When you design a machined part, choose the right material is the most important method for saving cost. It’s not the most expensive material that is best for you. You have to find the most suitable material according to the purpose and function of the parts.
There are many materials with almost the same performance, but the price is a huge difference, you can check whether these alternative materials can meet the functional use. For example, in common use mold ejector pin, use SKD61 material instead of SKH51 can save 50%-70% cost.
In order to give you a general idea of the range of costs that may be required to select materials, I conducted a quick search of the prices of different materials to find 6″x 6″ x 1″ plates. While ordinary plastics like ABS will cost you about $15, peek of the same size, known for its robustness and dimensional stability, costs as much as $225. Similarly, for metals, a 6061 aluminum plate costs about $24, a 304 stainless steel plate costs $139, and a precision ground 316 stainless steel plate costs as much as $285 each!
On the other hand, the softer materials such as aluminum 6061, cut more easily, which means less machining time. The harder materials require more expensive machining tools, and are more likely to break and wear tools. To sum up, harder material will take long processing time and tool wear rate then will increase the cost of machined parts.