CNC machining is an important technique, and one that can greatly benefit the production process. In addition to helping improve the quality and precision of machining jobs, CNC can be automated, which lessens the risks to operators and helps boost efficiency.
That being said, when it comes time to start comparing CNC quotes, you’re going to want to understand what factors are driving the price, and what—if anything—you can do to help control costs on a job. Read on, and we’ll cover some of the most significant elements that come into play when determining CNC machining costs.
The Material Selection
The materials that are used on a job actually have a two-fold way of expressing themselves in the final price. Firstly, there’s the raw price of materials, which can vary based upon rarity and other critical factors. Using more rare and expensive materials, obviously, will cause the price of a job to increase. Beyond this, though, there’s also the material machinability to consider.
Some materials are harder to work with than others on account of their physical properties. The more difficult it is to machine a material, the more that material is going to add to the final cost of a production job. Be sure you review your options thoroughly before selecting a material.
The Order Quantity
Generally speaking, the more of something you order, the higher your final bill is going to be. This generally holds true in CNC machining as well, and bulk orders with large quantities are going to cost more overall. Important to note, however, is the fact that in some cases, large orders might actually produce the cost-per-unit on the back end of things, and the inverse may be true for smaller orders (with inexpensive upfront costs that stack up over time).
The Tolerances, Geometry, and Design
When you hear talk of “tolerances” in manufacturing, it’s typically in reference to the precision and accuracy needed to complete the job satisfactorily. The “tighter” the tolerances, the greater the precision, and the greater the price because manufacturing at tight tolerances requires complex machinery and ample skill to get it right.
Similarly, you should think about the geometrical design of your products prior to fabrication, and consider how it might affect the cost of machining. More complex parts require more deft machining, will take more time to complete, and are thus more expensive.
Finally, the design (in particular how large or small your design is) will play a significant role in the final cost. This is because larger parts require more materials, and will be more expensive as a result. Double check your CAD drawings for accuracy when it comes to sizes.
For any job, you’ve got to pay the machinists for their time and experience. This goes double on complicated production runs with very complex parts—an endeavor in which expertise can make all the difference in making sure the process carries on efficiently. Just remember that the more you’re asking from a machinist to complete the work, the more that work is going to cost.