abrasive cut off machine mini project

DESIGN & FABRICATION OF ABRASIVE CUT-OFF MACHINE.

ABSTRACT A cutoff is one of the most commonly

used machinery in the manufacturing process, and almost every workshop has one. It is easy to use, maintainable and cost effective.

ABSTRACT contd…

Abrasive cut off machine is one which uses the abrasive wheel to cut the materials. The basic calculations are made using mathematical relations. The designing is carried out and then fabrication is done. Finally the machine is made to work and the faults are corrected.

CONCEPT-1

In the concept the hinge point is situated at the rear of the machine. Pulleys with V-belts will be used to transmit power from the motor to the arbor shaft.

CONCEPT-2

In this concept the hinge is located slightly in front of the motor (if the cutting disc is said to be the front), this will act like a “see-saw”. When the machine is not busy cutting steel, the cutting disc will be kept in the air due to the weight of the motor at the back. Pulleys and a V-belt will be used for power transmission.

CONCEPT-3

Fixing the cutting disc to the motor shaft directly.

CONCEPT EVALUATION

CON.1 CON.2 CON.3

Simplicity 4 4 4 Practicability 5 3 2 Manufacturability 4 4 5 Maintainability 4 4 5 Yielding Possibility 4 4 2 Safety 4 3 1 Cost 3 3 5

BLOCK DIAGRAM

We choose concept-1.

SPECIFICATION

PART DIAGRAMSPULLEY SHAFT AND COUPLING….

ABRASIVE WHEEL

BASE

DESIGN CALCULATIONDESIGN OF SHAFT 1

Material Used :45C8

[Refer PSG DB page no.1.9]

TENSILE STRENGTH=700N/mm²

YIELD STRENGTH=350N/mm²

TORQUE=(3.14×t×d³)/16

TORQUE ON SHAFT:

P=(2×3.14×N×T)/60

3.75×10³=(2×3.14×2950×T)/60

T=12.138Nm=12.138×10³Nmm.

Shear stress t=ultimate strength/factor of safety.FOS=4.t=700/4=175N/mm².[FOS>2.15 [Refer PSG DB page no.7.22]

T=(3.14×t×d³)/1612.138×10³=(3.14×175×d³)/16d=7.06mmNormally we use shaft of diameter 20-25mm.DESIGN OF SHAFT-2TORQUE ON SHAFT:

P=(2×3.14×N×T)/60

3.75×10³=(2×3.14×4000×T)/60

T=8.95Nm=8.95×10³Nmm.T=(3.14×t×d³)/168.95×10³=(3.14×175×d³)/16d=6.38mmNormally we use shaft of diameter 20-25mm.

N1=4000rpmN2=2950rpmP=3.75KWSELECTION OF BELT:For P=3.75kw [Refer PSG DB page no.7.58]Select B type belt.Small pulley diameter:For B dpmin=125mm [Refer PSG DB page no.7.62]demax=dpmax×Fbmax

de=equivalent pitch diadp=pitch dia of smaller pulleyFb=small dia factor

DESIGN OF V-BELT AND PULLEY

For demax [Refer PSG DB page no.7.62]demax=175mmSpeed ratio:i=N1/N2

i=4000/2950=1.35For i=1.35Fb=1.1 [Refer PSG DB page no.7.62]demax=dpmax×Fbmax

175=1.1×dpmax

dpmax=159mmFor standard dia [Refer PSG DB page no.7.20 R20 series]It should be between dpmin & dpmax

dp=140mmCENTRE DISTANCE :C/D=1(assume)N1/N2=D/dD=1.35×140=189mmD=200mm For standard dia [Refer PSG DB page no.7.20 R20

series]

C/D=1C=200mm[Refer PSG DB page no.7.61]Cmin=0.55(D+d)+TFor T [Refer PSG DB page no.7.58]

Normal thickness T=11mmCmin=0.55(200+140)+11Cmin=198mmCmax=2(D+d) [Refer PSG DB page no.7.61]Cmax=2(200+140)=680mmCalculated value of C lies between Cmin & Cmax

LENGTH OF BELT:[REFER PSG DB P.NO:7.61]L=2C+[(3.14/2)×(D+d)]+[{(D-d) ²}/4C] =2×200+[(3.14/2)×(200+140)]+[{(200-140) ²}/(4×200)]Pitch length: L=938.57mm

NOMINAL INSIDE LENGTH: [Refer PSG DB page no.7.59]For nominal inside length corresponding to nominal pitch length(965mm) is 1008mm.Length correction factor Fc=0.83 [Refer PSG DB page no.7.59]

ANGLE OF CONTACT:Θ=180-[60{(D-d)/C}] =180-[60{(200-140)/200}]Θ =162deg

angle correction factor Fa=(v-v belt)For Θ=163 Fa=0.96 [Refer PSG DB page no.7.68]For service factor [Refer PSG DB page no.7.69] medium duty Fs=1.1(for up to 10 hrs)POWER RATING:[Refer PSG DB page no.7.62]KW=[{0.79×S-0.09}-(50.8/de)-{(1.32×10^(-4) ×(S²)}]SS=(3.14×d×N)/60 =(3.14×4000×140)/(60×1000)S=29.32m/s.de=dp×Fb

=140×1.1 de=154mm

KW=[[{0.79× (29.32)-0.09}-(50.8/154)-{(1.32×10-4 ×(29.32²)}] ×29.32]

KW =4.04NUMBER OF BELTS:

[Refer PSG DB page no.7.70]No. of belt=(P×Fa)/(KW×Fc×Fd)=(3.75×1.1)/(4.04×0.83×0.96)=0.98 ~1FINAL CENTRE DISTANCE:[Refer PSG DB page no.7.61]C=A+{[(A²)-B]1/2}A=(L/4)-(3.14× [(D+d)/8]) =(1008/4)-(3.14× [(200+140)/8])A=118.48mmB=[(D-d) ²]/8 =[(200-140) ²]/8B=450mm

C=A+{[(A²)-B]1/2}

C=118.48+{[(118.48²)-450]1/2}

C=235mm

SPECIFICATION:

1) Type of drive=V-belt2) Belt used =B965-IS24943) Number of belt=14) Smaller pulley diameter=140mm5) Larger pulley diameter=200mm6) Centre distance=235mm

VICE Vice is to hold the work piece in

position.

PROVISION FOR ANGULAR CUTThis part is to cut the work piece angularly.

TOP VIEW

STOPPERSStoppers provided for the safety and to provide limits.

MOTOR STOPPER

SPRING TO RETAIN THE MOTOR BACK TO ORIGINAL POSITION.

MOTOR BED

PULLEY

MOTOR COUPLED WITH THE PULLEY

BELT USED TO CONNECT MOTOR PULLEY WITH THE ABRASIVE WHEEL PULLEY

PHOTOGRAGH SHOWS THE LEVERAGE HINGE POINT AND THE MOTOR BED

ABRASIVE CUTTING DISC

WASHERS & NUT TO GRIP AND HOLD THE CUTTING DISC IN POSITION

CUTTING DISC HOUSING

HANDLE TO OPERATE

PARTLY ASSEMBLED VIEW

Right Side View

Left Side View

Front View

Front View

Rear View

Top View

Project video

CONCLUSION & FUTHER DEVELOPMENT

This presentation has discussed the idea of abrasive cut off machine and demonstrating the functionality and performance of the abrasive cut off machine. An overview of the machine has been discussed. A detailed design calculation has been described, offering an economical safer and rather simple, yet reliable, way to meet the requirement of a workshop.

CONCLUSION & FUTHER DEVELOPMENT contd..

It is important to mention that the machine can perform more complex tasks by applying simple modifications on the design. For instance, mounting different sensors in the machine would inform the user of changes in the behavior of the material while cutting.

In addition we can modify the operation from manual to automatic for better performance and to reduce the time for operation

THANK YOUTHANK YOU