I. Raw Material Stage: Loose control at the source affects the performance of the finished product

　　The quality of raw materials used in roller production directly determines the lifespan and stability of the final product. Common issues in this stage primarily revolve around two key areas: improper material selection and insufficient raw material purity.

　　1. Ceramic raw materials fail to meet purity standards (specifically for ceramic rollers)

　　Common problem manifestations: After firing, the ceramic surface develops pores and cracks, with hardness falling below standard values (e.g., alumina ceramics failing to reach HRA 90), leading to a significant drop in wear resistance and making the material prone to easy wear and flaking during use.

　　Cause of the problem:

　　Select low-purity ceramic powders (such as those with alumina content below the labeled 92%/95%), which contain excessive impurities (e.g., silica, iron oxide).

　　Improper storage of raw materials leads to moisture absorption and caking, resulting in uneven mixing of the powder material.

　　Mixing raw materials from different batches leads to significant compositional variations, resulting in unstable performance after firing.

　　Solution:

　　Establish a raw material supplier access mechanism, prioritizing large manufacturers with qualified credentials, and require a component testing report for each batch of raw materials.

　　Before raw materials enter the warehouse, conduct sampling inspections (such as using a laser particle size analyzer to measure particle size distribution, or an X-ray fluorescence spectrometer to determine composition). Any non-conforming materials will be firmly rejected and returned.

　　Store raw materials by designated areas, implement effective moisture-proof measures, and clearly label each batch separately to prevent cross-contamination.

　　2. Metal shaft material does not match

　　Common problem manifestations: Insufficient shaft strength, leading to bending and deformation during use; poor corrosion resistance, resulting in rusting within a short period when exposed to humid or corrosive environments, which causes the bearing to seize up.

　　Cause of the problem:

　　To reduce costs, ordinary Q235 steel is used instead of 45 steel or 304 stainless steel, resulting in material hardness and toughness that fail to meet the required standards.

　　The shaft undergoes missing or non-standard heat treatment processes (such as failing to perform tempering), resulting in insufficient surface hardness.

　　Solution:

　　Procure steel materials strictly according to customized specifications, requiring suppliers to provide material certification documents, and verify surface hardness using a hardness tester upon入库 (entry into the warehouse).

　　Standardize the heat treatment process for shaft components, clearly specifying the tempering temperature (e.g., for No. 45 steel, the tempering temperature is 820–840°C) and holding time, to ensure the shaft hardness reaches HB220–250.

　　For shafts requiring corrosion protection, an additional chrome/galvanized treatment is applied, with a coating thickness of ≥0.01mm, enhancing their corrosion resistance.

　　 II. Molding and Processing Stage: Insufficient process precision affects structural stability.

　　This stage involves ceramic body shaping, metal component machining, and roller assembly. Common issues center around dimensional deviations and structural defects, directly affecting the compatibility between the rollers and the conveyor belt.

　　1. Excessive dimensional deviation in the ceramic roller body

　　Common issue manifestations: The diameter and length of the ceramic roller exceed ±0.5mm in error, resulting in uneven contact with the conveyor belt during installation and leading to accelerated localized wear. Additionally, the end faces at both ends are uneven, causing excessive clearance when fitted into the bearing housing, which generates abnormal noises during operation.

　　Cause of the problem:

　　During dry pressing, insufficient mold precision (such as mold wear or dimensional deviations) or uneven pressing pressure (with edge pressure lower than the center) may occur;

　　Improper temperature control during the sintering process (such as excessively rapid heating or insufficient holding time) leads to uneven shrinkage of the roller body.

　　The subsequent polishing process was missing, resulting in a surface roughness of Ra > 1.6 μm, which affects the friction coefficient with the conveyor belt.

　　Solution:

　　Regularly calibrate the molding die, and inspect the die dimensions after every 500 pieces are produced; replace it promptly if wear exceeds the specified limit.

　　Optimize the sintering curve by setting the heating rate according to the ceramic material (e.g., for alumina ceramics, the heating rate should be ≤5°C/min), ensuring an insulation time of at least 4 hours to minimize shrinkage deviation.

　　Increase the fine grinding and polishing process by using diamond grinding wheels to finish the surface and end faces of the ceramic roller, ensuring that the diameter tolerance is ≤ ±0.3 mm, the surface roughness Ra ≤ 0.8 μm, and the end-face flatness ≤ 0.02 mm.

　　2. Improper assembly clearance between the bearing housing and the shaft

　　Common problem manifestations: Too-small clearance leads to high bearing rotation resistance, severe heating during operation, and shortened bearing life; excessive clearance causes the shaft to wobble within the bearing housing, resulting in radial runout exceeding the standard (>0.1mm) and causing unstable conveyor belt operation.

　　Cause of the problem:

　　Insufficient machining accuracy of the bearing housing bore diameter (e.g., bore diameter error > ±0.02 mm), or deviations in the shaft diameter during machining;

　　During assembly, improper use of non-specialized tools (such as a press) and forceful hammering resulted in deformation of the bearing housing, leading to abnormal clearances.

　　Solution:

　　Using CNC lathes to machine the bearing housing and shaft body, ensuring that the bore diameter tolerance of the bearing housing is controlled within H7 grade, the shaft diameter tolerance is maintained at h6 grade, and the mating clearance remains between 0.01 and 0.03 mm.

　　Standardize the assembly process by using a press to carefully press the bearing into the bearing housing, ensuring that pressure is maintained within the range of 5–8 kN to prevent forceful or improper installation.

　　After assembly, the radial runout of the idler rollers is checked using a radial runout detector; products exceeding the standard must be disassembled and readjusted.

　　3. Sealing Structure Assembly Defects

　　Common problem manifestations include misaligned installation of seals (such as O-rings and retaining rings), or excessively large sealing gaps, allowing dust and moisture to enter the bearing during operation. This leads to accelerated bearing wear and, in the short term, causes seizing failures.

　　Cause of the problem:

　　Improper selection of seals (such as using a standard rubber seal instead of a high/low-temperature or oil-resistant seal), or mismatched dimensions with the bearing housing;

　　During assembly, the seal was not fully seated in the groove, or the groove was machined to an insufficient depth, resulting in a loose seal.

　　Solution:

　　Select the corresponding seal based on operational requirements (e.g., choose a fluororubber sealing ring for high-temperature applications, capable of withstanding temperatures from -20°C to 200°C; opt for PTFE seals in corrosive environments), ensuring that the seal dimensions precisely match the bearing housing keyway.

　　Before assembly, inspect the seal for any damage or deformation. During assembly, use specialized tools to fully press the seal into the groove, ensuring a snug and tight fit.

　　After assembly, perform a sealing test (e.g., IP65-rated test: Use a water spray gun to direct water at the sealed area at a 30° angle for 5 minutes; no water should enter the interior for the test to pass).

　　 III. Quality Inspection Stage: The inspection process is missing, allowing non-conforming products to enter the market.

　　Some companies, in their pursuit of efficiency, simplify or even skip critical inspection steps, resulting in substandard rollers being delivered to customers and triggering after-sales disputes. Common issues in this process often revolve around incomplete inspection items and unclear inspection standards.

　　1. Missing Key Performance Testing

　　Common issue manifestations: Failure to test the wear resistance and load-bearing capacity of idlers, resulting in short-term wear and breakage after delivery; failure to assess rotational resistance, leading to significantly higher-than-expected energy consumption during customer use.

　　Cause of the problem:

　　Without professional testing equipment (such as a wear-resistant tester or dynamic load testing machine), it is impossible to conduct core performance tests.

　　The detection standards are vague, relying solely on visual inspection of the appearance without establishing quantitative metrics (such as wear resistance life or load-bearing capacity).

　　Solution:

　　Configure the necessary testing equipment: a wear resistance tester (simulating conveyor belt friction; passing criteria is ceramic wear no more than 0.1 mm after 1000 hours of testing), a dynamic load testing machine (applying 1.2 times the rated load and running continuously for 2 hours; passing criteria is that the idler rollers show no deformation), and a rotational resistance tester (passing criteria is a rotational resistance coefficient of ≤0.02).

　　Establish the "Roller Bearing出厂 Inspection Standards," clearly defining the mandatory inspection items (appearance, dimensions, hardness, sealing performance, rotational resistance, and load-bearing capacity). For each batch, randomly select 5% of the samples for testing. If a batch fails inspection, a full inspection must be conducted until all nonconforming products are identified and removed.

　　2. Sample testing phase omitted (for customized idlers)

　　Common issue manifestation: Customized idlers designed for complex operating conditions were put into mass production directly, without first conducting small-batch sample trials or on-site testing. As a result, after delivery, these products failed to meet the actual operational requirements—for instance, bearings malfunctioned in high-temperature environments, and shafts rusted in corrosive conditions.

　　Cause of the problem:

　　To shorten the delivery cycle, skip the sample testing step;

　　The technical team misjudged the operating conditions and failed to recognize the necessity of sample testing.

　　Solution:

　　Clearly stipulated: For orders with customized quantities of 100 pieces or more and complex operating conditions (high temperature/strong corrosion/heavy-duty impact), a trial run of 3 to 5 samples must be conducted first.

　　Send the sample to the customer's site for a 72-hour operational test, recording data such as wear rate, temperature changes, and operating noise; then optimize the mass production plan based on the test results.

　　After the customer confirms that the sample meets the requirements, mass production will commence to avoid large-scale rework caused by issues with operational compatibility.

　　 4. Finished Product Outbound Process: Improper packaging and protection lead to damage during transportation.

　　Even if the preceding processes meet quality standards, inadequate packaging and insufficient transportation protection before delivery can still lead to damage of the rollers, ultimately affecting the customer’s user experience.

　　1. Insufficient packaging protection

　　Common problem manifestations: Ceramic roller bodies develop cracks and chips due to collisions; metal components, lacking a protective film, get scratched and rusted during transportation.

　　Cause of the problem:

　　It is packaged in simple cardboard boxes, with no foam cushioning or dividers added inside—instead, the rollers come into direct contact and collide with each other.

　　Metal components were not fitted with protective film on their surfaces, or the protective film lacked sufficient adhesion and came off during transportation.

　　Solution:

　　Customized dedicated packaging: Each individual roller is wrapped in pearl cotton (thickness ≥5mm), then carefully placed into a corrugated cardboard box, with dividers inside to prevent any mutual collisions.

　　Apply a PE protective film (width ≥ shaft diameter) to the surface of the metal shaft and bearing housing, ensuring complete coverage.

　　When transporting in bulk, use pallets stacked together and secure them with stretch film to prevent tipping during transit.

　　2. Missing identification information

　　Common issue: The packaging lacks markings for roller model numbers, customized customer information, production dates, and quality inspection labels, making it difficult for customers to quickly verify the contents upon receipt or complicating traceability during after-sales service.

　　Cause of the problem:

　　Before leaving the factory, a complete labeling process was not established, or labels were missed or applied incorrectly during manual labeling.

　　The labeling is too simplistic and lacks critical traceability information, such as batch numbers and quality control inspector IDs.

　　Solution:

　　Establish the "Finished Product Labeling Standards," clearly specifying the information that must be marked on each package: product model (e.g., Ceramic Roller φ133 × 1150mm), customer name, production date, batch number, and quality inspection pass mark (including the inspector's ID).

　　Adopting laser marking instead of manual labeling ensures clear, durable markings that are resistant to peeling.

　　A "Product Certificate of Conformity" is included with the shipment, featuring a summary of the inspection report (such as hardness and sealing test results), making it convenient for customers to perform acceptance checks.

　　 V. Summary of Common Issues and Recommendations for a Prevention System

　　Problems in roller production often stem from "uncontrolled raw materials, non-standardized processes, and missing inspections," necessitating the establishment of a comprehensive, end-to-end prevention system:

　　Establish a full-process traceability system covering raw materials, production, testing, and factory release—recording the source of raw materials, production parameters, and testing data for each batch of products, facilitating problem identification and root cause analysis.

　　Regularly conduct employee skills training, focusing on critical processes such as molding, sintering, and assembly. Clearly define operational standards, and employees may only start working after passing the assessment.

　　Set up quality inspection nodes at four critical checkpoints: upon raw material entry into the warehouse, after molding, after sintering, and before finished products leave the factory. Each node will be overseen by a dedicated inspector, ensuring that any nonconforming items are strictly prevented from moving to the next stage.