Injection Molding Cost| Factors |Echofast

1.Mold Costs (Tooling Costs)

Mold costs or tooling costs are one of the cost drivers in injection molding. Molds for injection molding are typically made with the following three methods:

3D printing

3D printing is suitable for producing injection molds with a low cost at a rapid speed. It requires very limited equipment, which means that minimal setup and operational intervention are required. The test and change of the design can be made in time before mass production due to the 3D printing. Stereolithography (SLA) 3D printing is an excellent option for injection molding process because of the smooth surface finish and high precision. Desktop SLA printers work well with injection molding because they are easy to implement, operate, and maintain.

CNC machining

It is a common and precise manufacturing process for aluminum and stainless steel molds. Material is removed by a spinning tool and fixed part in CNC machining. The method can produce injection molds with intricate and complex designs, but multiple tool changes sometimes are required. It means that costs increase with complexity. Because CNC machining requires specialists and high machine costs, mold production is generally outsourced to service providers.

Electrical discharge machining (EDM)

It is the most suitable for creating highly complex mold designs, which is a highly accurate process without the requirement of additional post-processing. This method utilizes a workpiece and a tool electrode to create the desired mold shape. Like CNC machining, EDM machining is a outsourced to third-party service providers.

2.Material Costs

Injection molding is compatible with a wide array of plastics. These include ABS, PS, PE, PC, PP, or TPU, and the price of each material is different. Thermoplastic pellets used in the process can cost between $1 to $5 per kg. Material cost varies depending on a mold’s design, the material selected, and the amount of material used.

Type of Thermoplastic Material	Unique Features	Common Applications	Price per pound
ABS	durable, lightweight	electronics, keyboards, phone hardware, LEGO bricks, drainpipe systems, kitchen appliances	$1.30
polyethylene	flexible, impact-resistant, leech resistant, moisture resistant, recyclable	food packaging, milk jugs, toys	$1.20
polypropylene	leech resistant, flexible	Tupperware, kiddie pools, toys, utensils, car batteries	$0.90
polystyrene	warp, shrink and impact resistant	compact disc cases, packaging applications, household appliances	$1.00
nylon / (POM)	heat-resistant, durable	high-ware parts, quick-release buckles, gears, hand cranks	$2.20
polycarbonate	impact resistant, optical clarity, vulnerable to chemicals	automobile headlights, bulletproof glass, eyeglasses, greenhouses, DVDs, mobile phones	$2.30

Data is recent as of 2020 and is taken from Rex Plastics.

3.Equipment Costs

The injection molding process requires special-purpose machines, ranging from smaller desktop injection molding machines to large industrial injection molding machines. The cost of a machine is determined by the size and its level of sophistication, which is usually measured by automation. A smaller desktop injection molding machine, which is suitable for low-volume injection molding, can cost about $ 10000 or less. The cost of a large industrial injection molding machine that works well with high-volume injection molding ranges from $50,000 to $200,000+. The following types of injection molding machines that affects the injection molding costs should be taken into consideration.

Hydraulic Injection molding machines

Hydraulic Injection molding machines utilize a hydraulic pump to perform injection molding operations. They are characterized by high durability, consistent ejection and injection,and economical initial purchase cost. However, the result can be imprecise and excessive energy can be consumed with this kind of machine.

Electric Injection Molding Machines

Electric injection molding machines control the machine with an electro-servo in the process of injection molding. They are accurate and easy to use. They also have low operating and maintenance costs because of less energy consumption. However, the initial investment cost is high and routine maintenance is required.

Hybrid Injection Molding Machines

Hybrid injection molding machines boast the advantages of electric and hydraulic injection molding machines. They allow for high precision, repeatability, low emissions, less noise, and energy savings. Nevertheless, they require high initial investment costs and heavy maintenance because of the use of electric motors and hydraulic pumps. Most businesses outsource mass production to service providers instead of buying a machine, and the equipment costs can be included in the service costs.

4.Part Costs

Part costs vary based on the size, design and volume of injection molded components, which can influence injection molding costs. Below are factors you need to take note of.

Part Size

Making a large part can lead to a higher cost of the injection molded parts, which results from the requirement of more injection molding material. In addition, operators had better use the proper injection molding machine and manufacture the right mold size when dealing with large parts.

Part Complexity

In the process of producing complex parts, a mold of equal complexity should be made using manufacturing methods such as 3D printing, CNC machining, or EDM machining. More material is required to fill the mold for the creation of complex parts, increasing the material cost of injection molding. Meanwhile, injection molding cycle time can be longer due to the part complexity, which is indicative of higher costs.

Part Design for Manufacturability

Design for manufacturability is one of the important factors that influence the part costs, because it can reduce errors by eliminating undercuts or changing the part line. The part costs can be reduced with a proper design because of the enhanced productivity and efficiency.

5.Labor Costs

While injection molding machines rely on automation to perform the injection molding process, the labor costs are still involved in the process.

Setup costs

Configure and set up the injection molding machine. It takes a lot of time due to the required technical expertise and accuracy.

Repair costs

Replace defective parts, and use tools to perform maintenance procedures. This can increase costs.

Monitoring costs

Though injection molding machines are highly automatized, monitoring the process is an essential task for operators to facilitate the injection molding process. This increases the operator costs, further increasing the total cost of the injection molding process.

Best Practices to Reduce Costs in Injection Molding

The followings are several ways to lower injection molding costs.

1.Reduce unnecessary part features

Basic features help lower injection molding costs whereas too many features and too much functionality can increase costs significantly. It is significant to focus on the former features. This is because basic features can ensure the part’s optimum performance, maximizing design efficiency. The ultimate cost of injection molding can be reduced.

2.Eliminate cosmetic finishes and appearances

Remove any features that only add cosmetic finishes, and the overall costs of injection molding can be reduced. While glossy or shiny finishes can add aesthetic appeal, but they may be not worth the extra costs. It is important to consider the relevance between the part appearance and the project’s market values.

3.Choose the right injection molding material

There are a variety of injection molding materials with different properties, and the purchasing cost of each material is different. The final cost of the injected material is closely connected with the used amount and the required design. Choosing the right material is of vital importance to reduce the overall injection molding cost.

4.Reuse plastic waste

Reuse plastic waste that harden in the sprue and runner and post-processing.Once the plastic waste is reused, the material costs can be reduced. However, recycling too many times can damage the plastic’s mechanical properties.

5.Use self-mating parts

Using self-mating parts reduces the need to create multiple molds when similar results can be achieved with one universal mold.

6.Choose insert molding

Insert molding is a subset of injection molding techniques where one product is inserted inside a mold and encased in plastic. The process can be used to eliminate assembly and thus saves costs in the long run. It is a versatile and economical technique.