The tooling used for plastic injection molding is called a plastic mold or plastic injection mold. The plastic mold is made from a combination of steel plates and other mold components, coupled to form an overall mold, which is then reliably assembled and installed in an injection molding machine, then applies a thermoplastic resin to the desired shape to fulfill the intended purpose.Most plastic products are molded by plastic molds.According to the molding plastic characteristics, plastic molds are divided into thermosetting and thermoplastic mold.Injection mold must satisfy a multitude of demands simultaneously when the molding process is being conducted. To form a plastic component having the shape of the mold cavity, the mold must contain the polymer melt inside the mold cavity.
Advantages of Plastic Mold
High production efficiency
Plastic molds can achieve rapid production and can produce complex shapes and precision components. In modern industrial production, the application of plastic molds can greatly reduce manual operations, production time and costs. Compared with traditional manual processing, the production efficiency of plastic molds is several times higher.
Cost control advantage
The manufacturing cost of plastic molds is relatively low, and they can be mass-produced. During the plastic molding process, only simple tools and equipment are needed, which has certain advantages in cost control. In addition, in some large enterprises, plastic molds can also be processed and repaired for secondary processing, which can achieve more sustainable production.
Stable quality
Plastic molds use modern manufacturing processes and materials to ensure the quality and precision of plastic products, thereby achieving a certain quality stability. Compared with traditional production methods, the quality of products produced by plastic molds is more uniform, avoiding errors and instability during manual processing, and ensuring the consistency and reliability of product quality.
Strong design flexibility
Plastic molds can be customized according to different customer needs, and can produce plastic products with different shapes and high precision to meet the needs of different industries and fields. In terms of design, plastic molds are more flexible and can adapt to different production needs, helping companies to produce more efficiently.
Why Choose Us
Our Factory
Shenzhen Innolead Intelligent Co.,Ltd is a local company in Shenzhen, China. Innolead specializes in effective outsourcing of manufacturing metal and electronic products for worldwide companies, guaranteed with ISO 9001:2015 standard certificate. By establishing a reliable supply chain management overseas, Innolead offers customers the fastest, lowest cost, and best quality products.
Company Certificate
We have received the ISO 9001 certification. With great efforts in the past several months, each of our departments has successfully gone through strict inspection adopted for ISO 9001. We will always produce trustworthy products for our clients, which is our promise and ultimate aim.
R&D Capability
Innolead is backed by a strong R&D team, which is composed of creative and motivated professionals. Our experienced R&D department provides new product designs by manipulating science and research functions to better serve our clients and promote our products.
Services
Our services include creative problem solving in all areas, either by designing a new solution or implementing an existing solution, often in a new context.
Basic Fundamentals of Plastic Mold Designing
Part Design Considerations
Plastic mold design begins with the part requirements. Designers carefully analyze the part geometry, dimensional tolerances, and surface finishes to determine the best approach for creating the mold. The part geometry should be under the confines of the machine clamp to ensure it is moldable, and the draft angles must be correct to enable easy ejection of the part.
Material Selection
Material selection is a crucial aspect of plastic mold design. The material properties, such as viscosity and thermal conductivity, impact the mold design, such as cooling channels, mold temperature, and injection pressure. Designers must consider the melting point, shrinkage, and warpage characteristics of the material to develop an effective mold design.
Gate Design
The gate design is crucial for the successful production of an plastic molded part. The gate is the point where the molten plastic enters the mold cavity and sets the stage for the filling process. The gate size needs to be appropriate based on the product type, material properties, and injection pressure, and its location should be optimized for ease of removal.
Mold Design
Mold design includes elements such as the number of cavities, runners, cooling systems, parting line determination, and ejection. These elements contribute significantly to the quality and efficiency of the plastic molding process. The balance of filling, packing pressure, and cooling are crucial elements that need consideration while designing the mold.
Design for Manufacturing
Designers must consider the manufacturing process in the mold design process. Features such as undercuts, threads, and snap-fits can be challenging to produce unless they are carefully designed and implemented. Including part-specific projections, chamfers, ribs, and alignment features in the mold can ease the production and improve the performance of the component.
Documentation
Plastic mold design should not stop with the creation of the mold. Comprehensive documentation, including 2D/3D drawings, bill of materials, maintenance and repair guidelines, and safety procedures, is crucial for ensuring efficient communication and easy navigation of the mold's life cycle. Regular updates to the documentation ensure it remains accurate and up-to-date.
Plastic Mold Structures Are Divided by Function and Which Include
Pouring systems
This is the part of the runner before the plastic enters the cavity from the injection nozzle and includes the main flow channel, the cold cavity, the manifold, and the gate. The pouring system and molded parts are in direct contact with the plastic and vary with the plastic and the product. They are the most complex and varied parts of the mold, requiring the highest degree of finish and precision.
Molded parts system
It is a combination of various parts that make up the shape of the product, including the dynamic mold, the fixed mold and the cavity (concave mold), the core (convex mold), the forming rod, and other components.
The core forms the inner surface of the product and the cavity (concave mold) forms the outer surface of the product. After the mold is closed, the core and cavity form the cavity of the mold.
According to the process and manufacturing requirements, sometimes the core and concave mold are combined by several blocks, or sometimes they are made into a whole and only difficult-to-process parts use inserts.
Temperature regulation system
To meet the mold temperature requirements of the injection process, a temperature regulation system is required to regulate the temperature of the mold. In the case of thermoplastic injection molds, the cooling system is designed to cool the mold (the mold can also be heated).
The common method of cooling the mold is to open a cooling water channel in the mold using the circulating cooling water to take away the heat from the mold. The mold can be heated by using hot water or hot oil in addition to the cooling water. However, the process can also be done by installing electric heating elements in and around the mold.
Exhaust system
To carry out the injection molding process in the cavity of the air, plastic melting is generated by the gas out of the mold and set up. A plastic mold exhaust system is usually a slot in the mold to open the air outlet to discharge the original cavity air and melt into the gas.
Guidance system
To ensure that the moving and fixed molds are accurately aligned and set up when the mold is closed, guiding elements must be provided in the mold. In injection molds, four sets of guide pillars and guide bushings are usually used to form the guiding parts. Sometimes it is necessary to set up the inner and outer tapered surfaces on the moving and fixed molds respectively to assist in the positioning.
Ejector system
It generally includes: ejector pin, front, and rear ejector plate, ejector pin guide bar, ejector pin reset spring, ejector plate locking screw, and other parts. When the product is molded and cooled in the mold, the front, and rear molds are separated and opened. Additionally, the plastic product and its condensed material in the runner are pushed out or pulled out of the mold cavity and runner position by the pushing mechanism - the ejector pin in the injection molding machine, to carry out the next injection molding work cycle.
Materials Used in Plastic Mold
Nylon (PA)
Nylon is the name for a family of synthetic polymers composed of polyamides (PA). Nylon is a silk-like thermoplastic, typically made from petroleum, that can be melt-processed into fibers, films, or shapes. Nylon polymers are used in many commercial applications.
ABS Plastic
ABS (acrylonitrile butadiene styrene) is a high-strength general-purpose engineering plastic used for many commercial products. ABS is durable and lightweight. It is a terpolymer created by polymerizing styrene and acrylonitrile in the presence of polybutadiene. The proportions can differ from 15% to 35% acrylonitrile, 5% to 30% butadiene and 40% to 60% styrene.
Polycarbonate (PC)
Polycarbonate is a high-performance, transparent, engineering-grade thermoplastic that can be used in higher temperature environments, due to its relatively high melting point (155℃). Those qualities come together with a higher price tag, but this aspect is balanced by the versatility polycarbonate.
The main features of this thermoplastic revolve around toughness and high strength, which translates into resistances to impacts and fracture resistance. These resistances are complemented by the material's high density (1.2 – 1.22 g/cm3).
Acetal Copolymer (POM)
Acetal is the common name for a family of thermoplastics with the chemical name "PolyOxy-Methylene." As a semi-crystalline material, acetal is has a low coefficient of friction and good wear properties.
Acetal Homopolymer
Acetal Homopolymer is a tough, resilient plastic that has rigidity, good creep resistance, toughness, dimensional stability, lubricity, surface hardness, and low moisture absorption.
Engineered Thermoplastic Polyurethane (ETPU)
Thermoplastic Polyurethane is soft and elastic, with excellent tensile and tear strength. For this reason, it is often used to make parts that demand a rubber-like elasticity. ETPU is more expensive than other resins, but there is no substitute for many applications, such as protective wire and cable sheaths. Another advantage is that TPU improves the grip for products that need to be held securely in hand.
Liquid-crystal Polymer
Liquid-crystal polymers, or LCPs, are polymers with liquid crystal properties, usually containing aromatic rings as mesogens. In spite of uncrosslinked LCPs, polymeric materials like liquid crystal elastomers (LCEs) and liquid crystal networks (LCNs) can also exhibit liquid crystallinity. They are both crosslinked LCPs but have different cross-link density. They are commonly used in the digital display market.
Linear Low-density Polyethylene
Linear Low-density Polyethylene is one of the most commonly used packaging films in the packaging industry. The density reduction comes about by using comonomers that put side groups on the main chain that act like branches in decreasing crystallinity. It is a soft, flexible material.
Acrylic (PMMA)
PMMA, also known as acrylic glass, is a transparent thermoplastic often used as a replacement for shatterproof glass. PMMA is fully recyclable, but due to its similarities to glass, it is usually combined with various additives or fillers to enhance specific properties such as impact resistance, flame retardancy, chemical resistance or UV light filtering.
Polystyrene (PS)
Polystyrene is a very commonly used plastic in packaging applications and consumer goods due to its relatively low cost. However, PS-based litter takes a very long time to decay. Depending on the type, PS can either be classified as a thermoplastic or thermoset (a plastic that is not melted for processing).
Polypropylene (PP)
Polypropylene is made of a combination of propylene monomers. It's used in everything from industrial automotive to consumer products. A notable feature of this plastic is its glue resistance, meaning that glue will have a hard time sticking to parts made of this material. For this reason, welding is usually employed whenever bonding is needed.
Types of Plastic Mould
Low / High Cavitation
Single cavity molds are designed to produce one part per cycle. They are a cost-effective approach when part volumes are low as they are less expensive to build. They also have a shorter lead time.
Family Mold
A family mold has a single mold base but two or more different cavities, allowing for the production of two or more different parts. All the parts can either be produced simultaneously or shut-offs can be used to isolate production to selected cavities. For best results in molding, the parts should be similar in size, shape, resin, and anticipated volumes, especially if the intention is to run all parts at the same time. Automation may be necessary to separate the pieces during or after production.
Unscrewing Molds
Unscrewing molds are the most common method of creating threaded holes within a plastic part. These molds are automated with small drive systems (rack & pinion, electric, or hydraulic motors) that are tied into the process and rotate threaded features to extract undercut features. Threads can be internal or external, and the extraction is tied into the press cycle.
Hot Runner Molds
Hot runner tools use a temperature-controlled manifold to greatly reduce or eliminate runner scrap from the cycle. Injection points can be outside the part or directly into the part. This can greatly improve cycle times, as a sprue or runner system is often a determining factor on the mold cycle. And, eliminating the runner saves expensive wasted material.
Cold Runner Molds
Cold runner molds are good examples of more traditional tooling in that they utilize sprues and runners to gate into the part. This is typically the least complicated form, however may result in larger amounts of wasted material and slower running cycles. Depending on the application, a percentage of wasted material may be re-ground and re-processed for future use, though this could affect the physical properties of the resin.
Insulated Runner Molds
Insulated runner tools resemble more traditional cold runner molds but utilize cartridge heaters or other methods of heating to form a surrounding layer of molten resin, forming an insulated “cull” to create a similar effect to a hot runner system. This approach is less expensive than using a hot runner which requires a temperature controller and also has the benefit of allowing for faster color and material changes. However insulated runners are not suitable for all types of materials and typically do not work well with more demanding engineering grade resins.
Two / Three Plate
Three-plate molds are cold runner tools, but by adding a third plate to the runner system, you are able to locate your injection point into virtually any location on the tool. This is usually less expensive than adding a hot runner system, however this type of mold often has large and unwieldy runners, which can be more difficult to automate.
How to Maintain Plastic Mold
Cleaning
Regular cleaning is essential. Dirt, debris, and residues can impair the performance of the mold and the quality of the products. Use non-abrasive cleaning methods like ultrasonic cleaning or dry-ice blasting to ensure the mold's integrity.
Inspection
After cleaning, inspect the mold for signs of wear, damage, or misalignment. Look for cracks, wear, rust, and other imperfections. Pay close attention to the vents, which can become clogged and lead to part burns or short shots.
Lubrication
Lubricate the moving parts of the mold to reduce wear and ensure smooth operation. Use a lubricant that is compatible with the material you are molding to avoid contamination.
Polishing
Polish the mold's surfaces to maintain a good finish on the plastic parts. Do not over-polish since this can alter the mold's dimensions and lead to part inconsistency.
Repair
If you find damaged components during the inspection, repair or replace them immediately. A small problem can quickly become a big one if not addressed promptly.
Preventive Maintenance
Implement a preventive maintenance schedule based on the manufacturer's recommendation and your tool's specific use history. This should include tasks like checking for looseness in the mold, lubricating, and cleaning.
Temperature Management
Ensure the cooling/heating system of the mold works effectively. Temperature variations can cause stress, leading to cracks and warping in the mold.
Storage
When not in use, store the mold in a controlled environment to prevent rust and degradation. Seal it properly and keep it in a dry, temperature-controlled area.
FAQ
Q: What is a plastic mold?
Q: What is the strongest plastic mold?
Q: How many types of plastic mold are there?
Q: What are plastic molds made from?
Q: How long do plastic molds last?
Q: How do you use plastic molds?
Q: Are plastic moulds reusable?
Q: How to select plastic for injection molding?
Q: What is the working principle of injection mould?
Q: What is the structure of plastic injection mould?
As one of the most professional plastic mold manufacturers and suppliers in China, we're featured by quality products and competitive price. Please rest assured to buy customized plastic mold made in China here from our factory.
Small Neck 24mm 30mm 28mm Pco Plastic Preform Injection Mold, Injection Stretch Blow Molding Service, Precision Plastic Silicone Rubber Injection Mold For Electronic Enclosure