Plastic is extensively used in various industrial applications. There are two main processes of plastic molding: injection molding and thermoforming, you can use these methods to mold the plastic according to your specification. As the technology is evolving, the need for plastic injection molding and thermoforming techniques is also overlapping. Choosing the right method in this situation is crucial to get started. In this article, we will discuss some in-depth features, applications, advantages, and working principles of Injection molding and thermoforming.
What is Injection Molding?
Injection molding is a manufacturing process that led the production of the parts in large volumes. Injection molding works by injecting molten materials into molds. It is used for the production of a large number of similar products. Injection molding is most commonly used with thermosetting polymers and thermoplastic but metal, glass, and confections can also be processed. This process is used for a variety of parts ranging from small parts to the entire body. For creating automotive parts, bottle caps, toys, pocket combs injection molding is ideal.
What is Thermoforming?
Thermoforming is the multifaceted famous process in the manufacturing sector for its cost-effectiveness and easy operating attributes. It’s the process of softening and using a heated sheet of thin plastics and turning them into products. Thermoforming is not an end-to-end solution. It may create parts that can be used in the larger piece or act as a complement of another part. Most industries at one point or another used thermoforming process, so understanding its strength and weakness is crucial.
Features and Benefits of Injection Molding and Thermoforming
Injection molding allows manufacturers to produce a large number of detailed plastic parts. Plastic parts with high quantity production need consistency and repeating that is ensured by injection molding. The benefits of injection molding are mentioned below.
- Large quantity can be produced before tooling needs maintenance.
- The injection molding process produces very low waste in the manufacturing process.
- The injection molding process makes plastic extremely flexible and gives manufacturer freedom of choice for design.
- Low labor cost because the majority of the process is automated.
Thermoforming is an ideal procedure for the smaller production quantity. Parts and tools modification in thermoforming is quick and economical. Some benefits of thermoforming are mentioned below.
- It has a lower maintenance cost as compared to the injection molding
- Thermoforming provides quick product development and prototyping.
- This process has more options than injection molding like different textures and bright colors.
- Controlling is easy with simple adjustment and extremely adaptable.
How Injection Molding Works
In the injection molding procedure, thermoplastic pellets are heated in high temperatures to turn them into liquid then inject into a custom 3D mold at high pressure. The melted plastic material fills the void in the 3D mold. The material is then cooled to turn it into a solid state in the shape of the intended desired part. Then the molded plastic part is removed and required finishing is done like the surface painting to get the final product. Injection molding is used for small intricate parts and large production runs.
How Thermoforming Works
In the thermoforming process, a custom design single-sided 3D form plastic is created with aluminum. After that, the sheet of the plastic is heated to a pliable temperature then molding it around the custom design through suction from vacuum or suction and pressure. The final pieces of the thermoformed pieces are trimmed. Now, they can be used uncoated, silk-screened, or painting for the finishing purpose. Thermoforming is used for the large design and smaller production runs.
Advantages of Injection Molding and Thermoforming
While injection molding is more costly than thermoforming, performing undercutting or streamlining and simplifying the part design significantly reduces the price per part. The parts that are created with injection molding are durable and their strength can be increased by extra engineering. It has more options in size and complexity than thermoforming. Injection molding can be useful in low and large manufacturing. This process gives you more free hand to control the color of the products with masterbatches and compounding. In injection molding, you can use fillers to reduce the density of the plastic while being molded and increase the strength of the end product.
Thermoforming is used simple single side molding from highly formable material, so making design modified is easier than injection molding. The plastic used in thermoforming is of higher quality and more durable than the plastic used in injection molding. Thermoforming is suitable for JIT (just in time) production strategy with larger parts and wider designs. It is also used in converting thick sheets into thin-walled parts which are ideal for weight-sensitive applications. All thermoformed materials are recyclable.
Total Expense of Molding
To anticipate the expense of injection molding and thermoforming, first, you have to determine the factors like material, part size, complexity, and output quantity you want to produce. These factors help you forecast the estimated overall cost of the plant. Generally, injection molding requires heavy-duty, dual-side mold that can bear the 530 tons of pressure so it requires more expensive materials like steel, beryllium copper alloy, and heavy aluminum.
Once the installation and tooling are done, you can cost-effectively produce repeated large orders. While thermoforming is less expensive than injection molding. It uses a less expensive single-side tool. Because the pressure used in thermoforming is not as great as in injection molding, the tooling can be from aluminum, a less costly material. Thermoforming also has a much shorter time lead as compare to Injection molding.
Applications of Injection Molding and Thermoforming
Speedy development in the plastic industry with continuous enhancement in the plastic strength and precision, the application in plastics items are also expanding. Some applications of injection molding and thermoforming in different industries are mentioned below.
- Food & Beverage: Injection molding use BPA-free and non-toxic plastics that are safe for food and resist temperature changes
- Car Industry: High quality and low-cost production has made injection molding the best option for car manufacturers to turn to injection molding.
- Medicine: Cheaper medical parts like heart pumps, monitors, and other medical equipment can be produced from injection molding which makes healthcare accessible to more people across the world.
- Aerospace Industry: Aerospace industry uses an injection molding process because of its complex geometry and tight tolerance features for producing parts like turbine housing, lenses, panels, bezels, and chassis components.
- Packaging: Thermoformed plastic trays and containers are used in prepackaging fresh meats, eggs, and fresh fruits. Producing thermoformed products near the food preparing facility reduces the cost of inventory and shipping.
- Transportation: Interior finishing parts like seats, armrests, fold-down tray table, glove compartment, and spoilers are formed using the thermoforming technique.
- Appliances: Thermoforming is the widely used process in the manufacturing of freezers door liners, refrigerators, dishwashers, cloth dryers, and television and computer cabinets.
- Recreational Equipment: Exercise and fitness, protective glass, RV external panels, and equipment enclosures are the recreational equipment that is formed using the thermoforming method.
Which process should you use?
Injection molding and thermoforming are the two main manufacturing processes for crafting plastic parts. This process offers unique advantages depending upon the application.
If you are a manufactures that needs highly detailed components with variable thickness, sharp corners, and angels you should go with injection molding. Smaller plastic parts producer who needs to fill frequent large orders always opt injection molding as process to go with. If you have the large investments and has the requirement similar to ones mentioned above you should pick injection molding.
If your production is based on large plastic pieces and combining many components into a single piece then thermoforming is for you. Thermoforming is used for smaller orders or creating a large part for one time. Manufacturers use this method for products that don’t require complicated design and varying thickness. Thermoforming doesn’t need a large investment and has a short lead time as compared to injection molding.
After discussing the differences between injection molding and thermoforming and briefly go through every consideration you should look at before making a decision, you are in a position to select the best option for the application you need in your manufacturing.
If you need world-class service for the installation of any facility no matter it is injection molding or thermoforming DEK should be your first choice. DEK is the top-notch demand manufacturing and machining service, provider. We have high-end manufacturing technologies with strict control to ensure high quality. Place your order today to receive your product at your business address. You can also contact our engineers for technical support.