How Injection Molding Works
The introduction of newer technologies has completely transformed the manufacturing industry, and one of these technologies is injection molding.
The injection molding process was developed to help manufacturers produce a wide range of parts, including plastic components for cars, appliances, kitchenware, clothing, and many more. Injection molding helps improve product quality while reducing the overall production cost significantly.
Here are the basic steps in injection molding.
Design the Product
The first step is designing the product. The design of a part or component should be very detailed, so the manufacturers will have complete knowledge about its production and assembly.
Designing the product using computer-aided design (CAD) software allows manufacturers to visualize a product and test it on different screens easily. Using this technology, product designers can create models with high accuracy and in very little time.
Create a Mold for the Product
The next step in injection molding involves creating a mold for the product. The process of creating molds involves selecting suitable materials and designing them according to the required specifications.
At any phase of a project, drawing tools help designers to communicate their ideas with other people involved in the design process, such as analysts, engineers, and project managers. In addition, analysis and simulation tools come in handy when designing a mold.
Prepare and Measure the Material
Manufacturers should prepare the material for injection molding in a precise way. You should measure the material accurately to ensure that it meets design requirements and conforms to standards.
Suppliers generally provide the material used for injection molding as pellets or granules or in liquid form. It is then mixed with dyes, pigments, or flame retardants to produce the required color and finish. This mixture is then heated in an extruder to convert it into a typical “plastic” material with uniform properties.
Prepare the Mold
You must prepare a mold for product manufacturing after measuring and mixing the material that will be molded. The molding process cannot begin until the mold is ready for it.
The process of preparing a mold starts by assembling two halves. For example, if the material being molded is an object with hollow spaces inside, such as pipes or bottles, then each half will have separate cavities and openings for injecting the molten product into them. You can also make molds with a single cavity for creating solid objects.
To create the mold, manufacturers should use materials that will not shrink or warp when exposed to high temperatures and pressures. Materials such as aluminum, copper, steel, and plastics are commonly used. For example, metal molds are often manufactured with a casting process.
Fill the Mold
After a mold has been prepared, the material that will be molded, such as thermoplastics is injected into it. The mold should be tightly-closed so that nothing can leak out of it.
The process of injecting liquid materials like plastic into molds uses an injection machine. The machine forces the molten material from a holding tank through tubes and injectors, which regulate the pressure and flow rate.
To create a product with different colors and decorative patterns, manufacturers can use multi-injection machines that inject several materials into separate areas of the mold at once. In addition, manufacturers can use transparent materials such as glass to create translucent parts to get an interesting visual effect.
Allow Time for Solidification
Once the material has been injected into the mold, manufacturers need to cool it down for a while. This step is called “solidification” and usually takes several minutes or hours.
For certain products, such as light bulbs with metal housings, solidification can take days. After the product cools down, you must shut off the cooling machine.
Open the Mold and Remove the Product
The final step in injection molding involves opening the mold and removing the plastic, metal, wax, or other materials that have been molded.
If there is a need to manufacture large quantities of products, the time required for each cycle will depend on factors such as material quality, mold design, size, and weight of the product.
For simple products such as small toys or pens, the process will take no more than 20 minutes. However, some manufacturers can spend entire days producing a single product that is only available in limited quantities.
Final Thoughts
There is a lot more involved in injection molding than just putting plastic in a machine and pressing a button.
To get the right material and product quality, manufacturers need to consider design ideas, production requirements, and process feasibility. Ensure you are aware of all the issues before deciding to select this method for your injection molding needs.
