The shut-off nozzle helps to reduce part defects and material waste.
3. Valve gate nozzle: It is also known as hot runner nozzle. It is used in hot runner systems. These systems keep the molten plastic at a consistent temperature throughout the injection molding process. This eliminates the need for the plastic to solidify and re-melt each cycle. They have a valve pin that controls the opening and closing of the nozzle. This precisely controls the flow of plastic into the mold cavity.
4. Multi-tip nozzle: It consists of multiple nozzle tips. These are arranged in a single assembly. They are used for multi-cavity molds where several identical parts are produced simultaneously. Multi-tip nozzles allow the efficient filling of multiple cavities. This is done with a single injection molding machine which reduces cycle time and increases productivity.
5. Mix-head nozzle: It is used for injection molding processes that involve mixing multiple components or colors. These nozzles have separate channels for each component. Here the materials are mixed within the nozzle before being injected into the mold. They are commonly used in applications like multi-color parts or parts with special effects.

Quality Assurance: Conducting inspections to ensure each part meets the quality standards and specifications.

Injection Molding: Injecting molten plastic into the molds to form the parts. Parameters like temperature, pressure, and cooling time are optimized for quality and efficiency.

The finish of the surface is a crucial factor to think about when it comes to injection molding, as the parts are usually made for their appearance and ultimate production use. 

It’s important to note that a textured surface will need more draft compared to a smoother finish in order to ensure the part easily comes off the mold and to properly apply bead blast to the tool.

Trimming: Removing excess material and sprues from the molded parts.

Assembly: If required, assembling multiple parts to form complete components.

Utilizing high-frequency acoustic vibrations, ultrasonic welding is a method of joining two plastic materials together. These vibrations are transmitted to the molded plastic through a horn, while the parts are securely held in place by a fixture. Unlike other bonding methods, ultrasonic welding does not require any additional material to bond the parts together.

In the adhesive method, a material is used to connect two parts without changing the chemical properties of the plastics involved, which is typically suitable for most types of plastics.

On the other hand, solvent bonding involves the use of a liquid material that coats and softens each plastic, allowing them to bond together under pressure. As the solvent evaporates, the plastic molecules blend together to create a permanent bond. However, this method is most effective with thermoplastics.

Ultraviolet (UV) bonding involves the use of high-intensity light to cure adhesives or coatings quickly, creating strong, durable bonds that improve production efficiency and reduce rejected parts. However, for this method to work effectively, it is important to choose a transparent resin that allows UV light to pass through.

If you anticipate needing to separate injection molded parts bonded together, mechanical fastening may be the best option.

Common types of mechanical fasteners include nuts, screws, rivets, and bolts.

To enhance durability, plastic parts that require frequent disassembly often have threaded metal inserts.

Pickouts: Inserts called pickouts are created separately from the tooling and inserted into the mold before material is injected. These are employed to create undercuts on the inside surfaces. Pickouts are released along with the plastic part and reinserted into the mold. While pickouts allow for greater flexibility in shape and positioning, they are more expensive than sliding shutoffs or side-actions.

Part Decoration: Applying surface finishes, painting, or other treatments as specified by the OEM customer.

After being removed from the mold, plastic parts are occasionally left without any decoration. It is advisable to embellish the part if you wish to enhance its appearance or provide instructions or identification. Pad printing, laser marking, and inkjet printing are commonly utilized by manufacturers to decorate parts in traditional ways.

The pad printing process: Uses a silicone pad to transfer 2-D images or text onto a 3-D object. Rigid parts with round surfaces are effectively stamped since the silicone pad wraps around the shape of the item without distorting the text or image. 

Using laser marking techniques provides a quick way to adorn your plastic component.

This approach creates detailed effects on the molded part without the need for any surface preparation beforehand. Other popular laser methods include:

Laser etching: Involves applying a high amount of energy to a small area, causing it to melt and expand and leaving a raised mark on the plastic surface. Typically, etching is used for permanent markings like serial numbers, barcodes, and matrix codes.

Finishing: Applying surface finishes, painting, or other treatments as specified by the OEM customer.

In the United States, plastic injection molding companies and mold builders utilize inkjet printing as a precise, non-contact method of printing. The ink used is specially formulated to enhance the quality of the print. It dries quickly, ensuring it adheres to the surface promptly. Additionally, the ink is designed to resist both oil and heat to prevent any smudging that could obscure the printed images. Colored and pigmented ink is used to create high-contrast, nearly photo-quality texts and images on darker surfaces, making them easier to read.

Inspection: Detailed inspections to ensure dimensions, material quality, and overall part integrity are up to standards.

Testing: Conducting functional and stress tests, if necessary and as required by the OEM client, to validate part performance.

ISO 13485 is the established criteria for the healthcare sector. This encompasses design validation (DV), operational validation (OV), and performance validation (PV).

PPAP is a quality assessment procedure commonly employed in the automotive field. It is utilized to confirm that a manufacturing process can consistently generate a high-quality component. There are 18 elements to a PPAP assessment that span from customer endorsement to prototype part fabrication.

Preparation: Preparing the parts for delivery, including counting, sorting, and quality checking.

Packaging: Utilizing appropriate packaging materials and methods to ensure the parts are protected during transit.

Logistics Planning: Arranging the logistics for timely delivery, considering the OEM’s location and requested timelines.

Shipping: Transporting the parts to the OEM customer’s location using reliable carriers.

Documentation: Including all necessary paperwork, certifications, and documentation required by the OEM customer.

After-Sales Support:

Customer Support: Offering support for any queries, concerns, or additional requirements the OEM customer might have.

Feedback Collection: Gathering feedback to ensure customer satisfaction and improve future processes.

Communication: Maintaining open and transparent communication with OEM customers throughout the process.

Customization: Tailoring every aspect of the process to meet the specific needs and specifications of the OEM customer.

Compliance: Ensuring all parts are produced and delivered in compliance with industry standards and regulations.

This process is meticulously planned and executed to ensure the plastic injection molded parts are produced to the highest standards of quality and delivered on time to meet the OEM customer’s production and market needs.