CNC machining remains one of the most diverse manufacturing processes in the industry today. With the aid of Computer-aided controls, manufacturers can produce high-accuracy end-use parts with complex geometries at affordable and cost-effective rates. Even with all the benefits of using CNC machining, the technique does have some limitations. Use these simple and actionable tips to help reduce the production cost for your next custom part.
Always go with the best materials There might be instances where multiple materials may be fit for a single project. In cases like this, consider the end application and functionality of the part before concluding on what material is or be used. Materials that boast of high structural integrity will typically be more tasking to the machine. This will also impact their machining cost. As a general rule of thumb, always select the cheapest material that is easily machineable without loss of quality and functionality.
More often than not, aluminum is used for CNC machining because of its affordability. Other alternatives including steel, plastic, brass, polycarbonates, and other alloys have higher structural integrity and therefore demand more machining cost. Titanium is the most expensive to be machined and should only be used when super strength is imperative to your design. At CNC Prototyping Shop, we have a variety of materials suitable for a wide array of applications. If you are confused about your best choice of material, reach out to us and get a free quote based on different materials, processes, and quantities.
Tips for Reducing CNC Machining Cost
To help with cost reduction, you can make changes in CNC machining time, start-up costs, materials costs and more. There are some product requirements that you won’t be able to change, but taking steps to ensure your design is optimized can significantly reduce costs. Here are a few of our tips for reducing CNC machining costs.
- Use Less Expensive Materials
Typically, softer metals are less expensive to work with compared to harder materials. Softer metals are less expensive to machine because they cut more easily, which means less machining time. Harder materials require more expensive tools to machine properly, and are more likely to break and wear tools, which can add to the project cost.
- Order Larger Quantities
It’s true that modern CNC machines can combine multiple operations to run more effectively, however, they still require programming and setup. Ordering multiple quantities of the same part helps generate production efficiencies and lower the cost per piece. At the production phase (up to 10,000 parts), CNC machining can provide maximum cost-efficiency.
- Expand Thin Walls
CNC machined parts with thin walls are more likely to chatter, which ultimately slows down the machining process. They can also lead to distortion, which makes it difficult to hold tolerances. In order to keep machining costs low, thing walls should have a minimum width of 1/32” If very thing walls are needed it’s often more cost-effective to use other methods, such as sheet metal fabrication.
- Avoid Deep Pockets
Parts designed with deep internal pockets are often time-consuming and expensive to create because these designs call for fragile tools that are susceptible to breaking during the machining process. In order to avoid this issue, either an end mill must be progressively “stepped down” in smaller and smaller increments to reach the desired specs, or other forms of machining can be used. Try to design parts with lengths up to 4x their depth— going beyond this can make the part more expensive to manufacture.
- Enhance Tapped Holes
If your part requires tapped holes, there are two main factors that can add cost: hole depth and tap size. Contrary to popular belief, increasing the length of the thread in a hole does little to hold the bolt tighter; in reality, it’s just the first two or three turns that do most of the work. Considering this, you likely don’t need to thread a hole more than three times the hole’s diameter. Going deeper than this will inevitably increase the likelihood of tap breakage and add time to the tapping operation.
When it comes to CNC machining, even small design decisions can have a significant impact on the price.