Design considerations for CNC machined parts

Traditional machining has evolved over the years, giving way to an era of more complex machining systems that are cost-effective and highly efficient. Computer numerical control (CNC) machining is a subtractive process of manufacturing that utilizes an automated power that is computer-integrated to control tools such as lathes, boring, and drilling machines. It is used to produce parts of high quality with high dimensional accuracy in a cost-effective manner. There has been tremendous growth in the use of CNC machining, thereby revolutionizing the manufacturing industry. As such, this technology has reduced the human resources required in the production of sophisticated parts as the machines can work on a large number of work-pieces for mass production. This way, the consumer’s demands are easily met over a short period of time while at the same time producing high-quality products.

CNC machining process
A design is first drafted using computer-aided design (CAD) and loaded into the CNC machine that interprets the design into special codes. The material, which is often a block work-piece, is then placed in the CNC and clamped in position. The work-piece is then machined automatically following the design fed into the CNC computer.

Design consideration for CNC machining
The design for CNC machining parts is quite flexible but often limited by the capability of a particular CNC machine and its tooling. Designers are therefore required to adhere to specific requirements for the successful production of high-quality parts. Parts tolerance is an essential consideration in design for parts to be machined in CNC as such tight tolerances may lead to unwanted costs due to an increase in scrap, the requirement of specialized tools, and fixtures. Therefore standard tolerances should be applied based on the type of material to be machined. Tight tolerances should only be used in critical design requirements.

The size of the material blank is another factor of interest during design. It is recommended that the size of the blank be 0.125 inches larger than the actual dimensions of the part to be machined. This will ensure that the part dimensions are retained even after machining.

The type of material is considered a vital driver that determines the overall cost of the component. The material type has a significant impact on the overall price of the part based on the geometry and the size of the component. Designers should consider cheaper material of the design that doesn’t warrant the material properties of a material that is more expensive. The wall thickness of the part to be manufactured plays a crucial role in determining the overall strength of the region to be machined. Designers should avoid too thin walls or too thick walls in their designs as they limit the part’s structural integrity. Undercuts should also be considered in the design. Undercuts results when some features of the part to be machined are unbelievable. Undercuts with non-standard dimensions may require additional special tools to create a custom feature, which results in the additional cost of producing a part.

Conclusion
To sum up, CNC machining offers numerous benefits in manufacturing, such as high dimensional accuracy of the part to be produced. However, designers should be careful when designing parts to be machined in a CNC machine to produce high-quality parts.