When Demagnetization Fails: The Long-Term Effects of Incomplete Demag Cycles in Electromagnetic Chuck Controllers

In precision manufacturing, small oversights can lead to major long-term problems. One such issue that often goes unnoticed until it's too late is a faulty demagnetization cycle in an electromagnetic chuck controller.

While it may seem minor at first—maybe a part is slightly harder to lift or there’s a faint “cling” when switching pieces—over time, this incomplete demag cycle can compound into serious consequences for your tooling, quality, and workflow.

What Is the Demagnetization Cycle in an Electromagnetic Chuck Controllers?

Electromagnetic chucks use direct current (DC) to create a magnetic field that holds ferrous workpieces securely during machining. In order to properly turn the AC power available in shops to DC voltage that the chuck needs, an electromagnetic chuck controller is needed.

After the work is done on the electromagnetic chuck, the chuck typically must go through a demagnetization cycle—an electronic process that ramps down and reverses current to effectively "neutralize" the magnetic field. If this cycle doesn’t fully complete or is poorly designed, residual magnetism remains in both workpiece and chuck body.

Signs of Incomplete Demagnetization

• Parts are difficult to remove from the chuck

  
  

• Workpieces stick to each other after removal

  
  

• Precision measuring instruments give inconsistent readings

  
  

• Decreased throughput due to handling delays

  
  

• Quality control issues due to magnetized chips or burrs

Trusting your chuck controller to demagnetize parts when needed is one of the more essential steps of machining

The Long-Term Impacts

1. Part Quality Degradation

Residual magnetism attracts fine metallic particles like grinding swarf or chips, which can adhere to the surface of the workpiece. Over time, this leads to:

• Surface finish issues

  
  

• Contaminated assemblies

  
  

• Increased likelihood of rework or scrap

2. Tool Wear and Machine Damage

If residual magnetism is present, chips may not evacuate properly during machining. These stray particles can:

• Accelerate wear on cutting tools

  
  

• Clog coolant systems

  
  

• Cause spindle or bed scoring from abrasive buildup

3. Workpiece Handling Risks

Parts that “stick” to the chuck or each other can lead to operator frustration, slow changeovers, and even injury if excessive force is needed to remove them.

4. Calibration and Inspection Errors

Magnetized parts can interfere with precision measuring tools, leading to inaccurate dimensional readings. This impacts inspection, tolerance validation, and downstream processes.

5. Increased Maintenance and Downtime

Over time, the extra strain caused by residual magnetism can damage not just the chuck, but also the controller and wiring. Brushes, collectors, and even the chuck coils may wear prematurely—adding cost and production interruptions.

While the chuck is an essential part of the workholding equation, pairing your chuck with a high-quality controller can be even more important than the chuck

What Causes Incomplete Demagnetization?

• Aging controllers with worn-out or underperforming circuitry

  
  

• Outdated demag technology with no ramp-down or polarity reversal

  
  

• Improper voltage settings or mismatched chuck/controller pairs

  
  

• Skipping the cycle due to operator oversight or time pressure

How to Fix or Prevent the Problem

• Upgrade to a modern electromagnetic chuck controller with a true polarity-reversing, multi-step demag cycle.

  
  

• Perform routine residual magnetism checks using a handheld Gauss meter.

  
  

• Train operators on proper demag procedures and when to spot failures.

  
  

• Schedule preventative maintenance to inspect coil resistance, terminal integrity, and controller performance.

A poorly functioning demagnetization cycle isn’t just a nuisance—it’s a liability. If you're seeing the signs of residual magnetism in your shop, it's time to take a closer look at your chuck controller. Upgrading to a controller with a robust demag function is a simple, effective way to safeguard your machines, improve quality, and avoid costly downtime.

Ready to make the switch to a proven chuck controller that is trusted by manufacturers around the world? Request more information about our FluxMaster V chuck controller here.

Have questions about our chuck control units? Check out our FAQ section below...

Do you service Electro-Matic chuck controllers?

Unfortunately, Electro-Matic chuck controllers are no longer serviceable. We are able to provide troubleshooting advice to keep your Electro-Matic chuck controller running but cannot provide parts for it. Our technicians 50+ years of experience with chuck controllers allows our team to give you support for as long as the Electro-Matic chuck controller is functioning.

Do your chuck controllers work on other brands of chucks, such as Blanchard or Walker?

Yes, our chuck controllers are compatible with every chuck brand and provides superior holding, dependability, and service no matter what chuck you have.

Can I get parts for an older chuck controller?

We do provide service for our chuck controllers, no matter the age. While direct part replacement might be difficult, our team is willing to work with you to keep your controller running.

Obsidian Manufacturing Industries, Inc. is a Rockford, Ill. manufacturing company and is the OEM for Magna-Lock USA workholding, MagnaLift & Power-Grip lift magnets, and Arter Precision Grinding Machines as well providing surface grinding services. They are located at 5015 28th Ave. in Rockford, Ill. with a phone number of 815-962-8700. Check out more at obsidianmfg.com/brands.