Encoders are one of the most critical components in any roll forming machine. They control length measurement, flying saw positioning, punch timing, feed speed, servo alignment, and production accuracy. When an encoder becomes miscalibrated — even slightly — your entire production process can drift out of tolerance.

Signs of encoder miscalibration include:

• Wrong panel length

• Inconsistent cut accuracy

• Punch out of sync

• Flying saw missing the cut

• Jerky servo movement

• PLC showing unstable speed readings

• Motor struggling to follow commands

• Encoder “pulse loss” or “direction error”

This blog explains why encoders drift, how recalibration works, early warning signs, preventive maintenance, and how Machine Matcher technicians recalibrate encoders for peak accuracy.

1. Why Encoder Calibration Matters in Roll Forming

Encoders convert mechanical motion into an electrical pulse signal. The PLC and servo drives use these pulses to control:

• Feed speed

• Cut length

• Punch timing

• Flying saw travel

• Line synchronization

• Motor speed precision

1 pulse out of place = a length error.
100 pulses out of place = a production disaster.

A properly calibrated encoder ensures:

• Accurate panels

• Reduced scrap

• Faster cycle times

• Stable servo performance

• Reliable VFD feedback

• Safe flying saw synchronization

Without calibration, production slowly drifts until major failures occur.

2. How Encoders Become Miscalibrated

Encoders do not stay perfect forever. Several factors cause drift:

2.1 Mechanical Issues

• Loose encoder couplings

• Slipping encoder wheel

• Worn bearings

• Shaft misalignment

• Dirty or slipping timing belts

• Worn measuring wheel (on friction encoders)

2.2 Electrical Issues

• Noise from VFDs

• Poor grounding

• Incorrect shield termination

• Weak 24VDC supply

• Broken encoder wire strands

• Bad A/B/Z channel connections

2.3 Software / Parameter Issues

• Wrong PPR (pulses per revolution)

• Incorrect scaling factor

• Wrong gear ratio

• Incorrect servo tuning

• PLC misconfiguration

• VFD speed scaling errors

2.4 Environmental Issues

• Metal dust

• Oil contamination

• Vibration

• Heat or humidity

Encoders only work as well as their environment allows.

3. Symptoms of Encoder Miscalibration

3.1 Incorrect Panel Length

The most common symptom.
Panels become too long, too short, or vary dramatically between cuts.

3.2 Flying Saw Timing Errors

• Saw arrives too early

• Saw arrives too late

• Cut happens at wrong position

• Actual cut drifts as speed increases

3.3 Punching & Notching Misalignment

Punch fires at wrong moment due to inaccurate feedback.

3.4 Servo Drive Position Errors

Servo triggers:

• Following error

• Overspeed

• Oscillation

• Jitter

• Axis fault

3.5 Speed Reading Instability

PLC or HMI shows unstable speed when line is running at a constant rate.

4. How Encoder Recalibration Works (Professional Method)

Machine Matcher uses a step-by-step process to recalibrate encoders.

Step 1 — Mechanical Inspection

Check:

• Encoder coupling

• Shaft alignment

• Belt tension

• Measuring wheel pressure

• Encoder bracket rigidity

• Cable condition

Fixing mechanics FIRST is critical — software cannot compensate for mechanical defects.

Step 2 — Clean & Test the Encoder

• Remove metal dust

• Check LED indicators

• Measure output pulses with oscilloscope or PLC monitor

• Verify power supply voltage

• Check A/B/Z channels for equal amplitude

Step 3 — Confirm Encoder Specifications

We verify:

• PPR (pulses per revolution)

• Voltage type (5V TTL / 24V open collector / differential)

• Wiring configuration

• Direction

Incorrect PPR or direction causes major cut-length errors.

Step 4 — Recalibrate Scaling & Length Factors

In the PLC or servo drive, we adjust:

• Scaling factor

• Encoder distance per pulse

• Gear ratio

• Flying saw sync factor

• Punch timing offset

• Shear calibration curve

This creates accurate, repeatable manufacturing.

Step 5 — Test at Multiple Speeds

We run tests at:

• Slow speed

• Medium speed

• Maximum line speed

Mis-calibration often appears ONLY at high speed due to inertia and encoder lag.

Step 6 — Lock in Final Values

The final calibration values are saved in:

• PLC program

• Servo drive parameter backup

• VFD memory

• Maintenance record

This ensures settings can be restored if a module fails.

5. Preventive Maintenance to Keep Encoders Accurate

✔ Clean encoder and bracket weekly

✔ Inspect for oil and dust accumulation

✔ Tighten encoder couplings every month

✔ Replace worn measuring wheels quarterly

✔ Verify encoder distance calibration after major mechanical adjustments

✔ Keep encoder cables away from VFD motor leads

✔ Maintain stable 24V power

✔ Check grounding and shielding annually

✔ Replace encoders every 3–5 years (high duty)

Most encoder failures are preventable.

6. Special Considerations for Different Encoder Types

Shaft Encoders

Prone to:

• Slippage

• Misaligned shafts

Friction / Measuring Wheel Encoders

Prone to:

• Dirt buildup

• Worn rubber wheels

• Inconsistent contact pressure

Magnetic Encoders

Prone to:

• Metal dust interference

Servo Motor Encoders

Prone to:

• Servo tuning drift

• Heat damage

• Connector vibration

Machine Matcher technicians handle all encoder types.

7. When to Call an Electrical Technician

Contact a professional if you experience:

• Wrong panel length

• Inconsistent cut accuracy

• Flying saw crashing or mis-timing

• Punching out of sync

• Encoder pulse loss

• Servo following errors

• High-speed drift only at certain speeds

• Length errors after mechanical changes

Machine Matcher provides:

• Encoder recalibration

• Encoder replacement

• Mechanical alignment correction

• PLC scaling adjustments

• Servo tuning

• VFD synchronization

• 24/7 remote support

• Worldwide on-site technicians

Conclusion

Encoder recalibration is one of the most important maintenance tasks for any roll forming machine. If the encoder drifts, the entire production process becomes inaccurate — leading to scrap, downtime, and customer complaints.

Routine encoder inspection and recalibration protect cut accuracy, flying saw timing, servo stability, and overall production efficiency.

Machine Matcher provides complete encoder services, from diagnostics to recalibration to replacement, ensuring your machines stay accurate and reliable worldwide.

Machine Matcher now offers full electrical technician services for roll forming machines — including diagnostics, rewiring, testing, encoder calibration, PLC programming, electrical audits, and preventive maintenance.
We support all machine types and all global regions.
Contact us today for immediate technical assistance or to schedule a full electrical inspection at your factory.

Looking for the right roll forming machine or expert guidance on your next project? Machine Matcher is here to help. Our global team provides 24/7 technical support, expert advice, and guidance on machine selection, setup, and maintenance—ensuring your operations run smoothly from day one.

With team members based worldwide—including the UK, USA, Middle East, and beyond—we are equipped to assist buyers across the globe. Whether you’re sourcing a single machine or upgrading an entire production line, our experts are ready to provide tailored solutions and support every step of the way.

Get in touch now and let Machine Matcher help you find the perfect roll forming machine for your business.

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Phone: +44 20 335 56554

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Email: [email protected]