Parul institute of engineering and technology (DS 2nd
shift)
OVALITY OBSERVED IN BALL
BEARING BY
RITESH J PATEL (096380319590)
Guided by
MR.RAJESH RANA
Asst.professor
Department of mechanical engineering
Parul institute of engineering & technology (DS 2ndshift)
(Affiliated to Gujarat technological university)
P.O. LIMDA, TA. WAGHODIA, DIST. VADODARA-
391760.
Gujarat, INDIA
[2011-2012]
Parul institute of engineering and technology (DS 2nd
shift)
PARUL INSTITUTE OF ENGG.& TECH. AT POST – LIMDA, WAGHODIA- 391760
C E R T I F I C A T E
This is to certify that MR.RITESH J PATEL. of
Diploma 5th
Semester in mechanical engineering,
Registration No.096380319590 has completed
satisfactorily his project-I entitled ” for the term 2011-
12, He has under gone training at NHB BALL &
ROLLER LTD. WORKS From 19/6/11 to 9/7/11
DATE:
Sign Of Guide Sign of HOD
Parul institute of engineering and technology (DS 2nd
shift)
INDUSTRY DEFINED PROBLEM / PROJECT (IDP) STATEMENT
FORM
STUDENT PARTICULARS
FIRST NAME RITESH
LAST NAME PATEL
MOBILE NO 9726798920
EMAIL [email protected]
COLLEGE NAME PARUL INSTITUTE OF
ENGINEERING & TECHNOLOGY
ADDRESS P.O. LIMDA. TAL. WAGHODIA-
391760 DIST. VADODARA ,
GUJARAT(INDIA)
BRANCH MECHANICAL ENGINEERING
SEMESTER 5TH
TEAM NAME MB-1
SIGNATURE OF STUDENT R.J.Patel
------------- INDUSTRY COORDINATES----------------------
NAME NIMESH HASMUKHBHAI PATEL
CONTACT ADDRESS KHARSAD, KODGARA FALIA,
TA: JALALPORE DIST: NAVSARI
MOBILE NO. +919825674899
EMAIL [email protected]
-----------------------------------INDUSTRY---------------------------
NAME NHB Ball & Roller Ltd.
ADDRESS Andhkeshwar Road, Amalsad – 396310,
Dist: Navsari, Gujarat
CONTACT NO 02634-272255/56
NAME OF INDUSTRIAL ESTATE AMALSAD
COMPANY LOGO
Parul institute of engineering and technology (DS 2nd
shift)
INDUSTRY DEFINED PROBLEM STATEMENT FORM
TITLE OF PROBLEM/PROJECT
OVALITY OBSERVED IN BALL BEARING.
PROBLEM SUMMARY
The problem summery may be a concise description of the industry related
technical issues which can state the problem, which the student has found out while
visiting the industry.
DETAILED DESCRIPTION OF PROBLEM
The problem statement has to be well defined in 3-5 pages with detailed
facts and figures as and when possible. The description can have figures/inputs
from floor persons from industries/ parameters related to specific domain of
technology.
EXPECTED OUTCOME
The students while interacting with industry persons have to note
down the expected out comes (in 1-2 page) from that particular industry due to the
proposed innovation either in product or processes. This will gauge the industrial
needs and students progress while working on the final year project.
OTHER DESCRIPTION (IF ANY)
The students are advised to do some literature research related
to the corresponding problem/innovation both before and after visiting the
industry/MSME during summer vacation. They have to suggest some suggestions
about the issues based on literature research of corresponding problems/projects in
feasible cases.
The format of documentation may be slightly modified as per the need of specific
branch. For example in the documentation of any industrial waste, one may have to
state. (Composition of waste, type of waste (Solid, Liquid, Gas, Semi-Solid), quantity
of waste etc. The problem/project reports are scouted from Industries have to be
submitted to Departmental HODs of corresponding GTU College in softcopy. GTU
will evaluate them in August 2011 as a part of Curriculum.
DISCIPLINARY | INTER-
DISCIPLINARY
DISCIPLINE
Parul institute of engineering and technology (DS 2nd
shift)
IDENTIFICATION
Name:- Ritesh J Patel
Enrollment no.:-
096380319590
Course:- Diploma Engineering
Branch:- Mechanical Engineering
Semester:- 5th SEM. [2nd shift]
Project name:- “Ovality observed in ball bearing”
Study center:- Parul Institute of Engineering & Technology, vadodara [Gujarat]
Parul institute of engineering and technology (DS 2nd
shift)
ACKNOWLEDGEMENT
Gratitude is an attitude without which any person is
incomplete. Hence, I take this space to thank all who
involved directly or indirectly in this project.
It has been a very good experience for me to
prepare this minor project on “ovality observed in
ball bearing”
I would like to thank my guide RAJESH RANA, who has help us a lot, without whose kind support this
project would have been almost impossible. I thank my sir for having given the information about various
resources.
Parul institute of engineering and technology (DS 2nd
shift)
WHAT IS PROJECT?
A project is a temporary endeavor undertaken to create a
unique result or change. Temporary means that the
project has an end date. Unique means that the project’s
end result is different than the results of other functions of
the organization…
“Project” means the whole of an action which has a
potential for resulting in a physical change in the
environment, directly or ultimately, and that is any of the
following: An activity directly undertaken by any public
agency, including but not limited to public works
construction and related…
A project may be a group of related reclamation activities
with a common objective within a political subdivision of
a state or within a logical, geographically defined area…..
Parul institute of engineering and technology (DS 2nd
shift)
INDEX
Company profile………………09
Ovality
Summary………………………11
Bearing Failure: Causes and Cures………………………………..15
Excessive Loads…………16
Overheating……………….17
True Brinelling……………18
False Brinelling…………..19
Normal Fatigue Failure..20
Reverse Loading…………21
Contamination……………22
Lubricant Failure…………23
Corrosion………………….24
Misalignment……………..25
Loose Fits…………………26
Tight Fits…………………..27
Seizure……………….28
Parul institute of engineering and technology (DS 2nd
shift)
Ovality measurement systems…………………26 Laser End Measurement
System……………………………..30 OmniPro Vision Systems..33 AccuScan Measurement
System………………………………36 Solution………………………...41
Conclusion…………………….43
Parul institute of engineering and technology (DS 2nd
shift)
Company Profile
Company logo:
Basic Information
Company Name: NHB BALL AND ROLLER LTD
Business Type: Manufacturer
Product/Service
(We Sell): Steel Ball
Product/Service
(We Buy): Wire
Brands: NHB
Number of Employees: 101 - 200 People
Trade & Market
Main Markets:
North America
South America
Eastern Europe
Western Europe
Main Customers: SKF,FAG
Total Annual Sales Volume: US$1 Million - US$2.5 Million
Export Percentage: 61% - 70%
Total Annual Purchase
Volume: US$1 Million - US$2.5 Million
Factory Information
Factory Size (Sq.meters): 5,000-10,000 square meters
Factory Location: GUJARAT
QA/QC: In House
Number of Production
Lines: Above 10
Number of R&D Staff: 5 - 10 People
Number of QC Staff: 5 - 10 People
Management Certification: ISO/TS 16949
Contract Manufacturing: OEM Service Offered
Parul institute of engineering and technology (DS 2nd
shift)
Industry Review
The bearing industry comprises mainly ball and roller bearings. The prospects of the bearing industry are directly linked to the performance of automotive and industrial sector.
Automotive Industry After the road-block of global economic recession, the automobile industry has come back in the top gear. The domestic
automobile sales revived, registering stupendous growth in 2009-10. Exports too have recovered, albeit at a slower pace.
Parul institute of engineering and technology (DS 2nd
shift)
OVALITY
SUMMARY-
Ovality observed in ball bearing.
Ovality is a term to used to measure "out of roundness". Ovality
designates how close to a perfect circle a bar is at the point being
measured. Of all the machines in the process the grinder has the
largest impact on ovality.
The grinder fine tunes the product but the turning machine has to
get it right first. The pre-straightening machine is also important as
the straighter the bar going into the turner the more consistent the
roundness and finish coming out.
Parul institute of engineering and technology (DS 2nd
shift)
In the peeling process, the bar moves horizontally thru the turner
while carbide cutting tools rotate around the bar on a spindle
peeling the bar which leaves a spiral mark which in the industry
are called barber poles. The tools in the peeler, peels the rusty
surface from the bar similar to the way a knife is used to peel an
apple. When there is no overlap the bar receives one wrap or one
peel per inch of length. Two wraps per inch gives a rounder better
finished bar than one wrap. The more the wraps the better the
quality of the bar produced. One has to decrease the thru put speed
to get more wraps which means the cost of production increases.
There is an obvious trade of between quality and production costs
in both the turning machine and the grinder. A commodity bar will
have the least number of wraps possible whereas, a custom-
engineered bar will have the optimum number of wraps.
If the grinder takes one pass to remove a certain amount of
material the finish will not be as good as if it takes two passes. The
amount of reduction in a grinder is a function of the grit in the
grinding wheel. The rougher the grit, the more the reduction, but
the rougher the finish. All things being equal the more the passes
in the grinder the better the finish and the better the ovality.
Parul institute of engineering and technology (DS 2nd
shift)
Bearing Failure:
Causes and Cures
Parul institute of engineering and technology (DS 2nd
shift)
Excessive Loads
• Excessive loads usually cause premature fatigue. Tight fits, brinelling and improper preloading can also bring about early fatigue failure. • The solution is to reduce the load or redesign using a bearing
with greater capacity.
Parul institute of engineering and technology (DS 2nd
shift)
Overheating
• Symptoms are discoloration of the rings, balls, and cages from gold to blue. • Temperature in excess of 400F can anneal the ring and ball materials. • The resulting loss in hardness reduces the bearing capacity causing early failure. • In extreme cases, balls and rings will deform. The temperature rise can also degrade or destroy
lubricant.
Parul institute of engineering and technology (DS 2nd
shift)
True Brinelling
• Brinelling occurs when loads exceed the elastic limit of the ring material. • Brinell marks show as indentations in the raceways which increase bearing vibration (noise). • Any static overload or severe impact
can cause brinelling.
Parul institute of engineering and technology (DS 2nd
shift)
False Brinelling
• False brinelling - elliptical wear marks in an axial direction at each ball position with a bright finish and sharp demarcation, often surrounded by a ring of brown debris - indicates excessive external vibration. • Correct by isolating bearings from external vibration, and using greases containing
antiwear additives.
Parul institute of engineering and technology (DS 2nd
shift)
Normal Fatigue Failure
• Fatigue failure - usually referred to as spalling - is a fracture of the running surfaces and subsequent removal of small discrete particles of material. • Spalling can occur on the inner ring, outer ring, or balls. • This type of failure is progressive and once initiated will spread as a result of further operation. It will always be accompanied by a marked increase in vibration. • The remedy is to replace the bearing or consider redesigning to use a bearing
having a greater calculated fatigue life.
Parul institute of engineering and technology (DS 2nd
shift)
Reverse Loading
• Angular contact bearings are designed to accept an axial load in one direction only. • When loaded in the opposite direction, the elliptical contact area on the outer ring is truncated by the low shoulder on that side of the outer ring. • The result is excessive stress and an increase in temperature, followed by increased vibration and early failure. • Corrective action is to simply
install the bearing correctly.
Parul institute of engineering and technology (DS 2nd
shift)
Contamination
• Contamination is one of the leading causes of bearing failure. • Contamination symptoms are denting of the bearing raceways and balls resulting in high vibration and wear. • Clean work areas, tools, fixtures, and hands help reduce contamination failures. • Keep grinding operations away from bearing assembly areas and keep bearings in their original packaging until
you are ready to install them.
Parul institute of engineering and technology (DS 2nd
shift)
Lubricant Failure
• Discolored (blue/brown) ball tracks and balls are symptoms of lubricant failure. Excessive wear of balls, ring, and cages will follow, resulting in overheating and subsequent catastrophic failure. • Ball bearings depend on the continuous presence of a very thin -millionths of an inch - film of lubricant between balls and races, and between the cage, bearing rings, and balls. • Failures are typically caused by restricted lubricant flow or excessive temperatures that
degrade the lubricant’s properties.
Parul institute of engineering and technology (DS 2nd
shift)
Corrosion
• Red/brown areas on balls, race-way, cages, or bands of ball bearings are symptoms of corrosion. • This condition results from exposing bearings to corrosive fluids or a corrosive atmosphere. • In extreme cases, corrosion can initiate early fatigue failures. • Correct by diverting corrosive fluids away from bearing areas and use integrally sealed bearings whenever possible.
Parul institute of engineering and technology (DS 2nd
shift)
Misalignment
• Misalignment can be detected on the raceway of the nonrotating ring by a ball wear path that is not parallel to the raceways edges. • If misalignment exceeds 0.001 in./in you can expect an abnormal temperature rise in the bearing and/or housing and heavy wear in the cage ball-pockets. • Appropriate corrective action includes: inspecting shafts and housings for runout of shoulders and bearing seats; use of single point-turned or ground threads on non hardened shafts and ground threads only on hardened shafts; and using precision grade locknuts.
Parul institute of engineering and technology (DS 2nd
shift)
Loose Fits
• Loose fits can cause relative motion between mating parts. If the relative motion between mating parts is slight but continuous, fretting occurs. • Fretting is the generation of fine metal particles which oxidize, leaving a distinctive brown color. This material is abrasive and will aggravate the looseness. If the looseness is enough to allow considerable movement of the inner or outer ring, the mounting surfaces will wear and heat, causing noise and runout problems.
Parul institute of engineering and technology (DS 2nd
shift)
Tight Fits
• A heavy ball wear path in the bottom of the raceway around the entire circumference of the inner ring and outer ring indicates a tight fit. • Where interference fits exceed the radial clearance at operating temperature, the balls will become excessively loaded. This will result in a rapid temperature rise accompanied by high torque. • Continued operation can lead to rapid wear and fatigue. • Corrective action includes a decrease in total interference.
Parul institute of engineering and technology (DS 2nd
shift)
Seizure
Meaning= to bind or fasten together Results: Discoloration, and welding of raceway surface, rolling contact surfaces
Parul institute of engineering and technology (DS 2nd
shift)
Causes: Poor heat dissipation
Poor lubrication or improper lubrication.
Smaller Clearance.
Excessive load (or pre-load).
Installation error.
Solutions
Improper dissipation of heat from bearing
Prevention of misalignment
Improvement in clearance
Selection of suitable lubricant and determination of
optimum lubricant feeding rate
Parul institute of engineering and technology (DS 2nd
shift)
Ovality measurement
systems
Laser End Measurement System
OmniPro Vision Systems
AccuScan Measurement System
Parul institute of engineering and technology (DS 2nd
shift)
Laser End Measurement System
Laser End Measurement System, which measures external and internal diameters, wall thickness, external and internal ovality and eccentricity.
Market Situation
Increasingly, the offshore industry demands
tighter dimensional tolerances on pipe ends
in order to reduce installation cycle time.
For line pipe subject to high dynamic loads,
such as Steel Catenary Risers and fatigue
sensitive flowlines, a full geometrical
assessment of pipe ends enables a more
efficient alignment prior to welding.
Parul institute of engineering and technology (DS 2nd
shift)
Process Laser End Measurement System utilizes
laser optical displacement sensors, which
measure the distance between the sensor’s
measuring head and the surface of the tube
with great accuracy.
Applications • Replaces manual inspection
and provides 100% automated
process control.
• Provides information about
each pipe end (OD, ID and
WT max, average and min).
• Additional services that can
be offered to simplify welding
operations are:
- Identification of pipes with
families of tolerances
- Identification of pipes sequences and the rotation
angles for all the pipes that comply with the max
Hi/Lo required. The sequences are calculated by
Tenaris Best Match software using Laser End
Measurement System data, evaluating the best fit that
can be achieved with pipes accurately aligned on ID
axis.
Parul institute of engineering and technology (DS 2nd
shift)
Advantages • Offers the capability to record 100% of the data,
which can be customized and saved on a CD.
• Provides a full dimensional scan of pipe ends
with very detailed information (up to 1,000
measurements).
• Performs the inspection offline/online so that the
information is available as soon as the material is
ready for shipment, reducing time, logistics and
costs.
• Reduces the chance for human
error.
• Sorts information by families or best sequence for
welding, based on customer requirements.
Capabilities • Outside Diameter Range from 5 1/2” to 16”.
• Inside diameter larger than 110 mm.
• Takes up to 1,000 measurements per turn.
• Measures in a section whose position can be set up
to 120 mm from the pipe end.
If requested, additional measurements can be agreed.
• Data output tailored to customer requirements and
recorded on CD.
Parul institute of engineering and technology (DS 2nd
shift)
OmniPro Vision Systems
Inspection system for ovality measurement
Cross section profile measurement by light section methods
Over 1000 profile measuring points
Continuous inline measurement and product roundness control
Different gauge heads depending on accuracy demands
Reject reduction by process optimization
Fast integration in the production process
Advantages Complete contour image
Trend display
No abrasive wear
Maintenance free
Easy to calibrate
Fast and easy integration in production lines
Parul institute of engineering and technology (DS 2nd
shift)
Data for reliable production quality adjustment
Product quality optimization
Results ovality measurement
Parul institute of engineering and technology (DS 2nd
shift)
Application range
Cable, wire and bearings
Round steel bars and other round profiles
Pipes, tubes and inner tubes
Features Contactless roundness measurement
Gauge heads with variable resolution
Display of all relevant dimensions, e.g. minimum, maximum and average radius/Diameter, ovality etc.
Acceptable tolerance monitoring and alarm function
Measurement data logging for continuous process quality documentation
Seamless PC-integration in an available Windows network
Parul institute of engineering and technology (DS 2nd
shift)
AccuScan Measurement System
AccuScan systems from Beta LaserMike provide on-line precision measurements of the diameter and ovality of cables. Using laser scanning technology, AccuScan systems are able to perform diameter measurements in an intelligent gauge head during production and communicate those measurements to a host system or controller.
Parul institute of engineering and technology (DS 2nd
shift)
The AccuScan Advantage
Increase measurement accuracy with uniquely
designed and crafted optics.
Increase measurement repeatability with intelligent Digital Signal Processor (DSP).
Increase up-time and reduce maintenance cost with built-in air purge system that keeps lenses free of dust and debris.
Increase durability with rugged construction sealed to IP 65 (NEMA 4) standards.
Flexible communication integration with RS-232, DeviceNet, and Profibus protocol support.
Parul institute of engineering and technology (DS 2nd
shift)
Parul institute of engineering and technology (DS 2nd
shift)
Laser Scanning Measurement
Principle
In 1972, the founders of Beta LaserMike introduced the world’s first laser scanning micrometer (the “LaserMike”). AccuScan gauges employ this laser scanning measurement principle, which uses a low-power helium-neon laser that is scanned at high speed through a measurement window and across the cable.
Parul institute of engineering and technology (DS 2nd
shift)
When the laser first scans across to the receiver, the light hits the photocell and the voltage rises. The voltage drops when the light is blocked by the cable and rises again when the light reaches the photocell. The change in time ( t) that the light is blocked by the cable is proportional to the cable’s outside diameter.
Parul institute of engineering and technology (DS 2nd
shift)
SOLUTION
Three ways to benefit from use of Low Ovality Technology
1. Reduce ovality of coiled pipe (by up to 60%) # Eliminates need for re-rounding on site. # Enables easier jointing and improves joint integrity. # Improves coil stability, minimising coil failure during storage and risk of coil rejection by customer.
2. Supply standard coil lengths at smaller dimensions # Reduce transport costs by increasing the number of coils per truck.
# Reduce requirement for use of special low trailers.
Parul institute of engineering and technology (DS 2nd
shift)
Quality Bar mandates the following quality-
control steps in its manufacturing process:
1. Incoming hot rolled raw bundles are inspected for split ends
and serious surface defects.
2. Bars are visually inspected when exiting the # 1 pre-
straightener.
3. Bars are randomly tested for ovality as they exit the turner.
4. Bars are randomly in-line tested for straightness as they exit
the #2 post straightener.
5. Every bundle of TP bars is tested for finish and ovality before
packaging with the test results being saved with the order.
6. Bars are continually monitored via a digital readout for ovality
during grinding.
7. 100% of the TG&P bars are inspected after grinding.
8. Every bundle of TGP bars is tested for finish and ovality by
the packer before packaging and their results are saved with
the order.
9. Bars throughout the process are randomly tested off line for
straightness.
Parul institute of engineering and technology (DS 2nd
shift)
Conclusion
Bearing Maintenance 1. Statistical Method (bearing life estimation) – Probabilistic rolling contact fatigue.
– Few bearings breakdown earlier than their life.
– Unnecessary replacement of few
perfectly good condition bearings.
2. Bearing Condition Monitoring
– Detect crack size. – Warns if crack area > 6.45 mm2 (0.01 in2).
– Needs crack propagation theory (-ies)