The manufacturing process of thin section bearings is a complex and precision-driven endeavor, often more challenging than that of standard bearings due to their extremely thin cross-sections and precise tolerance requirements.

Thin section bearings manufacturing process

1. Raw Material Selection:

High-quality steel alloys are typically chosen for their strength, durability, and wear resistance. Common materials include chrome steel (100Cr6) and stainless steel (X65Cr13, 440C).

For demanding applications, specialized materials like high nitrogen steel (X30CrMoN15-1) for corrosion resistance or ceramic (silicon nitride) for balls (reducing friction and improving heat resistance) may be used.

Cage materials vary, including pressed steel, machined bronze, fabric-reinforced phenolic material, or high-performance plastics like PEEK or Polyamide-imide.

2. Forging (for bearing rings):

This is the initial step for creating the basic shape of the inner and outer rings.

For larger sizes and thin-section bearing rings with a small aspect ratio, a “combined forging” method is often used, where two or more blanks are forged together. After rough grinding, they are separated by wire cutting. This reduces processing difficulty, minimizes deformation, saves material, and improves efficiency.

The steel is typically heated to high temperatures (e.g., 1200 degrees Celsius), buckled, pierced, and milled.

Smaller rings might be cut directly from tubes or bars.

3. Turning Process:

Once the basic ring blanks are formed, they undergo precision machining on multi-spindle lathes.

This step involves removing material to create the precise inner and outer dimensions, including the raceways for the rolling elements and grooves for seals.

Due to the thin cross-section and poor rigidity of thin-section bearings, clamping and positioning are critical to avoid deformation. Manufacturers often use specialized fixtures (e.g., multi-point clamping chucks with a large envelope circle contact area) and adjust cutting parameters (e.g., high-speed cutting, small back cutting amount, larger main deflection angle) to minimize machining stress, thermal deformation, and vibration.

An additional tempering process after rough turning may be applied to eliminate stress.

4. Heat Treatment:

This crucial step enhances the strength, hardness, and wear resistance of the bearing components.

Parts are heated in a hardening furnace (e.g., to 800-830 degrees Celsius) and then rapidly cooled, or “quenched,” by immersing them in a salt or oil bath.

During this process, the internal structure of the steel undergoes phase transformation (e.g., austenite to martensite), leading to volume expansion and internal stress.

Die quenching is often used to control deformation. If die quenching isn’t feasible, methods like comprehensive shaping and tempering are used to correct excessive outer diameter deformation.

5. Grinding and Honing (Fine Grinding):

After heat treatment, the bearing components are ground to their precise final dimensions. This involves using specialized grinding machines and various grinding media.

The goal is to achieve extremely smooth and accurate raceway surfaces for optimal performance and minimal friction.

Multiple fine adjustments of the machine tool are often required for the outer diameter surface.

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For more detailed information on the manufacturing process of thin section bearings, please click here: https://www.lynicebearings.com/a/blog/thin-section-bearings-manufacturing-process.html

Graphite crucibles are essential tools in foundries and metal casting operations, prized for their excellent thermal conductivity, high-temperature resistance, and chemical stability. These crucibles are commonly used for melting and holding non-ferrous metals such as aluminum, copper, brass, and precious metals. Despite their durability, graphite crucibles are still vulnerable to damage from thermal shock, improper handling, and poor maintenance practices.

Maintenance Tips for Graphite Crucibles in Foundries

1. Proper Handling and Storage:

Inspect upon receipt: Carefully check new crucibles for any chips, cracks, or abrasions. Never use a damaged crucible. A “ring test” with a hammer can help identify internal cracks (a clear bell-like sound indicates no damage, a dull thud might mean mishandling).

Handle with care: Graphite crucibles are durable under heat but can be brittle when cold. Always use properly fitting tongs and lifting equipment to avoid physical damage. Avoid dropping or stacking them directly inside each other.

Store in a dry environment: Moisture absorption is a primary enemy of crucibles. Store them in a dry, warm place, off the floor. If they’ve been exposed to humidity, thoroughly dry them before use. Some recommend storing them in a sealed container with a desiccant.

Avoid rolling: Never roll crucibles, as this can damage the protective glaze.

Protect surfaces: Don’t expose crucibles to substances that can react with graphite or the crucible’s binding materials, such as certain strong acids, alkalis, or specific metal compounds.

2. Crucial Preheating Procedures:

Eliminate moisture: This is perhaps the most critical step. New crucibles, or those that have cooled completely or been exposed to a humid environment, must be preheated to remove all absorbed moisture. Failure to do so can lead to thermal shock, cracking, or even bursting due to steam expansion.

Gradual heating: Start at a low temperature and gradually increase it. A typical preheating cycle might involve:

Heating slowly to 200°C (390°F) to eliminate moisture (hold for at least 20 minutes, or longer for larger crucibles, rotating if possible for even heating).

Increasing the temperature to 600°C (1110°F) on low power.

Then increasing to a bright red heat (around 850-950°C) and holding for 30-60 minutes to develop the protective glaze.

Preheat with the furnace: Ideally, place the crucible in the furnace as it heats up to ensure uniform temperature distribution.

Continuous use: If a crucible is used continuously, it usually doesn’t need to be preheated again between melts unless it has cooled significantly or absorbed moisture.

3. Optimal Charging Practices:

Prevent physical damage: Never drop heavy ingots or casting returns into an empty crucible. Start by gently loading smaller, lighter charge materials to create a cushion. Then carefully lower heavier materials.

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For more detailed information on maintenance techniques for graphite crucibles in foundries, please click here: https://www.czgraphite.com/a/news/maintenance-tips-for-graphite-crucibles-in-foundries.html

Graphite molds are widely used in metal casting, glass molding, electronic metallurgy and other fields, due to its excellent high temperature resistance, chemical stability and good thermal conductivity is widely adopted. However, after experiencing high temperature casting process, the surface of the mold will often residual metal oxides, carbides, lubricant residues or other impurities, if not cleaned in a timely manner, will not only affect the accuracy of the mold and the quality of the surface, but also accelerate the aging of the mold, shorten the service life.

Cleaning graphite molds after casting is crucial for maintaining their performance and extending their lifespan.

How to Clean Graphite Molds After Casting

Why clean graphite molds?

Extend the life of the mold: removing residue reduces heat stress buildup and chemical corrosion;

Ensure casting quality: a clean mold surface enhances the finish of the next round of casting;

Avoiding dimensional errors: mold residues may cause molding deviations;

Improve productivity: avoid scrap or rework due to contamination.

Common cleaning methods

Mechanical cleaning

Use soft bristle brush or plastic scraper to remove surface impurities;

For thicker residues, micro-sand blasting (low-pressure sand blasting) can be used.

Heat treatment cleaning

The mold is placed in an oven and heated to break down the attached organic impurities;

Often used in conjunction with an inert gas atmosphere (e.g. nitrogen) to avoid oxidation.

Chemical Cleaning

Soak or scrub the graphite surface with a non-corrosive cleaning solution;

Avoid the use of solutions containing strong acids or bases that may damage the graphite structure.

Ultrasonic cleaning (precision molds)

Suitable for micro-fine structure molds, can effectively remove tiny particles;

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For more information on how to clean graphite molds after casting, please click here:https://www.czgraphite.com/a/news/how-to-clean-graphite-molds-after-casting.html

Thin section bearings, characterized by their small and constant cross-section regardless of bore diameter, are designed for applications where space and weight are critical. Within this category, a key distinction lies between sealed and open bearings, primarily concerning their protection against the environment and lubrication management.

Differences Between Sealed and Open Thin Section Bearings

1. Protection from Contaminants:

Sealed Thin Section Bearings: These bearings have integrated seals (typically made of rubber or other elastomeric materials) that create a barrier, preventing dirt, dust, moisture, and other contaminants from entering the bearing’s internal components.

Advantages:

Excellent Contamination Prevention: Ideal for harsh, dirty, or wet environments.

Extended Bearing Life: By keeping contaminants out, wear and damage are significantly reduced.

Reduced Maintenance: Often “lubricated for life” and do not require re-lubrication, leading to lower maintenance costs and less downtime.

Lubricant Retention: The seals effectively retain the internal lubricant (usually grease), ensuring consistent lubrication and preventing degradation.

Disadvantages:

Higher Friction: The contact between the seals and the rotating components can generate more friction, potentially leading to slightly higher operating temperatures and limiting maximum speeds.

Higher Initial Cost: The manufacturing process for integrating seals adds to the initial cost.

Limited Accessibility for Inspection/Maintenance: The seals make it difficult to access the internal components for inspection or troubleshooting. If the internal lubricant degrades, the bearing typically needs to be replaced rather than re-lubricated.

Potential for Seal Failure: Seals can wear and degrade over time, especially in demanding conditions, leading to potential contamination ingress if they fail.

Open Thin Section Bearings: These bearings do not have seals or shields, leaving their internal components exposed to the environment. They are typically used where the bearing is immersed in a lubricating fluid or in very clean, controlled environments.

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For more detailed information about the differences between sealed thin-walled bearings and open thin-walled bearings, please click here:https://www.lynicebearings.com/a/blog/differences-between-sealed-and-open-thin-section-bearings.html

Excessive wear of a cone crusher is a common issue that can lead to reduced efficiency, increased downtime, and higher operational costs. Troubleshooting it involves systematically examining various aspects of the crusher’s operation and maintenance.

Troubleshooting Cone Crusher Excessive Wear

1. Identify the Location and Pattern of Wear

Different wear patterns can indicate different underlying problems. Observe where the wear is most prominent:

Even wear across liners: This might suggest normal operation but still points to a need to optimize settings or consider different liner materials for extended life.

Localized wear (e.g., top, middle, or bottom of liners):

Top wear (near feed opening): Often due to oversized feed, bridging of material, or an uneven feed distribution where larger material impacts the upper part of the chamber.

Bottom wear (near closed side setting – CSS): Can be caused by too small a feed size, where most crushing occurs at the bottom, or an incorrect CSS for the material.

Uneven wear on one side: Indicates segregated feed (material biased to one side), poor alignment, or issues with the eccentric throw.

Wear on non-liner components (e.g., bevel gears, bearings, main frame): This suggests more severe mechanical issues, lubrication problems, or foreign objects.

2. Review Operational Parameters

Incorrect operational settings are a primary cause of premature wear.

Closed Side Setting (CSS):

Too tight: Increases crushing forces, leading to high stress on liners and potentially overloading the crusher. It can also cause excessive fines and increased power consumption.

Too wide: Reduces the reduction ratio and can lead to inefficient crushing, poor product shape, and uneven wear as material “slips” rather than being crushed.

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For more detailed information on how to troubleshoot excessive wear in cone crushers, please click here:https://www.yd-crusher.com/a/news/troubleshooting-cone-crusher-excessive-wear.html