Rakar has specialized in custom molding for over 60 years, offering injection, compression & transfer molding.
Rakar has specialized in custom molding for over 60 years, offering injection, compression & transfer molding.
MANUFACTURING
Plastic Molding Services
We have specialized in custom molding for the Aerospace, Defense, Automotive, Medical and Consumer Industries for nearly 70 years, offering injection, compression and transfer molding, toolmaking, and metal over-molding. Our experience, knowledge, and understanding of engineering plastics, means that you can rely on us for the most challenging applications. Our team of engineers & material specialists here at Rakar will help you choose the right materials and processes for your project.
Plastic molding is a manufacturing process for producing parts from both thermoplastic and thermoset raw material. Which is fed into a heated barrel, mixed and forced into a mold cavity where it cools and hardens to the configuration of the mold cavity. Injection molding is widely used for manufacturing a variety of parts, from the smallest component like small Lego accessories to entire body panels of cars. Injection molding is used to create many things such as wire spools, packaging, electrical connectors, bottle caps, pocket combs, and most other plastic products available today. Injection molding is the most common method of manufacturing parts. It is ideal for producing high volumes at high production rates, repeatable low tolerances, the use of a wide range of materials.
Molding tolerance is a specified allowance on the deviation in parameters such as dimensions, weights, shapes, or angles, etc. To maximize control in setting tolerances there is usually a minimum and a maximum limit on thickness, based on the process used. Surface finishes of two to four micro-inches or better can be obtained. Rough or pebbled surfaces are also possible.
• Utilizes a screw-type plunger to force molten plastic material into a mold cavity.
• Produces a solid or open-ended shape that has conformed to the contour of the mold.
• Uses thermoplastic or thermoset materials
• Produces a parting line, sprue & gate marks
• Ejector pin marks are usually present
Our proprietary method of molding utilizes a heated mold cavity which is closed with a top force, as pressure is applied to push the material into contact with all molding areas. Heat and pressure are maintained until the molding material has cured. The process employs thermoset resins in a partially cured stage, either in the form of granules, putty-like sheets/logs, or preforms.
Compression molding is a high-volume, high-pressure method suitable for molding complex, high-strength fiberglass reinforcements. The advantage of compression molding is its ability to mold large, fairly intricate parts. Materials that are typically manufactured through compression molding include Polyester fiberglass resin systems (SMC/BMC), DAP (short and long glass-filled), Epoxy (short & long glass-filled), & many grades of Phenolic.
In compression molding there are six important considerations that an engineer should keep in mind:
1. The proper amount of material.
2. Amount of energy required to heat the material.
3. The time required to heat the material.
4. The appropriate heating technique.
5. Predicting the required force, to ensure that the shot attains the proper shape.
6. Designing the mold for rapid cooling after the material has been compressed into the mold
7. The use of thermoset plastic compounds characterizes this molding process from many of the other molding processes. These thermosets can be in either preform or granule shapes. Unlike some of the other processes, the materials are usually preheated and measured before molding. Inserts, usually metallic threaded studs or bushings, can also be molded with the plastic.
Transfer molding, like compression molding, is a process where the amount of molding material (thermoset plastic) is measured and inserted before the molding takes place. The molding material is preheated & loaded into a chamber known as the pot. A plunger is then used to force the material from the pot through channels known as a sprue and runner system into the mold cavities.
The mold remains closed as the material is inserted and is opened to release the part from the sprue and runner. The mold walls are heated to a temperature above the melting point of the mold material; this allows faster flow of material through the cavities. The molds in both compression & transfer molding remain closed until the curing reaction within the material is complete. Ejector pins are usually incorporated into the design of the molding tool and are used to push the part from the mold once it has hardened. These types of molding are ideal for high production runs as they have short production cycles. Transfer molding, unlike compression molding, uses a closed mold, so smaller tolerances and more intricate parts can be achieved. The fixed cost of the tooling in transfer molding is greater than in compression molding and as both methods produce waste material, whether it be flash or the material remaining in the sprue & runners, transfer molding is the more expensive process.
Transfer molding differs from compression molding in that in the Transfer process the resin is inserted into the "closed" clamped mold (or tool) and the resin pressed into place by a transfer ram (plunger). In compression molding, the compounds are placed into an "open" mold which is then closed to force the material into the cavity.
MATERIALS
Rakar's vast knowledge and understanding of engineering plastics allow us to take on and tackle even the most challenging molding application. Our team of engineers and material specialists here at Rakar will help you choose the right materials for your project.
Rakar uses Engineering Grade Thermoset molding materials produced from various resins including Phenolic (General Purpose & Glass Filled), Epoxy, DAP, Silicone and Polyester compounded with various reinforcements and fillers. The resulting composites meet some of the most demanding engineering requirements presented in the industry. Engineering Thermoset plastics are excellent replacements for metallic or thermoplastic components and offer high-temperature resistance, mechanical strength including toughness, firewall use, conductivity, electrical insulation, chemical resistance, and other important properties other materials cannot offer.
PHENOLIC
(Phenolic)
Properties:
1. High Temperatures
2. Low Smoke Emissions
3. High Chemicals Resistance
4. Excellent Creep Resistance
5. High Mechanical Strengths
Applications:
1. Military & Defense
2. Automotive & Electrical
4. Pot & Pan Handles
5. High Voltage Connectors
6. DC Motor Parts
MELAMINE PHENOLIC
(Melamine)
Properties:
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Variety of Colors
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Low Smoke Emissions
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High Chemical Resistance
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High Temperatures
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High Mechanical Strengths
Applications:
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Military & Defense
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Consumer & Electrical
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Dishes/Plates
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Switch I.D. Buttons
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Engine Parts
DIALLYL PHTHALATE
(DAP)
Properties:
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No to Low Outgassing
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High Temperatures
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Low Smoke Emission
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High Chemical Resistance
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Inert to Fungus Growth
Applications:
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Military & Defense
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Automotive & Electrical
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High-End Connectors
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Insert Molded Switches
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High Voltage Connectors
EPOXY
(Epoxy)
Properties:
1. Several Different Formulations
2. Low to None Outgassing
3. High Temperatures
4. Low Smoke Emissions
5. High Chemicals Resistance
6. Unaffected by Sea Water
7. Strong Resistance to
Thermo Shock
Applications:
1. Aerospace, Military, & Defense
2. Consumer & Marine
3. Connectors
4. Medical Implants
5. Potting Encapsulations
6. "B" Stage Adhesive
POLYESTER
(Polyester)
Properties:
1. Excellent Surface Appearance
2. High Chemical Resistance
3. V-O Flame Resistant
4. High Mechanical Strengths
Applications:
1. Military & Defense
2. Automotive & Electrical
3. Electrical Connectors
4. Insulators, & Housings
5. Automotive Part
SILICONE
(RTV)
Properties:
1. High Temperature
2. LO & Variable Udometers
3. Some Color
4. High Impact Strength
Applications:
1. Aerospace, Military, & Defense
2. Electrical Applications
3. 600° F Insulators
4. Seals & Gaskets
5. Firewall Connectors
Thermoplastics
Rakar has the knowledge and capability to mold many types of thermoplastic materials. We are experts in harnessing the flexibility of engineering grade resins ranging from Nylon & Polyester to high-performance resins such as PEEK & LCP. Rakar can meet your specific injection molding requirements from simple to complex sizes, shapes & tolerance. Thermoplastic Resins having specific properties are compounded with additives such as reinforcements (glass or carbon), UV inhibitors, flame retardants, conductive elements, lubricants, or toughness agents, to attain desired properties. Some thermoplastic property benefits include:
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Resins which are available in a wide variety of material & color options.
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Proven Durability
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High Corrosion & Chemical Resistance
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High-Temperature Tolerance
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Excellent workability, thermoforming & molding characteristics
ACRYLONITRILE BUTADIENE
(ABS)
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STYRENE
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ACETAL
(Delrin, Celcon)
Manufacturers: Dupont, Ticona
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ACRYLIC
(Lucite, Plexiglas)
Manufacturers: Dupont, Rohm & Haas
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BUTYRATE
(Tenite)
Manufacturer: Eastman
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POLYIMIDE
(Nylon)
Manufacturer: Dupont
POLYIMIDE
(Nylon)
Manufacturer: Dupont
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POLYCARBONATE
(Lexan)
Manufacturer: General Electric
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POLYESTER (PBT, PET)
(Valox, Celanex)
Manufacturers General Electric, Ticona
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POLYETHERIMIDE
(Ultem)
Manufacturer: General Electric
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POLYPHENYLENE SULFIDE
(Ryton, Fortron, PPS)
Manufacturers: Phillips, Ticona
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POLYPHENYLENE OXIDE
(Noryl)
Manufacturer: General Electric
POLYPROPYLENE
(PP)
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POLYSTYRENE
(PS)
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POLYURETHANE
(PU)
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POLYETHER ETHER KETONE
(PEEK)
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STYRENE ACRYLONITRILE
(SAN)
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THERMOPLASTIC ELASTOMERS
(Santoprene, Krayton)
Manufacturers: Exxon Mobil, Shell
CAPABILITIES
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Insert Molding
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Assembly
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Bonding
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Machining
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De-Gating
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De Flashing
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Tapping
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Polishing
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Grinding
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Bead Blasting
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Annealing
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Pad Printing
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Bar Coding
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Custom Packaging
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Warehousing
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Drop-Shipping.
INSERT MOLDING
Insert molding is a valuable, yet comprehensive process, that should only be trusted to a quality molding company. This meticulous, custom molding process has many variables to consider. One question molders are often addressing is how to keep inserts, which may need a specific orientation, from spinning or moving as the material is injected into the mold. Our team here at Rakar has tackled and achieved success overall Insert Molding issues.
AS9100 QUALITY ASSURANCE
AS9100 Quality Assurance
The Quality process starts upon delivery of the inserts to our receiving inspecting department. Once the parts are inspected and approved, they are released for use in production. From there, we have four additional inspection processes. After the initial run of parts, they are sent to our quality control department for full dimensional & visual approval. If the part is to specification, then they are sent back with approval to continue running the parts.
Part of our success is all of our molded parts are continually checked throughout the molding process. This in-line continuity testing ensures that quality, durability, and tolerance are never compromised. In addition to In-Line Testing, the parts are sent back to inspection for "Final Shot" approval. Once approved, the final shots are run to complete the job. At this time, the completed job is back to quality control for the final inspection before being sent to the customer.
QUALITY ASSURANCE DEPARTMENT PAGE
SECOND OPS
Secondary Operations
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Fabrication
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Assembly
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Bonding:
Adhesive Bonding
Ultrasonic Welding
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Heat Staking
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Secondary Finishing Operations:
Machining (Pre & Post)
De-Gating
De-Flashing
Tapping
Polishing
Grinding
Bead Blasting
Annealing
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Insert Molding:
Threaded Inserts
Over Molding Plastic
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Ultrasonic
Heat Staked
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Custom Inserts
Connectors & Pins
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Pad Printing
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Bar Coding
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Custom Packaging
Warehousing
Drop-Shipping
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