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MUFFAKHAM JAH COLLEGE OF ENGINEERING AND
TECHNOLOGY
PROJECT SEMINARPROJECT GUIDE: D.SRINIVAS RAO
(ASSOCIATE PROFESSOR)
BY : MD NASEERUDDIN SHAH 1604-11-736-072 IBRAHIM MD AMEENUDDIN 1604-11-736-075 MOHD JALEELUDDIN 1604-11-736-105 MD SOHAIL KURANI 1604-11-736-135
DESIGN , FABRICATION AND ANALYSIS OF CRANK AND
SLOTTED LEVERQUICK RETURN MECHANISM
Introduction Defining the Problem Design ANSYS Validation Analysis Manufacturing and Fabrication Future Scope Application Conclusion Bibliography
INDEX
Quick return mechanism, (QRM), is used in machines like Shaper, Planar, Slotter.
INTRODUCTION
Whitworth Quick Return Mechanism
Crank and Slotted Lever Quick Return Mechanism
Lower Quick Return Ratio
Vibrations due to non linear velocity
Defining Problem
Rigid structure
Selection of material
Changing the slider height
Overcoming the problem
1.Link lengths
2.Forces acting on each link
3.Selecting materials
4.Suitable cross section
5.Power Calculations
Factors To Be Considered In Design
Design
Specifications
Stroke length = 270mm
Quick return ratio = 5/3
No. of strokes/min = 100 strokes/min
Crank Length = 75mm
Length of Coupler =100 mm
Link Lengths
Length of AC =r/cos(90-α/2)= 75/cos(68)= 200 mm
Length of slotted lever (AP)=P1Q/sin(90-α/2)= 135/sin(22)= 360 mm
Length of AR= AQ + QR= AP cos (90-α/2) + PR sin(90-α/2)= 360 cos(22) + 100 sin(22)= 375 mm
Calculation of Forces F6 = τAl *d* w F6 = 50*2*5 F6 = 500N F5 = F6 /cos(90-α/2) F5 = 500 /68 F5 = 539N F4 =F5 = 539 N
Dynamic Analysis
Mean Cutting Velocity = L*S* (360/α)= 270*100*(360/136) = 71.47 m/min
Cutting Power = F6 * Vmean = 596 W Power required at Crank Pin = Power / η
= 596/0.8= 745 W
L = length of strokeS = number of strokes / minuteη= mechanical efficiency
Power Calculations
Design of Crank Pin Torque at Crank Pin (Tcr) = (P*60)/(2*π*N)
= (745*60) /(2*π*100)= 71.14 N-m
Force at Crank Pin (Fcr) = Torque / crank radius= (71.14*1000) / 75= 948 N
Max Force at Crank Pin (Fcrm) = Fcr * I.F= 948*2= 1896 N
Diameter of Crank Pin = sqrt(4F/πτ)=sqrt(4*1896 / π*50)=7 mm
=8 mm (standard size pin)
Design of Shaft
Torque acting on shaft =(P*60)/(2*π*N) =(745*60)/(2*π*100) = 142 N-m
Diameter of the shaft (d)=cube root(16T/ πτ)=cube root(16*142*1000 /π*75)= 20 mm
Design Of Slotted BarMaximum Force acting on Slotted Bar = 539 * Impact Load Factor
= 539*3 = 1617NCross-sectional Area Of Crank = Max Load / Permissible Stress
= 1617/30 = 54 mm2 ………..1
ANSYS
•ANSYS is a general purpose software, used to simulate interactions of all disciplines of physics, structural, vibration, fluid dynamics, heat transfer and electromagnetic for engineers.
•To validate the design QRM structural analysis where used.
•Static Analysis-Used to determine displacements, stresses, etc. under static loading conditions. Both linear and nonlinear static analyses.
View of the model afterApplying loads
Meshed model
SLOTTED LEVER
Deformed + Undeformedshape
Displacement Vector Sum
Von Mises Stresses Principle Stresses
COUPLER LINK
View of the model afterApplying loads
Meshed Model
Displacement Vector Sum Von Mises Stresses
RAM
View of the model after applyingloads
Meshed Model
Meshed Model after applying Loads Displacement Vector Sum
Graphical Method
Analytical Method
Software Method
Experimental Method
Analysis of Mechanism
Graphical Method
Graphical method starts with position analysis by simply drawing the linkage mechanism to scale. Then the velocity analysis is performed which requires the angular position of the links to be determined beforehand. Similarly it is necessary to know angular velocities of links for acceleration analysis. Thus, the sequence for kinematic analysis of mechanisms is - position analysis, then velocity analysis and then acceleration analysis.
Ground length = 25mm
When crank radius tends to ground length , QRR tends to infinite
Crank radius = 10mm
When ground length tends to crank radius length , QRR tends to infinite
QRR Vs Crank Radius , QRR Vs Ground length
MATLAB ANALYSIS
Graph: Instantaneous slider velocity Vs Crank angle
Variation in cutting force with variation in crank angle for different slider heights
EXPERIMENTAL SETUP
Crank Angle
Slider Position
0 10
20 15
40 20
60 40
80 65
100 100
120 140
Crank Angle
Slider Position
220 260
240 240
260 220
280 175
320 70
340 35
360 0
Crank Angle Slider Position
140 180
180 230
200 245
EXPERIMENTAL OBSERVATIONS
SAMPLE CALCULATION OF VELOCITY
At 100 rpm time required for 20 degrees= 20/(100*360)
= 1/30 s
Velocity of the slider at beginning = d/tof the stroke
= 5 / (1/30)
= 0,15 m/s
Velocity of the slider at middle of the = 50 / (1/30)stroke
= 1.5 m/s
Velocity of the slider at the end of = 35 / (1/30)the stroke
= 1.05 m/s
Manufacturing and Fabrication
Fabrication is an industrial term refers to building metal structures by cutting, machining and drilling.
For construction of mechanism in these project billets standard of sizes were taken.
Some of the machine tools used where centre lathe machine, radial drilling machine, tapping, vertical milling machine, grinding machine, files, hydraulic press machine.
Shaft
Machine tools used:
Lathe
Operations performed:
Facing
Turning
Circlip groves
Chamfering
Bull Gear
Machine tools used
LatheAC Arc Welding MachineRadial Drilling MachineVertical Milling Machine
Operations performed:
FacingTurningWeldingDrillingMillingChamfering
Slotted Lever
Machine tools used
Radial Drilling Machine
Vertical Milling Machine
Bench Grinder
Operations performed:
Drilling
Milling
Grinding
Coupler Link
Machine tools used
Radial Drilling Machine
Bench Grinder
Operations performed:
Drilling
Grinding
Guide ways
Machine Tools Used
Hydraulic Press Machine
Radial Drilling Machine
Operations
Pressing to required shape
Drilling
Filing
RamMachine Tools Used
Hydraulic Press Machine
Radial Drilling Machine
Tapping equipments
Operations
Pressing to required shape
Drilling
Tapping
Filing
Frame
Machine Tools Used
Band Saw Machine
Drilling Machine
Operations
Cutting
Slotting
Drilling
Future Scope
• Accurate instantaneous velocity measurement can be done by using precise instruments.
• Comparison can be made with Whitworth Quick Return Mechanism.
• Vibration analysis can be performed.
• Model can be made to achieve higher quick return ratio.
• Kinematic and dynamic analysis can be performed.
Machine tools
Shaping machines
Power-driven saws
Slotter machines
Applications
Conclusion• Quick return ratio is limited to strength of the material. By incorporating stronger materials QRR can be increased.
• Backlash can be minimized by choosing close tolerances and proper assembly techniques.
• With increase in slider height, QRR increases.
• Friction at the interface of guide ways and ram can be minimized by using turcite tape.
• Ram velocity varies from zero at beginning, maximum at middle of the stroke and zero at the end.
BIBLIOGRAPHY• R.S Khurmi & J.K Gupta• Joseph E. Shigley• S S Rattan• Thomas Bevan•http://engineering.myindialist.com/2013/kinematic-inversions-of-four-bar-chain-slider-crank-and-double-slider-crank-mechanism/•https://www.wisc-online.com/learn/career-clusters/stem/eng20704/quick-return-mechanism-velocity-calculations•http://theengineeringdiary.blogspot.in/2011/06/crank-and-slotted-lever-quick-return.htmlhttp://www.quora.com/What-are-differences-between-crank-and-slotted-lever-mechanisms-and-a-Whitworth-quick-return-mechanism