Injection molding is a process by which you can make components using heated plastic. This heated plastic is injected into a mold and allowed to solidify. Then, it is removed from the mold once ready. Choosing the correct type of plastic is essential in this case, as the project’s quality relies on the component’s quality. As such, the project requirements will determine which plastic you select.
Following is a guideline on how to choose the right plastic for injection molding parts
The Process of Selecting a Material
Identify the Design Requirements
The first thing to do is to identify what exactly your requirements are. It includes but is not limited to thoroughly understanding the function of the finished product, the expected lifespan of the component, the conditions under which it is expected to operate, etc.
Identify the Material Selection Criteria
It is the part where you should consider the stiffness, strength, chemical resistance, thermal properties, and overall cost of different types of plastics.
Identify Candidate Materials
Once you know what type of material you need and what conditions you need it for, you can begin to shortlist the materials you know will perform well under your requirements. You can start this process by consulting supplier catalogs and material databases or working with material experts.
Evaluate Candidate Materials
You should have a list of possible materials to select at this stage. It is when you should test these materials against your requirements through simulations or by collecting data from material suppliers.
Select the Material
It is the final step in selecting materials, and choosing the material best fits the design requirements and the selection criteria is critical.
Factors to Consider During Material Selection
Thermal and Physical Properties
These properties include density, melting point, thermal conductivity, strength, and stiffness. For example, materials with high melting points can withstand high temperatures, while materials with high stiffness are ideal for applications that require durability.
Injection Molding Capability
The material selected should be suitable for the injection molding process, meaning that it should be capable of flowing easily, filling the mold cavity without any defects or air bubbles, and should solidify relatively quickly.
Aesthetics and Dimensional Accuracy
The material should be able to produce parts with the required surface finish, texture, and color so that, in terms of aesthetics, it looks and feels good. Additionally, the material should maintain dimensional accuracy, which is crucial for parts that require precise fitting and alignment.
Resistance to Chemicals and Weather
Materials used in outdoor products should withstand exposure to sunlight, water, and extreme temperatures. Materials used in factories with hazardous gasses should not react negatively with those chemicals, and so on.
What you select should be compatible with the assembly process, including fastening, bonding, and welding (if need be).
Some materials are more expensive than others, and some may have a significant environmental impact during production and disposal. Optimizing the balance between material cost and product performance is crucial for achieving a successful and profitable injection molding process.
When selecting the material, strike a balance between cost, performance, and environmental impact. It is essential to evaluate the environmental impact of plastic during material selection for injection moldings, such as biodegradability and recyclability. Choosing eco-friendly plastics helps to minimize waste and contribute to a more sustainable future
Common Plastic Materials and Their Properties
PVC (Polyvinyl Chloride)
PVC is a rigid plastic resistant to chemicals, weathering, and impact.
PP is a versatile plastic that is lightweight, durable, and resistant to chemicals and heat.
ABS (Acrylonitrile Butadiene Styrene
ABS is a tough and rigid plastic resistant to impact and heat.
PA is a strong and lightweight plastic resistant to abrasion and chemicals.
POM is a stiff plastic that can withstand abrasion and moisture.
PC is a durable and transparent plastic that resists impact and heat.
PMMA is a transparent plastic that is resistant to impact and weathering.
PE is flexible, lightweight, and resistant to chemicals and moisture.
UHMWPE (Ultra High Molecular Weight Polyethylene)
UHMWPE is a strong and durable plastic resistant to abrasion and impact.
Example Materials for Different Industries
- PP: Used for interior and exterior parts such as bumpers, dashboards, and door trims due to its high strength, impact resistance, and good chemical resistance.
- ABS: Used for exterior parts such as body panels and grilles due to its high impact resistance and strength.
- PC: Used for electronic enclosures and covers due to its high impact resistance, clarity, and ability to withstand high temperatures.
- ABS: Used for computer cases and keyboards due to its toughness and resistance to high temperatures and humidity.
- PPO: Used for circuit boards and connectors due to its high dielectric strength, good dimensional stability, and ability to withstand high temperatures.
- HDPE: Used for pipes, barriers, and safety equipment due to its high strength, flexibility, and resistance to UV rays and moisture.
- PVC: Used for window frames, pipes, and roofing materials due to its durability, low cost, and resistance to weather and chemicals.
- PC: Used for skylights and roofing panels due to its high impact resistance, transparency, and ability to withstand extreme temperatures.
- TPE: Used for grips and handles due to its flexibility, durability, and resistance to sweat and moisture.
- PVC: Used for exercise mats and flooring due to its cushioning properties, slip resistance, and durability.
- ABS: Used for weight plates and dumbbells due to their toughness, impact resistance, and ability to withstand repeated use.
Lawn and Garden
- PP: Used for garden tools, planters, and irrigation systems due to its resistance to UV rays, moisture, and chemicals.
- HDPE: Used for outdoor furniture and decking due to its resistance to moisture, UV rays, and insects.
- PC: Used for greenhouse panels and covers due to its high impact resistance, transparency, and ability to withstand extreme temperatures.
View more molded parts in various industries!
Zhongde has a wide variety of materials and an extensive library because of our large supplier base. We have exactly what you need, and our team of experts understands plastic materials better than anyone else! It is why you should choose Zhongde for your injection molding plastic needs.