Product Details
PML Electro-Permanent Magnetic (EPM) Chucks are advanced magnetic workholding systems for CNC milling, machining centres and heavy-duty metalworking. Electro-permanent technology delivers powerful, uniform clamping force while consuming power only during the magnetisation and demagnetisation pulses — an efficient, fail-safe hold that improves machining accuracy from the first setup.
Unlike conventional mechanical clamping, an EPM chuck leaves the workpiece unobstructed on multiple sides — more machining operations in a single setup, with less deformation and less vibration.
How Electro-Permanent Technology Works
The chuck combines permanent magnets with reversible-polarity magnets. A brief electrical pulse flips the reversible magnets' polarity, directing magnetic flux into the workpiece to create clamping force; a second pulse reverses the field internally and releases the part. Power is needed only during switching — the energy efficiency of permanent magnets with the convenience of electromagnetic control.
Key Features
- Strong, Uniform Clamping
Even force distribution across the entire workpiece — suitable for heavy stock removal.
- Fail-Safe by Design
No loss of holding force during a power failure; the hold is magnetic, not electric.
- Fast Setup and Release
Workpiece changeovers in seconds, with dramatically reduced fixture complexity.
- Accuracy You Can Measure
Uniform holding minimises vibration and movement, improving dimensional accuracy and surface finish.
- Gentle on the Part
Distributed clamping prevents the crushing, bending and surface damage of concentrated mechanical clamps.
- Configurable
Multiple pole configurations and sizes for different work envelopes.
What This Means in Production
Enhanced productivity. Magnetic clamping cuts setup times versus conventional fixtures — faster changeovers, better machine utilisation.
Superior machining accuracy. Uniform holding across the workpiece minimises vibration during cutting, for tighter dimensions and better finishes.
No workpiece deformation. Thin and delicate parts keep their shape — force is spread, not concentrated.
Fail-safe reliability. Once magnetised, the chuck holds without continuous power; parts stay clamped through unexpected power failures.
Improved tool access. With no clamps in the way, operators machine multiple faces in one setup.
Available Variants
- Circular Pole EPM Chucks
For smaller workpieces requiring high magnetic efficiency and precision workholding. Minimum workpiece size: 84 × 84 × 15 mm.
- 50 × 50 Pole EPM Chucks
Ideal for medium-sized components and general-purpose milling. Minimum workpiece size: 150 × 150 × 12 mm.
- 70 × 70 Pole EPM Chucks
Engineered for larger workpieces and heavy-duty machining needing higher holding forces. Minimum workpiece size: 200 × 200 × 20 mm.
- Fine Pitch EPM Chucks
Optimised for thin, small and precision components where maximum magnetic coverage and uniform holding are critical.
Applications
- CNC milling machines, VMCs and HMCs
- Tool & die and mould manufacturing
- Aerospace and automotive components
- Energy equipment and heavy engineering components
- Precision machining, fabrication workshops and general metalworking
Optional Accessories
- I-SMART Controller
- EPM-DM Controller
- Wireless remote operation
- Multi-chuck control systems for up to 8 chucks
Frequently Asked Questions
What happens if power fails during machining?
The part stays clamped. Holding force comes from permanent magnets; electricity is used only for the switching pulse.
Will a magnetic chuck distort thin parts?
The opposite — because force is distributed evenly across the whole contact face, EPM clamping avoids the local distortion that mechanical clamps cause on thin or delicate parts. The Fine Pitch variant is designed specifically for them.
Which variant suits my machine?
Match the pole format to your workpiece size: Circular Pole from 84 × 84 × 15 mm, 50 × 50 Pole from 150 × 150 × 12 mm, 70 × 70 Pole from 200 × 200 × 20 mm, and Fine Pitch for thin precision parts. Our engineers will confirm the right configuration for your application.
Can multiple chucks run together?
Yes — multi-chuck control systems coordinate up to 8 chucks, with wired, wireless and HMI control options.
Why Buy From PML
- 65+ years of magnetic expertise — Permanent Magnets Ltd has designed and manufactured magnetic products for 65+ years, and our consumer range is built to the same engineering standards we supply to global industrial leaders.
- Made and tested in-house — magnets, assemblies and finished products are manufactured and quality-checked at our own facilities, so every unit performs to its stated specification.
- Honest specifications — the ratings you read on this page are the ratings you get. If your application needs a different size or strength, our engineers will tell you exactly what works — and what won't.
- Support from real engineers — from product selection to after-sales, your questions are answered by the team that builds the product.
Need help choosing, or a custom specification? Enquire now and our engineering team will guide you to the right solution.