Master Thesis
Erasmus Mundus Master of Mechanical Engineering
Setup of the Manufacturing Process and Economic
Study of the Gear Box for Industrial Vehicle
Report
Author: Sarawut WONGTHIANCHAI
Adviser: IRENE BUJ CORRAL
Escola Tècnica Superior
Acknowledgments
No any accomplishment of any significance is achieved solely by the effort of one person and that is certainly true of this project. I am deeply indebted to Prof. Irene Buj Corral, my advisor, who has been a true mentor and guide, and to the member of my project committee, Prof. Joan Vivancos Calvet for the assistance he has provided. I am also indebted to Prof. Ana Barjau Condomines and Prof. Jean- Claude BOYER ( INSA DE LYON ) as well as the European Commission who have provided me the greatest opportunity of my life, the chance to study master degree in INSA DE LYON and ETSEIB, UPC.
I would like to thanks every professors in INSA DE LYON and ETSEIB for the everything you gave me during these 2 years. Thank you to my Erasmus Mundus colleague for the friendship and pleasure.
Finally, I must acknowledge my fiancée for without her love, patience, encouragement and support, this project would never have been completed.
To all, a sincere thank you
Table of Contents
Page Acknowledgments………... 1 List of Figures………. 6 List of Tables……….. 9 Abstract………... 12Introduction of the Project………..…... 13
Objectives of the Project ……….... 14
Gear Box Overview…...….………. 15
1. Marketing study……….. 16
1.1. Introduction……… 16
1.2. Objective……… 16
1.3. Estimation Method………. 16
1.4. Assumptions………... 17
1.5. Estimation For Year 2008, main targets are in Spain………. 17
1.6. Estimation For Year 2009 - 2012, main targets are expanded to Europe………. 18
1.7. Conclusion………. 20
2. Manufacturing Process of Shaft 1………... 21
2.1. The Raw Material……….. 21
2.2. The Process and Calculation of Phase10………... 21
2.3. The Process and Calculation of Phase20………... 21
2.4. The Process and Calculation of Phase30………... 25
2.5. The Process and Calculation of Phase40………... 26
2.6. The Process and Calculation of Phase50………... 30
2.7. The Process and Calculation of Phase60………... 33
2.8. The Process and Calculation of Phase70………... 35
2.9. The Process and Calculation of Phase80………... 36
2.10. The Process and Calculation of Phase90………. 36
2.11. The Process and Calculation of Phase100………... 36
2.12. Calculation of Cycle Time for Shaft1……….. 39
3. Manufacturing Process of Shaft 2………... 43
3.1. The Raw Material……….. 43
3.2. The Process and Calculation of Phase10………... 43
3.3. The Process and Calculation of Phase20………... 43
3.4. The Process and Calculation of Phase30………... 46
3.5. The Process and Calculation of Phase40………... 47
Page
3.7. The Process and Calculation of Phase60………... 51
3.8. The Process and Calculation of Phase70………... 53
3.9. The Process and Calculation of Phase80………... 54
3.10. The Process and Calculation of Phase90………. 54
3.11. The Process and Calculation of Phase100………... 54
3.12. Calculation of Cycle Time for Shaft1……….. 56
4. Manufacturing Process of Casing………... 58
4.1. The Raw Material……….. 58
4.2. The Process and Calculation of Phase20………... 58
4.3. The Process and Calculation of Phase30………... 62
4.4. The Process and Calculation of Phase40………... 65
4.5. Calculation of Cycle Time for Casing………... 69
5. Manufacturing Process of Sliding part……… 70
5.1. The Raw Material………... 70
5.2. The Process and Calculation of Phase10………... 70
5.3. The Process and Calculation of Phase20……… 71
5.4. The Process and Calculation of Phase30……….... 73
5.5. Calculation of Cycle Time for Sliding part………. 74
6. Manufacturing Process of Clutch Fork………. 75
6.1. The Raw Material………... 75
6.2. The Process and Calculation of Phase20……… 75
6.3. The Process and Calculation of Phase30……… 77
6.4. The Process and Calculation of Phase40……… 78
6.5. The Process and Calculation of Phase50……… 79
6.6. Calculation of Cycle Time for Clutch Fork……… 79
7. Manufacturing Process of Pin………... 80
7.1. The Raw Material……….... 80
7.2. The Process and Calculation of Phase10………. 80
7.3. The Process and Calculation of Phase20………. 80
7.4. The Process and Calculation of Phase30………. 82
7.5. The Process and Calculation of Phase40………. 83
7.6. The Process and Calculation of Phase50………. 85
7.7. Calculation of Cycle Time for Pin………... 85
8. Manufacturing Process of Sealing plate 1-2... 86
8.1. The Raw Material………. 86
8.2. The Process and Calculation of Phase10……….. 86
8.3. The Process and Calculation of Phase20……….. 89
8.4. Calculation of Cycle Time for Sealing plate 1-2……….. 93
9. Manufacturing Process of Transmission Plate 2………. 94
9.1. The Raw Material……….. 94
9.2. The Process and Calculation of Phase20……….. 94
Page
9.4. The Process and Calculation of Phase40………... 98
9.5. The Process and Calculation of Phase50………... 99
9.6. The Process and Calculation of Phase60………... 102
9.7. Calculation of Cycle Time for Transmission Plate 2………. 103
10. Manufacturing Process of Washer 2………. 104
10.1. The Raw Material………... 104
10.2. The Process and Calculation of Phase10……… 104
10.3. The Process and Calculation of Phase20……… 104
10.4. Calculation of Cycle Time for Washer 2……… 108
11. Manufacturing Process of Gear1……….. 109
11.1. The Raw Material………... 109
11.2. The Process and Calculation of Phase20……… 109
11.3. The Process and Calculation of Phase30……… 111
11.4. The Process and Calculation of Phase40……… 113
11.5. The Process and Calculation of Phase50……… 113
11.6. The Process and Calculation of Phase60……… 115
11.7. Calculation of Cycle Time for Gear1………. 116
12. Manufacturing Process of Gear2……….. 117
12.1. The Raw Material………... 117
12.2. The Process and Calculation of Phase20……… 117
12.3. The Process and Calculation of Phase30……… 119
12.4. The Process and Calculation of Phase40……… 121
12.5. The Process and Calculation of Phase50……… 121
12.6. The Process and Calculation of Phase60……… 122
12.7. Calculation of Cycle Time for Gear2………. 123
13. Choosing the proper machine... 124
13.1. CNC Lathe Machine……….. 124
13.2. CNC Milling Machine………... 125
13.3. Manual Grinding Machine……… 128
13.4. Broaching Machine……… 129
13.5. Hobbing Machine……….. 130
13.6. Manual Disc Saw Machine……… 132
13.7. Manual Sensitive Press……….. 133
14. Calculation of the Machines Amount Required……… 134
15. Calculation of the Workers Amount Required………. 135
16. Economic Study……… 137
16.1. The calculation of Hour Cost………. 137
16.2. The calculation of The Price of the cost of the Product…………. 140
16.3. The calculation of Inversion Cost……….. 142
16.4. The calculation of the Selling Price of the Product……… 142
16.5. The Situation of the Company in the Next 5 years……… 143
Page
16.7. The calculation of the Period of Pay Back………. 144
16.8. The calculation of “ Net Present Value “ (NPV)………. 145
16.9. The calculation of “ Internal Rate of Return “ (IRR)……… 146
17. Production Plant Layout and the Company’s Location……… 147
17.1. Production Plant Layout………. 147
17.2. The Company’s Location………... 148
18. Waste Management and Security Policy for Workers………... 151
18.1. Waste Management……… 151
18.2. The Security Policy for Workers……… 153
19. Conclusions……….. 154
List of Figures
Figure Page
2.1 Operation of Phase10 of Shaft1………... 21
2.2 Operation of Phase20 Step1 of Shaft1……….... 22
2.3 Operation of Phase20 Step2 of Shaft1……… 24
2.4 Operation of Phase30 Step1 of Shaft1……… 25
2.5 Operation of Phase30 Step2 of Shaft1……… 26
2.6 Operation of Phase40 Step1 of Shaft1……… 26
2.7 Operation of Phase40 Step2 of Shaft1……… 27
2.8 Operation of Phase40 Step3 of Shaft1……… 28
2.9 Operation of Phase40 Step4 of Shaft1……… 29
2.10 Operation of Phase40 Step5 of Shaft1……… 29
2.11 Operation of Phase50 Step1 of Shaft1……… 30
2.12 Operation of Phase60 Step1 of Shaft1……… 33
2.13 Operation of Phase60 Step2 of Shaft1……… 34
2.14 Operation of Phase60 Step3 of Shaft1……… 35
2.15 Operation of Phase70 of Shaft1……….. 36
2.16 Operation of Phase90 of Shaft1……….. 36
2.17 Operation of Phase100 Step1 of Shaft1………... 37
2.18 Operation of Phase100 Step2 of Shaft1……….. 39
3.1 Operation of Phase10 of Shaft2……….. 43
3.2 Operation of Phase20 Step1 of Shaft2……… 44
3.3 Operation of Phase20 Step2 of Shaft2……… 44
3.4 Operation of Phase20 Step3 of Shaft2……… 45
3.5 Operation of Phase20 Step4 of Shaft2……… 45
3.6 Operation of Phase30 Step1 of Shaft2……… 46
3.7 Operation of Phase30 Step2 of Shaft2……… 46
3.8 Operation of Phase40 Step1 of Shaft2……… 47
3.9 Operation of Phase40 Step2 of Shaft2……… 48
3.10 Operation of Phase40 Step3 of Shaft2……… 49
3.11 Operation of Phase40 Step4 of Shaft2……… 50
3.12 Operation of Phase50 Step1 of Shaft2……… 51
3.13 Operation of Phase60 Step1 of Shaft2………. 52
3.14 Operation of Phase60 Step2 of Shaft2……… 52
3.15 Operation of Phase70 Step1 of Shaft2………. 53
3.16 Operation of Phase70 Step2 of Shaft2……… 53
3.17 Operation of Phase90 of Shaft2………... 54
3.18 Operation of Phase100 Step1 of Shaft2……….. 55
3.19 Operation of Phase100 Step2 of Shaft2……….. 55
4.1 Operation of Phase20 Step1 of Casing……… 58
4.2 Operation of Phase20 Step2 of Casing……….... 59
4.3 Operation of Phase20 Step3 of Casing……… 60
4.4 Operation of Phase20 Step4 of Casing……… 60
4.5 Operation of Phase20 Step5 of Casing……… 61
4.6 Operation of Phase30 Step1 of Casing……… 62
4.7 Drawing for tool’s movement path calculationof Phase30 Step1 of Casing………. 63
Figure Page
4.9 Operation of Phase30 Step3 of Casing……… 64
4.10 Operation of Phase40 Step1 of Casing……… 65
4.11 Operation of Phase40 Step2 of Casing……… 66
4.12 Operation of Phase40 Step3 of Casing……… 66
4.13 Operation of Phase40 Step4 of Casing……… 67
4.14 Operation of Phase40 Step5 of Casing……… 67
5.1 Operation of Phase10 of Sliding part………... 70
5.2 Operation of Phase20 Step1 of Sliding part…... 71
5.3 Operation of Phase20 Step2 of Sliding part…... 72
5.4 Operation of Phase30 Step1 of Sliding part…... 73
6.1 Operation of Phase20 Step1 of Clutch Fork………... 75
6.2 Operation of Phase20 Step2 of Clutch Fork………. 76
6.3 Operation of Phase20 Step3 of Clutch Fork………. 76
6.4 Operation of Phase30 Step1 of Clutch Fork………. 77
6.5 Operation of Phase30 Step1 of Clutch Fork………. 78
7.1 Operation of Phase10 of Pin……….. 80
7.2 Operation of Phase20 Step1 of Pin……… 81
7.3 Operation of Phase20 Step2 of Pin……… 81
7.4 Operation of Phase30 Step1 of Pin……… 82
7.5 Operation of Phase30 Step2 of Pin……… 83
7.6 Operation of Phase40 Step1 of Pin……… 84
7.7 Operation of Phase40 Step2 of Pin……… 84
8.1 Operation of Phase10 Step1 of Sealing plate 1-2………….. 86
8.2 Operation of Phase10 Step2 of Sealing plate 1-2………….. 87
8.3 Operation of Phase10 Step3 of Sealing plate 1-2………….. 87
8.4 Operation of Phase10 Step4 of Sealing plate 1-2………….. 88
8.5 Operation of Phase20 Step1 of Sealing plate 1-2………….. 89
8.6 Operation of Phase20 Step2 of Sealing plate 1-2………….. 90
8.7 Operation of Phase20 Step3 of Sealing plate 1-2………….. 90
8.8 Drawing for cutting volume calculation of Phase20 Step3 of Sealing plate 1-2……… 91
8.9 Operation of Phase20 Step4 of Sealing plate 1-2………….. 91
9.1 Operation of Phase20 Step1 of Transmission Plate 2……… 94
9.2 Operation of Phase20 Step2 of Transmission Plate 2……… 95
9.3 Operation of Phase20 Step3 of Transmission Plate 2……… 95
9.4 Operation of Phase30 Step1 of Transmission Plate 2……… 96
9.5 Operation of Phase30 Step2 of Transmission Plate 2……… 97
9.6 Operation of Phase30 Step3 of Transmission Plate 2……… 97
9.7 Operation of Phase40 Step1 of Transmission Plate 2……… 98
9.8 Operation of Phase50 Step1 of Transmission Plate 2……… 99
9.9 The cutting surface of part in Broaching Process………….. 101
10.1 Operation of Phase10 of Washer2………. 104
10.2 Operation of Phase20 Step1 of Washer2………... 105
10.3 Operation of Phase20 Step2 of Washer2………... 105
10.4 Operation of Phase20 Step3 of Washer2………... 106
10.5 Operation of Phase20 Step4 of Washer2………... 106
10.6 Operation of Phase20 Step5 of Washer2………... 107
Figure Page
11.2 Operation of Phase20 Step2 of Gear1………... 110
11.3 Operation of Phase20 Step3 of Gear1………... 110
11.4 Operation of Phase30 Step1 of Gear1………... 111
11.5 Operation of Phase30 Step2 of Gear1………... 112
11.6 Operation of Phase40 Step1 of Gear1………... 113
12.1 Operation of Phase20 Step1 of Gear2………... 117
12.2 Operation of Phase20 Step2 of Gear2………... 118
12.3 Operation of Phase20 Step3 of Gear2………... 118
12.4 Operation of Phase30 Step1 of Gear2………... 119
12.5 Operation of Phase30 Step2 of Gear2………... 120
12.6 Operation of Phase40 Step1 of Gear2………... 121
13.1 CNC Lathe Machine Model: SL-10HE………. 124
13.2 CNC Milling Machine Model: CNC Supra Vertical Knee-Type………. 126
13.3 8” CNC Rotary Table……… 127
13.4 Manual Grinding Machine Model: PMT/300/125………… 128
13.5 Broaching Machine Model: Slotting CNC-200S…………. 130
13.6 Hobbing Machine Model: LC-200………... 131
13.7 Manual Disc Saw Machine Model: YY-131-004…………. 132
13.8 Manual Sensitive Press Machine Model: 10 T………. 133
16.1 Diagram of the Period of Pay Back……….. 145
17.1 Plant Layout……….. 148
17.2 Map of Spain………. 149
17.3 Map of Barcelona………. 149
17.4 El Prat de Llobregat Industrial Area, Barcelona…………... 150
List of Tables
Table Page
1.1 Number of company in Spain………... 17
1.2 Number of Company in 4 European Country, year 2004……. 19
1.3 Total expected production from year 2008-2012………. 20
2.1 Calculation data of Phase10 of Shaft1... 21
2.2 Class of surface rugosity………... 23
2.3 Calculation data of Phase20 of Shaft1……….. 25
2.4 Calculation data of Phase30 of Shaft1……….. 26
2.5 Calculation data of Phase40 of Shaft1……….. 30
2.6 Tool size data for gear shape tool………. 32
2.7 Number of tool data for gear shape tool………... 32
2.8 Cutting speed and advance of teeth for different materials….. 33
2.9 Calculation data of Phase50 of Shaft1……….. 33
2.10 Data of external groove at section A-A of Shaft1………. 34
2.11 Calculation data of Phase60 of Shaft1……….. 35
2.12 Cutting speed (Vc) for grinding process………... 37
2.13 Calculation data of Phase100 of Shaft1……… 39
2.14 Cycle Time for Shaft1………... 41
2.15 Proper Cutting Speed……… 42
3.1 Calculation data of Phase10 of Shaft2……….. 43
3.2 Calculation data of Phase20 of Shaft2……….. 46
3.3 Calculation data of Phase30 of Shaft2……….. 47
3.4 Calculation data of Phase40 of Shaft2……….. 50
3.5 Calculation data of Phase50 of Shaft2……….. 51
3.6 Calculation data of Phase60 of Shaft2……….. 53
3.7 Calculation data of Phase100 of Shaft2……… 56
3.8 Cycle Time for Shaft2……….. 56
4.1 Calculation data of Phase20 of Casing………. 62
4.2 Calculation data of Phase30 of Casing………. 64
4.3 Calculation data of Phase40 of Casing………. 68
4.4 Cycle Time for Casing……….. 69
5.1 Calculation Data of Phase10 of Sliding part... 70
5.2 Calculation Data of Phase20 of Sliding part... 73
5.3 Calculation Data of Phase30 of Sliding part... 74
5.4 Cycle Time for Sliding part... 74
6.1 Calculation data of Phase20 of Clutch Fork………. 77
6.2 Calculation data of Phase30 of Clutch Fork………. 78
6.3 Calculation data of Phase40 of Clutch Fork………. 79
6.4 Cycle Time for Clutch Fork………. 79
7.1 Calculation data of Phase10 of Pin………... 80
7.2 Calculation data of Phase20 of Pin………... 82
7.3 Calculation data of Phase30 of Pin………... 83
7.4 Calculation data of Phase40 of Pin………... 84
7.5 Cycle Time for Pin……… 85
8.1 Calculation data of Phase10 of Sealing plate1-2……….. 88
8.2 Calculation data of Phase20 of Sealing plate1-2……….. 92
Table Page
9.1 Calculation data of Phase20 of Transmission Plate2………… 96
9.2 Calculation data of Phase30 of Transmission Plate2………… 98
9.3 Calculation data of Phase40 of Transmission Plate2………… 99
9.4 Calculation data of Phase50 of Transmission Plate2………… 102
9.5 Cycle time for Transmission Plate2……….. 103
10.1 Calculation data of Phase10 of Washer2……….. 104
10.2 Calculation data of Phase20 of Washer2……….. 107
10.3 Cycle time for Washer2……… 108
11.1 Calculation data of Phase20 of Gear1……….. 111
11.2 Calculation data of Phase30 of Gear1……….. 112
11.3 Calculation data of Phase40 of Gear1……….. 113
11.4 Data for external gear of Gear1……… 114
11.5 Calculation data of Phase50 of Gear1……….. 115
11.6 Cycle time for Gear1……… 116
12.1 Calculation data of Phase20………. 119
12.2 Calculation data of Phase30………. 120
12.3 Calculation data of Phase40………. 121
12.4 Data for external gear of Gear1………... 122
12.5 Calculation data of Phase50………. 122
12.6 Cycle time for Gear2………... 123
13.1 The Maximum machine power and rotation speed of turning operation……….. 124
13.2 The Maximum machine power and rotation speed of milling operation……….. 125
13.3 The Maximum machine power and rotation speed of grinding operation……… 128
13.4 The Maximum machine power of broaching operation…….. 129
13.5 The Maximum machine power of gear machining operation 130
13.6 The Maximum machine power of saw operation…………... 132
14.1 The amount of Machines………. 134
15.1 The amount of workers ( Operator of Machine )…………... 136
15.2 The amount of workers and salary rate for all positions……. 136
16.1 The Amortization Cost……… 137
16.2 Show the details of investment cost of each machines and its amount……… 138
16.3 Total Electric Power Cost per Year……… 138
16.4 The Constants to be used in equation54………. 139
16.5 Total Salary Cost per year……….. 139
16.6 Total General Cost……….. 139
16.7 Hour Cost……… 140
16.8 Steel Price……… 141
16.9 Raw Material Cost for each part………. 141
16.10 The Price of the Cost of the Product………... 142
16.11 Inversion Cost for the first 3 months……….. 142
16.12 The Selling Price of the Product………. 143
16.13 The Situation of the Company in the Next 5 years…………. 143
16.14 Cash Flow……… 144
Table Page 16.16 The results of the calculation of NPV……… 145 16.17 The calculation of IRR……… 146 17.1 The estimation of the required area for production plant…... 147 18.1 The list of the waste management company in Spain and
Abstract
The concept of the project is to setup the manufacturing process and the economic study as well as the production plant layout and waste management of the gear box for industrial vehicle. The gear box contains 21 main parts and 11 parts will be explained in this project, including: Shaft1, Shaft2, Casing, Sliding part, Clutch fork, Pin, Sealing plate1-2, Transmission Plate2, Washer2, Gear1 and Gear2.
Firstly we have to do the marketing study in order to estimate the amount of the production we expect to sell in the first and the following years. The marketing study is done by analyzing the data from Spain and European database in industrial section together with the assumption based on reality. The results from this part are the expected production per year which can let us make the decision for the machine type and it will be used in economic study as well.
Then the proper manufacturing process and specific tool’s type for each part will be decided and written on the Phase Document and the Summary of the Operation. These 2 documents are in the form that suitable to be used in reality effectively. Not only the manufacturing procedure, we also indicate the proper cutting condition and the calculations of cycle time, cutting force, machine power and the quality verification for each part. The data obtained by the calculation will be used to choose the specific model of machines, the amounts of machines and workers required to achieve the expected production.
After we have the clear image of the production line, we shall advance to the economic study. The economic study is a good and reliable tool to indicate the profitability of the business. Every possible cost of the company will be taken into account and be presented as “ Hour Cost “. As well as the economic indicators such as Cash Flow, Period of Pay back, Net Present Value ( NPV ) and Internal Rate of Return ( IRR ) will be presented to be sure that the investment of this business will be profitable.
The final tasks are the production plant layout and the waste management. The production plant layout will be designed sketchily as well as the specific suitable location. The waste management is the explanation the way to deal with the chips and chemical waste to be responsible for the social and environment.
Introduction of the Project
The Manufacturing Process in general is not a very complicate task but it’s difficult to define the best solution for one process. There are many alternative methods to achieve the same result, but each one has dissimilarity itself and the toughness is to indicate the best solution. The good decision will be depended on both theory and experience and this decision will effect to the profit of the company in long-term.
The aim of this project is to define the setting-up the manufacturing process and do the economic study of the gear box for industrial vehicle. Imagine that the we want to manufacture the gear box which is already designed. It’s always strongly necessary to study it before investing the production plant in order to know the profitability of the business.
All the necessary data are prepared in this project and the remainder of this document is organized as follows:
Chapter1: The Marketing Study to estimate the productions expected to produce. Chapter2 to Chapter12: Manufacturing Process and the Calculation of Shaft 1, Shaft2 , Casing, Sliding part, Clutch Fork, Pin, Sealing plate 1-2, Transmission Plate 2, Washer 2, Gear1, Gear2.
Chapter13: Choosing the proper specific model of each machine from the
manufacturer’s catalog as well as its price to be used in the economic study .
Chapter14: Calculation of the Machines Amount Required to achieve the expected production quantities.
Chapter15: Calculation of the Workers Amount Required both direct and indirect workers to achieve the expected production quantities.
Chapter16: Economic Study to indicate the profitability of the investment. Chapter17: Production Plant Layout and the Company’s Location.
Chapter18: Waste Management policy to show the responsibility for the Social and Environment.
Objectives of the Project
The main idea of this project is to be a tool for making the right decision to invest in manufacturing of the gear box for industrial vehicle as well as to prepare the manufacturing process for each part to be able to use in reality. At the end of the project, we expect to have the entire of important task to set-up the manufacturing process and the key point to indicate the profitable of this business. The objectives of the project are defined as follows:
- To define the operations as well as the quality verifications that are necessary to manufacture a number of gear boxes per year according to the marketing study.
- To prepare the Documents: Phase of Manufacturing Cycle which will be composed of the clearly process explanation, drawings for each step with the verification points, raw material details, specific tool’s type and measuring tool.
- To prepare the Documents: Summary of Operations which will be composed of the brief process explanation of every phase for each part.
- To select the specific type of machines according to the data from calculation part.
- To calculate the number of machines and direct workers according to the cycle time obtained in the calculation part.
- To carry out the economic study of the project to indicate the its profitability by obtaining these indicators: Hour Cost, Price of the cost of the product, Inversion Cost, Selling Price of the product, Cash Flow, Period of Payback, NPV and IRR.
- To propose the production plant layout and the location for the company. - To propose the waste management and the security policy
After getting all the above information, the investor will be confident enough to progress this business effectively as well as the risk of ruin.
Gear Box Overview
Gear Box is the Transmissions provide a speed-power conversion known as gear reduction (in speed) to a higher torque (rotational force) using gear sets. In motor vehicles, the transmission provides different speed-power ratios known as "gears" or "speeds", some of which may be in the reverse direction. Tractors and large trucks especially may have a dozen or more forward "gears" which vary from a crawling speed at high torque to high speed at low torque where the only torque needed with a load coasting along at a given speed are that small additional energy (force) needed to overcome ongoing friction and other road losses such as climbing a grade. When the torque needed to surmount a grade is insufficient at a higher rotational speed, the gearbox is shifted into a lower gear to provide more power, as was needed when initially accelerating said vehicle to the desired road speed. Gearing has much in common with the mechanic and mechanical factors present in pulley systems. One trades distance (numbers of rotations) for increased force.
Early transmissions included the right-angle drives and other gearing in windmills, horse-powered devices, and steam engines, in support of pumping, milling, and hoisting. Most modern gearboxes either reduce an unsuitable high speed and low torque of the prime mover output shaft to a more usable lower speed with higher torque, or do the opposite and provide a mechanical advantage (i.e increase in torque) to allow higher forces to be generated. Some of the simplest gearboxes merely change the physical direction in which power is transmitted. Many typical automobile transmissions include the ability to select one of several different gear ratios. In this case, most of the gear ratios (simply called "gears") are used to slow down the output speed of the engine and increase torque. However, the highest gears may be "overdrive" types that increase the output speed.
Gear boxes have found use in a wide variety of different often stationary applications. Transmissions are also used in agricultural, industrial, construction, mining and vehicle equipment. In addition to ordinary transmission equipped with gears, such equipment makes extensive use of the hydrostatic drive and electrical adjustable speed drives.
The simplest transmissions, often called gear boxes to reflect their simplicity (although complex systems are also called gear boxes in the vernacular), provide gear reduction (or, more rarely, an increase in speed), sometimes in conjunction with a right-angle change in direction of the shaft (typically in helicopters). These are often used on PTO-powered agricultural equipment, since the axial PTO shaft is at odds with the usual need for the driven shaft, which is either vertical (as with rotary mowers), or horizontally extending from one side of the implement to another (as with manure spreaders, flails mowers, and forage wagons). More complex equipment, such as silage choppers and snow blowers, have drives with outputs in more than one direction. Regardless of where they are used, these simple transmissions all share an important feature: the gear ratio can not be changed during use. It is fixed at the time the transmission is constructed.
1. Marketing Study for “ Gear Box of Industrial Vehicle “ in Spain
1.1. Introduction :
We are studying to setup the manufacturing process to fabricate the Gear Box for Industrial Vehicle. The Gear Box contains of 21 main mechanical parts which required the different process to fabricate and of course different machines. At the beginning phase of the project, it’s necessary to decide the way of fabrication, in this case means the type of machine we will employ.
There are 2 main machine types, CNC and Manual Machine. The CNC type has better capacity and precision but higher investment cost. In the other hand, the Manual type requires lower budget but lower capacity and the precisions are depended on the man skill which can be vary a lot.
In order to make a decision for machine type, we will point out to the marketing point of view. We will estimate the selling amount of our company by analyzing the numbers of Industrial Vehicles in the target area. In the first year, our target area is mainly in Spain and for the following 5 years we will expand to Europe. This analysis will be shown in the following part of this study.
1.2. Objective :
To estimate the expected production per year in order to make a decision for the main category before designing the fabrication line and its operation, including : Type and number of machine.
1.3. Estimation Method :
Because of our product is Gear Box which mainly use for industrial vehicle. In order to estimate the amount of productions per year, we have to point out to two ways, the quantity of industrial vehicles existed in the industrial company and the total selling amount of new industrial vehicle per year.
In reality, it’s very difficult to know the exact number of existed industrial vehicle in Spain or in Europe. We propose the estimation by knowing the amount of industrial company in Spain and Europe which are the possible data to be obtained. With the number of company, we add the assumptions base on reality and norm of each area to get finally the estimation amounts of industrial vehicles existed in Spain and Europe. We can also estimate the total selling amount of new industrial vehicle per year by utilizing the amounts of industrial vehicles existed. Finally, with these two data, we can proceed this study in the following part
1.4. Assumptions : In Spain:
- The company with under 20 employees has 1 Industrial Vehicle. - The company with 20 or more employees has 3 Industrial Vehicles.
- The selling amount of New Industrial Vehicle is equal to 30% of the total amounts of Industrial Vehicle existed in Spain.
- 10% of the total amounts of Industrial Vehicle existed in Spain have to change the new gear box every year.
- Market share of our company in Gear Box for Industrial Vehicle in Spain is 10%
In France, UK, German and Switzerland:
- Each company in France, UK, German and Switzerland (with 20 or more employees ) has 3 Industrial Vehicle.
- The selling amount of New Industrial Vehicle is equal to 30% of the total amounts of Industrial Vehicle existed in France, UK, German and Switzerland.
- 10% of the total amounts of Industrial Vehicle existed in France, UK, German and Switzerland have to change the new gear box every year.
- Market share of our company in Gear Box for Industrial Vehicle in Spain is 5%
1.5. Estimation For Year 2008, main targets are in Spain
Data :
Number of company in Spain Year with under 20 employees with 20 or more employees 2001 124047 23076 2002 120104 23424 2003 119728 22941 2004 120806 22375 2005 119218 22869
Table1.1: Number of company in Spain [15]
Variables:
- Ntot = Number of Industrial Vehicles existed in Spain (unit)
- Nsell = The selling amount of New Industrial Vehicle in Spain (unit)
- Mgear = The amounts of Industrial Gear Box be sold in the Spanish Market (unit/year)
Calculation :
In this calculation, we use the data in year 2005.
We begin with the calculation of the number of Industrial Vehicles existed in Spain (Ntot). According to table1, the number of company in Spain with under 20 employees are 119218 companies and the number of company in Spain with 20 or more employees are 22869 companies. From the previous assumption, we can calculate The number of Industrial Vehicles existed in Spain (Ntot) by the following equation,
Ntot = (119218 * 1) + (22869 * 3) = 187825 units
With the number of Industrial Vehicles existed in Spain (Ntot), we can calculate the estimation of selling amount of New Industrial Vehicle (Nsell) by the following equation,
Nsell = Ntot * 0.3 = 187825 * 0.3 = 56347.5 units
Now we already got the two important parameters Ntot and Nsell to calculate the amounts of Industrial Gear Box be sold in the Spanish Market per year (Mgear) by the following relation,
Mgear = ( 10% * Ntot ) + ( Nsell ) = ( 0.1 * 187825 ) + ( 56347.5 ) Mgear = 75130 units/year
Finally, we can estimate the expected production of our company for the year
2008 (only in Spain) by considering that our market share is 10%, the calculation is
shown below,
Pexpect = 10% * Mgear = 0.1 * 75130 = 7513 units/year
1.6. Estimation For Year 2009 - 2012, main targets are expanded to Europe
As we have calculated in the previous part, in the first selling year ( year 2008 ), we only point to the market in Spain. In the following years (year 2009, 2010, 2011, 2012) , we consider to open European market in order to increase the sell volume of our company.
At the beginning, we will consider the market in the European country which is big enough to get its market share, including France, United Kingdom, German, Switzerland. Their data are shown in the following table.
Country Enterprise France 20414 German 37680 United Kingdom 79664 Swizerland 37129 Total 174887
Table1.2: Number of Company in 4 European Country, year 2004 [16]
* Scope of coverage: Taking to account only the enterprises with 20 or more employees
Variables:
- N’tot = Number of Industrial Vehicles existed in France, UK, German and Switzerland (unit)
- N’sell = The selling amount of New Industrial Vehicle in France, UK, German and Switzerland (unit)
- M’gear = The amounts of Industrial Gear Box be sold in the Market of France, UK, German and Switzerland (unit/year)
- P’expect = The expected production (unit/year)
Calculation:
In this calculation, we use the data of France, UK, German and Switzerland in year 2004.
We begin with the calculation of the number of Industrial Vehicles existed in France, UK, German and Switzerland (N’tot). According to table2, the total number of company in the 4 European country is 174887 companies. From the previous assumption, we can calculate The number of Industrial Vehicles existed (N’tot) by the following equation,
N’tot = 174887 * 3 = 524661 units
With the number of Industrial Vehicles existed in France, UK, German and Switzerland (N’tot), we can calculate the estimation of selling amount of New Industrial Vehicle (N’sell) by the following equation,
N’sell = N’tot * 0.3 = 524661 * 0.3 = 157398.3 units
Now we already got the two important parameters N’tot and N’sell to calculate the amounts of Industrial Gear Box be sold in the Market of France, UK, German and Switzerland (M’gear) by the following relation,
M’gear = ( 10% * N’tot ) + ( N’sell ) = ( 0.1 * 524661 ) + ( 157398.3 ) M’gear = 209864 units/year
Finally, we can estimate the expected production of our company for the year
2009 - 2012 ( in France, UK, German and Switzerland ) by considering that our
market share is 5%, the calculation is shown below,
P’expect = 5% * M’gear = 0.05 * 209864 = 10493 units/year
We expect that the selling amount for France, UK, German and Switzerland will increase 25% of P’expect every year continuously. So The selling amount from year 2009 – 2012 are :
For year 2009 = 0.25 * P’expect = 0.25 * 10493 = 2623.25 units/year
For year 2009 = 0.50 * P’expect = 0.50 * 10493 = 5246.5 units/year For year 2009 = 0.75 * P’expect = 0.75 * 10493 = 7869.75 units/year
For year 2009 = 1 * P’expect = 1 * 10493 = 10493 units/year
The total expected production are shown in the following table :
Year In Spain (units/year) In Europe (units/year) Total (units/year) 2008 7513 0 7513 2009 7513 2623.25 10136.25 2010 7513 5246.5 12759.5 2011 7513 7869.75 15382.75 2012 7513 10493 18006
Table1.3: Total expected production from year 2008-2012
1.7. Conclusion :
As we can see in Table3, the expected productions are not too large in year 2008 and it could be possible to employ Manual Machine. However if we observe the following year, the amount of expected productions are increasing year by year. In this case, it seems to be unsuitable to employ Manual Machine due to its low capacity and flexibility. Due to this reason, it would be better to choose CNC Machine for the main process and Manual Machine for the support function.
2. Manufacturing Process of “ Shaft 1 “
2.1. The raw material:
In order to machine this part, we use cylindrical bar steel 16 Mn Cr 5 with diameter 73 mm because we have to add 1.5 mm. to the final shape ( Maximum diameter of part is 70 mm.) in radial direction to be machined in Finishing Operation.
2.2. Phase 10:
The cylindrical bars usually come with the long length shape. To be suitable for the Lathe Machine, the bars have to be cut by Manual Disc Saw Machine. The total distance of the final shape is 172.75 mm., we have to add 1.5 mm. for the both end of bar to be machine in Finishing Operation. So we have to cut the bar to have the length 175.75 mm. with the tolerance +1, -0 mm.
The calculation can be done by the same method as milling machine in the following step. In this case we consider that the diameter of disc (d) is 210 mm. with the thickness (b) 2 mm. The number of teeth (zt) is 60 and the advance of teeth (az) is 0.015 mm. We use the cutting speed (Vc) 40 m/min and the mechanical efficiency (η) is 0.75. We use the maximum width of part to calculate the maximum power, so the cutting width (p) is 73 mm. and the cutting length (L) is also 73 mm. The results of the calculations are shown in table2.1.
Figure2.1: Operation of Phase10
Tool Data
Step d(mm) az(mm.) Zt(teeth) n(rpm) av(mm/turn) Vam(mm/min)
1 210 0.015 60 60.63 0.9 54.567
p(mm) b(mm) Fc(N) Pc(kW) Pm(kW) L(mm) tc(min)
73 2 262800 0.239 0.319 73 1.338
Table2.1: Calculation data of Phase10
2.3. Phase 20:
This process employ CNC Lathe Machine by fix the part with fixing plate with hard jaws. The part will be fixed at one end and will be machined at another end.
Step1:
We start machining the part by taking out front surface. In this operation, we employ Stellram cutting tool SNMG120408E-3G with the holder MSKNR/L-124B [2]. The tool insert SNMG120408E-3G is square shape which is suitable for machining front surface and rough machining. The tool is Right hand tool because we fix the part with Lathe Machine on the left.
Figure2.2: Operation of Phase20 Step1
Calculation of Step1:
In this operation, we fix cutting speed Vc = 150 m/min which is the proper value for the material of tool and part. We employ CNC Lathe, so the tangential speed at the surface of part is always fixed at 150 m/min. The rotation speed will be vary due to the changing of diameter, but in this calculation we use the average diameter of this step to calculate the rotation speed by the formula below[1].
n = ( 1000 * Vc ) / ( π * d) (1)
Where: n = Average rotation speed of machine (rpm) Vc = Cutting speed (m/min)
d = Average diameter of the process (mm.)
The advance of the tool can be calculate by knowing tool radius and the average roughness of the machined surface. With the tool information, we know that the edge radius of tool rp = 0.031 mm. and the average roughness of this process is Ra = 1.6 μm (see table1.1). The advance velocity a (mm/turn) is calculated by the formula below [1].
a = sqrt{(Ra * rp)/25} (2)
Where: a = Advance velocity of tool (mm/turn) Ra = Average roughness of the surface (μm) rp = Radius of the edge of tool (mm.)
Class of rugosity Ra (μm) N12 50 N11 25 N10 12.5 N9 6.3 N8 3.2 N7 1.6 N6 0.8 N5 0.4 N4 0.2 N3 0.1 N2 0.05 N1 0.025 Table2.2: Class of surface rugosity [1]
The cutting force required for this process (Fc) is needed to be calculated in order to calculate the machine power in the following step. By knowing that the cutting depth of this step (p) is equal to 1.5 mm and the value of σt and k from table1.2, we can obtain Fc by utilizing the following formula [1].
Fc = k * σt * S (3)
Where: k = constant depending on the type of material k = 3 for elastic material
k = 5 for less or non elastic material (ex. Casting ) σt = Resistant of traction stress of material (N/mm2
)
S = Cutting surface perpendicular to the cutting velocity (mm2) S = a * p ; a = advance velocity (mm/turn)
p = Cutting depth (mm.)
The cutting power (Pc) and the machine power (Pm) will be calculated in order to choose the proper machine. The formulas are shown below[1].
Pc = (Fc * Vc)/60000 (4) Pm = Pc/η (5) Where: Pc = Cutting power required to cut material (kW)
Pm = Machine power (kW)
η = Efficiency of lathe machine = 0.7 – 0.8
We also have to calculate the cutting time tc. In order to calculate it, we have to find the cutting length and cutting velocity. Cutting length (L) is all paths that tool have to pass and cut the material. In this step, cutting length is 36.5 mm. ( from the surface to the center of the bar). The calculation process can be done by the following formula[1].
Va = a * n (7)
Where: L = Cutting length (mm.)
Va = Cutting velocity (mm/min) a = advance velocity (mm/turn) n = rotation speed (rpm)
Step2:
This operation is to drill a hole for fixing with tail stock. The drilling tool has a special shape with angle 60 degree. In this case we use drill Garant 111050A with edge diameter 2 mm.
Figure2.3: Operation of Phase20 Step2
Calculation of Step2:
The material of drill is high speed steel, so the proper cutting speed Vc is equal to 25 * 0.8 m/min (For drill, we multiply the cutting speed of lathe or milling by 0.8). To calculate the rotation speed of tool, in this case the diameter of hole is not constant, so we use the average diameter to calculate (davg = (10 + 2)/2 = 6 mm.) The rotation speed can be calculated by the same formula as we have calculated in Step1.
The advance speed of drill depends on the diameter of drill. The formula below shows how to calculate it [1].
a = d / 100 (8)
Where: a = advance speed of drill (mm/turn) d = average diameter of drill (mm)
Generally, normal drill has 2 cutting edges. To calculate the cutting force of drilling operation, we consider only one side and finally we multiply by 2 to have to whole cutting force for drill. The formula is shown below [1].
Fc = 2 * k * σt * (a/2) * (d/2) (9)
Where: Fc = cutting force (N)
k = constant depending on the type of material k = 3 for elastic material
k = 5 for less or non elastic material (ex. Casting ) σt = Resistant of traction stress of material (N/mm2
a = advance speed of drill (mm/turn) d = average diameter of drill (mm)
The cutting power required for cutting process (Pc) is the product of cutting force Fc and the average cutting velocity (0.8 * Vc)/2. If we divide Pc by drilling efficiency (ηdrill), we will get the power required for the machine. The formulas are shown below [1].
Pc = Fc * (0.5 * 0.8 * Vc) /60000 (10) Pm Pc / ηdrill (11)
Where: Pc = cutting required to cut the material (kW) Pm = the power required for the machine ηdrill = efficiency of drill = 0.7 – 0.8
The cutting time for this process (tc) can be calculated by utilizing the equations 6 and 7.
Step rp(mm) d(mm) n (rpm) p(mm) Ra(mm) a(mm/turn) S(mm2)
1 0.031 36.5 1308 1.5 1.6 0.045 0.067
2 6 1061 0.06
Step Fc(N) Pc(kW) Pm (kW) L (mm) Va(mm/min) tc(min)
1 120 0.301 0.401 36.5 58.267 0.626
2 324 0.027 0.036 10.6 63.662 0.167
Table2.3: Calculation data of Phase20
2.4. Phase30:
This Phase is almost the same process as in Phase20. We only change the machining surface to the other end of the raw part and following the operation in Step1 and Step 2 of Phase20.
Figure2.5: Operation of Phase30 Step2
Step rp(mm) d(mm) n (rpm) p(mm) Ra(mm) a(mm/turn) S(mm2)
1 0.031 36.5 1308 1.5 1.6 0.045 0.067
2 6 1061 0.06
Step Fc(N) Pc(kW) Pm (kW) L (mm) Va(mm/min) tc(min)
1 120 0.301 0.401 36.5 58.267 0.626
2 324 0.027 0.036 10.6 63.662 0.167
Table2.4: Calculation data of Phase30
2.5. Phase40:
This process employ CNC Lathe Machine by fix the part with fixing plate with hard jaws at one end. The part will be fixed by pressing tail stock at the 2 ends. It will be driven by the jaws at one end. The advantage of this fixing system is that we can machine the profile of the part in only one phase (without changing of fixing position)
Step1:
This step is to do rough machining. We will machine the part to be similar to the final profile but adding 1.5 mm. in radius and axial direction for finishing operation. The tool we employ is Stellram cutting tool SNMG120408E-3G with the holder MSKNR/L-124B, the same tool as Phase20 Step1.
Calculation of Step1:
In order to calculate rotation speed (n), cutting force (Fc), cutting power (Pc), machine power (Pm), cutting time (tc) and advance velocity (Va), all can be calculate by the equations 1,3,4,5,6 and 7. In this step, we use the average diameter to calculate the rotation speed as we have said in the calculation of phase20 step1 but we use the cutting speed (Vc) for rough machining (see table1.2).
The advance speed for rough machining is 0.5-0.8 mm/turn [1], so it’s not necessary to define the surface roughness (Ra). The only different in this step is the way to calculate L.
This step is the rough machining by utilizing CNC Lathe machine and fix cycle. We use the cutting depth of each pass (p) 3 mm. By considering the manner of fix cycle path, we can calculate the total cutting length (L) by the equation below.
L = (5*89.75) + (1*37.75) + (5*23.5) + (2*78) + (5*33) + (1*29) = 954 mm.
Step2:
This step is to machine finishing surface. The part will have almost the same shape as the final part after this step. We use Stellram tool insert DNMG150408E-3G and tool holder MDJNR/L-124B, both right and left hand.
Figure2.7: Operation of Phase40 Step2
Calculation of Step2:
In order to calculate rotation speed (n), advance speed (a), cutting force (Fc), cutting power (Pc), machine power (Pm), cutting time (tc) and advance velocity (Va), all can be calculate by the equations 1,2,3,4,5,6 and 7. In this step, we use the average diameter to calculate the rotation speed as we have said in the calculation of phase20 step1 and we use Vc for finishing surface with carbide tool (see table1.2).
According to the drawing, the sign of rugosity class is N7 which is equal to the average roughness Ra = 1.6 μm. (see table1.1) and the edge radius of this tool (rp) is 0.031 mm. With these 2 values, we can find the advance velocity.
In this step, we leave the material 0.15 mm. in radius direction at diameter 16 h5 mm. and 25 k6 mm. because they require high precision and need to be done by Grinding process.
The cutting length in this step can be done in the similar way as rough machining. But in this process, we machine only 1 pass with cutting depth (p) 1.5 mm.
Step3:
This step is to make a round shape groove at the shaft surface. We use the grooving tool from Kyocera, the tool insert is GMM6020-30R and the tool holder is KGML2525M-6T30 [3]. In this case the length of tool insert should be longer than 14 mm. to avoid crash with the diameter 70 mm. of the part. The length of tool insert GMM6020-30R is 20 mm., so we don’t have the risk of crash.
In this process, it’s not necessary to define the average roughness (Ra). So we can choose the advance speed (a) equal to 0.1 mm., it’s the suitable value for the finishing surface [1].
Because the shape of the tool in this process is curve shape, we propose to use the average cutting depth to calculate in this process. The average cutting depth is equal to : (maximum depth + minimum depth) / 2 = (6 + 0) / 2 = 3 mm.
Figure2.8: Operation of Phase40 Step3
Calculation of Step3:
In order to calculate rotation speed (n), cutting force (Fc), cutting power (Pc), machine power (Pm), cutting time (tc) and advance velocity (Va), all can be calculate by the equations 1,3,4,5,6 and 7 and use Vc for finishing surface with carbide tool (see table1.3).
Step4:
The objective of this step is to make a groove and chamfer at the external surface of the part. In this step we use Kyocera tool, tool insert KCG2094L and tool holder KKCL 1212M-2-150F [3]. The width of tool is 2.4 mm. but the width of groove profile is 7 mm. So the tool has to work 3 times in order to have 7 mm. groove, 1st is 2.4 mm., 2nd is 2.4 mm. and 3rd is2.2 mm. After that the tool will move out with the angle 30 degree from the part o make a chamfer.
In this process, it’s not necessary to define the average roughness (Ra). So we can choose the advance speed (a) equal to 0.1 mm., it’s the suitable value for the finishing surface [1].
The cutting length of this process can be considered that the lengths for each cutting pass are equivalent. The total cutting length is the summation of the 3 vertical cutting pass and 1 inclination for chamfer. The equation below shows the calculation of total cutting length.
Figure2.9: Operation of Phase40 Step4
Calculation of Step4:
In order to calculate rotation speed (n), cutting force (Fc), cutting power (Pc), machine power (Pm), cutting time (tc) and advance velocity (Va), all can be calculate by the equations 1,3,4,5,6 and 7 and use Vc for finishing surface with carbide tool (see table1.3).
Step5:
The objective of this step is to make a groove at the external surface of the part. In this step we use Kyocera tool, tool insert TGF32R130 and tool holder KTGFRL1010K-16F [3]. The width of this tool is exactly 1.3 mm., so we need only 1 cutting pass for this step.
In this process, it’s not necessary to define the average roughness (Ra). So we can choose the advance speed (a) equal to 0.1 mm., it’s the suitable value for the finishing surface [1].
Figure2.10: Operation of Phase40 Step5
Calculation of Step5:
In order to calculate rotation speed (n), cutting force (Fc), cutting power (Pc), machine power (Pm), cutting time (tc) and advance velocity (Va), all can be calculate by the equations 1,3,4,5,6 and 7 and use Vc for finishing surface with carbide tool (see table1.2).
Step rp(mm) d(mm) n (rpm) p(mm) Ra(mm) a(mm/turn) S(mm2) 1 0.031 44.057 1084 3 0.5 1.5 2 0.031 41.143 1393 1.5 1.6 0.045 0.067 3 39 1469 3 0.1 0.3 4 40 1432 2.4 0.1 0.24 5 24.6 2329 1.3 0.1 0.13
Step Fc(N) Pc(kW) Pm (kW) L (mm) Va(mm/min) tc(min)
1 2700 6.75 9 954 541.87 1.761
2 120 0.361 0.481 222.3 62.03 3.583
3 540 1.62 2.16 3 146.912 0.02
4 432 1.296 1.728 9.695 143.239 0.068
5 234 0.702 0.936 0.7 232.91 0.003
Table2.5: Calculation data of Phase40
2.6. Phase50:
This phase we move the part to CNC Milling Machine. The part will be fixed by the Index Plate with soft jaws which is suitable for cylindrical part and it’s possible to rotate the part.
Step1:
This step is to make external grooves of section C-C. The grooves have gear shape which need a special tool to machine. The tool we use in this process should has the shape according to DIN 5480.
Figure2.11: Operation of Phase50 Step1
Calculation of Step1:
We have to start the calculation by finding the gear module of the part. The module (m) will be necessary for the next step. It can be calculated by the following formula [1].
Where: m = gear module
dp = pitch diameter (mm.) zp = number of teeth
The next step is to choose the number of teeth of milling tool from catalog (see table1.7). For ex. We choose tool with 22 teeth, we get number of tool (Nm) equal to 4.Then we shall find the tool size by the following equation [1].
Size = m / Nm (13)
Where: Size = tool size (see table1.6) m = gear module
Nm = Number of tool
With the Size obtained from equation13, we can get the external diameter of tool from table1.6. This external diameter let us be able to calculate the rotation speed of tool. The formula is shown below [1]. The cutting Vc is chosen from table1.2.
n = (1000 * Vc) / (pi * d) (14)
Where: n = rotation speed tool Vc = Cutting speed
d = external diameter of tool
The next step is to calculate the advance speed (av) of milling tool. The formula is shown below [1].
av = az * z (15) or Vam = az * z * n (16)
Where: av = advance speed of tool (mm/turn) z = number of teeth (teeth/turn)
az = the distance between tool’s teeth (mm/tooth), choose from table1.8 Vam = advance speed of tool in mm/min
n = rotation speed tool
The cutting force required for this process (Fc) is needed to be calculated in order to calculate the machine power in the following step. We choose cutting depth of each pass p = 2 mm. and the width of tool b = (3.65+1.5)/2 = 2.575 mm. (the avg of tool profile), the value of σt and k are from table1.2, we can obtain Fc by utilizing the following formula [1].
Fc = k * σt * p * b (17)
Where: k = constant depending on the type of material k = 3 for elastic material
k = 5 for less or non elastic material (ex. Casting ) σt = Resistant of traction stress of material (N/mm2
p = cutting depth of each pass (mm)
b = average width of the cutting profile (mm)
The cutting power (Pc) and the machine power (Pm) will be calculated in order to choose the proper machine. The formulas are shown below[1].
Pc = (Fc * Vam) / 60000000 (18) Pm = Pc / ηmill (19)
Where: Pc = Cutting power required to cut material (kW) Pm = Machine power (kW)
η = Efficiency of milling machine = 0.6 – 0.75
We also have to calculate the cutting time tc. In order to calculate it, we have to find the cutting length and cutting velocity. Cutting length (L) is all paths that tool have to pass and cut the material. In this step, cutting length 0f each pass is 32 mm. and the tool will repeat 28 passes. So, the total cutting length is equal to 32 * 28 = 896 mm. The calculation process can be done by the following formula[1].
tc = L / Vam (20) Where: tc = cutting time (min)
L = total cutting length (mm)
Vam = advance speed of tool in mm/min
Tool Size 0.5 0.75 1 1.25 1.5 1.75 2 2.25 2.5 2.75 3 3.25 3.5 3.75 4 4.25 4.5 4.75 OD (mm.) 40 40 50 50 63 63 63 63 63 80 40 40 50 50 63 63 63 63 ID (mm.) 16 16 16 16 22 22 22 22 22 27 16 16 16 16 22 22 22 22
Table2.6: Tool size data for gear shape tool [4]
Number of tool 1 2 3 4 5 6 7 8
Number of
teeth 12 to 13 14 to 16 17 to 20 21 to 25 26 to 34 35 to 54 55 - 134
more than 135 Table2.7: Number of tool data for gear shape tool [4]
Material
Cutting Speed (m/min)
Advance of teeth, az (mm)
Soft Cast Iron 200B 20 to 25 0.005 - 0.015 Hard Cast Iron 200B 9 to 12 0.005 - 0.01
Ductile Cast Iron 20 to 25 0.005 - 0.01 Steel 50 N/mm^2 25 to 50 0.005 - 0.025 Steel 600-700 N/mm^2 15 to 25 0.005 - 0.015 Steel 700-1100 N/mm^2 10 to 18 0.005 - 0.010 Stainless Steel 8 to 12 0.015 - 0.025
Soft Brass 30 to 45 0.005 - 0.03
Hard Brass and Bronze 15 to 22 0.005 - 0.01 Table2.8: Cutting speed and advance of teeth for different materials [4]
Tool Data
Step Zp Dp m Nm Size d(mm) az(mm.) Zt(teeth) n(rpm) av(mm/turn) Vam(mm/min)
1 28 58 2.07 4 0.52 40 0.015 25 1194 0.375 447.623
p(mm) b(mm) Fc(N) Pc(kW) Pm(kW) V(mm3/min) L(mm) tc(min)
2 2.575 9270 0.069 0.099 2305.26 896 2.002
Table2.9: Calculation data of Phase50
2.7. Phase60:
We still use the CNC milling Machine in this phase and the part will be fixed by the Index Plate with soft jaws.
Step1:
The purpose of this process is to drill 3 holes with 5 mm. diameter and deep 10 mm at section A-A. The 3 holes should be 120 degree between each other. We choose the drill Garant drill 113260 diameter 5 mm. [4] which is suitable for this material. This step is to prepare the hole for the next step which will be done by Mandrel Drill in order to have diameter 8 H7 mm. Because normal drill can make only a hole with the precision IT 9-10 but Mandrel Drill can reach IT 8-9.
Calculation of Step1:
The calculation of this step can be done by follow the method and formula in Phase20 Step2. We use the diameter 5 mm. and the depth 30 mm. The total cutting length is the summation of the depth of the 3 holes.
Step2:
In this step, we will increase the hole diameter to 8 H7 mm. by utilizing Mandrel Drill. We choose the drilling tool Garant Mandrel Drill 163500 diameter 8 mm.[4]. The process is similar to the previous step.
Figure2.13: Operation of Phase60 Step2
Calculation of Step2;
The calculation of this step can be done by follow the method and formula in Phase20 Step2. We use the diameter 8 mm. and the depth 30 mm. The total cutting length is the summation of the depth of the 3 holes
Step3:
This step is to make external grooves of section A-A. The grooves have gear shape which need a special tool to machine. The tool we use in this process should has the shape according to the data in table1.10.
Figure2.14: Operation of Phase60 Step3
Calculation of Step3:
Every calculation of this step is similar to Phase50 Step1. We can use the formula 12,13,14,15,16,17,18,19 and 20 to calculate it with the data in table1.6, 1.7, 1.8.
In this case, we choose the number of tool’s teeth (z) equal to 25 and the average width of tool’s profile (b) is (5.84 + 4.38) / 2 = 5.11 mm.
Tool Data
Step Zp Dp m Nm Size d(mm) az(mm.) Zt(teeth) n(rpm) av(mm/turn) Vam(mm/min)
1 5 1273 0.05 63.662
2 8 795.8 0.08 63.662
3 12 41.2 3.43 4 0.86 40 0.015 25 1194 0.375 447.623
Step p(mm) b(mm) Fc(N) Pc(kW) Pm(kW) V(mm3/min) L(mm) tc(min)
1 225 0.038 0.054 30 0.471
2 576 0.046 0.066 30 0.471
3 2 5.11 18396 0.137 0.196 4574.71 306 0.684
Table2.11: Calculation data of Phase60
2.8. Phase70:
This phase is the manual operation to protect the small slot groove from carburizing operation. We shall paint the slot by anti-carburizing paint because the width and the depth of the slot are quite small, their distances can be changed if we let them pass the carburizing process.
Figure2.15: Operation of Phase70
2.9. Phase80:
We will do the Heat Treatment for this part by Carburizing Process. We will heat the part to 900 – 930 C in the carburizing oven which has more concentration of carbon than in the part. The time required for Carburizing Process is 720 min/lot ( 1 lot contains 20 parts). Then we have to do Quenching process which required 180 min/lot and finally Tempering process which required 30 min/lot. The total time required for this phase is 930 min/lot or 46.5 min/part ( This operation will be done by the external company ).
2.10. Phase90:
The part after heat treatment process could be bent and need to be straightened. This operation will solve this problem by straightening the part with sensitive press machine.
Figure2.16: Operation of Phase90 2.11. Phase100:
We shall move the part to the Manual Grinding Machine which is the last operation. The part will be fixed with axial fix at the ends of shaft by Driving Point with soft jaws.
