Common Problems with Used Roll Forming Machines — And How to Avoid Them

Unlike new equipment, used machines carry unknown wear history, prior overload events, inconsistent maintenance standards, and possible design limitations.

Many of the most expensive failures are not obvious during casual inspection. They reveal themselves only under load.

This guide outlines the most common mechanical, electrical, structural, and production problems found in used roll forming machines — and how to identify, prevent, and correct them.

1. Oil Canning in Roofing Panels

What It Looks Like

• Visible waviness in flat panel areas

• Light reflection distortion

• Surface rippling between ribs

Why It Happens in Used Machines

• Roll surface wear

• Uneven roll gap

• Frame flex under load

• Excess forming pressure

• Improper pass progression

• Shaft deflection

Older machines often lack frame rigidity compared to modern builds.

How to Avoid It Before Buying

• Run sample panels at full speed

• Inspect under direct lighting

• Test multiple gauge thicknesses

• Check shaft runout with dial indicator

• Inspect roll chrome condition

Correction Options

• Re-adjust roll gaps

• Replace worn rolls

• Reduce forming pressure

• Install support rollers (in some cases)

If frame flex is root cause, repair may not be economical.

2. Rib Misalignment

Symptoms

• Ribs drifting left or right

• Inconsistent rib spacing

• Panel width variation

• Uneven rib height

Root Causes

• Shaft runout

• Stand misalignment

• Roll keyway wear

• Bearing seat damage

• Frame twist

Even minor shaft deflection can create visible rib errors.

Prevention During Inspection

• Measure rib spacing across 3+ panels

• Measure rib height at multiple points

• Check shaft runout tolerance (≤0.05mm ideal)

• Verify stand vertical alignment

Fix Potential

• Replace bearings

• Shim stands properly

• Replace worn shafts

• Re-machine keyways

Severe frame twist is often non-repairable.

3. Popping Noises During Forming

A common issue in used lines.

Sounds Like

• Sudden metallic popping

• Intermittent clicking under load

• Noise at specific stand location

Likely Causes

• Material stress release

• Roll surface damage

• Uneven forming pressure

• Shaft keyway movement

• Loose stand bolts

• Chain slack

Inspection Steps

• Identify which stand produces sound

• Inspect roll surface at that station

• Check torque on stand bolts

• Inspect keyway integrity

• Check chain tension

Often caused by uneven stress progression between forming passes.

4. Excessive Vibration

Symptoms

• Machine shaking at high speed

• Frame oscillation

• Bearing overheating

• Panel chatter marks

Causes

• Shaft imbalance

• Bearing wear

• Gearbox backlash

• Frame fatigue

• Misaligned drive system

How to Test

• Run machine at incremental speeds

• Observe vibration threshold

• Check bearing temperature

• Inspect gearbox for noise

Vibration accelerates wear exponentially.

5. Gearbox Backlash & Drive Wear

Used machines frequently show drive fatigue.

Symptoms

• Jerky start-up

• Inconsistent forming tension

• Delayed response

• Noise under load

Causes

• Gear tooth wear

• Oil contamination

• Output shaft play

• Coupling misalignment

Inspection

• Lock input shaft

• Check rotational play at output

• Inspect oil condition

• Listen during load

Gearbox rebuilds can significantly affect cost justification.

6. Hydraulic Shear Sticking

Very common in older machines.

Symptoms

• Shear slow return

• Shear sticking at top

• Inconsistent cut timing

• Jerky cutting motion

Causes

• Contaminated oil

• Worn seals

• Valve blockage

• Pump fatigue

• Air in system

Inspection

• Cycle shear repeatedly

• Check oil color and smell

• Inspect hose condition

• Check cylinder leakage

Hydraulic rebuilds are common but manageable.

7. Cut Length Inaccuracy

Symptoms

• Panel length variation

• Short cuts

• Overcuts

• Inconsistent tolerance

Causes

• Encoder drift

• Loose encoder mounting

• PLC lag

• Slipping drive wheel

• Hydraulic timing error

Test

• Cut 5 identical lengths

• Measure with calibrated tape

• Compare programmed vs actual

Tolerance beyond ±1mm suggests control issue.

8. Tooling Surface Damage

Symptoms

• Roll marks on panel

• Scratches

• Chrome flaking

• Dull edges

• Profile tolerance drift

Causes

• Abrasive materials

• Lack of lubrication

• Roll regrind history

• Overloading gauge thickness

Tooling replacement cost must be factored into negotiation.

9. Bearing Overheating

Symptoms

• Excessive heat

• Noise

• Vibration

• Shaft wobble

Causes

• Misalignment

• Contamination

• Lack of lubrication

• Overload

Test by running machine 20–30 minutes and checking temperature.

10. Frame Fatigue & Cracking

Serious issue.

Indicators

• Hairline cracks near stand mounts

• Uneven stand heights

• Weld repair patches

• Anchor bolt stress marks

Structural fatigue compromises entire machine.

Often a deal breaker.

11. Electrical Obsolescence

Problems

• Unsupported PLC

• No spare parts

• Outdated relays

• Poor wiring modifications

• Burn marks

Risks

• Downtime

• Inability to repair

• Compliance failure

PLC upgrades are common in used machines.

12. Punch Timing Errors (Purlin & Structural Machines)

Symptoms

• Off-center holes

• Burr formation

• Punch hitting partially formed material

• Misaligned slotting

Causes:

• Servo lag

• Encoder inaccuracy

• Mechanical backlash

Precision punching requires tight synchronization.

13. Chain & Sprocket Elongation

In chain-driven machines:

Symptoms

• Inconsistent forming timing

• Noise

• Slack chain

• Worn sprocket teeth

Chain elongation alters stand synchronization.

14. Motor Overheating

Causes

• Overloading gauge thickness

• Mechanical resistance

• Bearing friction

• Electrical imbalance

Check:

• Amp draw vs rating

• Insulation integrity

• Cooling fan condition

15. Overstated Machine Capacity

Very common in used listings.

Seller claims:
“Runs 24 gauge”

But machine was designed for:
29–26 gauge only.

Overloading results in:

• Shaft deflection

• Bearing fatigue

• Profile distortion

• Motor strain

Always verify actual test material.

How to Avoid These Problems Before Buying

1. Conduct structured mechanical inspection.

2. Demand test run under load.

3. Measure shaft runout.

4. Inspect roll surface closely.

5. Verify documentation.

6. Confirm gauge capacity with real material.

7. Test cut tolerance.

8. Check vibration at full speed.

9. Inspect gearbox backlash.

10. Budget for proactive spare parts.

Never rely on appearance alone.

The True Risk of Skipping Inspection

Skipping inspection can lead to:

• Immediate downtime

• Tooling replacement cost

• Compliance fines

• Scrap rate increase

• Customer dissatisfaction

• Loss of reputation

A used machine can deliver excellent ROI — but only if mechanical risk is controlled.

Frequently Asked Questions

What is the most common issue with used roll forming machines?

Oil canning and rib misalignment are among the most common defects.

Are used machines more prone to vibration?

Yes, especially if shafts or bearings are worn.

Can gearbox wear be repaired?

Yes, but rebuild costs must be considered in valuation.

Is hydraulic sticking serious?

It is common and usually repairable.

How do I detect frame fatigue?

Inspect welds, anchor areas, and stand mounts carefully.

Should I replace bearings immediately after purchase?

Often recommended as preventative maintenance.

How do I avoid buying an overloaded machine?

Verify real gauge capacity with test material.

Can PLC systems be upgraded?

Yes, modern PLC retrofits are common.

What’s the biggest hidden cost?

Tooling replacement and structural damage.

When should I walk away?

If structural frame damage or severe shaft bending is found.

Final Conclusion

Used roll forming machines fail for predictable reasons:

• Mechanical wear

• Structural fatigue

• Electrical obsolescence

• Improper maintenance

• Overloading beyond design limits

None of these problems are random.

They are detectable through structured inspection.

When identified early, most are manageable.

When ignored, they become expensive.

Proper due diligence transforms a used machine from a gamble into a strategic asset.