The Pros and Cons of CNC Machining

The Pros and Cons of CNC Machining

When it comes to deciding on CNC machining or manual production for part creation, it’s necessary to evaluate both the advantages and disadvantages. While automated processes have elevated production methods – driving down costs and increasing accuracy in many situations – there are still times when it’s advantageous to use a different method.

Every task is individual, requiring a careful evaluation to define the production process that brings the best in accuracy speed and value for money. While, very often, CNC machining comes out on top, it’s not always the case. Determining the optimal method requires an understanding of the benefits and limits that the process brings.

The Advantages of CNC Machining

Precision CNC machining works by creating a program that drives the various axes of the machining tool/s. CNC stands for Computer Numerical Control, whereby each movement is sequenced, repeating this over and over to manufacture identical pieces with minimal to no human intervention.

The types of precision machining that can be programmed into a single unit include:

  • Turning
  • Grinding
  • Milling
  • Sawing
  • Polishing
  • Brushing

It’s suitable to use on a variety of materials, including metals, wood, plastics, and foam.

The advantages of CNC production are:

  • Combined operations: One of the greatest benefits comes from combining a variety of machining steps in a single unit.
  • Tight tolerances over large production runs: Repeatability and accuracy are very high.
  • Reduced manual handling: As well as reducing manual workload, the process lowers the number of times materials need to be touched. Potentially, this also helps increase the quality of each part.
  • Faster production: Automating leads to a far quicker production process.
  • Lowered costs: Less material wastage and lowered labour costs. A single operator can supervise multiple machines at the same time.

The Disadvantages of CNC Machining

While the above benefits make a strong case for embracing the technology, it’s important to understand what the process can’t achieve.

  • Programming can take time: This skilled task takes anything from a few minutes for simple part production to days (or even weeks) for extremely complex items. In addition, the process has to be deemed safe to run. Therefore, dry runs have to take place before the process goes into full production.
  • Low visibility: The nature of automation means that the process needs to be enclosed to protect those in the vicinity. These guards and screens reduce access and visibility.
  • Tool pre-setting: Each tool needs to be mounted in place to ensure the cutting tip is in the correct position. This is either performed manually or by entering the details into the program. Whichever is done, accuracy is imperative as, while the program drives the tool axis, this relies on the tooltip being in the right place.

When Would Manual Production be Preferable to CNC Machining?

Proven parts that need to be produced en masse are definitely best served with an automated process. Manual machining is preferable when:

  • Creating prototypes: Being able to visualise and make easy alterations if far better carried out manually.
  • One-off requirements: If the part requirement isn’t likely to be needed again, then removing the lengthy step that is CNC programming can be beneficial.
  • Large-size workpieces: There’s a limit to the size of a workpiece that can be produced by CNC machining.
  • Repairs: The same goes for repairs, where parts need to be re-adjusted on a one-off basis.

In short, large-scale part production is usually best served by CNC precision machining. While the technology has largely taken over the manufacturing of parts, it’s important not to discount manual processes in certain situations, such as during the design stage.

All precision manufacturing, from CNC machining to CNC cutting, EDM wire cutting and more, has pros and cons that are defined by the nature of the task involved.

As a leading Australian provider of advanced manufacturing processes, Sixde provides end-to-end, cutting-edge solutions with an international reach. Get in touch today to discuss your requirements.