Injection Mold Maker | Selection of Plastic Molding Materials
Plastic Injection Molding
Details
Details:
Model
Material
Brand
Origin
Application
Booling-Injection-1
P20, 718, S136, 2738 etc
Booling
China
Automotive parts, industrial parts, medical parts, household
Plastic injection molding is a highly flexible and precise technology, and makers have a wide range of material choices, including but not limited to thermoplastic materials such as ABS, PVC, PP, and PC.
Advantages of Plastic Injection Molding：
- High Precision and Repeatability
- Low Cost per Part
- Fast Production Rate
- Wide Material Choice
- Little Waste
Related Hot Products
Plastic injection molding mold maker mainly provides services related to molds and products, such as design, precision manufacturing, sample testing, packaging, and labeling of plastic or liquid silicone injection molding molds. They can also provide services for rapid prototyping plastic injection molding. The design and production of custom injection molding molds are precise and complex, and the product positioning must be determined based on materials, applications, technology, and equipment.
The products of a general injection mold maker have a wide range of applications, involving industries such as automotive, electronics, medical, household goods, industrial, military, etc. The molds and plastic products are sold nationwide, even to countries such as Japan, South Korea, India, Germany, the United States, and Spain.
Selection Criteria for Plastic Injection Molding Materials
When selecting plastic materials for an injection molding mold maker, they should consider the performance and usage environment of the materials, and choose the plastic that is most suitable for this product or process.
- Thermal Stability
In the injection molding process, the injection molding material selected by the mold maker needs to be able to undergo long-term processing in a high-temperature and high-pressure environment without decomposition, which requires consideration of the material’s thermal stability and thermal conductivity. Generally speaking, the higher the thermal stability of raw materials, the longer they can withstand high temperatures and pressures, resulting in a longer service life and better durability of the products produced.
- Flexibility
The toughness of materials is also one of the factors that injection mold maker needs to consider. Plastic materials with better toughness can better withstand external impacts and vibrations during use, have better durability and aging resistance, and are less prone to brittleness or cracking and deformation.
- Requirements for the Final Product
Different plastic products have different uses and require different performance requirements for the materials. Therefore, when selecting materials, it is necessary to focus on understanding the requirements of the final plastic molded parts. For example, some plastic products require a high degree of surface smoothness, so injection mold maker needs to choose plastic materials with high hardness and high molecular density. However, some plastic molded parts do not have special requirements for smoothness, and an injection mold maker can choose mold materials with low hardness, low density, and low transparency, and even use recycled materials.
- Corrosion Resistance
In the process of injection molding, materials may be corroded by various chemicals, so injection mold maker also needs to consider the corrosion resistance of materials. Generally speaking, different plastic products have different requirements for the corrosion resistance of mold materials, and it is necessary to choose mold materials that can withstand the corrosion of specific chemical substances.
- Processing Flexibility
The processing flexibility of mold materials is also one of the selection factors. The materials selected by injection mold manufacturers are generally not only used for the production of one product but also need to be applied to other products, so the selected materials should have a certain degree of processing flexibility.
- Hardness
The hardness of materials is one of the selection factors for manufacturers in injection mold processing. Mold materials with high hardness can withstand greater pressure and wear, and have a longer service life. However, plastic mold materials with excessively high hardness are also more prone to problems such as cracking and deformation, so injection mold maker needs to choose the appropriate material hardness based on specific circumstances.
Basis for Purchasing Raw Materials for Injection Molds
Plastic injection molding mold maker has a very strict procurement process for raw materials. Raw materials are the beginning and foundation of the entire injection molding process, determining the quality and performance of subsequent products.
- Each material department needs to assign weighing tasks to the weighing personnel based on the procurement information and supply time of the materials. The weighing personnel have the main responsibility for monitoring the quality of the materials, and all weighing materials must not flow out and must enter the site. Injection mold manufacturers should try their best to avoid night loading and eliminate the possibility of major errors.
- An injection mold maker should strictly control the cost of raw materials to avoid significant impact on material costs due to price fluctuations and strengthen quality control on this basis.
- Each department of the injection mold maker is responsible for the quality and quantity of materials and should propose certain measures to deal with this, such as conducting quality spot checks on purchased materials from time to time to avoid passing off inferior materials as good, reporting problems promptly, and replacing a batch of better quality materials.
- Injection mold suppliers should provide the required material quantity and expected delivery time to the Material Procurement Department at least 3 days in advance, to select better material suppliers.
Performance Basis of Raw Materials
Mold maker should select plastic raw materials based on their injection molding performance and product requirements, and process them accordingly.
- ABS
-Drying treatment: Before ABS injection molding processing, drying treatment must be carried out to ensure that its humidity and moisture content are less than 0.04%. It is recommended to dry at 90-110 ℃ for at least 2 hours.
-Melting Temperature: 230~300 ℃
-Mold Temperature: 50~100 ℃
-Injection Pressure: It depends on the specific shape, size, and performance of the plastic part.
-Injection Speed: Within a reasonable range, an injection mold maker should strive to increase the injection Speed as much as possible
-Chemical and Physical Properties: Injection grade ABS material is a high-performance engineering plastic, and its injection molded products have good impact resistance and can maintain a certain degree of toughness at lower temperatures. It has good electrical insulation performance and is easy to process and shape. ABS material is not corroded by the vast majority of chemical agents and its performance is relatively stable.
- High-Density Polyethylene (HDPE)
-Drying: If the mold maker stores HDPE properly before injection molding, there is no need to dry it in advance.
-Melting Temperature: 220~260 ℃
-Mold Temperature: 50~95 ℃. The specific situation needs to be set according to the wall thickness of the plastic part. For example, plastic parts with a wall thickness of less than 6mm should use a higher mold temperature, while plastic parts with a wall thickness of more than 6mm should use a lower mold temperature. Once the temperature of the mold is selected, it cannot be easily changed to prevent differences in shrinkage rate.
-Injection Pressure: 700~1050bar.
-Injection Speed: If possible during actual processing, try to choose a higher injection speed.
-Chemical and physical properties: HDPE has high crystallinity, which determines its high density, tensile strength, high-temperature resistance, flowability, and chemical stability. Compared to LDPE, HDPE has stronger resistance to permeability and airtightness, but its impact strength is lower. The characteristics of HDPE are mainly determined by its density and molecular weight distribution, and the molecular weight distribution of injection-grade HDPE is very narrow.
- Low-Density Polyethylene (LDPE)
-Drying: Generally, drying is not required before the injection molding process
–Melting Temperature: 180-280 ℃
-Mold Temperature: 20~40 ℃
-Injection Pressure: up to 1500bar maximum
-Pressure Holding: up to 750 bar maximum
-Injection Speed: It is recommended to use a fast injection speed to improve injection efficiency when processing permits.
-Chemical and Physical Properties: The density of LDPE material is approximately 0.91~0.94 g/cm3. LDPE has a certain permeability to gases and water vapor, but its airtightness is not strong. LDPE has a high coefficient of thermal expansion and is not suitable for processing products that have been used for a long time. After reaching a certain lifespan and time, it may experience cracking, greatly reducing its performance. The actual shrinkage rate of LDPE during processing also depends on the injection molding process parameters set by the injection mold maker. Similar to HDPE, LDPE is prone to environmental stress cracking.
- Polycarbonate (PC)
-Drying Treatment: PC materials have a certain degree of moisture absorption, so drying before processing is very important. The recommended drying temperature is between 100 ℃ and 200 ℃, with a minimum drying time of 3 hours. Injection molding manufacturers must ensure that the humidity before processing is less than 0.02% and carry out subsequent drying and ventilation work.
-Melting Temperature: 260~340 ℃
-Mold Temperature: 70~120 ℃
-Injection Pressure: Use a higher injection pressure as much as possible within the allowable range of conditions
-Injection Speed: Use low-speed injection for smaller gates and high-speed injection for other types of gates.
-Chemical and Physical Properties: Polycarbonate (PC) is an amorphous engineering material with particularly good impact strength, thermal stability, glossiness, antibacterial properties, flame retardant properties, and environmental performance. The shrinkage rate of PC materials is very low, generally ranging from 0.1% to 0.2%. Meanwhile, PC has good mechanical properties, but poor flow characteristics, making the injection molding process of this material difficult and often resulting in uneven wall thickness. When processing products that do not require high wall thickness but require high impact strength, polycarbonate materials can be chosen.
Plastic injection molding mold maker needs to be very cautious in their plastic material selection. Once put into use, unsuitable materials can cause significant losses.
Related News
Applied’s expertise in modifying materials at atomic levels and on an ihdustrial scaleenables our customers to transform possibilities into reality.
