How To Shield Noise From CNC Router in 2022?

If you are a mechanical enthusiast or a pro-grade CNC router operator, you would admit the fact that the noise problems and backlash are the biggest causes of disturbances to ever occur. Today we will check everything about the noise problem resulting from a CNC router and how we can shield it.

Noise can result from varied electrical sources that include unexpected tripping of limit switches, uncontrolled movements, and issues with the servo encoder.   

Well, there are many other sources of noise in a CNC router. But the ones that result from motors and Variable Frequency Drives (VFDs) are the worst of all.

So, what to do to reduce or shield this noise? Suppressing noise is a process of covering the noise generator with a grounded shield of metal. With sufficient Aluminium foiling and grounding, you can shield electrical noise.  

The good news is there are much simpler ways to reduce noise problems than what mentioned above. 

Here I have shared a list of effective tips that you may try if you, too, are facing noise problems with your CNC router.

Easy And Affordable Noise Reduction Tips

1. Use Twisted Pair or Shielded Cables

Encoder wiring, limit switch wiring, and shielded cabling for the servo or stepper motor wiring is fit resisting, reducing or shielding electrical noise.

Here are what you need to buy:

  • A 500 feet spool of 6 conductor shield 22 AWG cable  For connectors
  • Some microphone connectors
  • A foil shield and 6 conductors (choose the right cable as per the type of motor you use) 

Ground the shield cables to your CNC router cabinet and get your limit switches going. That will be fine to shield the electrical noise in your CNC system. 

Note: Cinch Connectors are another resort you can utilize for motors. They carry more current compared to microphone connectors or DINs (Deutsches Institut für Normung)

2. Higher The Voltage Control Signals, Better The Noise Resistance

When it is about better noise immunity,  3 to 5 Volt DC is quite marginal. Voltage of 12 Volt or above to the limit switches makes the CNC router system less prone to electrical noise generation. Sadly, this is something not in your hand as the voltage limit would be already decided for your breakout board. For example, some breakout boards like ATX provide 3.3, 5, or 12 Volt, etc. 

There are opto-isolators which allow differential voltages of +5 Volt to the breakout board and 24 Volt to the switch circuits.

3. Higher Current Also Immunes to Electrical Noise 

In case, you couldn’t go well with the above tip, then try using some 100 ohm pull-up resistors to +5 on switch. This will supply 50 mA of current via the switch, thereby increasing reliability. 

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