1. Problem Description and Scope

Belt conveyors are an essential part of many industrial processes. Conveyor misalignment, also known as 'mistracking', is a common problem that can lead to significant operational disruption and damage. This diagnostic manual focuses on the systematic identification and elimination of the root causes of tire misalignment. It is designed to provide maintenance technicians with the necessary expertise to accurately diagnose and resolve problems on site.

This manual covers the following symptoms:

Lateral deviation of the conveyor belt, resulting in contact with the frame or structural components.
Uneven wear patterns on the conveyor belt, often concentrated on one side.
Damage to the edges of the conveyor belt, including delamination or cracks.
Build-up of material on the underside of the belt or on return rollers.
Excessive spillage of product on the sides of the conveyor.
Damage to roller bearings or pulley bearings due to incorrect loading.

The analysis in this manual is applicable to all types of belt conveyors, including horizontal, inclined, ascending and descending systems, and systems with both trough rollers and flat carrier rollers.

Ernst's classification:

The severity of tire misalignment can be classified into the following categories:

Critical: Immediate production stop, immediate safety risk due to potential energy release, or serious and irreparable tire damage leading to high replacement costs and long downtimes. Action is required immediately.
Major: Significant reduction in operational efficiency, increased tire and component wear, and periodic product loss. Requires urgent planning and implementation of corrective actions to prevent escalation.
Minor: Incipient lateral deviation without direct impact on production progress or safety. Although not acute, this indicates an underlying problem that needs attention to prevent further development and costly repairs.

2. Safety measures

SAFETY FIRST. Before performing any diagnostic or corrective work on a belt conveyor, it is absolutely critical to strictly follow all relevant safety procedures. Failure to do so can lead to serious injuries or fatalities.

WARNING:

1. Lock and label (Lockout/Tagout - LOTO): Ensure that the conveyor is completely isolated from all energy sources (electrical, hydraulic, pneumatic) and locked according to the NEN-EN-ISO 14118 standard. Confirm the absence of energy through measurements where applicable. This is essential to avoid unexpected starts.

2. Stored Energy: Be aware of stored energy in the conveyor itself (tension), spring-loaded tensioners, or counterweights. Take appropriate measures to release or safeguard this energy in a controlled manner before carrying out work in the immediate vicinity.

3. Personal Protective Equipment (PPE): Always wear the correct PPE in accordance with EN standards: safety shoes (EN ISO 20345), cut-resistant gloves (EN 388), eye protection (EN 166) and hearing protection if necessary. Additional PPE may be required when working below the belt or in confined spaces.

4. Moving Parts: NEVER work on a conveyor that is in operation or may be started. Be alert for pinch points, rotating rollers and the movement of the belt itself. Even minor adjustments must be made under LOTO conditions.

5. Fabric and Material: Be careful with fabric and loose material. This can be irritating to the eyes or respiratory tract. Use respiratory protection if necessary.

6. Fall hazard: When performing inspections at height, always use approved fall protection and work platforms. Provide a stable surface.

3. Required Diagnostic Tools

The following tools are essential for a thorough diagnosis of belt misalignment. Make sure all equipment is calibrated and in good working order.

Tool	Specification / Model	Measuring range / Setting	Goal
Digital Multimeter	True RMS, CAT III/IV	Voltage (AC/DC), Resistance (Ω), Current (mA)	Check electrical components, motor current (load indication), sensor signals.
Infrared Thermometer (Pyrometer)	Laser guided, ±1°C accuracy	-30°C to 500°C	Detect overheating of bearings, rollers, pulleys (indication of friction or defect). Normal operation: ambient temperature +10°C. Alarm: +30°C above ambient temperature or >80°C absolute.
Digital Tachometer	Contact / Non-contact (laser)	0-99,999 RPM	Measuring belt speed and motor speed; check for slip.
Tension gauge (for belt tension)	Ultrasonic or Mechanical	Depending on belt type (N/mm width)	Accurately measure tire pressure. Essential for correct adjustment.
Laser leveler (or rotary laser)	Accuracy ±0.5 mm/10 m	N/A	Checking the levelness and alignment of the conveyor frame and rollers (according to EN ISO 14030).
Laser Alignment Device (for pulleys)	±0.05 mm/m accuracy	N/A	Precision alignment of drive and idler pulleys, crucial for belt running properties.
Measuring tape / tape measure	5 meters, class II	Millimeter nauwkeurigheid	Measuring distances, clearances, dimensions of components, position of belt guides.
Torque wrench	½” drive, 20-200 Nm range	Specified tightening torque (see OEM)	Checking and securing bolted connections (e.g. roller attachments, frame components) in accordance with DIN EN 14407-1.
Vibration Analyzer	Triaxial accelerometer, FFT analysis	Frequency range 0-10 kHz, Amplitude (mm/s RMS)	Diagnose bearing condition, roller imbalance, misalignment. ISO 10816 standards: Good (<1.8 mm/s), Acceptable (1.8-4.5 mm/s), Alarm (4.5-7.1 mm/s), Hazard (>7.1 mm/s) for bearings and rollers.
Strobe	Flash frequency 30-30,000 FPM	Synchronization with rotation speed	Visual inspection of moving parts during operation to identify defects or irregularities without stopping the machine (with appropriate safety measures).
Vernier caliper / feeler gauge	0-150mm, 0.02mm accuracy	N/A	Measuring clearances, wear of rollers, thickness of apron rubbers.

4. Initial Assessment Checklist

Before beginning detailed diagnostic steps, a thorough initial assessment is essential. Collect the following information and perform visual checks to get a complete picture of the situation. This helps in locating the problem area and using diagnostic resources efficiently.

Aspect	To Check / To Observe	Registration / Notes
Operating Conditions
Product type	What is transported? (Abrasive, sticky, grainy)	E.g. "Sand", "Gravel 0-16mm", "Moist clay"
Load (Kg/m³ or T/hour)	Is the load nominal, under or overloaded? Is the loading uniform?	E.g. "80% of nominal", "Highly fluctuating"
Belt speed (m/s)	Is the speed consistent? (Measure with tachometer)	E.g. "1.5 m/s (nominal 1.6 m/s)"
Ambient temperature	Influence on material behavior (band elasticity)	E.g. "10°C", "35°C"
Recent Changes / Events
Maintenance activities	Has any recent maintenance been performed (belt replacement, roll change, splitting)?	E.g. "Tire split 2 weeks ago", "Replace bearings A1-A4"
Incidents	Have there been shocks, overloads or production stops?	E.g. "Large chunk of material in loading zone", "Emergency stop 3 days ago"
Component replacement	Have any rollers, pulleys or other components been replaced recently?	E.g. "Replace drive pulley bearing"
Alarm history / Operating system
Alarm logs	Are there error messages related to the conveyor (e.g. misalignment switch activation)?	E.g. "Misalignment switch activated zone C, 5 times in 24 hours"
Operating time / Start cycles	Frequency of start and stop affects wear	E.g. "Continuous operation", "Intermittent (10 starts/hour)"
Visual Inspection (under LOTO)
Tire wear pattern	Is the wear evenly distributed or concentrated? Are the tape edges damaged?	E.g. "More wear on right edge", "Starting tears on left side"
Product build-up	Is there material buildup on the carrier rollers, idlers, pulleys or frame?	E.g. "Dirt accumulation on return rollers C1-C5", "Material under drive pulley"
Roll condition	Are all reels spinning freely? Are there any stuck, crooked, damaged or missing rollers?	E.g. "Roller B3 stuck", "Roller C2 bearing noise"
Fission(s)	Is the fission intact? Is it straight and the same thickness as the rest of the tire?	E.g. "Fission slightly tilted", "Edge of fission beginning to separate"
Frame Integrity	Is the conveyor frame level, square and undamaged? Are all bolted connections tight?	E.g. "Frame slightly sagging at support D", "Bolts loose at roller B5"
Tire tension	Does the belt appear to be properly tensioned? (Visual assessment as starting point)	E.g. "Tire seems weak in return zone"
Loading zone	Is the loading hopper centered? Are the apron rubbers correctly adjusted and intact?	E.g. "Loading hopper 10mm off center", "Apron rubbers worn"

5. Systematic Diagnosis Flow Chart

Follow this flowchart to determine the main cause of belt misalignment in a structured manner. Always start with a LOTO procedure for any step that requires physical inspection or adjustments.

Observe the misalignment pattern:
1. Is the misalignment consistent over the entire belt length?
  - YES: Go to step 2 (Overall alignment and tension).
  - NO: Go to step 3 (Local anomalies).
Overall Alignment and Belt Tension:
1. Check frame alignment:
  - Use laser leveler to check the entire conveyor frame for levelness and squareness (NEN-EN-ISO 14030). The maximum tolerance for deviation from level or perpendicularity is 1 mm per 5 meters of frame length. Violation of this tolerance indicates a problem.
  - - DEVIATION: Root Cause: Incorrect frame alignment. Go to 'Root Cause Analysis' and 'Resolve Procedures'.
    - NO DEVIATION: Continue with b.
2. Check drive and idler pulley alignment:
  - Use laser alignment device for precision alignment of the pulleys relative to the belt track. Maximum parallel deviation: 0.5 mm per meter center distance. Maximum angular deviation: 0.2 degrees.
  - - DEVIATION: Root Cause: Pulley alignment errors. Go to 'Root Cause Analysis' and 'Resolve Procedures'.
    - NO DEVIATION: Continue with c.
3. Check tire pressure:
  - Measure the tire pressure with a tension gauge. Compare with the belt manufacturer's specifications (e.g. for PVC/PU belts: 6-10 N/mm bandwidth). Deviation of more than ±10% from the nominal value is an indication.
  - - INCORRECT PRESSURE: Root Cause: Incorrect tire pressure. Go to 'Root Cause Analysis' and 'Resolve Procedures'.
    - CORRECT VOLTAGE: Go to step 3 (Local deviations).
Local Deviations / Specific Zones:
1. Load misalignment:
  - Visual inspection of product load: Is the load centered and uniform across the bandwidth? Consistent eccentric loading of more than 1/3 of the bandwidth is problematic.
  - - UNBALANCED LOAD: Root Cause: Uneven product load. Go to 'Root Cause Analysis' and 'Resolve Procedures'.
    - CHARGE CORRECT: Continue with i.
  - Checking loading hopper and apron rubbers: Are the loading hopper and belt guides centered and correctly adjusted (clearance between apron rubber and belt: 2-5 mm per side)? Are the apron rubbers intact and not worn (thickness less than 50% of original)?
  - - DEVIATION / DAMAGE: Main cause: Loading zone components. Go to 'Root Cause Analysis' and 'Resolve Procedures'.
    - ALL CORRECT: Continue with b.
2. Misalignment on the carrying side (under the load) or return side (empty belt):
  - Inspect all carrying and return rollers:
  - - Are all rollers turning freely? (Turn manually under LOTO, listen for sounds, feel friction.) Use infrared thermometer: a temperature difference of >15°C with respect to adjacent rollers or an absolute temperature of >70°C indicates a stuck roller or defective bearing.
    - - STUCK/HEAVY ROLLERS: Root Cause: Stuck/Damaged Rollers. Go to 'Root Cause Analysis' and 'Resolve Procedures'. (Use infrared thermometer and vibration analyzer for confirmation).
      - RUN FREE: Continue with ii.
    - Are rollers clean? (Dirt accumulation of >5 mm on the roller jacket can cause misalignment).
    - - DIRT ACCUMULATION: Main cause: Dirt accumulation on rollers/pulleys. Go to 'Root Cause Analysis' and 'Resolve Procedures'.
      - CLEAN: Continue with iii.
    - Are rollers aligned and perpendicular to the belt track? (Use spirit level or laser leveler). Maximum tolerance: 2 mm over the roll width.
    - - MISALIGNMENT: Root Cause: Improper roll alignment. Go to 'Root Cause Analysis' and 'Resolve Procedures'.
      - PROPER ALIGNMENT: Continue with c.
3. Misalignment related to the tire split:
  - Inspect the entire split:
  - - Is the cleavage intact and smooth? (Visual check for loose edges, cracks, thickening >2 mm compared to the band thickness).
    - - DEFECTIVE SPLIT: Root Cause: Defective/incorrect tire split. Go to 'Root Cause Analysis' and 'Resolve Procedures'.
      - INTACT: Continue with ii.
    - Is the split aligned with the rest of the tire? (Check for lateral deviation of the split edges).
    - - IMALIGNMENT: Root Cause: Improper tire split alignment. Go to 'Root Cause Analysis' and 'Resolve Procedures'.
      - ALL CORRECT: Go to step 4 (Other factors).
Other factors (if no cause yet found):
1. Check belt material and condition: Is the belt uniform in thickness and width over the entire length (tolerance ±1% of nominal width)? Is there structural damage, kinks or deformations?
2. Check guide rollers / steering rollers: Are they correctly adjusted and functioning as intended? (Not too tight, not stuck).
3. Moisture / Environmental factors: Does moisture or temperature influence the tire properties locally?
4. Inspect pulley lining: Is the lining intact and uniform? Loose or worn upholstery can cause slippage and misalignment.
5. Refer to OEM manual: Check manufacturer's specific recommendations and tolerances.

6. Error Cause Matrix

This matrix presents an overview of common symptoms of tire misalignment, the likely causes ranked by likelihood, the recommended diagnostic tests, and the expected results that confirm the cause.

Symptom	Probable Causes (ranking)	Diagnostic Test	Expected Result at Confirmed Cause
Belt runs to one side in loading zone	1. Uneven product load 2. Loading hopper/guide alignment 3. Damaged apron rubbers	Visual inspection of loading, measurement of loading hopper position, inspection of apron rubbers for wear (thickness <50%)	Load not centered (>1/3 bandwidth deviation), loading hopper not centered (>10mm), apron rubbers worn or incorrectly adjusted (>5mm clearance)
Band runs consistently to one side over entire length	1. Frame alignment error 2. Drive pulley alignment error 3. Idler pulley alignment error 4. Incorrect tire pressure	Laser leveling frame (NEN-EN-ISO 14030), laser alignment pulleys, belt tension measurement with tension gauge (±10% of nominal)	Frame not level or square (>1mm/5m), pulley alignment out of tolerance (>0.5mm/m), tension out of specification
Belt misalignment and/or damage during splitting	1. Defective/incorrect tire splitting 2. Improper cleavage alignment	Visual inspection of cleavage for loosening/cracks/thickening (>2mm), measurement of cleavage thickness and width, check straightness	Cleavage damaged, not flat, or deviated laterally from the tire
Local misalignment on the carrying or return side	1. Stuck/Damaged Roller 2. Dirt accumulation on roller/pulley 3. Improper roller alignment	Manual check for free rotation (under LOTO), infrared thermometer (>15°C difference), vibration analysis (>4.5 mm/s RMS), visual inspection for dirt accumulation (>5mm), spirit level/laser check roll alignment (>2mm deviation)	Roller stuck/turning heavily, roller is hot, high vibration values, visible dirt accumulation, roller not perpendicular to belt track
Tire "wobbles" (unstable running)	1. Insufficient tire pressure 2. Uneven belt thickness/wear 3. Excessive play in roller bearings	Measurement of belt tension, visual inspection of belt for thickness variations (>2mm), check roller bearings for play (feeler gauge >0.2mm)	Belt pressure too low, variations in belt thickness/profile, noticeable radial play in bearings

7. Analysis of Root Causes per Error

A deeper understanding of the root causes is essential for both correction and prevention.

7.1. Uneven Product Loading

Why it happens: This is a common cause, especially in the loading zone. It occurs when product is not delivered centrally and evenly onto the conveyor belt. This can be due to a poorly designed loading hopper, a clogged or damaged loading hopper, improper feed rate leading to excessive product build-up on one side, or an uneven placement of the loading hopper relative to the belt. The lateral force of the uneven mass pushes the tire in one direction.

How to confirm: Visual observation of the belt in operation (if safe and possible, with strobe light for detail) will immediately indicate whether the product is centrally loaded. Measurements with a tape measure can confirm the eccentricity of the loading hopper relative to the tire width. The belt must be evenly loaded for at least 2/3 of its width.

Damage if left unresolved: Prolonged uneven loading results in accelerated, uneven wear of the conveyor belt, damage to the belt edges, frequent activation of misalignment switches, product spillage, and increased stress on the bearings of the carrier and return rollers, which can lead to premature bearing failure.

7.2. Incorrect Frame Alignment

Why it happens: The integrity of the conveyor frame is the basis for stable belt running. Installation errors, subsidence, mechanical impacts, or insufficient structural stiffness can result in an out-of-level or out-of-square frame. A bent or twisted frame forces the tire to deviate sideways.

How to attach: Use a laser leveler to check the levelness and squareness of the entire conveyor frame, in accordance with NEN-EN-ISO 14030. Guidelines allow a maximum deviation of 1 mm per 5 meters of frame length. Measure across the entire length and width of the structure.

Damage if left unresolved: Structural overload of the frame, accelerated and uneven wear of the belt, bearing damage from continued lateral forces, and potential structural failure of the conveyor.

7.3. Pulley alignment errors

Why it happens: Both the drive pulley and idler pulley must be perfectly perpendicular to the longitudinal axis of the conveyor and aligned parallel to each other. Installation errors, bolt connections loosening due to vibration, or mechanical shock can lead to angular misalignment (parallel offset) or twisting (angular misalignment) of the pulleys. Even a small deviation of 1 mm per meter of pulley width can cause significant misalignment.

How to install: Use a laser alignment tool for precision pulley alignment. The maximum parallel deviation may not exceed 0.5 mm per meter of center distance, and the maximum angular deviation may not exceed 0.2 degrees. These measurements are critical for a correct diagnosis.

Damage if left unresolved: Aggressive wear of belt edges, overheating of pulley bearings, accelerated wear of the pulley covering, and in extreme cases, shaft breakage due to imbalance and stress.

7.4. Incorrect Tire Pressure

Why it happens: Belt tension is critical to transferring motive power and maintaining stable belt running. Too little tension will cause the belt to slip on the drive pulley, causing uneven wear and misalignment. Too much tension places unnecessary stress on the belt and bearings and can lead to belt stretching or tearing. Incorrect adjustment of the tensioner, belt stretching due to aging or defective tensioning elements are common causes.

How to attach: Measure the tension accurately with a suitable tension gauge. Compare the measured value with the belt manufacturer's specifications (e.g. for PVC/PU belts 6-10 N/mm bandwidth). A deviation of more than ±10% from the rated voltage is a clear indication of a problem. Check the functionality of the tension element.

Damage if left unresolved: Belt slippage (leading to fire hazard due to friction), accelerated wear of the belt jacket and pulley covering, belt breakage, and excessive loading and premature failure of bearings and drive.

7.5. Defective/Incorrect Tire Splitting

Why it happens: A split is the weakest point of the conveyor belt. Errors during the splicing procedure, use of incorrect materials (glue, clamps), poor quality of execution, or the natural aging of the splicing can lead to delamination, thickening, cracks, or an uneven splicing. These irregularities disrupt the balance and tension of the tire, which directly leads to misalignment.

How to attach: A thorough visual inspection of the splice for loose edges, cracks, uneven thickness (>2mm relative to the rest of the belt), and lateral deviations is required. Ultrasonic inspection can reveal internal defects. Check the straightness of the split with a straight lath.

Damage if left unresolved: Ultimate belt failure (critical failure), severe lateral misalignment, damage to the conveyor frame from contact with the defective splice, and hazard to personnel from sudden failure.

7.6. Stuck/Damaged Rollers

Why it happens: Carrier and return rollers must rotate freely and smoothly. Dirt build-up (e.g. sticky product, dust), corrosion, bearing damage due to water penetration or overload, and inadequate lubrication are common causes of stuck or heavy spinning rollers. A stationary roller generates excessive friction with the belt, leading to belt deviation. A crooked or damaged roller also sends the belt in an undesirable direction.

How to attach: Under LOTO, manually rotate each roller to check for free movement and sounds. Use an infrared thermometer to detect overheating; a temperature difference of >15°C with adjacent rollers or an absolute temperature >70°C indicates friction. Vibration analysis (ISO 10816) can confirm bearing damage (values >4.5 mm/s RMS). Visual inspection for dirt buildup (>5mm) or damaged bearing seals is also critical.

Damage if left unresolved: Accelerated and localized wear of the conveyor belt, nicks in the belt, overheating of roller bearings (which can lead to a fire hazard with flammable products), increased energy consumption, and damage to the conveyor frame due to continuous contact with the belt.

8. Step-by-Step Resolution Procedures

The following procedures describe corrective steps for the identified root causes. Always follow the LOTO procedure before you start.

8.1. Solution for Uneven Product Loading

Safety: Make sure the carrier is under LOTO.
Cleaning: Remove all product build-up in the loading area, including the loading hopper and the immediate area.
Loading Hopper Alignment: Use tape measure to position the loading hopper centrally above the tire. Adjust the hopper so that the product spreads evenly over the center of the belt, with a maximum eccentricity of 5% of the belt width.
Checking and Adjusting Apron Rubbers:

Check the apron rubbers for wear. Replace rubbers that have less than 50% of their original thickness. Use wear-resistant rubbers in accordance with EN ISO 284 for fire safety if applicable.
Adjust the apron rubbers with a clearance of 2-5 mm from the tire. Make sure that the rubbers lightly touch the tire but do not cause excessive friction.

Belt Guides Install/Adjust: Consider installing V-guides or side rollers just in front of and in the loading zone to center the belt before loading product. Adjust these guides so that they guide the belt lightly without excessive pressure.
Test and Observe: Remove LOTO, start the conveyor and observe the loading and belt movement. Adjust the adjustments incrementally until the belt run is stable.

8.2. Fix for Incorrect Frame Alignment

Safety: Transporter under LOTO.
Diagnosis Reconfirm: Perform laser measurements again to determine the precise location and nature of the frame deviation.
Support Customize:

Identify the frame support points that are off.
Use leveling plates or shims to level and square the frame, with a tolerance of ±1 mm over every 5 meter section.

Bolted connections Check: Check all bolted connections of the frame and supporting structure. Tighten loose bolts with a torque wrench to the torque specified by the OEM (according to DIN EN 14407-1).
Structural Strengthening: In case of subsidence or structural weakness, consider strengthening the support or frame.
Test and Check: After correction, remove LOTO and start the conveyor. Observe the belt running and, if necessary, repeat the laser measurements during operation.

8.3. Fix for Pulley alignment errors

Safety: Transporter under LOTO.
Preparation: Clean the pulleys and shafts thoroughly to ensure accurate measurements.
Laser Alignment:

Use a laser alignment tool to align the drive and idler pulleys.
Adjust the pulleys so that the parallel offset is not more than 0.25 mm per meter of axle distance and the angular deviation is a maximum of 0.1 degree. This often requires incremental adjustments to the pulley bearing adjustment screws.

Bearings and Shaft Check: Inspect the bearings (according to ISO 15242) and shaft for wear or damage. Replace if necessary.
Bolts Lock: Tighten all pulley and bearing mounting bolts to the specified torque.
Test and Observe: Remove LOTO, start the conveyor at low speed and observe the belt movement. Repeat alignment if necessary.

8.4. Fix for Incorrect Tire Pressure

Safety: Transporter under LOTO.
Check tensioning mechanism:

Inspect the tensioning mechanism (screw tensioner, hydraulic tensioner, counterweight) for free movement, damage or stuck components.
Clean and lubricate moving parts.

Measuring Tire Pressure: Use a tension gauge to accurately measure the current tire pressure.
Voltage Adjustment:

Adjust pressure according to tire manufacturer's specifications, typically ±5% of rated value.
For rubber tires this can vary from 8-15 N/mm tire width, depending on the type.

Idler Wheels Alignment (if equipped): Make sure the tension wheels or pulley are perpendicular to the belt track and move evenly.
Test and Observe: Remove LOTO, start conveyor and observe belt movement. Take repeated measurements to check the voltage over time, especially after the first few hours of operation.

8.5. Fix for Broken/Incorrect Tire Splitting

Safety: Transporter under LOTO.
Inspection and Marking: Locate the defective cleavage and mark the extent of damage.
Repair or Replacement:

Minor Damage: Minor delaminations or cracks can sometimes be repaired with a cold vulcanization method or special tire repair kits. Strictly follow the manufacturer's instructions (in accordance with NEN-EN-ISO 15236).
Major Damage/Non-straight Fission: The most reliable solution is to remove the defective fission and perform a new, correct fission, preferably by qualified personnel and using the correct materials and techniques (hot or cold vulcanization). The cleavage must be perfectly square and of uniform thickness.

Split Alignment: Make sure the new splice is perfectly aligned with the rest of the tire and has no lateral deviations.
Test and Observe: Remove LOTO, carefully start the conveyor at low speed and observe the split and belt movement. Check for any remaining misalignment or irregularities.

8.6. Fix for Stuck/Damaged Rollers

Safety: Transporter under LOTO.
Identification: Locate the stuck, heavy-rotating, or damaged roller(s) by visual inspection, thermography, or vibration analysis.
Cleaning: Remove any dirt buildup from the roller and the immediate area. Use suitable cleaning agents that do not damage the belt and rollers. A dirt layer of 5 mm can already cause problems.
Role Replace:

Disassemble the defective roller.
Inspect the bearing housing and shaft. Clean or replace if necessary.
Install a new roller with the correct specifications (diameter, length, bearing type). Make sure bearings are properly lubricated (according to ISO 4381).

Role Align:

Place the new roll perfectly perpendicular to the longitudinal axis of the conveyor. Use a spirit level or laser leveler. The maximum tolerance for alignment is 2mm across the roll width.
Make sure the roller fasteners are tight (torque according to OEM).

Test and Observe: Remove LOTO, start the conveyor and observe the belt movement in the area of the replaced roll. Check the temperature of the new roll with the infrared thermometer.

9. Preventive Measures

Prevention is the most cost-effective strategy to prevent belt misalignment and maximize the life of your conveyors.

Main cause	Prevention strategy	Monitoring method	Recommended Interval
Uneven Product Loading	Optimization of loading zone design, installation of impact and abrasion resistant lining (e.g. UHMW-PE), installation of belt guides	Periodic visual inspection of loading pattern, check for wear of apron rubbers, inspection of product flow properties	Weekly (visual), Quarterly (detailed)
Incorrect Frame Alignment	Regular inspection of foundation and frame for subsidence or damage, adequate structural support during installation	Laser measurement of frame alignment (NEN-EN-ISO 14030), visual inspection for structural integrity	Semi-annually to annually (depending on environment)
Pulley alignment errors	Use of laser alignment equipment during installation and maintenance, securing mounting bolts with specified torque	Laser alignment check of pulleys, vibration analysis (ISO 10816) of pulley bearings	Semi-annually to annually
Incorrect Tire Pressure	Implementation of automatic tensioning mechanisms (e.g. with counterweight), regular checking of manual tensioners	Measurement of belt tension with tension gauge, inspection of tensioning mechanism for wear and free movement	Monthly
Defective/Incorrect Tire Splitting	Carrying out fission by certified personnel (CE/TÜV), use of high-quality fission materials (NEN-EN-ISO 15236), quality control after each fission	Visual inspection of cleavage for delamination or cracks, ultrasonic inspection for internal defects	Quarterly (visual), Annually (ultrasonic)
Stuck/Damaged Rollers	Regular cleaning of rollers and frame, implementation of adequate lubrication program, use of sealed bearings (e.g. with ATEX certification in hazardous areas)	Infrared thermography (EN 13187), vibration analysis (ISO 10816), visual inspection for free rotation and dirt accumulation	Monthly (visual), Quarterly (thermography/vibration)

10. Spare Parts and Components

The timely availability of critical spare parts is essential to minimize downtime when belt misalignment occurs. UNITEC-D GmbH offers an extensive range of high-quality components.

Item Description	Specification	When to Replace	UNITEC Category
Conveyor belt	Type (PVC, PU, rubber), width (e.g. 600mm), thickness (e.g. 8mm), tensile strength (N/mm), material quality (e.g. wear-resistant, oil-resistant)	In case of severe delamination, irreparable tears, excessive elongation (>3%) or excessive uneven wear	Conveyor belts
Carrying rollers	Diameter (e.g. 108mm), shaft length, bearing type (e.g. 6204 2RS), roller material (steel, HDPE), trough angle (e.g. 30°)	If stuck, heavy turning, audible bearing noise, excessive vibration (>7.1 mm/s RMS) or visible damage	Rollers & Bearings
Reverse rollers / Return rollers	Diameter, shaft length, bearing type, roller material (steel, fitted with rubber discs for cleaning)	Same as carrying rollers. Specific attention to dirt accumulation and wear of the cleaning discs	Rollers & Bearings
Bearings (for rollers and pulleys)	Type (e.g. ball bearing, roller bearing), dimensions (ID, OD, width), seal type (2RS, ZZ), quality (e.g. C3 clearance)	In case of excessive play, heat development (>80°C), audible noise or high vibration values	Rollers & Bearings
Drive pulley / idler pulley	Diameter, width, shaft diameter, coating type (e.g. rubber, ceramic), coating (smooth or ribbed)	In case of excessive wear of the upholstery, irreparable misalignment, or structural damage	Pulleys
Apron rubbers	Material (e.g. polyurethane, rubber), dimensions (thickness, height), wear resistance	In case of wear of more than 50% of the original thickness, cracks or insufficient sealing	Cladding & Seals
Tire splitting material	Type (cold/hot vulcanization kit, mechanical clamps), sizing for specific bandwidth/thickness	With every new split or repair of an existing split	Tire repair

For a complete overview of available parts and specifications, including the possibility of direct ordering, please refer to the UNITEC-D e-catalogue: https://www.unitecd.com/e-catalog/

11. References

NEN-EN-ISO 14118: Safety of machines - Prevention of unexpected starts.
NEN-EN-ISO 14030: Geometric product specifications (GPS) – Alignment measurements of machines.
ISO 10816-1: Mechanical Vibration – Evaluation of machine vibration by measurements on non-rotating parts.
ISO 1940-1: Vibration – Balance quality of rotating rigid rotors.
ISO 15242: Rolling bearings – Characteristic frequencies for condition monitoring.
EN 13187: Thermography – Qualitative and quantitative analysis of heat losses from buildings.
EN 388: Protective gloves against mechanical risks.
EN 166: Personal Eye Protection – Specifications.
EN ISO 20345: Personal protective equipment – Safety shoes.
DIN EN 14407-1: Fastening elements – Mechanical properties of nuts.
NEN-EN-ISO 15236: Conveyor belts – Material for splits and repairs – Rubber or plastic covered.
Manufacturer specific OEM manuals and maintenance documentation.