Troubleshooting Guide

Systematic Diagnosis of Common Paper Machine Clothing Issues

Paper machine problems are the #1 killer of machine efficiency. This guide provides systematic diagnostic methods.

Diagnostic Methodology

1. Identify Problem Pattern: Fixed location or moving? Immediate or gradual onset?
2. Rule Out Variables: Check raw materials, chemicals, machine settings
3. Fabric vs. Machine: Mark fabric edge — does defect follow fabric or stay?
4. Systematic Inspection: From headbox to reel, check each section
5. Data Collection: Record speed, vacuum levels, tensions, temperatures

Forming Fabric Issues

Sheet Marking (Wire Marks)

• Symptoms: Visible pattern on paper surface
• Causes: Binder knuckle protrusion (standard triple-layer most common), insufficient tension, mesh too coarse for basis weight, excessive vacuum
• Solutions: Upgrade to SSB, increase tension within 4-8 kN/m, optimize mesh count, reduce vacuum to minimum needed

Edge Wear / Cracking

• Causes: Excessive deckle pressure, roll misalignment (high edge tension), uneven tension, fabric-frame friction, chemical attack from edge showers
• Diagnosis: Clean cut = alignment issue. Multiple small cracks = tension/support issue

Short Life

• Investigation: Check stock changes (fiber source, recycled %, new fillers), machine changes (foil/vacuum/roll adjustments), cleaning system failures, chemical changes
• Corrective: PA yarns in wear zones, higher shower pressure (25-40 bar), more frequent inspection

Press Felt Issues

Rapid Plugging / Filling

• Causes: Inadequate showering (<20 bar) or clogged nozzles, chemical precipitation, excessive carryover from forming section, felt too dense for stock
• Solutions: Weekly nozzle inspection, check pH and implement chemical cleaning, improve retention, specify more open fiber layer

Premature Edge Wear

• Causes: Deckle board friction (adjust to 3-5mm gap), roll misalignment (laser alignment), uneven tension, vacuum box edge seal issues
• Diagnosis: Mechanical damage (cuts) vs. fatigue cracks

Nip Dryness Drop >3%

• ≈12% more steam consumption
• Check: Felt void volume/CFM (<60% of new = replace), shower pressure (20-35 bar), nozzle condition, uhle box vacuum (30-50 kPa), nip load settings, press roll surface condition
• Gradual decline = felt degradation. Sudden = process/mechanical issue

Dryer Fabric Issues

Fabric Tracking / Misalignment

• Check: Uniform cross-machine tension, annual laser alignment of all rolls, gradual temperature ramp-up (10-15°C/30min) to prevent shrinkage, monthly guide board/roll inspection
• PAPTEX dryer fabrics: <0.5% width shrinkage at 180°C

Seam Failure

• Causes: Seam material unsuitable for temperature, rapid heating, seam passing over stationary elements, uneven tension, pin line wear from insufficient lubrication, seam not perpendicular to machine direction
• Prevention: Verify material grade, follow 10-15°C/30min ramp, proper lubrication schedule

Moisture Streaks After Dryer Section

• Check: Uneven dryer fabric CFM distribution, seam CFM mismatch (streak frequency = seam spacing), blocked pocket ventilation, press section cross-machine moisture profile, condensate removal issues

When to Contact PAPTEX Immediately

Contact PAPTEX when:

1. Life drops unexpectedly >30%
2. Catastrophic failure occurs
3. Quality issues can't be resolved within 24 hours
4. Planning major process changes
5. Installation guidance needed
6. Any safety concerns

24/7 WhatsApp or engineering@paptex.com. Provide photos, videos, data, and fabric samples.