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Advantages and Limitations
of CNC Machining

Advantages and Limitations of CNC Machining

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Computer numerical control machining’s advantages make it the preferred manufacturing method for several industries, such as medical equipment, automobile and aerospace. This manufacturing process can deliver highly precise made-to-order parts.

Due to the accuracy of this process, delicate parts that must adhere to strict designs are among the best types of projects for CNC machines. However, with all these advantages, CNC machining has some limitations. When choosing part creation methods, learn as much as you can about CNC machining. When you understand how the process works, you can make an informed decision that balances your budgetary needs with the requirements of your project’s precision. Is CNC machining the option for you? Or do you need an alternative for your project?

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Advantages of Using CNC Machinery

As with any manufacturing process that has lasted for decades, CNC machining offers numerous advantages over other part creation methods. Using computer control allows you to get consistently precise and accurate results with various materials. Additionally, you do not need to create large orders — CNC machines can make a single prototype to give you a tangible example of your proposed project. These machines can also skip the prototype process and create an initial design in the machine to save time and material.

1. Constant Use With Minimal Maintenance

Manual machining can only occur as long as skilled workers are present. When the workers take a break, progress stops. However, CNC machines can operate 24 hours a day. Depending on the project’s design, the operator can program the computer and set the machine to create the required part. The machine then automates the part manufacturing, allowing the programmer to move to set up another machine. By freeing up operators, CNC machines require fewer workers and increase machine shop production scalability.

CNC machines also allow for rapid changes in production. If the operator needs to produce small orders of various parts, all they need to do after completing one design is to change the program to set the next form. With this increased flexibility compared to other manufacturing processes, CNC machine shops can fulfill many orders, from large batches of the same parts to individual prototypes.

While CNC machines operate 24 hours a day with minimal maintenance, the future promises even greater efficiency. With the Internet of Things technology on the horizon, CNC machines can have sensors that track the amount of wear on parts. These sensors can then signal the operator whenever the machine needs maintenance instead of waiting for the device to break down. The IoT could also integrate CNC machines with other robots to automate the removal and packing of completed products from the machines.

CNC machining’s current automation level gives us an exciting preview of manufacturing technology’s future. Today’s CNC machining will only improve with tomorrow’s technological improvements and IoT integration. With so many possibilities for improving efficiency, creating relationships with CNC machine shops today lets you take advantage of this manufacturing method’s current and future benefits.

2. Precision

A machine’s precision refers to how fine a tolerance it can produce. Not all CNC machines are capable of high precision. Discuss the precision capabilities of any CNC machine shop you work with. Typically, aerospace and defense industries frequently rely on high-precision, machined parts. Creating these parts to their specifications could save lives due to their potential installation in aircraft, automobiles or defense equipment.

3. Accuracy

How closely the produced part matches the plans reflects the project’s accuracy. With human machinists, mistakes can create minor differences in precision that could cause significant problems. Applications that require parts to meet strict design guidelines may fail with even small deviations from the correct design. Automating production with CNC machining reduces accuracy problems, but the operator still has some control over the process.

Machining projects’ accuracy depends heavily on the operator. Because the operator plays such a pivotal role, finding a machine shop that puts extra effort into projects is critical to getting the results you want.

To improve accuracy, the user controls the tool calibration and operating environment when operating a CNC machine. Operators must also recognize when machining tools get too dull to create required results and if the machine requires service to restore accuracy.

CNC machining’s added accuracy makes repeatability possible. If you have a large order of multiple replicas of a part, with CNC machining, you can have those parts produced with improved accuracy compared to handmade components.

4. Versatility

With alternatives to CNC machining, such as 3D printing, you will encounter limitations in the types of materials you can choose from for your parts. However, CNC machining can occur with various materials.

Talk to your machine shop about their material selection. Not all places have the same breadth of choices for parts. At American Micro Industries, we can use the following materials with CNC machining:

  • Plastics
  • Phenolic materials
  • Rigid foam
  • Carving foam

When choosing a material for your applications, you’ll need to consider several factors, including heat tolerance, stress resistance, hardness, fastening and design tolerance.

5. Simulated Models or Prototypes

The old method of making prototypes was to have a machinist create the design by hand. At the time, a manufactured prototype was the only way to examine the part in three dimensions. This time-consuming process did not guarantee accuracy in continued production.

Today, you can have a CNC machine create a single prototype if you require one. However, if you only want to view the part in three dimensions, you can do that in the computer program used to send directions to the CNC machine.

Using a CNC machine gives you the option of creating a prototype. The computer lets you see the model from all sides before its production. You can save material and time if you do not require a physical model.

6. More Capability

When paired with continuously advancing computer and design software, CNC machines can create products that even the most experienced engineers couldn’t replicate. Advanced software allows CNC machines to produce a wider range of shapes, sizes and textures than manual or conventional machines. With this machinery, you have more options for designing and making your necessary parts.

For example, CNC machines can consistently produce and replicate intricate and precise parts for applications with particular needs.

More Capability

7. High Production and Scalability

Once the CNC machine’s operator has programmed the design specifications, the only thing stopping it is the user. Once started, CNC machines are highly productive and can produce many parts in no time. Plus, CNC machines offer a wide range of scalability. Unlike other manufacturing methods, CNC milling allows machine shops to produce large quantities or a single model. CNC machines don’t limit you to how many parts you can have manufactured at once, allowing you to use your money and resources more efficiently.

8. Uniform Product

There is always room for error with manual production, and each product could vary slightly due to human inaccuracies. CNC machining allows for uniform outputs. CNC machines can perfectly match the design specifications every time they create a part. This precision ensures you’re getting parts that will fit your application, reducing the risk of damaging your equipment or slowing your operations.

9. Design Retention

CNC machines are capable of saving prototype designs for future production. Design retention helps with efficiency and ensures the finished products are identical, regardless of operator changes. For example, it doesn’t matter who starts the machine because the designs are pre-loaded and it can create uniform products. With manual manufacturing methods, not every operator will know each design by heart, which leaves room for discrepancies and inaccuracies in the parts.

Design Retention

CNC machines’ ability to store designs eliminates the need to keep additional copies. For example, you can free up some space without needing excess files or other computer files of outdated designs. While you’ll likely still want to keep a backup copy of prototype designs, storage for hard copies can be a thing of the past.

Limitations of CNC Milling Machines

While CNC machines have several advantages, they come with some limitations. Cost, size restrictions and human error could impact your project plans. Weighing these disadvantages against the positive aspects of using CNC machines will give you the information you need to make the most informed decision for manufacturing your made-to-order parts.

1. Cost

One common complaint with the CNC machining process is the cost. CNC machining may be more expensive than other methods, but with that cost, you have the extra benefits of added accuracy and precision. However, the total cost is not always a set value.

Changing your requested attributes can reduce your CNC machining project’s cost. Some things you can do to make your CNC machining project more budget-friendly include keeping the project simple, reducing the need for extra-thin walls on parts and increasing tolerances.

2. Size Limitations of CNC

One of the benefits of hand production is the machinist’s ability to manipulate a large part. For some CNC machining projects, the measurements of the part you have machined may have limitations.

The size of the enclosure and the travel distance of the tools both determine the size of part a shop can machine.

Travel distances typically have measurements along the X, Y and Z axes. However, some machines may operate on four or five axes, adding more dimensions that the machine can work on at one time. To find out about size limitations, ask the machine shop about their equipment capabilities.

Even if the part size fits into the working area, large components have other issues that may make CNC machining challenging to use. The size of the part may impact the accuracy of the tools working on it. Extra weight puts additional stress on the material, increasing the chances of distortion. To complete the manufacturing process, the machine may require special setup or operator training to ensure the machining tools have the correct starting positions relative to the design and part size.

Depending on what you need to have created, extra-large or cumbersome parts may not work well with CNC machining. Since some facilities have the equipment necessary to manufacture large parts with CNC machines, always ask about any size limitations when requesting a quote or information about your order.

3. Operator Error

The operator has a significant level of control over a CNC machining project’s accuracy. While operator error can cause problems with the accuracy of the machined part or the program used to create it, you can do some things to avoid these issues.

First, find a machine shop with well-trained personnel who know how to get maximum accuracy from the machine.

Secondly, the shop should verify the accuracy of products produced to ensure they match expectations. The manufacturing company you choose should work with you throughout every stage of the project. If you bring a part request, the company should help you with creating a CAD drawing, choosing materials, getting approval for the design, creating a prototype and manufacturing the entire order. These steps help avoid possible errors.

Thirdly, look for a company that acknowledges and learns from its mistakes. While CNC machining has a lower chance for human error than manual part creation, mistakes can happen. The company should correct the error and change procedures based on what the experience taught its workers. When you find a company willing to correct and learn from mistakes, you can develop a relationship with a shop that will continue improving and providing you with better service.

Should You Use CNC Machining?

Do you need CNC machining for your project? The answer depends on what you need and how quickly you need it. Alternatives to CNC machining may take much longer to execute or have higher chances of errors.

Many projects that require the following tasks are suitable for CNC machining:

  • Milling
  • Drilling
  • Turning on a lathe

CNC machining works well in creating parts that require these operations, need high levels of precision and accuracy and have moderate sizes.

Pros and Cons of CNC Machining

CNC machining offers some drawbacks, such as cost, size limitations and the potential for human error. However, with the many ways you can make decisions before and during the process of getting your project completed, you may mitigate the effects of some of these negative points on your order.

For many in the defense, aerospace, medical, marine, automotive and electrical industries, CNC machining provides unmatched precision, repeatability and accuracy. Companies in these industries and many others request made-to-order parts through a machine shop because they can quickly get the high-quality components they need.

By programming the computer and setting the device to run, employees at machine shops can work on orders 24 hours a day, reducing creation time. With a consistent program, the machine produces replicas with identical accuracy and precision, regardless of the order’s size.

Finding balance when placing orders with a third-party company is always vital. If you need the advantages of this manufacturing style and can work with the few drawbacks it has, choose CNC machining for your next made-to-order part project.

Just as you carefully choose the type of manufacturing for your parts, put the same care into finding a company to fulfill your order. Worker training and customer service should not be afterthoughts. Find a company that will partner with you throughout the process. If they make a mistake, they should correct the error and ensure you feel confident in the integrity of the parts in your order. AMI is one such company that will complete these tasks and more for your satisfaction.

Make AMI Your First Choice for CNC Machining

If you select CNC machining for your project, trust us at AMI to complete the work. We pay exceptionally close attention to all the details of the parts we make. Every step of the process, from the initial plans to material selection to production, happens at the same location. We can even machine on non-metallic materials to produce a wider range of parts.

For more information about our CNC machining services or to request a quote for made-to-order parts, contact us at AMI.