1. ABSTRACT My project at spring shop in Integral coach factory “ACHIEVING INDUSTRIAL EXCELLENCE THROUGH DEPLOYMENT OF QUALITY MANAGEMENT PROCEDURES IN SPRING SHOP AT ICF” This project is one of the attempts at identifying, analyzing and correcting the causes that are responsible for removing the constraints from the Manufacturing department The springs which are essential for suspension in bogie are manufactured in mass quantity at the spring shop. During the production various errors occurs such as cracks, end coil crack, over heat, higher size (H/S), undersize (U/S) (bend, bite, taper ) etc., there are huge losses occurring in terms of cost and time, so I aim to analyze the various errors their causes and effects using the statistical process control tools. Then from the analysis I find out the rectification methods which can be implemented to reduce the rejection and rework, which helps to improve the overall production, product quality and operation time. This report is a summary of the observations made, actions taken, results obtained and recommendations for improvement in the Manufacturing department. 1
Transcript
1. ABSTRACT
My project at spring shop in Integral coach factory “ACHIEVING INDUSTRIAL
EXCELLENCE THROUGH DEPLOYMENT OF QUALITY MANAGEMENT
PROCEDURES IN SPRING SHOP AT ICF” This project is one of the attempts at identifying,
analyzing and correcting the causes that are responsible for removing the constraints from the
Manufacturing department The springs which are essential for suspension in bogie are
manufactured in mass quantity at the spring shop. During the production various errors occurs
such as cracks, end coil crack, over heat, higher size (H/S), undersize (U/S) (bend, bite, taper )
etc., there are huge losses occurring in terms of cost and time, so I aim to analyze the various
errors their causes and effects using the statistical process control tools. Then from the analysis I
find out the rectification methods which can be implemented to reduce the rejection and rework,
which helps to improve the overall production, product quality and operation time. This report is
a summary of the observations made, actions taken, results obtained and recommendations for
improvement in the Manufacturing department.
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CHAPTER 1
1.1) INTRODUCTION:
Integral coach factory is an manufacturing division come under Indian railways which is designed and manufacturing coaches which is based in Chennai. This factory account for produce nearly 15000 coaches per year.
My project is only concentrated on the spring shop. The springs which are essential for suspension in bogie are manufactured in mass quantity at the spring shop. Generally in coaches there are two type of springs are used i.e. air suspension and conventional spring in this shop they only manufacture conventional spring My project is an attempt to increase the quality of the spring manufacturing by reduce the rejection and rework.
1.2) REVIEW OF LITRATURE:
Quality is never an accident. It is always the result of high intentions, sincere efforts, intelligent
direction and skillful execution. It is an attribute or characteristic whose dictionary meaning is the degree of goodness or worth of a person, place or thing.
There are different approaches through which the concept of quality can be under stood.
According to the product-based approach, quality is an attribute, which can be measured
quantitatively. The manufacturing based approach on the other hand, uses universal
definition of conformance to requirements. The value-based approach says that the consumer
purchase decision is based on consistent quality at an affordable price.
Definition of Quality
W. Edwards Deming defines quality as: "Pride in Workmanship"
Dr. J. Juran defines quality as: "those product features which meet the needs of customers and
thereby provide product satisfaction." or "freedom from deficiencies."
Kaoru Ishikawa defines quality as: "total quality control, Japanese style, is a thought revolution in management."
Gary Griffith, in his book "The Quality Technician's Handbook," defines quality as: "the
totality of features and characteristics of a product or service that bear on its ability to satisfy given needs.
TQM
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DEFINITION
Total Quality Management (TQM) is an enhancement to the traditional way of doing business. The TQM philosophy evolved from the continuous improvement philosophy with a focus on Quality as the main dimension of business. It is a proven technique to guarantee survival in world-class competition. Analyzing the three words,
Total – Made up of the whole.
Quality – Degree of excellence of a product or a service provided.
Management – Act, art or manner of handling, controlling, directing, etc.
BASIC CONCEPTS:
A committed and involved management to provide long-term top to bottom or gravitational support.
An unwavering focus on the customer, both internally and externally. Effective involvement and utilization of the entire work force. Continuous improvement of the business and production process. Establish performance measures for the processes.
QUALITY: It is defined (ISO 9000:2000) as the degree to which a set of inherent characteristics fulfills requirement. It can be quantified as
Q = P / E
Where,
Q = Quality
P = Performance
E = Expectations
DIMENSIONS OF QUALITY:
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DIMENSION MEANING
Performance Primary product characteristics, such as the brightness of the picture
Features Secondary characteristics, added features
Conformance Meeting specifications or industry standards, workmanship
Reliability Consistency over time
Durability Useful life includes repair
Service Resolution of problem and complaints, ease of repair
Response Human to Human interface
Aesthetics Sensory characteristics, such as exterior finish
Reputation Past performance and other intangibles such as being ranked first
TOTAL PRODUCTIVE MAINTENANCE (TPM):
Total Productive Maintenance is keeping the current plant and equipment at its highest productive level through cooperation of all areas of the organization.
The overall goals of TPM are:
Maintaining and improving equipment capacity. Maintaining equipment for life. Using support from all areas of the operation. Encouraging input from all employees. Using teams for continuous improvement.
1.2) INDUSTRIAL PROFILE:
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LOCATION
Integral Coach Factory is located in Perambur at Chennai in the state of Tamil Nadu. It has a total area of around 19, 22,500 sq.mts. And it has a workshop covered area of 1, 89,229 sq.mts.
HISTORY
Integral Coach Factory, Chennai, is a premier Production Unit of Indian Railways manufacturing railway passenger coaches.ICF is the first of its kind to be established after Independence for the manufacture of light weight, all steel and all welded Integral railway passenger coaches.The factory was set up in the year 1955 in technical collaboration with M/s. Swiss car & elevator manufacture corporation ltd., Switzerland
ICFs business includes design, manufacturing and supply of railway passenger coaches.
ICF has so far manufactured about 43,150 passenger coaches of various designs.
ICF employs about 13,000 staffs including technician and administration.
The weight of our passenger coach is 35.5 tons
The departments are: General Administration, Accounts, Electrical, Civil Engineering, Mechanical, Medical, Personnel, Security and Stores.
DIVISIONS OF ICF
Mainly ICF is divided two divisions. They are:
Shell Division Furnishing Division
SHELL DIVISION
The coach manufacturing starts from shell division, where the body Shell and bogie assemblies are done. The body shell assembly is of all welded integrated design and it consists of Under Frame, Sidewall, Roof and End-wall assemblies. A shell is made of body shell fitted on two Bogies.
A sheet metal shop produces all sheet metal items required for the manufacture of Under-Frame, Sidewall and Roof.
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A main Assembly shop assembles the Under-frame, Sidewall, End-wall and Roof to form a like SHELL.
Final assembly painting of the shell and fitment of Air brake arrangement are done in the final assembly shop.
Bogies are manufactured by assembling the Bogies, Bolster, Wheel sets, Axle box and springs together.
The Body shells fitted on the bogies are dispatched to Furnishing division for furnishing work.
Shell division is further classified into many shed under which there are different shops which take care of various machining and fabricating process.
a) Sheet metal shop (Shop No 10 &11)b) Wheel and axle shop (Shop No 12)c) Forging and fabrication shop (Shop No 13)d) Spring shop (Shop No 15)e) Machine shop (Shop No 16)f) Doors and partition shop (Shop No 18)g) Side and end wall shop (Shop No 20)h) Under frame and roof assembly shop( Shop No 21)i) Body assembly shop (Shop No 22)j) Bogie frame manufacturing shop (Shop No 23)k) Bogie assembly shop ( Shop No 24)l) Paint shop( Shop No 26)
FURNISHING DIVISION
a) Aesthetic look, comfort and safety are very much essential for pleasant journey. Furnishing takes care of the above and furnishing the interior portion of the coaches. Furnishing of the coach is done in ten stages, viz.., Flooring, Wiring, Paneling on Sidewall, Window Fixing, Partition Paneling, Plumbing, Floor Molding, Light, Fan and Seats, Berths and Rack fixing and Buffer height adjustment. Compressed Plywood, Limpet)
b) Electrical multiple units wiring shop (Shop No 29)c) Main assembly shop (Shop No 30)d) Carpentry and wood working shop (Shop No 32)e) Machining/ finishing shop (Shop No 33)f) Trimming shop (Shop No 34)g) Special type coaches wiring shop (Shop No 35)h) Paint shop (Shop No 36)i) Millwright & maintenance shop (Shop No 80)j) Electrical distribution & maintenance shop (Shop No 85)
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k) Road & transport shop (Shop No 88)
MATERIAL INPUTS USED IN FURNISHING OF COACHES
Compreg plywood, NFTC, PVC sheets, Recron /PU cushion, feather touch vinyl cloth, stainless steel lavatory inlays are used to achieve good interior design, best passenger amenities and long life of the coach under tough running conditions.
TECHNOLOGY UPGRADATION IN FURNISHING INCLUDES:
A) Use of UIC rubber vestibules, roof mounted A/C package units in coaches.B) Fitment of controlled discharge toilet system.C) Use of polycarbonate seats in MRVC EMUs. D) Stainless steel paneling.
PRODUCTS MANUFACTURED
ICF has been meeting the needs of the Indian Railways for varied types of coaches, however sophisticated the type may be. Some of the important types are:
SELF PROPELLED COACHESElectric Multiple Units for suburban services in Metropolitan cities; Diesel Rail Cars; Metro Coaches for Kolkata Metro Railways; Diesel Electric Multiple Units & Diesel Hydraulic Multiple Units for non-electrified routes and Mainline Electric Multiple Units for long distance inter-city commutership.Accident Relief Trains / Medical VansOHE Inspection Cars
AIR-CONDITIONED & NON-AIRCONDITIONED PASSENGER COACHES Air-conditioned Sleeper Coaches of first & second class; Air-conditioned Chair Cars of first and second class; Double Decker Coaches with seating capacity for 148 passengers as against the conventional 90 passengers.
SPECIAL COACHES Air-conditioned & Non-air-conditioned Pantry Cars High Capacity Power Cars for Shatabdi & Rajdhani Express Trains Air-conditioned Military Ward and Saloon Cars for Indian Army.
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Air-conditioned Saloon Cars, Dining Cars, Bar & Restaurant Cars, luxury suites for luxury tourist trains like Palace on Wheels (WR), Deccan Odyssey (CR), The Golden Chariot (SWR), Royal Rajasthan on Wheels (NWR) and Maharajas Express of IRCTCLifeline Express for operation of hospital on wheelsJet Deflector Crane Cars, Inter Communication Coaches for DRDO
TYPES OF COACHES
FIRST CLASS COACHESFIRST AND SECOND CLASS COACHESTHIRD CLASS COACHES DAY COACHESPANTRY CARS AND KITCHEN CARSSECOND CLASS LUGGAGE AND BRAKE VANSELF PROPELLED COACHES
DIFFERENT DEPARTMENTS
MECHANICAL DEPARTMENT
A CAD Center is installed which assists in evolution and preparation of new drawings faster. Design office has a Design more than 175 types of coaches to three different gauges 1676mm, 1067mm, and 1000mm. it has produced over 3, 00,000 drawings for coaches layout and coach components.
Design office takes care of the changes in the availability of the new materials, standardization, and obsolescence, feedback reports from the user Railways and recommendations by standing committees study groups on the Indian Railways.
With the changing requirement of the Railways, the design office is challenged to drastically cut down the cycle time. The design office can proudly take the credit of development of the following new designed in the three years.They are:
1. MAINLINE ELECTRIC MULIPLE UNITS [MEMUS]2. DIESEL ELECTRIC MULTIPLE UNITS [DEMUS]3. DIESEL HYDRAULIC MULTIPLE UNITS [DHMUS]4. PALACE ON THE WHEELS COACHES [POWS]5. DIESEL ELECTRIC TOWER COACHES [DETCS]6. HIGH CAPACITY POWER CARS [DMU-HHPS]7. ACCIDENT RELIEF MEDICAL VANS [ARSMVS].
CIVIL ENGINEERING DEPARTMENT
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The Civil Engineering Department is in charge of all Civil Engineering construction and maintenance of the factory sheds and structures, service and welfare buildings, colonies and is also responsible for providing day-to-day service like water supply, sanitation and sewage disposal, for upkeep of parks, gardens and for all other estate management works.
ICF Estate owns an area of 192.254 Hectares (Shell division- 25.89 Hectares; Furnishing division - 50.82 Hectares; Colonies - 15.02 Hectares; Service and Welfare Buildings - 5.45 Hectares; Afforestation - 40.00 Hectares(approx.). Chief Engineer-cum-Estate Officer has powers for acquiring and disposing off lands, controlled by Railway Board. He is also responsible for licensing, leasing, auctioning, and to prevent encroachment, implementing the public premises eviction Act 1971. He is also the coordinating and liasoning authority with State and Central Governments with regard to estate matters.
STORES
ICF is an ISO 9001 certified organization, manufacturing different types of coaching stock for the Indian Railways, and other customers. The raw materials and components required for the manufacture of coaches is procured by the Materials Management Department, through tenders. The Department is headed by the Controller of Stores. In the year 2008-09, the total value of procurement by ICF was in the region of Rs.1139 crores. Normally all tenders are issued as e-tenders in IREPS website.
The procurement is arranged through the tendering system, as detailed below:
Bulletin Tenders: The Bulletin Tenders are issued to all registered suppliers of ICF. For registration with ICF, the suppliers are required to furnish the required information in the prescribed form, available with the Registration Section of the office of the Controller of Stores/ICF. The suppliers meeting the conditions mentioned in the form are registered for the item groups applied for. Initial registration is for two years and on satisfactory performance, the registration is made permanent.
Limited Tenders: Limited Tenders are issued to vendors on a selective basis, generally to the
registered vendors.
Open Tenders: Open Tenders are published in the leading newspapers. Unregistered suppliers can participate against the Open Tender subject to fulfilling the requirements mentioned in the tender documents.
ACCOUNTS DEPARTMENT
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Tenders should furnish NEFT particulars along with their quotations. Suppliers/Contractors payments will be made through NEFT only w.e.f. 01.06.2010.All the suppliers should enrol for NEFT payment made and option forms and e-mail id particulars are to be forwarded to FA & CAO's Office.Payment through NEFT is based on the vendor No. / supplier code available in the purchase orders. Suppliers may obtain Vendor No. from Stores Department. In case of contractors, the vendor code may be obtained from the concerned executive department and NEFT option forms may also be submitted to the concerned executive departments. Suppliers / Contractors should mention their vendor no, bank account no (in full) and IFSC in their bill which will be verified with the particulars already submitted by the firms.
ELECTRICAL DEPARTMENT:
The Electrical Department at ICF works under the overall control of the Chief Electrical Engineer. The Maintenance and Construction Organisation is headed by Chief Electrical General Engineer. Chief Electrical Engineer/Quality Control and Commissioning is responsible for Inspection and Quality Assurance of the components and coaches.
The functional Wings of Electrical Branch of ICF are as follows:
a. Designs- The Electrical Design Wing is responsible for evolving new designs of coaches, equipments and sub systems, drawings and specifications for components and assemblies.
b. Production – The Production Wing is responsible for manufacturing of harness, installation of electrical equipments, wiring and complete electrical furnishing of the various types of coaches. The Production wing has developed the expertise in handling of different types of self-propelled coaches including 3 phase AC DC EMUs, EMUs, DEMUs, Ac & non AC coaches including luxury trains for RTDC & IRCTC.
c. Inspection - The Inspection Wing is responsible for Quality assurance of electrical components and systems used for manufacturing of the coaches.
d. Contracts and Development- The Contracts & Development Wing is responsible for liaising with the purchase department for ensuring timely availability of materials for coach production, customer complaint redressal and discharge of warranty obligations, failure analysis and corrective and preventive actions, development of new Items for coach production and development of additional sources for limited source items.
e. Maintenance - The Maintenance Wing is responsible for maintenance of Plant & Machinery including numerically controlled & CNC machines, EOT cranes etc. This Wing is also
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responsible for maintaining power supply for Factories, ie. Shell & Furnishing, D&D Wing, Hospital, Colony etc.
TECHNICAL TRAINING CENTRE (TTC)
The Technical Training School in ICF was started in the year March 1954. The Training Centre was originally intended to train 200 Fitters , 200 Welders and 120 Machinists Trainees per Annum On the advent of APPRENTICE ACT 1961 , it was mandatory for the management of ICF to train 350 Apprentices in various trades at any time of an year commencing from 1964. The constant requirement of middle level management supervisors are trained in the Training Centre as Graduate and Apprentice Mechanics recruited through the RRB and given 1Year / 1 ½ Year training respectively in their respective trades.
Besides, it is an obligatory part of ICF to impart training to other Railway Personnel to maintain the Coaching Stock. Hence TTC provide training schedule for the other Railway Trainees as per the training Calendar.
Also, TTC conducts refresher Course for Skilled Artisans, Supervisory Development Courses, CNC Courses, Pre-Promotional Course etc.
ORGANISATION HIERARCHY AT ICF
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EXPORT PERFORMANCE
SL.NO.
YEAR TYPE NO. OF STOCK EXPORTED COUNTRYBOGIES SHELLS COACHES
A total of 481 coaches including AC coaches, Self-propelled coaches and Special coaches, have been exported to 10 Afro-Asian countries. In addition, 11 stainless steel shells were import coaches/shells/bogies/spares from India, exported to Malaysia. Are handled by RITES and IRCON.
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PRODUCTION OVER THE YEARS
These figures indicate the number of Coaches produced at ICF over the years.
YEARS PRODUCTION
1957-1962 928
1962-1967 2487
1967-1972 3273
1972-1977 3117
1977-1982 3585
1982-1987 4099
1987-1992 4679
1992-1997 4742
1997-2002 5098
2002-2007 5559
2007-2010 3760
TOTAL 41427
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ABOUT STAFFING PATTERN AND WELFARE
Department Group A Group B Group C Group D Total
Administration 3 8 82 146 239
Accounts 5 18 267 24 314
Electrical 11 10 1131 148 1300
Civil 2 4 188 427 621
Mechanical 21 36 7659 1378 9094
Medical 18 1 79 74 172
Personnel 1 6 285 17 309
Security 2 0 361 3 366
Stores 9 11 328 159 507
Total 72 94 10380 2376 12922
STAFFING PATTERN
EMPLOYEE WELFARE
WORKING HOURS
FACTORYDAY 7:00 AM - 11:30AM, 12:30PM - 16:30PMNIGHT 17:00PM - 21:00PM, 21:45PM - 02:30PMADMINISTRATION FROM 9:30 AM - 13:00 PM, 13:30PM - 17:30PM ( Monday to FRIDAY)
FROM 9:30AM – 12.25PM (Saturday)
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EMPLOYEE NUMBER o A unique six digit number is assigned to every employee of ICF. Number
will not change during entire career in ICF. ID-CARD
A separate ID card has been given to each employee.
PRIVILEGES Pass entitlements:
o Indian Railways offer free travel and concessionary travel facilities to its
employees.o During the first five years of the service, an employee is eligible for one set
free pass, which will entitle the holder to travel between any two stations on Indian Railways, free of cost. On completion of five years of service, he/she is eligible for 3 sets of passes.
MEDICAL FACILITIESo ICF has a 101 bedded Hospital where its employees, both serving and
retired and their family members are provided with free medical treatment for inpatients and outpatients with complete health care. Every employee has to apply for a medical card.
QUARTERSo Employees are provided with the facility of residential accommodation. and
based on the scales of pay the quarters will be allotted on their seniority.
SALARY & ALLOWANCESThe salary includes the following components
o Basic pay
o 50% of Basic Pay as Dearness Pay
o House Rent Allowance @ 30% of (i) & (ii) above subject to certain
conditions.o Dearness Allowance at the rates applicable from time to time
o Transport Allowance at the rates applicable (depending on the scale of
pay). o An apprentice trainee is not entitled for any of the allowances.
o Each employee is credited with 15 days of leave, called Leave on Average
Pay (LAP) for every half year in advance on 1st of January and 1st of July.This can be accumulated up to 300 days.
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CANTEEN FACILITIES o There are 4 canteens in I.C.F., One at each of the two divisions, i.e., Shell
and Furnishing for exclusive use of the staff working inside the factory with extension counters and one at each of the Division for the Administrative Office staff.
KALYANA MANDAPAMSo ICF has two Kalyana Mandapams, i.e., ICF Kalyana Mandapam and
Golden Jubilee Kalyana Mandapam, situated near the ICF bus terminus, which can be availed at concessional rates for performing the functions of the self, family members and dependants.
HOLIDAY HOME o There are Holiday Homes at the following locations,which are allotted to
employees at ICF at concessional rates:1. Udagamandalam - 4 units for staff.2. Kodaikanal - 4 units for staff and 2 for officers.
In addition, there are several other Holiday Homes at various locations spread over India, maintained by the respective Zonal Railways/ Production Units.
OTHER FACILITIESo All other facilities like schools, Post Office, Telegraph Office, Ration shop
with Cloth centre, Aavin Milk Cooperative Store, Banks/ ATM centers etc. are also available in the ICF area.
o ICF Stadium: There is a big stadium which has facility for athletics,
football, hockey and other fields sports.o Book Bank: A Book Bank with books on Engineering, Medical subjects
for lending to the wards of ICF employees.o Handicraft Centre: There is a Handicraft Centre where safety garments of
workshop employees are being stitched by the wives of the employees. Payment for stitching the garments is paid at fixed dates. This facility is provided to supplement the income of the employees.
o Loans and advances also been provided to ICF Employees.
o Creche, Typewriting and Tailoring Institutes are available.
o Training facilities to ICF employees ICF has a Technical Training Centre
with modern teaching and equipments to train its employees and also employees of other Railways.
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SPRING
ABOUT SPRING
SPRING
A spring is defined as an elastic body, whose function is to distort when loaded and to recover its original shape when the load is removed.
TYPES OF SPRINGS
Though there are many types of the springs, yet the following, according to their shape, are important for the subject point of view.
HELICAL SPRING
The helical springs are made up of a wire coiled in the form of a helix and are primarily intended for compressive or tensile loads. The cross-section of the wire from which the spring is made may be circular, square or rectangular. The two forms of helical springs are compression helical spring as shown in Fig 1 extension helical spring in Fig 2 and tension helical spring as shown in Fig 3
The helical springs are said to be closely coiled when the spring wire is coiled so close that the plane containing each turn is nearly at right angles to the axis of the helix and the wire is subjected to torsion. In other words, in a closed coiled helical spring, the helix angle is very small; it is usually less than 10oc.The major stresses produced in helical springs are shear stresses due to twisting. The load applied is parallel to or along the axis of the spring.
In open coiled helical spring, the spring wire is coiled in such a way that there is a gap between the two consecutive turns, as a result of which the helix angle is large. Since the application of open coiled helical spring is limited, therefore our dimension shall confine to closely coiled helical springs only.
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COMPRESSION SPRING
EXTENSION SPRING
Extension springs are springs, which absorb and store energy by offering to a pulling force as shown in Fig2. Most extension springs are wound with initial tension, which holds the coils together and offers resistance to a pulling force. Extension springs are the direct opposite of compression springs, in that they are close coiled helical springs that extend under a pulling force. Extension springs can have many different styles of hooked and looped ends.
Extension springs are found in garage door assemblies, visegrippliers, and carburetors. They are attached at both ends, and when the things they are attached to move apart, the spring tries to bring them together again. Extension springs are found in garage door assemblies, visegrippliers, and carburetors. They are attached at both ends, and when the things they are attached to move apart, the spring tries to bring them together again.
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CONICAL AND VOLUTE SPRINGS
The conical and volute springs, are used in Special applications where a telescoping spring or a spring with a spring rate that increases with the load is desired. The conical spring is wound with a uniform pitch where as the volute springs, as shown in are wound in the form a parabolic with constant pitch and lead angles. The springs may be made either partially or completely telescoping. In either case, the number of active coils gradually decreases.
The decreasing number of coils results in an increasing spring rate. This characteristic is sometimes utilized in vibration problems where springs are used to support a body that has a varying mass.
The major stress produced in conical and volute springs are also shear stress due to twisting.
TORSION SPRINGS
These springs may be of helical or spiral type as shown in Fig 3. The helical type may be used only in applications where the load tends to wind up the spring and are used in various electrical mechanisms. The spiral type is also used where the load tends to increase the number of coils and when made of flat strip are used in watches and clocks. The major stresses produced in torsion springs are tensile and compressive due to bending.
TORSION SPRING
LAMINATED OR LEAF SPRINGS
The laminated or leaf spring (also known as flat springs of carriage spring) consists of a number of plates (known as leaves ) of varying lengths help together by means of clamps and bolts, as shown in Fig 4 There are mostly used in automobiles.
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DISC OR BELLEVILLE SPRINGS
These springs consist of a number of conical discs held together against slipping by a central bolt of tube. These springs are used in applications where high spring rates and compact spring units are required. The major stresses produced in disc or Belleville springs are tensile and compressive stresses.
WIRE FORMS
Wire forms are any shape made out of wire- not just a coil as shown in Fig 5 There are a jillion different kinds of wire forms; here’s a common one.
BED SPRINGS
These are basically hourglass-shaped compression springs in which the ends wrap around themselves. They are made on special automatic machinery- I hope you don’t need one bad enough to try making it yourself-they can probably be made by hand, but it would not easy.
LIMITED –TRAVEL EXTENSION SPRINGS
Sometimes you will want to make an extension spring that only extends so far and then stops. You will see these sometimes on screen doors as shown in Fig 6.
SPECIAL PURPOSE SPRINGS
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These springs are air or liquid springs, rubber springs, ring springs etc. The fluids (air or liquid) can behave as a compression spring. These springs are used for special types of application only.
SNAP SPRINGS
Snap springs are easy. Just coil an extension spring with the right diameter and cut off springs, one at a time, with wire cutters.
SPRING SPECIFICATION:
SPECIFICATION WTAC-01-202
BOGIE BOLSTER (OUTER SPRING)
BOGIE BOLSTER (INNER SPRING)
SNUBBER SPRING
BG-AXLE SPRING
FREE HEIGHT 375 457 423 433 360
SECTION OF WIRE DIAMETER
33.5 35 26 21 33.5
TOTAL NO OF TURNS
6.75 9.5 12.5 13.5 6.75
OUTER DIAMETER
242 253 188 235 242
INNER DIAMETER 175 183 136 193 175
VARIATION IN FREE HEIGHT
±7 ±5 ±6 ±4 ±2
All dimensions are in mm
We concentrate on mainly BG-AXLE SPRINGS.
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CHAPTER 2
NEED AND OBJECTIVE:
2.1) NEED:
Quality is main thing for any business organization. To be success in an competitive world things with good quality is necessary. My work achieving industrial excellence through quality management procedure is an attempt to identify the present quality performance of ICF especially in spring shop.
One of the reasons for selecting this subject was to link theory with productivity and quality as implemented in industry. To be a success in today’s world it becomes mandatory for an organization to be Competitive in every aspect of business. This can be achieved through excellence in design, manufacturing, marketing and after sales service.
The keys to this excellence for any organization are its people and their productivity. The ever-changing business environment and its stringent requirements as regards quality, cost and delivery are putting undue pressure on the organizations to perform par excellence
2.2) OBJECTIVE
The major objective of the project is to analyze and find out the causes for the quality problem in the spring shop and indentify the effects of it and come up a solution to overcome them.
In order to do that we have to find out the rejection & rework in the spring shop. The analyze of the rejection and rework through various tests may help us to find errors in various process and come up with solution.
This leads to reduction of operation time, improvement in production and quality which make the process to come in control.
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CHAPTER 3
3.1) RESEARCH METHODOLOGY:
Research methodology indicates the systematic way to do the research work by the researcher. it includes various steps. The methodology of the project was standard DMAIC cycle, this methodology play a critical role where improvement is necessary The various processes being done in the spring shop has been studied and the relevant data has been collected.From the collected data the percentage of rework and rejection in each process has been identified.The calculated data are used for drawing the histogram which helps me to find out major area where the rejection is happened and the cause and effect diagrams are drawn in order to find out the major cause for the problem and follow the effects of the causes and come up with a suggestion.
DATA COLLECTION:PRIMARY DATA:
Accurate and reliable primary data are collected through
production statements (daily ,weekly and monthly statements)
Rejection Reports (P17 A- Inspection reports)
SECONDARY DATA
Dispatch position from production control organization
Internal records from shop floor The data from the tests conducted in the spring shop gives the idea about the control of the various processes. The statistical data of the following tests for which there were various numbers of rejection and rework the processes are
Spring management data thro rail net.(computer based data base )
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3.2) STATISTICAL TOOLS USED FOR STUDY:
Statistical process control tools are excellent problem solving tools. They do not use hard data but rely on subjective information. Application of these tools has been proven useful in process improvement, cost reduction, policy deployment and new product development. There are many tools under SPC, where histogram is used to analyze the data.
CAUSE AND EFFECT DIAGRAM:
A cause-and-effect (C&E) diagram is a picture composed of lines and symbols designed to represent a meaningful relationship between an effect and its causes. They are used to investigate either a “bad” effect and to take action to correct the causes or a “good” effect and to learn those causes that are responsible. For every effect there are likely to be numerous causes. Also each major cause is further subdivided into numerous minor causes. C&E diagrams are the means of picturing all these major and minor causes.
USES OF C&E DIAGRAM: Analyze actual conditions for the purpose of product or service quality improvement,
more efficient use of resources and reduced costs. Eliminate conditions causing nonconformities and customer complaints. Standardize existing and proposed operations. Educate and train personnel in decision-making and corrective-action activities.
HISTOGRAM:
The first “statistical” technique is the histogram. It describes the variation in the process, it graphically estimates the process capability and, if desired, the relationship to the specifications and the nominal target. It also suggests the shape of the population and indicates if there are any gaps in the data. The frequency of occurrence of the variable is drawn as a bar in the histogram. The variation pattern and the central tendency could be visualized easily using histogram. The dispersion of this variability can be assessed using the specification limits. In total Histogram are useful in studying the variation in the process and its capability.
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EFFECTCAUSES
OPERATIONAL EXCELLANCE METHODOLOGY:
It is also called as DMAIC cycle, it play critical role where improvement in the process is necessary. It help the researcher to define and identify the problem and help him to make the corrective step in order to make the process to come in control. The above cycle play a critical role in my project.
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CHAPTER 4
ANALYSE AND INTERPRETATION:
4.1) DEFINE PHASE
INTRODUCTION TO SPRING SHOP
Spring shop of ICF identified with the shop no:15. It is located in the 1 shed of ICF. The shop caters to the complete requirements of springs for ICF regular production and also supplies springs as spares to the zonal railway. The shop handles a product mix of around60 types of springs every year. These springs are manufactured from 13 different sizes of springs steel round supplied by firms Mukund ltd, SAIL, VISI etc. apart from spring manufacturing the shop also takes up heat treatment (hardening & tempering) of draw gear items.
NOTE: The spring shop of ICF is to be modernized and its capacity is to be augmented. An amount of Rs. 34.66 Crores has been sanctioned by railway board for this purpose. Completion of the modernization project is expected by 2011.
Spring manufacturing in the spring shop are used in the suspension system of main line coaches, EMU stock, Loco motive and Freight stock on the Indian Railways. This being a layout shop springs bar enters one side and finished springs leaves out of the shop.
The shop consists of three ways, raw materials enters through the middle bay and after magnaflux test the work piece enters second bay where operations from end forging to scragging are done.
Now springs are taken to the third bay where operations from end grinding to painting are done. There after springs are taken to assembly shop. 103type of springs are manufactured at the spring shop. Mostly BG/Axle and BG bolster springs are manufactured at the spring shop. Helical compression springs have applications to resist applied compression forces or in the push mode, store energy to provide the push. Different forms of compression springs are produced. There are conical, barrel, hourglass, or straight conical compression springs. These compression springs can be made with or without variable spacing between coils. Round wire springs can store more energy than rectangular wire compression springs.
Two type of materials used for spring manufacturing purpose.
Based on the annual production programmed the ICF work order for the manufacturing of different type of springs in batch shall be released from shop 15.
SSE/PC/S- can release the various production documents and the required quantity of the raw materials for the process.
Section JE shall receive the raw materials ad the relevant production document. The material shall be bundled and shall be provided with tag containing the following
details, Raw material specification, Drawing No., Batch order No., Quantity etc.
Springs are made of bars of fine grained special quality steel to IS: 3195. The spring manufacturer before taking up manufacturing of springs shall inspect and check all steel rounds for conformance with the requirements for the raw materials as given in this specification.
Only when the raw materials are found to be within the specific standards, it will be taken for manufacture of the springs. It will be the responsibility of the spring manufacture to ensure the quality of spring steel rounds.
MANUFACTURING PROCESS
The operations carried out in the spring shop are listed below,
The spring are to be cut to length on a band saw cutting machine based on the formula (L=Dm 3.14×Ne + 3.75).
Where, Dm = Mean Diameter of the spring Ne = Number of effective coils 3.75 is a standard factor for 1 ½ turns dead coil spring.
Then the ends are chamfered on a chamfering machine.
2. STRAIGHTENING The bars are to be straightened. The limit of out of straightness is 1 mm/Meter length.
3. BAR PEELING 100% of the bars are peeled to remove the skin by minimum of 1mm or 3% of
nominal dia as per specification.
4. STRAIGHTENING Peeled bars are too straightened again.
5. CENTERLESS GRINDING The bars are centre-less ground to a depth of 0.3 (i.e. 0.2 mm in rough pass and 0.1
mm as finish pass) to endure proper surface finish i.e. <5 microns.
6. MAGNAFLUX TESTING This is a method of Electro Magnetic Crack Detection. The spring’s bars are passed
with a low voltage current and a solution of kerosene mixed with colored iron powder is applied on the surface of magnetized bars. On passing current the cracks start to act as magnets and draw the colored iron powder accumulates in the crack and the cracks can be seen with naked eye.
7. END TAPERING Both sides of the bars are end tapered manually on a single acting hammer. This is done to ensure proper seating after coiling. All the axle and bolster outer springs are right hand coil and the bolster inner springs are of left hand coil.
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8. COILING The mandrel diameter equal to the inner diameter of the spring is selected for coiling. The pitch based on the no of coil is set on the m/c. The bars are heated to 880 c to 920 c and soaked for 1 min/mm diameter for uniform heating and then coiled on the coiling M/C. The springs are stamped on the dead coil with identification stampings like manufacturer, month & year of manufacture, material specification (CM/SM), drawing code of the spring etc. Then the springs are taken on the pitching table to maintain the square-ness, ensure proper seating and maintain the free height.
9. HEAT TREATMENT The coiled springs are Hardened and Tempered.
HARDENING: All the springs are heated to a temperature of 830 - 860C and soaked at that temperature for 1 min/mm dia for uniform temperature and quenched in straight mineral oil. The springs are kept in oil for 20-30 mins. The oil temperature should not exceed 65C.TEMPERING: The hardened springs are heated to a temperature of 480 - 540C for CM and 470 - 520C for SM and soaked for 1min/mm dia of the spring. For CM spring is then cooled in open atmosphere to 400C and then cooled in water SM material is cooled in water SM material is cooled to room temperature in open atmosphere.
10. HARDNESS TESTING The springs are tested for hardness by CMT. The brinell hardness number is checked
415 to 460 BHN-CM (chrome molybdenum steel) 380 to 460 BHN-SM (silicon manganese steel) The springs failed for low hardness is re-hardened. The springs failed for high hardness is re-tempered.
11. SCRAGGING The springs are loaded to its home height three times to induce the permanent set and to ensure that further set in height does not occur during functioning. The springs that go down in height from the free height plus grinding allowance is sent re-pitching and is then heat treated. If the spring are more than the above height is hot scragged (i.e. heated to the tempering temperature and pressure in the scragging M/C in hot condition)
12. END GRINDING Both the springs are ground to ensure proper seating of spring. The ¾ of the circumference of the end coils should be ground. The drawing height (free height is maintained at this stage)
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13. SHOT PEENING The end ground springs are shot penning M/C steel shot to a size of 1mm dia is forced on to the spring’s surface at 80 meters/second. This impinching will create a localized stress, in turn the surface become wear resistant. Moreover the surface is cleansed of oil, scale etc. making it ready for electromagnetic crack detection.
14. ELECTRO MAGNETIC CRACK DETECTION OF SPRINGS The principle is similar to that of the magnaflux testing. Here the iron powder is mixed with fluorescent powder in water and is applied on the spring. On magnetization the iron powder mixed with fluorescent powder mixed with fluorescent powder takes the shape of the crack. Now, UV light is projected on the surface of the springs and the cracks fluoresce. This M/C has an attachment called the central conductor to detect transverse cracks. The springs thus detected with cracks are scrapped.
15. LOAD TESTING The springs are tested in a load testing M/C. the height o the springs for the three specified loads are checked. The three specified loads are tare, gross load and shock load. The springs that pass these loads are grouped.
Grouping: The height range for the tare load is further divided in to three ranges. The springs that fall under the lowest range is classified a soft springs- yellow spring, the spring that falls in the middle range is grouped as medium springs-blue springs and the one that falls on the highest side of the height range is grouped as the tough spring-green spring.
16. PAINTING The springs are dipped with one coat of zinc oxide primer and black enamel paint.
17. COLOUR CODING Based on the classification done at the load testing stage the springs are color coded with yellow, blue & green respectively and the type of spring is written on one of the end ground face.
LAY OUT OF SPRING SHOP
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4.2) MEASURE PHASE
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The spring shop is a huge shop which contains various manufacturing processes which are already discussed in the previous chapters. The data from the tests conducted in the spring shop gives the idea about the control of the various processes.
So we collected the statistical data of the following tests for which there were various numbers of rejection and rework the processes are
The above are the test processes which are conducted for the springs which are conducted after the heat treatment and tempering processes.
These processes involves testing of a huge number of springs which are divided into batches of particular sizes, the springs are grouped into batches according to spring that passes the test are recorded and the number of springs under each category of error are recorded in the table and sent for rejection or rework.
The errors in the scragging test higher size (H/S) and the under size (U/S) are noted for the corresponding batches, also the number of the springs with crack, end coil crack, and over heat are entered in the respective batches of the EMCD test data table. The numbers of the springs with higher size and under size in the load test are tabulated.
I collected the data on the site for the month of APRAIL during the year 2011 and collected the rest of data for the remaining two years (2009 & 2010) from the quality control department of the spring shop.
The data which is collected for the test during the specified period are tabulated below. I collected the data for the past two years only, because I could better understand the characteristics of the production quality of the spring shop from this period.
RECORDING
The data collected for the past two years are recorded for the construction of control charts and the statistical process control tools. The data which were recorded are tabulated below.
The measurements were guided by the following Fishbone Diagram representing the
possible sources of problems
The following tools were used in the analysis of data collected
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Fish bone analysis
Histogram
Besides the above tools, visual inspection, observation and personal discussion with various
people who directly or indirectly could help in better analysis, was also conducted.
The following are the results of the analysis:
PROBLEMS IN SPRING MANUFACTURING Spring failure may be caused by breakage, high permanent set or loss of load.
Group I lists the causes that occur most frequently. Group II contains the less frequent causes and Group III lists causes that occur occasionally.
HIGH STRESS The majority of spring failures are due to high stresses caused by large deflection
and high loads. High stresses should be only for statically loaded springs. Low stresses lengthen fatigue life.
HYDROGEN EMBRITTLEMENT Improper Electro-plating methods and acid cleaning of springs, without proper
baking treatment, cause spring steels to become brittle and is a frequent cause of failure. Nonferrous springs are immune.
SHARP BENDS AND HOLES Sharp bends on extension, torsion and flat springs and holes or notches in flat
springs, cause high concentration of stress resulting in failure. Bend radii should be a large as possible, and tool marks avoided.
FATIGUE Repeated deflections of springs, especially above 1,000,000 operations, even with
minimum stress, may cause failure. Low stresses should be used for severe operating conditions.
SHOCK LOADING Impact, shock and rapid loading cause far higher stresses than those computed by
the rectangular spring formulas. High carbon steels do not withstand shock loading as well a alloy steels.
CORROSION
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Slight rusting or pitting caused by acids, alkali, galvanic corrosion, stress corrosion cracking, or corrosive atmosphere weakens the material and causes higher stresses in the corroded area.
FAULTY HEAT TREATMENT Keeping spring materials at the hardening for longer periods than necessary
causes undesirable growth in grain structure resulting in brittleness even through the hardness may be correct.
FAULTY MATERIAL Poor material containing inclusions, seams, slivers, and flat material with rough,
slit, or torn edges cause early failure. Overdrawn wire, improper hardness, and poor grain structure also result in early failure.
HIGH TEMPERATURE High temperature reduces spring temper (or hardness), lower the modulus of
elasticity thereby causing lower loads, reduces the elastic limit and increase corrosion. Corrosion resisting or nickel alloy should be used.
LOW TEMPERATURE Temperature below -40F lessen the ability of carbon steels to withstand shock loads. Carbon steels become brittle at -70F. Corrosion resisting, nickel or non ferrous alloys should be used.
FRICTION Close fits on rods or in holes result in a wearing of material and occasional failure. The outside diameters of compression springs expand during deflection but they become smaller on torsion springs.
OTHER CAUSES Enlarge hooks on extension springs increase the stress at the bends. Carrying too
much electrical current will cause failure. Welding and soldering frequently destroy the spring temper. Tool marks, nicks and cuts often become stress raisers. Deflecting torsion springs outwardly causes high stresses. Winding them tightly causes binding on supporting rods. High speed of deflection, vibration and surging due to operation near natural periods of vibration or their harmonics, causes increased stresses.
CAUSES FOR REJECTION
CRACK
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Crack is said to occur due to material fault. Material fault occurs due impurities and defective grain structures. Cracks are some dislocations that were introduced during solidification, during plastic deformation, and as consequence of thermal stresses that result from rapid cooling.
END COIL CRACK End coil crack is occurred due to various operations like end-coil grinding,
forging and also due to material imperfections.
END COIL BREAK End coil break is said occurs during grinding operations due to improper coiling.
OVER HEATING Over heating occurs during the hardening process which will result in
scale(crocodile surface) formation. It occurs when the temperature in the furnace exceeds the critical temperature and also when soaking time of the springs exceeds the time limit.
DENT Dent is a depression on the surface of the springs. Dent occurs due to man
handling. There is no provision for transporting the springs hence they are rolled on the floor.
TOOL MARKS Tool marks occurs during machining processes like peeling and grinding.
PITTING Pitting is the occurrence of tiny but visible pores on the spring surface. This is the
expression of impurities in the chemical composition of the material or due to inappropriate pressure of the shot peening balls.
THIN END COIL End coil become thin due to excessive grinding. This is purely attributed to the
negligence of the operator while loading the spring onto the end-coil grinding machine.
The above are the major causes of rejection in the manufacturing of spring.
CAUSES FOR REWORK
HIGHER SIZE (H/S) Higher size is a defect which occurs as a result of the mistakes in pitching. The
coiled springs are manually pitched after the coiling process , here the springs are pitched up to
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desired height and if the height exceeds the desired height it is called as higher sized effect. The mistakes in pitching causes variation in height called as higher size (H/S).
UNDER SIZE (U/S) The under size is a defect which occurs as a result of lesser height of the springs
than the desired height of the springs. These kinds of error occur due to the mistakes in the pitching process.
The above are the major causes of rework in the manufacturing process. Some minor causes like bend, bite and taper are categorized under the under size defect.
DATA ANALYSIS
After the collection of data and the recording of the data the next step is to perform a statistical test on the data. The statistical analysis involves the usage of the statistical control tools. First of all the control of the process must be known to check whether the process is within the control are not.
HISTOGRAM
HISTOGRAM FOR THE PERCENTAGE OF ERRORS IN EACH PROCESS
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CAUSE AND EFFECT DIAGRAM
THE CAUSE AND EFFECT DIAGRAMOF ERRORS IN SCRAGGING
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% REJECTION AND REWORK AT SPRING SHOP (2009-2011)
0
1
2
3
4
5
6
7
8
2009 2010 2011
YEAR
PE
RC
EN
TAG
EH/S IN SCRAGGING
U/S IN SCRAGGING
H/S IN LOAD TEST
U/S IN LOAD TEST
CRACK IN EMCD
ECC IN EMCD
OH IN EMCD
THE CAUSE AND EFFECT DIAGRAMOF ERRORS IN LOAD TEST
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THE CAUSE AND EFFECT DIAGRAMOF ERRORS IN EMCD
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4.4) FINDINGS:
INFERENCE OF THE ANALYSIS
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The statistical analysis of the processes in the spring shop ensures that the quality of the process can be further improved and the process control can be more effective. From the statistical analysis the following can be inferred,
1) The scragging process has the highest percentage of rework and the rework takes more working hours.2) Among the errors in the scragging process the undersize defect is the highest percentage of the error and the causes for it are the poor job handling and poor transfer of job facilities. The dust particles in the floor through which the pitched spring are transferred affect the springs and cause dent on the springs.3) The next highest percent of defect is the higher size of the springs , and the causes for it is found from the cause and effect diagram that the tools used for height measuring during pitching of the springs are not proper tools. So proper designed tools are necessary to avoid it.4) The electromagnetic crack detection graphs and pareto charts implies that the crack, end coil crack and over heat occurs at high percentage and deviates the control of the process more outside the limits.5) The causes for it is found that much of the methods used in the furnace must be re-modified, the first in lost out causes over heat and this leads to formation of crack and during the transfer of the springs for quenching even slight disturbance causes taper, bend and end coil crack etc.,6) The higher size and under size in load test can be controlled by implementing the changes suggested for the H/S and U/S in scragging test.
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4.5) IMPROVEMENT AND CONTROL PHASE
SUGGESTION FOR IMPROVEMENT.
The inference of the statistical analysis has spotted the areas which can be improved, by considerations of the statistical study and their inference we developed the following suggestions, by implementing these minor changes we can improve the productivity and reduce the errors to some desirable percentage so that the process can be brought in to control.
The following are the suggestions developed
1) Usage of height gauge with fixed reference,2) Usage of dust free transfer path ,3) Usage of tray for group heating and transfer of heated springs for quenching 4) Usage of time and temperature controller in the heating furnace.5) Giving training to the labours.6) Implementing skilled labours.7) Periodical performance check of all labours.
I developed the above suggestions for reducing the percentage of the defects and the design of the equipments and their functions are explained below.
HEIGHT GAUGE
This height gauge is more effective for measurement of the height of the springs after pitching and the scragging test. Unlike the present tool the desired height of the spring required can be fixed using the reference, and after fixing the reference the springs can be measured simultaneously and accurately. So the pitching process can be made accurate by which the optimum height range of the spring can be achieved and the rework due to H/S and U/S can be reduce.
TRANSFER PATH USING A PLATFORM
The transfer of the spring should be done through the dust free transfer path. This transfer path has to be designed in such a way that the dusts settling on it doesn’t stay on it, it escapes through the holes on the path. This phenomenon reduces the dent over the surface of the springs. The stresses made by the floor on the springs are reduced in this path so the bend, bite and taper are prevented. This transfer path can reduce the defects and control the process within the limits. The transfer path made of steels can be used for this purpose.
GROUP HEATING AND TRANFER TRAY
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This tray can be used in the furnace, a group of springs can be kept over the tray and then introduced in the furnace for heating and as soon as heating is over the springs can be taken out together. The tray taken out can be connected to the crane used at the quenching tank and then the tray can be transferred to the quenching tank for quenching. The disturbances encountered to the spring at the current transfer path are reduced by using the tray and the overheating, crack, bend, bite, taper are reduced. The tray should be manufactured using materials like aluminium, semi steel or cast iron. These materials can withstand the temperature inside the furnace without any disturbance to it strength and shape.
TEMPERATURE AND TIME CONTROL DEVICE
The temperature and time control device using PLC (programmable logical controller) can be implemented to maintain the required time and temperature inside the furnace . The desired temperature and time of heating process can be set in the device and this maintains the temperature and time of heating and alerts after the heating process is over.
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CONCLUSION
The conclusion of my project is that the spring shop which is responsible for the production of the springs required in large quantity by the coach factory. It has much scope for improvement of production quantity and quality. The statistical process tools which is one of the TQM concepts has helped me understand the causes and effects of the defects of the springs, by finding out the most important causes we have designed certain equipments by implementation of which these defects could be overcome.
The implementation of my suggestions can reduce the rework and rejection, this leads to reduction of operation time, improvement in production and quality and also decreases workers stress. The production cost of one spring will be reduced so the profit can be increased.
CHAPTER 5
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BIBLIOGRAPHY
PRODUCTION AND OPERATIONS MANAGEMENT BY R.ASWATHAPPA
