Generally, the injection molding process has no fixed cost for every application. Custom injection molding cost has a varying value that ranges from thousands to hundreds of thousands. Below are common factors that impact the cost of injection molding.
It is expensive to machine the mold and mold base for the products, even though the molding equipment is a one-time investment. Besides, the process used to create the molds determines the cost. The standard techniques used in making molds include CNC machining, electric discharge machining, and 3D printing.
The CNC machining process is well-suited for making metal molds from aluminum or steel materials. For instance, CNC machines use cutting tools to remove materials from an aluminum block to machine an aluminum mold. Besides, this machining method produces aluminum molds with high accuracy.
Electrical Discharge Machining (EDM) is an assisted technique for making molds with complex and precise features. It involves using electrical discharge to melt and form the metal workpiece into the desired size and shape. Although EDM offers excellent accuracy, it is compatible with only metal molds.
3D printing is one of the fastest procedures for making molds for plastic injection molding projects. This method uses a 3D printer and doesn’t necessarily require a skilled operator. Hence, it saves labor and mold costs. However, 3D printed components are often limited in dimensions due to the size of the 3D printer’s build platform. Similarly, printed molds are more likely to experience shrinkage.
The injection molding process requires unique equipment. However, the machine’s size and level of sophistication determine the cost and range from small to large machine. Therefore, it would help to consider the following injection molding machine types and how they influence injection molding costs.
Electric molding machines utilize an electro-servo motor to direct the machine during injection molding. They utilize less energy, incur low operating and maintenance costs, and are accurate and easy to use. Nevertheless, their initial investment cost is high and requires routine maintenance.
These hydraulic injection machines perform injection molding operations with a hydraulic pump. They are usually durable, offer highly consistent ejection and injection, and have economical initial purchase costs. However, they can be imprecise and consume excessive energy.
Hybrid injection molding machines combine the characteristics of electric and hydraulic injection molding machines. It uses a servo motor and hydraulic pump to distribute the oil used in producing hydraulic pressure that creates the component in the machine.
These machines provide high precision, repeatability, and energy efficiency. Furthermore, they have high initial investment costs and require heavy maintenance since they use electric motors and hydraulic pumps.
However, it may be ideal to outsource to injection molding service providers instead of buying a machine to avoid the high cost of an injection molding machine.
Plastic injection molding is compatible with an extensive range of plastic resins with varying availability, price, applications, and properties. Typical examples of plastic injection materials include PC, ABS, PU, PP, and PE.
The cost of plastic pellets material used in plastic injection molding technique ranges from 1 dollar per kg to 5 dollars per kg. However, the injected material’s final cost depends on the used amount and the required design.
Molded parts’ variables, such as design, size, and volume of injection molding components, often decide injection mold cost. You can optimize the cost of your project significantly when you understand how these variables impact the project’s plastic injection molding cost.
To make complex parts, you must create a mold with even complexity using manufacturing methods such as 3D printing, CNC machining, or EDM machining. Besides, you need more material to fill the mold to produce complex parts. Consequently, this increases the injection molding material cost. At the same time, complex parts may require extended production time since they may require additional steps in the production process.
Creating large molded parts will require more injection molding material, hiking the costs of injection molded components. Similarly, it would be best to use the proper injection molding machine and manufacture the right mold size when handling large parts.
Generally, the undercut injection molding features complicate and in some instances prevent parts injection. Eliminate them if possible. If you find it hard to get rid of them, try sliding shutoffs, pass-through cores, or change the parting line and draft angles to simplify the mold build.
Unnecessary features that do not add significant value to your final products will increase plastic injection molding costs. Textured surfaces, for instance, may simply not be needed. This holds true for cosmetic add-ons like bead blasting or high mold polish too. Remember that excess features might also require more mold cavities that further drive costs north.
Most procedures associated with injection molding are automated and controlled by software systems. However, typical labor costs involved in injection molding include: