MASS PRODUCTION THROUGH PLASTIC INJECTION MOLDING
The Use of Injection Molding in Manufacturing
In order to remain competitive in today's market, plastic injection molding manufacturers must make use of the most cost-effective materials and production processes. Injection molding is one method many plastic injection molding companies employ to maintain an edge over their competitors. A closer examination of the plastic injection molding process reveals a number of advantages that have more and more plastic injection molding manufacturers integrating it into their production processes.
What Is Plastic Injection Molding?
Plastic injection molding is a manufacturing process that injects molten materials like glass, various polymers, elastomers, confections, and metals (usually referred to as die-casting) into a pre-designed form or mold. This allows for the mass production of a single item or component in a simple or complex shape in a single process, which can be joined or fastened to other parts in an assembly.
Plastic Injection Molding Process
The plastic injection molding process requires six main steps, including plastic injection mold design, plastic injection mold construction, preparation of casting material, plastic mold injection, cooling and finishing.
Plastic Injection Mold Design
The most critical element in the plastic injection molding process revolves around the formation of the dye or mold. Precision is a critical element in mold design. The mold design process includes 3D rendering of the mold design as well as mold flow analysis. These aspects of the design process allow designers to predict how the molten material will flow and cool within the mold. The process also allows for the addition of cooling channels within the mold to facilitate uniform, conformal cooling. The use of these design tools helps save time and money in mold design while ensuring more predictable product quality and performance.
Plastic Injection Mold Construction
Following mold design creation is the process of mold construction. Mold construction includes the machining of the metal used to form the mold. Computer numeric control (CNC) allows for automated machining with a much higher degree of accuracy, which is extremely important when working with complicated shapes. This high degree of precision is especially critical where the edges of the two halves of the mold come together, limiting defects and decreasing the amount of time invested in finishing the component.
Materials Used in Plastic Injection Mold Construction
Mold construction material choice is a critical element in plastic injection mold construction. The most common materials used include:
- Tool Steel - Favored because it is easy to machine, or tool and holds up well for high volume production
- Stainless Steel - Often used in situations where corrosion might cause contamination issues
- Aluminum - Is easily formed and lightweight, but does not hold up as well when high volume production is necessary
Preparation of Polymer Material
Polymer material preparation follows mold creation and placement into the plastic injection-molding machine. Preparation includes heating of the raw material into a molten state. Polymer material usually comes in the form of pellets, fed by a hopper into a large cauldron where they are heated. Various types of materials produce different end-product properties or better facilitate the production process and cooling. Formulation of the exact composition of the raw material is often the result of flow analysis used in the mold design phase.
Types of Polymer Materials Used
Thermoplastic and thermoset polymers are the typical materials used in injection molding with thermoplastics being the most common choice. Thermoplastics contain certain characteristics that make them ideal for injection molding, including better viscosity, greater application versatility, and recyclability. Thermoplastics provide the highest level of cost-efficient production, especially in high volume production environments. There is a vast range of materials available for injection molding, including different variations and blends of polymers, and elastomers.
Plastic Mold Injection
Once heated into a molten state, the raw material is injected into the mold using sufficient pressure to ensure instant flow throughout the interior of the mold. The extreme temperature and pressure used in this stage of the process requires adequate mold durability, which is why steel is most common in mold construction.
Cooling
The molten material cools within the mold before the two halves of the mold open and eject the formed item. Uniform cooling, achieved through the integration of conformal cooling in the design process, ensures characteristic integrity throughout.
Finishing
The process of finishing usually includes inspection for defects using visual inspection equipment as well as the removal of any rough edges at the mold halves joints. Higher precision and lower tolerances in mold design, and machining, help limit the amount of finishing required.
Industries and Applications for Injection Molding
Plastic Injection molding best applies to situations requiring a high volume (several thousand to millions of units) production of a single item or part. Various industries and applications rely on the production of items and components produced by injection molding, including:
- Automotive Parts - Buttons, knobs, bushings, handles
- Medical Equipment and Instruments - Diagnostic instrument cases, probes, surgical instruments, sterilization trays
- Consumer Products - Hygiene items, cooking utensils, furniture, cleaning tools
- Packaging - Bottle caps, containers, case inserts
- Toys and Games - Game pieces, wheels, blocks, dolls
- Lawn/Garden Equipment - Implement handles, selector dials, housings, guards
- Appliance Components - Handles, shelves, drawers, controls
- Computers - Computer cases, keyboards, pointing devices, thumb drives
- Electronics - Buttons, cases, dials, headphones, earbuds
- Telecommunications - Cell phone cases, keypads, modems
These are some of the most common industries and applications, which utilize plastic injection molding in order to produce components for the items used on a frequent basis. This list scratches the surface of existing uses, but due to its many advantages, items produced through plastic injection molding is rapidly increasing.
Advantages of Injection Molding in Manufacturing
Plastic injection molding holds a number of advantages in manufacturing. Some of the most telling advantages include:
- Product Versatility - Because of the broad range of available materials allows for the manufacture of a wide range of products and applications.
- Capacity to Produce Complex Shapes - Advancements in design technology allow for complex 3D rendering and conformal cooling designs, which make forming complex designs feasible.
- Manufacturing Efficiency - Pre-designed precision allows manufacturers to meet the precise specifications of customers while the production process accommodates in high volumes with shorter run-cycles.
- Enhanced Strength - Fillers and the addition of compounds with various strengthening properties are possible.
- Predictable Outcomes - 3D rending, flow analysis, and conformal cooling allow designers to predict the exact end-product outcome during the design stage, saving clients plenty of time and money.
- Simultaneous Use of Materials - Injection molding allows for the simultaneous use of several materials with varying properties to produce a specific product outcome.
- Cost-Effective Production - Because of recyclability and availability, the raw materials used in injection molding reduce cost per unit. Technological advances also contribute to limiting the costs associated with prototype designs as well.
- Sustainable - The use of recyclable materials in the injection molding process making a sustainable manufacturing process.
To remain competitive in today's market, plastic injection molding companies have to apply cost-effective and process efficiency to their manufacturing operations. Plastic injection molding provides those solutions along with another range of advantages that limit production costs and cycles times without sacrificing profit margins. Bennett Plastics specializes is a plastic injection molding company. Plastic injection mold production spanning a broad range of industries and applications. We have the expertise and equipment to provide our clients with timely, cost-effective production using plastic injection molding. Contact us to learn more about the injection molding solutions available to your organization from our plastic injection molding company Bennett Plastics.
Please do not hesitate to contact Bennett Plastics to learn about our plastic injection molding manufacturing services!