You must understand the different factors that contribute to the costs in machining operations. Below are a few factors machinists consider in the CNC machining cost calculation:
- Material
This is a very important factor that machinists consider when doing the CNC machining cost calculation. As CNC machining is a subtractive process, it tends to use more material than what will be on the final product. Machinists buy these materials in blocks, and they calculate the prices per block. The two types of materials used mostly in CNC machining are metals and plastics. Let’s take a closer look at both of them:
– Metals
The common types of metals used in CNC machining include Aluminium 6061, Stainless Steel 303, and Brass C360. Machinists use aluminum 6061 the most due to its blend of economical price and good machinability. Stainless Steel 303 and Brass C360 offer a higher degree of machinability and cost more as a result. You can use our quoting platform to know more about how we factor material costs into your CNC costs.
– Plastics
Plastics are cheaper to use for CNC machining due to the lower average price for the bulk materials and the shorter machining times due to their lower hardness. Plastics like ABS, Nylon 6, and POM (Delrin) have approximately the same bulk costs as Aluminium 6061, although they might cost a little higher per block. Plastics like PEEK are really expensive and should only be used when absolutely necessary.
- Machining Cost
The machining cost depends on the type of machine. The two main types of machines used in CNC machining are mainly: 3-axis machines and multi-axis machines. In Europe, the 3-axis machines cost around $35-$40 per hour while the multi-axis machines cost around $75-$120 per hour.
Machining costs also depend on two factors: the price of the machine and the number of hours the machine is expected to operate in a year (which is 5000 hours on average). The machinists divide the machine’s price by the number of hours it will operate in a year to determine the machine shop rates (also known as the machining cost per hour).
- Labor
Due to a large amount of automation involved in the CNC machining process, you do not have to pay for a large number of staff members. The main labor costs are for design and digitalization. The labor costs for CNC manufacturing processes are mainly divided into three:
– Programming
This part of the labor costs is the most expensive because it involves design and digitalization costs. You need to outsource your product for a designer to make into a CAD file. You can bypass this by doing it yourself. Next is the manufacturing engineer who checks your design for reproducibility and gives suggestions on making it better. The last person is the programmer who converts the CAD file into a CAM file to help the CNC machine understand the design. All this expertise will come at a price.
– Set up
This part involves the machine operator. He spends time setting up the machine for a custom CNC job and making sure that everything is performed in a manner that results in a great result. The cost of setup depends on the quantity of the parts to be produced. For bulk parts production, the cost per part is lower as it spreads over the larger number of parts.
– Post-processing
After production, your production will require some assembly and transportation to your desired location. These processes will involve some manual labor which incurs additional costs.
