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Progress in Minimum Quantity Lubrication
Prof. YUAN Songmei Tel:86-10-82339630
Mobile:86-13681038158 Email:yuansm@buaa.edu.cn
Beihang University School of Mechanical Engineering & Automation
2014.10.23
A central location– Main campus located in Zhong
Guan Cun Science and Tech Park,
Haidian District in Beijing
– At the heart of higher learning and
science and technology
development
New Campus: 100 hectares, inShahe, Changping District
BEIHANG UNIVERSITY – QUICK FACTS
History
– Founded in 1952
Beijing Institute of Aeronautics (BIA)
- First aerospace university in China
- One of the first 16 key universities in China
– 1988
Beijing University of Aeronautics
and Astronautics (BUAA)
– 2002
Beihang University (BUAA)
BEIHANG UNIVERSITY – QUICK FACTS
27 Schools
Enrollment: 27,811
- Undergraduate Students: 14,428
- Master Students: 8,700
- Ph.D Students: 4,015
- International Students: 1,242
2,102 Faculty Members
- Full Professors: 514
- Associate Professors: 805
Over 150,000 Alumni
BEIHANG UNIVERSITY – QUICK FACTS
Full Prof., 37
Asso. Prof., 55
Assis. Prof., 57
PDRF +Technician
46
Faculty and Staff Members
Faculty: 149 Staff: 46
Introduction of SMEA(School of Mechanical Engineering and Automation)
Students
Enrolled Students: about 2000 (2013)
Most of our undergraduate students occupied the top 0.3% in National Higher Education Entrance Examination.
827
754
352
98
0
100
200
300
400
500
600
700
800
900
Undergraduate Master Ph.D. International students
Departments
Robotics Institute
Department of Industrial and Manufacturing
Systems Engineering
Dept. of Industrial Design
Dept. of Mechanical Design & Automation
Dept.of Mechatronics Engineering &
Automation
Dept. of Mechanical Manufact. & Automation
Dept. of Aircraft Manufacturing Engineering
Dept. of Material Processing & Control
Engineering
SMEA
Research Areas
No. 1
Optimum
Design Mechanical
Manufactur
ing
NDT & E
Aircraft
Manufacturing
Aircraft
Assembling
Measurement
Technology
Welding
Technics
Robotics
Quality
Management
No. 2 No. 3
No.5 No. 4 No. 6
No. 8 No. 7 No. 9
Research Incomes 160 Million RMB (about 26
million US $, 2013)
- 60 % National research projects (NSF, 863 plan, ...)
- 40% Industrial applied research funding (commercial
contracts)
Founding
Outline
Introduction 1
Key technologies 2
Progress of MQL in Beihang University 3
Cutting experiments of several materials 4
5 Conclusion
…….
The use of flood cutting fluid causes environmental pollution, health hazards,increased costs and other issues;
International Organization for Standardization Issued the ISO 14000series related to environmental management;
Manufacturing enterprises must explore a new cooling lubrication method tocreate a safe, clean production environment.
The background
Green Manufacturing
Cleaner Production
Machining Costs
Source: Huller Hille
Breakdown of Coolant Costs
Green Manufacturing
Dry Machining
today
Dry Machining
No pollution; The chips are clean and
can be recycled easily; No cutting fluid is
needed and the related cost is reduced.
切削热
In the absence of cooling, the dimensional accuracy of the workpiece is difficult to control ;
The dust is also difficult to control during the cutting process;
The application of dry machining is
limited.
formerly
Near Dry Machining
Near Dry Machining
Conventional Flooding
Dry Machining
Minimum Quantity Lubrication
Cryogenic Machining
Minimum Quantity Lubrication
with Cooling Air
Water Vapor as Coolant and
Lubricant in Green Machining
…
Minimum Quantity Lubrication with Cooling Air
Cooling air + MQL
Amount of lubricant supply is measured by ml/h,while The
amount of traditional wet method is measured by L/min.
The lubricants are environmentally friendly.
Liquid supply system is simple, small and easy layout.
Combine the advantages of the two technologies.
Reduce friction, inhibit temperature rise, prevent adhesion,
extend tool life, improve surface quality.
Feature:
Recycling of waste
Coolant storage tank of 500,000 gallons
Centrifugal filter
Pressure pump
Chemical additives
Disposal
Oil mist collector Residual oil mist
A coolant circulation system
After using MQL
Infrastructure greatly simplified
Oil mist collector Residual oil mist
Recycling of waste
Coolant storage tank of 500,000 gallons
Centrifugal filter
Pressure pump
Chemical additives
Disposal
× × ×
×
×
×
Oil generator
Chip exclusion system
Outline
Introduction 1
Key technologies 2
Progress of MQL in Beihang University 3
Cutting experiments of several materials 4
5 Conclusion
Key Technologies of MQL
System
Cutting Mechanism
Cutting Process
Oil Mist Characteristics
MQL Lubricants
MQL was first proposed by Klocke F in 1997
MQL System
MQL System
Micro-pump
Negative pressure
Pressure Separation
MQL System
External MQL
Internal MQL
•While processing groove, the interference between the
nozzle and the tool or workpiece is dissatisfied ;
•Small mist particles generated by external lubrication
can scatter, so a protective equipment is needed;
•The spindle and the tool system configuration become
complicated, hollow structures may affect the
performance of the machine tool;
• The generated mist particle diameter must be small
enough to remain suspended.
MQL Processing Technology
Turning
Dhar N R, 2006; Itoigawa F, 2006; Khan M M A, 2009; Leppert T, 2012; ...
Milling
Rahman M, 2002; S M Yuan, 2008; Kasim M S, 2013; ...
Drilling
Heinemann R, 2006; Tasdelen B, 2008; Bhowmick S, 2011; Murthy K S, 2012; ...
Grinding
Dasilva L R, 2007; Tawakoli T, 2010; Li Changhe, 2013; ...
Materials Steel: AISI4340, AISI 9310, AISI316L… Aluminum alloy: AlSi5, 7075… Titanium alloy: Ti-6Al-4V nickel-base super alloy: Inconel 718... cast magnesium alloy: AM60, AZ91 CFRP
Performance Better cooling and lubrication performance compared to dry and
flood machining; Reducing the cutting force & temperature; Improving tool life and better surface finish
Oil Mist Characteristics
Oil Mist Characteristics
Particle Size
Particle Velocity
Particle Volume
Flow Rate
Nozzle Distance
Air Pressure
Kyung-Hee Park, 2010.
Park K H, 2010; Duchosal A, 2013.
Internal Channel
Geometries
Air Pressure
Mist Settings
Oil Type
Internal Channel
Geometries
The higher nozzle pressure provided the more droplets but the smaller droplets were obtained while a smaller amount of droplets was deposited on the surface when the nozzle distance was increased.
Oil Mist Characteristics
Duchosal A, 2013.
Oil Mist Characteristics
Particle Size
Particle Velocity
Particle Volume
Flow Rate
Nozzle Distance
Air Pressure
Internal Channel
Geometries
Air Pressure
Mist Settings
Oil Type
Internal Channel
Geometries
Park K H, 2010; Duchosal A, 2013.
Oil Mist Characteristics
Duchosal A, 2013.
Oil Mist Characteristics
Particle Size
Particle Velocity
Particle Volume
Flow Rate
Nozzle Distance
Air Pressure
Internal Channel
Geometries
Air Pressure
Oil Type
Internal Channel
Geometries
Park K H, 2010; Duchosal A, 2013.
MQL Lubricants
Palm oil (MQLPO) produced lower cutting force and workpiece temperature than synthetic ester (MQLSE), almost equal to the flood condition when high speed drilling Ti-6Al-4V.
Rahim E A, 2011
Mineral oil, vegetable oil, synthetic ester
Lubricants with longer linear carbon chain can provide higher lubrication ability.
Rahim E A, 2011 Wakabayashi T, 2012
MQL Lubricants
Tai B L, 2011
Mineral oil, vegetable oil, synthetic ester
low fluid viscosity, high mist concentration, large mist droplet diameter and high wettability were best correlated with good machinability.
Fluid with low viscosity
high wettability (low contact angle)
high mist concentration
large mist diameter
relative lower thermal conductivity
large mist diameters
& high mist
concentration
improve surface finish & diameter accuracy
lower the energy consumption
Without corresponding cooling system, MQL has some disadvantages under specific cutting conditions:
Lack of cooling performance, especially when dealing with high cutting
temperature caused by difficult-to-cut materials.
Lubrication performance may be insufficient.
Lubricant film breakage under high cutting temperature, Lubrication
failure.
…
New strategies have to be taken to enhance the cooling & lubricating performance of MQL.
Minimum Quantity Lubrication with Cooling Air (MQL-CA)
Minimum Quantity Lubrication with Cooling Air, MQL-CA
Prof. He Ning from Nanhang University uses the low temperature liquid nitrogen mixed with oil mist to cut titanium alloy TC4. The result suggests that MQL-CA has a better effect in Inhibition of tool wear compared with Liquid nitrogen cutting.
Nguyen T’s research shows that, for low metal removal machining process, the cooling air can reduce surface erosion and cutting force. As for higher metal removal rate, adding vegetable oil mist in the cooling air can effectively improve the processing state.
[Su Y, 2006.]
[Nguyen T, 2003.]
Spanish scholars Sanchez JA et al research the performance of grinding AISI D2 tool steel by combining MQL with low temperature CO2 system. This experiment shows that the consumption of the lubricant was decreased during the grinding process, while protecting the abrasive wheel. Therefore, both the grinding wheel life and surface quality are improved.
[Sanchez J A, 2010.]
MQL Cooling Air
MQL Liquid Nitrogen
MQL Cryogenic CO2
Outline
Introduction 1
Key technologies 2
Progress of MQL in Beihang University 3
Cutting experiments of several materials 4
5 Conclusion
• In 2005, our research group engaged in MQL cutting technology and system;
• In 2006, got the funding of National Sci-tech Support Plan—Research on the green cutting process in the machinery
manufacturing;
• 2006.07.19, applied the first national invention patent in minimum quantity lubrication;
• 2008.03.17, applied the second national invention patent in minimum quantity lubrication;
• 2008.03, performed cutting experiments on cast iron and high strength steel in MQL condition;
• 2008.06.18, applied the third national invention patent in minimum quantity lubrication;
• 2008.08.26, applied the fourth national invention patent in minimum quantity lubrication;
• 2009.07.16, applied the PCT patent—a minimum quantity lubrication system
• In 2007, our research group engaged in MQL with cooling air cutting technology and system;
• 2008.11, developed the prototype of the cooling air system one;
• 2008.12, performed cutting experiments on titanium alloy in MQL with cooling air condition;
• 2009.01, developed the prototype of the cooling air system 2 and 3;
• 2009.06, applications of MQL and cooling air systems in aerospace companies;
• 2010.03, applied the national invention patent in MQL with cooling air system;
• 2012.01, got the funding of National Sci-tech Support Plan—Mechanism and device of MQL with cooling air cutting
technology.
• … ….
Research and development process of BUAA in MQL-CA
The development of MQL-CA systems
The MQL systems
Technical indicators
Air pressure: 0.4-0.8Mpa
Oil: MQL oil
Flow rate: 0~50ml/h
Pressure: Adjustable
Installation
The cavity is suspended on the machine bed
cooling pipe is fixed with a magnet
Cryogenic systems
Cooling Air System-Ⅰ
空气压
缩机
干燥过滤
器
蒸发器
制冷压缩
机
油水分离器
冷凝器
储液器
电磁阀
冷空气
膨胀阀
干燥过
滤器
Cooling Air System-Ⅱ
-60
-50
-40
-30
-20
-10
0
10
20
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
时间 /min
气流温度
/℃
双级制冷
单级制冷
Air flow rate: v=0.2~0.7m3/min; Temperature difference between the outlet and the inlet: △t=0~-40℃ Temperature fluctuations: △T≤±1.5℃
www.exair.com
National invention patent certificates
Outline
Introduction 1
Key technologies 2
Progress of MQL in Beihang University 3
Cutting experiments of several materials 4
5 Conclusion
压缩空气
低温
系统
Ⅰ型
MQL
系统
冷风
油/气
主轴
刀具
z
x
y
工件
电荷放大器
电脑
测力仪
The cutting experiment of superalloy GH4169
The experimental condition Machining
tool DMU 80T CNC Machining Center
Material GH4169(Inconel 718)
Tool Sandvik, two teeth
Blade Sandvik, 1030, 1030R08
Cutting speed 31.4m/min
Cutting depth 0.5mm, 0.75mm, 1.0mm, 5.0mm
Cutting width 20mm, 4.0mm
Feed per tooth 0.025mm/z, 0.075mm/z
MQL
parameters
Lubricant flow rate:12mL/h;
Compressed air flow rate: 88L/min
Cooling air
parameters
Lubricant flow rate: -5℃;
Compressed air flow rate: 280L/min
Wet cutting Emulsion(water based)
Cooling
method Flood cutting fluid, MQL-CA
30
32
34
36
38
40
42
44
46
48
-60 -40 -20 0 20 40 60
测试点距离工件中心的位置 /mm
已加工表面硬度
HR
C
传统浇注式切削
MQL-CA
The comparison of machined surface hardness values
The cutting experiment of superalloy GH4169
The comparison of surface roughness The comparison of tool wear
The cutting experiment of titanium alloy TC4
150
170
190
210
230
250
270
290
310
330
1 3 5 7 9 11 13 15 17 19 21 23 25
铣削时间 /min
铣削力
/N
MQL-CA 干切削
冷风 传统浇注式
MQL
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
1 2 3 4 5 6 7 8 9 10 11 12 13
铣削时间 /min
刀具后刀面磨损量
/m
m
传统浇注式 干切削
冷风切削 MQL-CA
MQL
Machining tool XK7132 CNC Milling Machining Center
Material TC4 (Ti-6Al-4V) alloy, 120×100×30mm
Tool Stellram,7792 VXD09
Blade Stellram, XDLT-D41
Cutting speed 126m/min
Cutting depth 0.25mm
Cutting width 32mm
Feed per tooth 0.25mm/rev
MQL
parameters
Lubricant flow rate: 80ml/h; Compressed air flow rate: 88L/min
Cooling air
parameters
The temperature of cooling air:-25℃; The flow rate of cooling air:280L/min
Cooling method Dry machining, flood cutting, cooling air
machining, MQL, MQL-CA
The change of cutting force while milling titanium alloy The process of tool wear while milling titanium alloy
The minimum cutting force is obtained during the MQL-CA cutting progress which has relatively better lubrication and cooling effect.
The tool wear is significantly controlled by using MQL-CA technology, which results in longer tool life.
During the progress of dry cutting, cooling cutting, and flood cutting, metal bonding is obviously observed on the tool tip.
During the MQL and MQL-CA cutting progress, no metal bonding is
observed on the tool tip.
The cutting experiment of titanium alloy TC4
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
后刀
面磨
损V
Bm
ax(mm)
切削时间(min)
干切削
传统切削
冷风切削
低温微量
润滑切削
干切削
传统切削
冷风切削
低温微量润滑切削
The cutting experiment of high-strength steel 30CrNi2MoVA
Machining tool VMC0850B Machine Center
Material 30CrNi2MoVA
Tool cemented carbide φ40mm, two teeth
Spindle speed 2000rpm
Back engagement 0.5mm
Cutting width 40mm (slot milling)
Feed per tooth 0.05mm/z
The flow rate
of lubricant 10~20ml/h
Cooling air
parameters -30℃; 500L/min
Cooling
method
Dry machining, flood cutting, cooling
air machining(-30℃), MQL-CA
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
1.5 3 4.5 6 7.5 9 10.5 12 13.5 15 16.5
表面
粗糙
度Ra(μm)
切削时间(min)
干切削
传统切削
冷风切削
低温微量
润滑切削
干切削 低温微量润滑切削
干切削 传统切削 冷风切削低温微量滑
切削
颜色
形状
400
450
500
550
600
650
700
750
1.5 3 4.5 6 7.5 9 10.5 12 13.5 15 16.5
切削
力(
N)
切削时间(min)
干切削
传统切削
冷风切削
低温微量
润滑切削
The cutting experiment of high-strength steel 30CrNi2MoVA
The machined surface under the microscope (Magnification 180)
Outline
Introduction 1
Key technologies 2
Progress of MQL in Beihang University 3
Cutting experiments of several materials 4
5 Conclusion
Conclusion
Manufacturing sustainability can be achieved by Minimum Quantity Lubrication with Cooling Air (MQL-CA) cutting technology.
MQL-CA uses very tiny amount of lubricant to maintain or surpass the cutting performance using traditional way.
It requires future efforts to face the scientific and technical challenges: Profound research on the cutting mechanism of MQL-CA is
required to provide scientific guidance for engineering application.
New MQL-CA system for machine tools with special structure, such as: multi-axis and turning-milling machine centers.
Eco-friendly and bio-degradable MQL/MQL-CA Lubricant Protection against oil mist, clean and safe work space Develop cutting parameter database for MQL-CA
Thank you for your attention!
Prof. YUAN Songmei
School of Mechanical Engineering and Automation
BEIHANG UNIVERSITY,BEIJING,P.R.CHINA
Tel:86-10-82339630
Mobile:86-13681038158
Email:yuansm@buaa.edu.cn
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