1. What is plastic injection molding?
1.1 What are plastic injection molds used for?
1.2 What is plastic injection molding process?
1.3 What plastic is good for injection Molding?
1.4 What are plastic injection molding advantages and disadvantages?
2. How much does plastic injection molding cost?
2.1 How do plastic injection molds work?
3. Why you need plactic injection molding?
What is plastic injection molding?
Plastic Injection molding also known as plastic molding processing. It is a general term for various processes that convert synthetic resin or plastic into plastic products, and is a larger production department in the plastics industry. Plastic processing generally includes plastic ingredients, molding, machining, joining, modification, and assembly. The last four processes are carried out after the plastic has been molded into a product or semi-product, which is also called secondary plastic processing.
What are plastic injection molds used for?
Plastic Injection molding is used to create many things such as wire spools, packaging, bottle caps, automotive parts and components, toys, pocket combs, some musical instruments (and parts of them), one-piece chairs and small tables, storage containers, mechanical parts (including gears), and most other plastic products available today. Injection molding is the most common modern method of manufacturing plastic parts; it is ideal for producing high volumes of the same object.
What is plastic injection molding process?
Usually, the plastic materials are formed in the shape of pellets or granules and sent from the raw material manufacturers in paper bags. With injection molding, pre-dried granular plastic is fed by a forced ram from a hopper into a heated barrel. As the granules are slowly moved forward by a screw-type plunger, the plastic is forced into a heated chamber, where it is melted. As the plunger advances, the melted plastic is forced through a nozzle that rests against the mold, allowing it to enter the mold cavity through a gate and runner system. The mold remains cold so the plastic solidifies almost as soon as the mold is filled.
What plastic is good for injection Molding?
Commonly used injection molding materials and plastic materials suitable for injection molding include PE, PP, PS and other plastics that have thermoplastic properties and are suitable for thermal injection molding.
PE material: PE, also called polyethylene, is one of the more commonly used polymer materials in daily life. It is widely used in the manufacture of plastic bags, plastic films, and milk barrels.
PP material: polypropylene, polypropylene has high crystallinity and regular structure, so it has excellent mechanical properties. The value of mechanical properties of polypropylene is higher than that of polyethylene, but it is still a low variety among plastic materials, and its tensile strength can only reach 30 MPa or a slightly higher level. Polypropylene with a larger isotactic index has higher tensile strength, but as the isotactic index increases, the impact strength of the material decreases, but it does not change after it drops to a certain value.
PS material: PS is polystyrene.
What are plastic injection molding advantages and disadvantages?
Advantages:
1. Plastic injection mold can be used to accurately control the wall thickness distribution of the parison, so that the wall thickness of the obtained container is more uniform, avoiding the thinning phenomenon that is easy to occur in the corner part of the general blow molded product, and the weight of the product can be controlled at + 0.1g, the accuracy of the thread can be controlled within 100μM, the mouth size is accurate, and the narrow neck product has high forming accuracy;
2. The obtained product does not need to be processed E times, without seams, and saves the finishing time of the product;
3. The parisons made by injection can all enter the blow mold for inflation molding, no waste is generated during the processing, and the waste of molding materials is reduced;
4. Products with smooth surface can be obtained, no scratches, and clear characters and patterns on the surface;
5. Small batch production can be carried out economically;
6. A wide range of applications for plastic varieties;
7. High degree of automation, multi-mode production is possible, and production efficiency is high.
Disadvantages:
1. The molding of the product must use two sets of injection molding and blow molding molds and a hollow core mold with a valve, and the mold of the injection parison should be able to withstand high pressure, and the cost of molding equipment is high;
2. The temperature of the injection parison is higher, and it needs a longer cooling and setting time after being blown in the injection mold, which prolongs the entire molding cycle of the product and affects the production efficiency;
3. The internal stress of the injection parison is large, and it is easy to be unevenly cooled during the mold conversion process. Stress cracking is prone to occur when producing products with complex shapes and large sizes. Therefore, the shape and size of the products are limited, and they are only suitable for production. Small products used in cosmetics, daily necessities and medicine packaging, food packaging and other fields;
4.Higher requirements on the operating skills of the operators.
How much does plastic injection molding cost?
The number of cavities incorporated into a mold directly correlate in molding costs. Fewer cavities require far less tooling work, so limiting the number of cavities lowers initial manufacturing costs to build an injection mold.
As the number of cavities play a vital role in molding costs, so does the complexity of the part's design. Complexity can be incorporated into many factors such as surface finishing, tolerance requirements, internal or external threads, fine detailing or the number of undercuts that may be incorporated.
Further details, such as undercuts, or any feature that needs additional tooling, increases mold cost. Surface finish of the core and cavity of molds further influences cost.
Plastic injection molding process produces a high yield of durable products, making it the most efficient and cost-effective method of molding. Consistent vulcanisation processes involving precise temperature control significantly reduces all waste material.
How do plastic injection molds work?
Plastic mold is a tool for producing plastic products. It is composed of several groups of parts, and there is a molding cavity in this combination. During injection molding, the mold is clamped on the injection molding machine, the molten plastic is injected into the molding cavity, cooled and shaped in the cavity, and then the upper and lower molds are separated, and the product is ejected from the cavity and out of the mold through the ejection system, and finally the mold is closed For the next injection, the entire injection process is carried out in cycles.
Generally, a plastic mold is composed of a movable mold and a fixed mold. The movable mold is installed on the movable template of the injection molding machine, and the fixed mold is installed on the fixed template of the injection molding machine. During injection molding, the movable mold and the fixed mold are closed to form a pouring system and a cavity. When the mold is opened, the movable mold and the fixed mold are separated to take out the plastic products.
Although the structure of the mold may vary widely due to the variety and performance of plastics, the shape and structure of plastic products, and the type of injection machine, the basic structure is the same. The mold is mainly composed of a pouring system, a temperature control system, forming parts and structural parts. Among them, the pouring system and molded parts are the parts that are in direct contact with the plastic and change with the plastic and the product. They are the most complex and the most variable parts in the plastic mold, requiring the highest processing finish and precision.
Why you need plactic injection molding?
The principal advantage of injection molding is the ability to scale production en masse. Once the initial costs have been paid the price per unit during injection molded manufacturing is extremely low. The price also tends to drop drastically as more parts are produced.
Here are the reasons why you need plactic injection molding:
Highly Efficient and Faster Production
Can Accommodate Complicated Designs
Enhanced Strength
It Offers Flexibility on the Choices of Colors and Materials
Reduced Waste
The Automation Process Lowers Manufacturing Costs
Plastic injection molding is very professional. I hope the above information can be helpful to you.
