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Ball Bearing Manufacturing
Basic Knowledge
Fitrun Bearing Co., Ltd.
Made by: Kenneth Huang
November 2012

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Contents
Ⅰ. Bearing MFG Basic Process
Ⅱ. Bearing Material
Ⅲ. Forging Process
Ⅳ. Turning Process
Ⅴ. Heat Treatment
Ⅵ. Grinding Process
Ⅶ. Bearing Assembly

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Ⅰ. Bearing MFG Basic Process
Bearing Ring (Outer and Inner)
Material Forging Turning Heat Treatment Grinding Assemble
Roller
Material Turning Heat Treatment Grinding Assemble
Cage (Brass Cage)
Material Casting Turning Milling Deburring Assemble

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Ⅱ. Bearing Material
Bearing Ring and Roller Material
NO Material Performance
1 High surface load capacity
2 Good abrasion resistance
3 High elastic limit
4 Good hardness
5 Toughness
6 Good size stability
7 Good rust resistance
8 Good processing performance
Common Material:
High-carbon chromium bearing steel:
Gcr15 Gcr15SiMn
Other Material:
Carburized bearing steel
Abrasion and corrosive resistance bearing steel
Heat resistance bearing steel

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Bearing Cage Material
Non-ferrous metal:
Brass HPb59-1, bronze QAL10-3-1.5, Aluminum alloy LY11CZ
Ferrous Metal:
Quality carbon steel thin plate
Non-metal:
Engineering nylon, Phenolic adhesive

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Ⅲ. Forging
Forging is the preliminary processing of bearing ring making, it’s also
named blank processing.
The main purposes of bearing ring forging processing are:
1. To obtain the semi-finished ring which is similar with the bearing, so as to
enhance the efficient of metal material and reduce the mechanical machining
work, and at last to save the cost of production.
2. To eliminate the inner defect of metal, improve metal organized system, so as to
make the metal be with proper streamline distribution and with good
compactness, and at last to enhance the life span of bearings.
Forging
Hot Forging —— metal is heated to be above the crystallization temperature
widely used.
Cold Forging —— metal is forged in the room temperature barely used.
Warm Forging —— metal is forged in the temperature between hot forging and cold
forging in test period.

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Bearing Ring Forging Procedure
Heating Cutting
Air Hammer
Press
Plain Forging
Machine
Staving
Machine
Shaper Anneal
Semi-
finished
Products
Material
Heating
800℃～1100 ℃ 800℃～1100 ℃ 780℃～810 ℃

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Ⅳ. Turning
Turning is for semi-finished bearing ring and roller, it’s also called
forming process.
The main purposes of turning:
1. To make the bearing ring and roller be the same shape with the finished
products.
2. To create good condition for the coming grinding processing.
Turning
Integrated Processing: to finish all the turning procedure in one
machine --- suitable for small quantity production.
Distributed Processing: to finish only one turning procedure
in one machine --- suitable for large quantity production.

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Bearing Ring Turning Process
semi-
finished
ring
inner
face
Outer
face
grinding marking roller
rail
oil
groove
Chamfer
Semi-
finished
products
Roller Turning Process
Steel
Material
Outer
Face
Cutting Outer
Face
Curvature Chamfer
Semi-
finished
Products
Usually, the equipments used are specially for bearing processing,
and are arranged according to the distributed procedure follow.

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Ⅴ. Heat Treatment
Heat treatment is the key processing procedure to
enhance the bearing inner quality.
The main purposes of heat treatment:
1. To change the material structure through treat treatment so as to enhance its
mechanical performance.
2. To enhance the bearing inner quality (abrasive resistance, toughness, etc), so as to
enhance the bearing life span.
Semi-
finished
ring
quenching cleaning tempering 2nd quenching
Quenched semi-
finished products
Bearing ring and roller heat treatment process
800℃～840 ℃ 190℃～210 ℃

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Ⅵ. Grinding
Grinding is the final processing of bearing ring and roller, it is called finished product
processing.
The main purposes of grinding process:
1. To make the bearing ring and roller be in accordance with the design requirements
in size and shape precision.
2. To prepare qualified rings and rollers for bearing assembly.
Grinding
Normally, it’s processed by distributed procedure; or the machines can
be connected to integrate into a production line by material loading and
unloading equipments so as to enhance the production efficient.

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Bearing Ring Grinding Process
Roller Grinding Process
Quenched semi-
finished ring
Facing
Inner or
Outer
Diameter
Roller
Channel
Tempering
Roller
Channel
Grinding
Outer
Diameter
Finished
Ring for
ASSY
Quenched semi-
finished roller Facing Outer
Diameter
Vibrating
Finishing
Finished roller
for assembly

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Ⅶ. Bearing Assembly
Bearing assembly is the final process of bearing manufacturing;
it has very important effect to the bearing performance.
The main purposes of bearing assembly:
1. To assemble the finished components (out rings, inner rings, rollers and cages) into
finished bearings.
2. To assemble the finished components into a variety of precisions, clearances and
special requirements of bearings according to different technological requirements.

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Finished inner ring
and outer ring
Finished roller Cosmetic Inspection Roller diameter size selection
Inner ring and outer ring roller rail
inspection and size selection.
Roller diameter
size selection
Match clearance
Assemble
Cage
Final
Inspection
Final
Inspection
Cleaning
Anti-rust
Treatment
Vacuum Inner
Packaging
Outer
Packaging
Warehouse
storage or shipping
Bearing Assembly Process
Inner ring and outer ring
roller rail inspection and
size selection.
Bore diameter, outer
diameter and thickness
inspection.

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Above is the simple presentation of bearing manufacture basic
knowledge. Hope you have had a preliminary knowledge of bearing
manufacture.
Bearing manufacture has many processing procedures and requires
high machining precision even though the bearing is just common
standard component. In order to produce high quality and high
precision bearing products to meet customers’ requirements, in
addition to above work mentioned, we still have a lot of work to do as
a ball bearing manufacturer .
We, Fitrun Bearing Co., Ltd., will keep hard working to exceed
customers’ expectation. Our main bearing products are: deep groove
ball bearing, flanged ball bearing and thrust ball bearing. They are
miniature sizes from BD of 1m to 12mm, and OD of 3mm to 40mm.