How to minimize the cost of CNC machining products? The answer lies in the design of your part. Here are some tips for reducing costs.
For example, in the aerospace industry, weight reduction is often a key design goal. In other industries, factors such as surface finish or aesthetics may be the top priority. However, in almost all cases, cost is the driving factor for the entire design and manufacturing process.
There are several ways to keep your goals within the production budget, especially when using CNC machining. First, you can shop around for the most cost-effective CNC machining service. However, some of the most important CNC machining cost-saving techniques come into play at the design stage.
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Low-cost design skills for CNC machining
When looking at the costs associated with CNC machining, there is an important rule to keep in mind: the longer it takes to machine a part, the higher its cost. The reason for this rule is many other factors, such as material selection (easier to process materials faster and therefore cheaper to use) and part design. Today, we will focus on part design and how certain design choices affect and reduce CNC machining costs.
1. Avoid thin walls
Although CNC machining can produce parts with very small tolerances and thin walls (approximately 1 mm), if cost is the driving factor for your product, it is recommended to have as thick walls as possible. The reason for this is because machining very thin walls can be tricky: if you do it too fast, you can damage the part due to vibration. Correct machining of thin walls requires repeated low cutting depths, which can significantly increase the time of the machining process. Therefore, integrating thicker walls in the parts as much as possible helps to speed up processing time and reduce costs.
2. Integral inner radius
When designing parts, integrating the internal radius instead of the 90-degree angle at the corner will save a lot of processing time (and cost!). Because CNC milling tools are cylindrical in nature, when they create corners in a part, they naturally have a curve or radius. Keeping this in mind, designing parts with internal radii instead of sharp corners can simplify the production process. In addition, the larger the inner radius, the larger the milling cutter that can be used, and the faster the processing time.
3. Avoid deep cavity
Another design technique that helps minimize the cost of CNC machining is to avoid deep cavities and grooves in the part. The reason for this is twofold. First, the deeper the cavity, the longer it takes to cut the material. Second, designing parts with cavities 4 times larger than the tool diameter may require specialized tools and increase production costs.
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4. Avoid deep threads
Following the previous technique, it is also recommended to keep the thread depth as low as possible to reduce processing costs. Unless absolutely important to a given part, it is usually not necessary to integrate threads with a depth greater than three times the hole diameter. Deeper threads (such as deep cavities) may require the use of non-standard tools, which will increase machining time and cost.
5. Adhere to standard tool sizes
When designing parts, you can save a lot of processing time by ensuring that the dimensions corresponding to standard CNC tools are maintained. For example, the diameters of holes, threads and cavities should correspond to the diameters of commonly used CNC tools. In addition, by maintaining the same hole and cavity size on the part, fewer tool changes are required, which speeds up the CNC machining process.
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6. Avoid high tolerances
Although CNC machining can withstand some of the highest tolerances in any manufacturing process, this does not mean that every part requires the strictest tolerances. In fact, using tight tolerances only when absolutely necessary can greatly reduce costs, because achieving high tolerances increases processing time (and inspection time).
Keep it simple
Generally speaking, if you follow these six CNC machining design tips, and the most important thing is to keep your parts as simple as possible, then the production cost can be significantly reduced. A part that has no thin walls, uses an internal radius, and has the same size of holes and threads throughout the part will be processed faster and at a lower cost than a more complex part.
