CNC machining is a popular choice for precision metal fabrication in many industries. This is because the method leverages a combination of advanced mechanical engineering and sophisticated software programming to deliver outstanding productivity. Its inception has led manufacturing units to shift from ad hoc manual processes to computer numerical control, or CNC.
Given CNC machining’s efficiency and flexibility, you might think it will be smooth sailing after its implementation. But this is unlikely to be the case—certain challenges may crop up during the installation or use of CNC machines. The good news is you can resolve many of these challenges with a little knowledge and skill.
Common CNC Machining Challenges (and Ways to Overcome Them)
Chattering
Machine vibration (chattering) can be a challenge for CNC operators. Chattering can shorten the lifespan of the machine and affect its functionality. Sometimes the vibration is so loud that you can even hear it from a distance. Chattering is usually triggered by machine conditions that are easy to solve.
Typical ways to reduce CNC chatter include:
- Increasing the RPM of the machine
- Reprogramming the cutter path to shift cutting forces to stiffer portions
- Using balanced tool holders
- Improving the spindle speed
In addition to taking these measures, you should make sure the CNC machine is on a solid concrete floor, free from cracks, jointing, or similar discontinuities. Correctly installed and adjusted feet are also key requirements to minimize chattering.
Slow Data Processing
Courtesy of its mechanical setup, CNC machining can operate well within the boundaries of the hardware. However, the underlying software plays a key role in its overall functioning. In many cases, the speed at which the computer transmits commands to the device under control is the determining factor for how fast CNC machining works.
To address this challenge, look for a software upgrade. The controlling software on your machine may be due for a replacement to make way for a more powerful and versatile alternative that can fully leverage its innate strengths. Additionally, check the computer that runs software–if it’s close to retirement, you should invest in better, more advanced hardware.
Costly Repairs
It doesn’t take a crystal ball to know that CNC machine repairs can be a significant investment. Because CNC machining requires a complex mix of software and hardware to function efficiently, any breakdown in the system may require a combination of programming and mechanical expertise to restore it to its original state.
But preventative maintenance can reduce the odds of catastrophic breakdowns in CNC machining. Regularly inspect both software and hardware and make timely replacements and upgrades to avoid serious issues that can put a dent in your finances.
Improper Settings or Tools
If the feed rate of your machine is too low, the part will remain on the surface of the cutting tool longer than necessary, resulting in the burning of the workpiece. If the cutter needs to be replaced or the feed rate is too high, you can see raised marks or rough edges.
Additionally, using an improper cutting tool, where the tooltip isn’t sharp or damaged, will lead to a poor surface finish on the part. It may even cause cutter marks on the material while simultaneously contributing to tool wear and tear.
To overcome these challenges, choose the tool according to the characteristics of the material. Also, adjust the settings to the proper specifications of the specific cutting tool.
Additional Setup
For machining large parts, some additional setup may be required, including a tooling system that enables the CNC plasma cutter to reach the essential areas and a jig or fixture to secure the part in place. You might also have to use a higher spindle speed to increase the process’s efficiency while reducing cycling time.
The best way to overcome this challenge is to work with an experienced partner. Leading CNC machine vendors can help you meet set-up requirements and ensure your parts are produced to the highest standards.
Complex Geometry
Although CNC machining will easily beat a skilled machinist when it comes to cutting in circular patterns or straight lines, it may struggle where an artisan can excel. For example, unique geometric or asymmetrical patterns may pose a challenge for CNC operators.
However, this is more of a technical limitation than anything complex, and you can easily overcome this by using a newer CNC machine with a good range of movement. Older CNC machines were limited to two or three axes, whereas newer machines have three to five axes and can operate along the XYZ plane (vertical axis, horizontal axis, and depth).
Your CNC burn table is an integral part of what you do and keeping it operating at its best is vital. If these solutions don’t fix the problem you are experiencing, reach out to an experienced plasma table expert to help you diagnose and fix the problem. They can have your table operating like new in no time.
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