Injection Molding Mold Cost and Part Cost:
What To Expect?

Injection molding is a manufacturing process widely known for its ability to produce parts cost effectively and consistently. While the process comes with significant cost benefits, unlike 3D printing and CNC machining, it demands a high level of ‘financial commitment.’ In this article we will go through

How much does injection molding cost?

So, how much can you expect injection molding to cost? Injection molding projects can cost anywhere from $10,000 or less to $100,000. The total cost of injection molding quote is essentially made up of two parts: mould cost + part cost. 

Mold Cost (Tooling Cost)

The injection molding mold cost is also known as the tooling cost. Tooling refers to the design and manufacturing of the mold used to create injection-molded parts and is often the most expensive component of an injection molding project. Simple molds are typically in the $3,000 to $6,000 range while the price for larger, more complex, higher-production / steel moulds, or multi-cavity moulds can cost from $7,000 and up.

Factors that determine tooling costs in injection molding include:

1. Materials

The most common materials used to make molds are steel and aluminum, with steel lasting longer. While it’s often said that aluminum costs less, this is not always the case. High-quality but low-cost Chinese steel grades, such as S50C and P20, suitable for rapid tooling and low-volume production purposes, can serve as cheaper alternatives to aluminium.

2. Machining Time

This is largely determined by the complexity and size of the mold, the number of cavities in the mold, and the level of precision required. Undercuts mean side actions, sliders and lifters which means added complexity, more work and higher costs. If you can reduce these features as much as possible and keep your design simple, you will significantly save on lead time and costs.

3. Quantity

Quantity of parts required will impact two fold, first in the tool design itself. If you are looking at very high numbers of parts it might make sense to go with multi-cavity tools, which are larger and more expensive but will bring part costs down. Also the higher the quantity required the better the steel used to machine the cavity, core and inserts will need to be. Low quantities can often be realized using low grade steels or aluminiums’ bringing costs down.

4. Textures

Achieving specific textures or finishes by applying an SPI or VDI finish on the molded part can will impact the costs of your tool. High polished or transparent finishes require both better quality steels and much more work to achieve than a standard polish. To keep costs down, only requests high quality finishes where necessary.

Tips to reduce injection mold tooling costs

There are several things you can do to help control and lower costs when it comes to mould making. The top tooling cost reduction tips include:

• Getting rid of undercuts as they make the tooling process more complicated and costly.
• Only specify tolerance where necessary.
• Only requests high quality textures and finishes where necessary.
• Planning ahead to determine the quantity required to optimize the selection of tooling type (multi-cavity, etc.) and material grade (low-grade aluminium or steels, etc.).
• Consider Chinese mold manufacturers for steel tooling.

Part Cost

Once the initial costs of the molds are covered, the cost per unit during manufacturing is relatively low. Typically, you can expect the cost per part to range from $0.20 to $10.00 per piece or higher, depending on the quantity.

Factors that determine injection molding part unit costs include:

1. Material

Plastic pellet resins used in injection molding can range from $1 per kg to $5 per kg or higher, depending on the type of material. Specialty materials, such as glass-filled polymers or elastomers used to achieve specific properties, will typically incur higher costs. To reduce costs, stick to readily available, easy to process material like PP or ABS as far as possible.

2. Cycle time

Cycle time or injection moulding time includes setup and running time for each part, this is where the manufacturer’s overheads are. More intricate designs, parts with complex features or larger parts may slow down the time it takes to remove the part from the mold, increasing overall cycle time and costs. Keep in mind that a high-viscosity will require longer injection and cooling time.

3. Secondary Operations

Any additional processes such as assembly, post-molding treatments, or finishing, will increase the unit cost. To keep molding costs and time and down, if it can be done in the tool itself, you should work with your supplier to try and achieve it that way.

Tips to reduce the injection molding per part costs

There are several things you can do to help lower the overall per part cost. The top tips to reduce the injection moulding per part costs include:

• Simplify part geometry to facilitate easier mold release and less wastage.
• Consider standard resins over specialty materials unless specific properties are essential.
• Design parts with finishes in mind to minimize additional post-processing steps.