Molding is an important process used in manufacturing to shape plastic, metal, glass and other materials. It involves pouring raw material into a hollow mold cavity to give it a desired shape. Molding is used to make a wide variety of products including automotive parts, medical devices, consumer electronics and more. When getting price estimates for molding, it is important to consider several factors as prices can vary significantly. In this article, we will provide an overview of the average costs of the most common types of molding along with the key variables that impact overall prices.
Types of Molding Processes
There are several major molding process categories, each with their own typical price ranges:
Injection Molding
Injection molding is the most common type of molding process. It works by injecting molten plastic material at high pressure into a mold. Once cooled, the molded part is ejected from the mold. Typical uses include consumer products, automotive components, medical devices and more. On average, injection molding costs between $5,000-$100,000 per mold depending on part size, complexity and material. Total costs for production can range from $0.50-$100 per part depending on order quantities.
Blow Molding
Blow molding involves inflating heated plastic material into a mold using compressed air. The plastic can conform to the mold for making hollow parts and containers. Typical blow molded parts include bottles, tanks, drums and industrial containers. Average blow molding costs range from $5,000-$80,000 for the mold. Per part costs are $0.10-$5 depending on quantities.
Rotational Molding
Rotational molding, also called rotomolding, consists of rotating molds while pouring plastic powder into them. The powder melts and coats the inside of the mold as it rotates. It is commonly used to make large hollow products like tanks, kayaks and playground equipment. Rotomolding molds can cost between $3,000-$50,000 on average. Per part costs range from $8-$100 depending on size and order volume.
Compression Molding
Compression molding uses hydraulic presses to mold parts out of plastic or composite materials. The materials are placed in an open mold cavity then compressed under heat and pressure causing it to take shape. It has applications including automotive, aerospace and electrical components. Compression molds cost approximately $2,000-$60,000. Part costs range from $0.50-$200 each depending on the industry.
Transfer Molding
Transfer molding forces heated liquid plastic into a closed mold through a sprue. Once cooled, the mold opens to eject the part. It is commonly used for electrical components and automotive parts. Transfer molds average $1,500-$25,000 in price. Per part costs can be $0.15-$100+ depending on complexity.
Thermoforming
In thermoforming, plastic sheets are heated until pliable then formed over a mold using vacuum, air pressure or mechanical force. Products made via thermoforming include packaging, trays, signs and plastic covers. Thermoforming molds cost $500-$5,000 on average. Per part costs are usually $0.10-$1.00.
Key Cost Factors
When estimating molding costs, there are several key factors that affect pricing:
Mold Complexity
The more complex the mold, the higher the cost. Intricate molds with tight tolerances, undercuts, side pulls, and core pins require extensive CNC programming and machining time which drives up costs. Simpler two-part molds are quicker to produce.
Mold Material
Harder, more durable mold materials like tool steel are more expensive than aluminum or soft metals. However, they allow longer production runs before replacement so can offset higher initial costs.
Mold Cavities
Molds with multiple cavities to allow making multiple parts per cycle demand higher prices but also increase outputs. Single cavity molds are simpler and cheaper.
Part Size
Larger molded parts require bigger molding machines and more material, increasing overall costs. Small parts can be mass produced quickly and cheaply.
Annual Volume
For high production volumes, large initial mold costs can be offset across each part making per-part costs lower. Lower volumes cannot spread out initial costs so per-part pricing is higher.
Secondary Operations
Adding secondary finishing or assembly operations after molding adds to costs. This includes part ejection systems, trimming, painting, printing, etc. Simple parts with no secondary work are cheapest.
Material
Common molding materials like plastics, metals and glass have vastly different costs. More expensive or exotic materials drive up overall pricing significantly.
| Molding Type | Typical Mold Cost Range | Typical Per-Part Cost Range |
|---|---|---|
| Injection Molding | $5,000 – $100,000 | $0.50 – $100 |
| Blow Molding | $5,000 – $80,000 | $0.10 – $5 |
| Rotational Molding | $3,000 – $50,000 | $8 – $100 |
| Compression Molding | $2,000 – $60,000 | $0.50 – $200 |
| Transfer Molding | $1,500 – $25,000 | $0.15 – $100+ |
| Thermoforming | $500 – $5,000 | $0.10 – $1.00 |
Getting Accurate Price Estimates
Because there are so many variables, it is important to work closely with mold makers and molders when getting pricing estimates for a new molding project. Provide them with a clear understanding of your part design, annual production needs, material selection, and any secondary operations required. With this information they can provide detailed quotes for the total costs.
Be sure to get multiple quotes as prices can vary between companies based on their capabilities and capacity. You also want to verify what is included in their pricing such as design reviews, material, and delivery. Make sure you understand payment terms as some firms require payments upfront or deposits to cover initial engineering and mold costs.
Also discuss estimated lead times. While a basic two-part injection mold may only take 2-4 weeks, complex multi-cavity molds could require 12-20 weeks depending on the shop workload. factor in these timelines when planning new molding projects.
Cost Saving Tips
Here are some tips that can help reduce overall molding costs for new projects:
– Standardize on common materials that molders already work with regularly. Exotic materials usually cost more.
– Design parts with draft angles and easy ejection in mind to simplify molds. Avoid complex side pulls or actions if possible.
– Use existing molds capabilities rather than investing in all new tooling.
– Combine multiple parts into one larger part to reduce mold costs and secondary operations.
– Consider Chinese manufacturers for high volumes but lower piece price. However quality control can be an issue.
– Work with mold makers to refine designs and remove unnecessary complexity. Simpler molds are cheaper.
– Consider using prototype tooling like aluminum molds first for pilot runs to test parts before full hard tooling investment.
– Order larger quantities if possible to spread initial mold costs over more parts and lower piece price.
– Make sure annual volume estimates are accurate as differing volumes drastically affect per-part pricing.
Conclusion
Molding is an essential manufacturing process used across many industries to produce quality plastic, metal and glass parts at scale. However, pricing can vary greatly depending on the complexity of molds, materials, quantities and other factors. Typical initial mold costs range from $500-$100,000 with per-part costs of $0.10 to $200 each depending on volumes. By understanding key cost drivers, working with multiple vendors, and implementing design and order strategies, manufacturers can keep their molding expenses in check while still producing high quality components.
