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FABRICATION OF PNEUMATIC SHEET CUTTERAnsita Mohanty

Jyoti Panda

Basundhara Pradhan

Shubhendu Verma

Rohit Ranjan

Smurtipiyush Sahoo

Mechanical engineeringSection A, Group no. A9

14th May, 2016

Guided By: Dr. D.N Thatoi

Asst. Prof. Sasanka Choudhary

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Mission Statement

• Use of pneumatically controlled Sheet metal cutter in an efficient way.

• Fabrication of pneumatic sheet cutting machine with minimization of cost as well as size.

• Making the machine automatic and user friendly so that it will be easier for operation.

• Determine the maximum out put from our model and make it satisfactory to the customer as well.

• Finally gain experience through individual and team performance.

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Introduction

What is a Sheet metal• Sheet metal is simply a metal formed into thin

and flat pieces. The thickness of sheet is calledits gauge. The thickness above 6mm falls in Plate category.

• There are many metals that can be made into sheet metal like Aluminum, Brass, copper, steel, tin etc. For decorative uses sheet metals of Silver, gold, platinum are also used.

• Sheet metals are used in Car bodies, medical tables, roofs for buildings etc. Use of sheet metal are now days in furniture, shelves or cupboards.

Schematic representation

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How Sheet Metal is cut:• The cutting process is done by applying Shear Force• Due to application of shear Force, the stress in the

material will exceed the ultimate shear strength and the material will fail and separate at the cut location.

• Shearing force is applied by 2 blades one above and one below the sheet.

• The upper blade delivers a quick downward blow to thesheet metal that rests on the lower blade.

• The upper tool penetrates on the sheet causing the shearing and material failure.

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Customer Need Statement and Importance Ranking

CUSTOMER NEEDS No. Of Occurrences (Out of 20) Weightage

Efficient Cutting 16 0.8

Reduce Human effort 14 0.7

Occupy Less space 15 0.75

Low Cost 13 0.65

Less Maintenance 10 0.5

Automatic Operation 11 0.55

Reduce Power Consumption 7 0.35

Safety During Machining 10 0.5

Portability 15 0.75

More thickness of Sheet 9 0.45

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SMOOTH OPERATION

TRANSMITMECHANICAL

ENERGY

PRODUCE CUTTING FORCE

PISTON CYLINDER

COMPRESS IT PNEUMATICALLY

LUBRICATIONDAMP VIBRATIONS

TRANSMIT FORCE TO CUTTING BLADE

ALIGNMENT OF WORK PIECE

LOCOMOTION OF CUTTING BLADE

OVER SHEET METAL

CUT THE SHEET

PROVIDE AIR

GENERATE NOISE

HOW? WHY?

REDUCE NOISE

ELIMINATELEAKAGE

FAST Method

PORTABILITY LINEAR SMOOTH OPERATION

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Function Structure

Open SystemClose System Support

Cutting blades

Execute Cutting

Store the split sheet Raw Metal sheet

Pressure force

AirSheet uncut

Cutting force

Release air

Sheared metal sheet

Provide elect. to compressor

Generation of compressed air

Stores compressed air

Flow of air to FRL unit

Compression & storage

Release into pneumatic cylinder

Cut the sheet

FRL Unit Expansion of air inside cylinder

Motion of connecting rod to

movement of blade

Shearing over the sheet

Electrical energy

Compressed air pressure

Air

Uncut Sheet

Sheared metal

K.E of blade

Cutting of metal as required

Desired cut

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Bill Of Material FormProject Name: Design and fabrication of Pneumatic Sheet cutter  

 

Engineers ANSITA MOHANTY, JYOTI PANDA, BASUNDHARA PRADHAN, SHUBHENDU VERMA, ROHIT RANJAN, SMRUTIPIYUSH SAHOO 

 

Date 04.03.2016   

 

Part No

Name Qty Functional Analysis DFM Cost Analysis  

Function Flows in Flows out Manuf. Process

Manuf. Cost

(In Rupees)

Dimensions Mass Material Finish

1 Shearing Blades

assembly

2 Cut the Sheet  Metal sheet

 Sheared sheet

Machining 320 L=200 mm, B=55 mm, t=12mm

2kg   High Speed Steel

 Smooth

2 Pneumatic cylinder assembly

1 Provide force to the blades

 Compressed air

 Expanded air

 Available in market

2449  Stroke=200mm, D=50mm, Pr.=10bar

 2.5kg  High Carbon Steel

 Smooth

3 Base frame

assembly

1 Support the blades and

cylinder

 Sheet metal

 Sheet metal

 Wood cutting

NA  As required  2kg  Wood  Rough

4 Nuts and bolts

As require

d

Tightening  -------  --------   80  As required    Mild steel  Rough

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Efficient cutting 1

Reduce human effort 2

Less space to occupy 3

Portability 4

Low cost 5

3 5 1 3 4

N cm2 kg bar Rs

562 1500 10 8 3000

570 1500 NA 10.3 4200

566 1350 NA 8 3500

Max

. cut

ting

Forc

e

Are

a of

bas

e

Wei

ght t

o ca

rry

Max

. Air

pres

sure

Equ

ipm

ent c

ost

Technical Difficulty

Measurement Unit

Object Target Value

Objective Measures

FIBER 500

Reference model

Strong Relationship

Medium RelationshipWeak Relationship

House of Quality

4 3

4 3

3 4

4 4

3 3

FIB

ER

50

0

Ref

eren

ce m

odel

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Sheet Metal Cutting

Human

Cutter alignment

Use of removable

cutterUse of single type of metal

sheet cutter

Expectation

Well trained

Analogies

Use of FRL unit

Use of solenoid

Use of regulating switch

Material alignment

Use of single variant of sheet

metal

Thickness within the limit

Manual application

Replacement of effort

application method

Hydraulic application

Pneumatic application

Mind Map Function

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PUGH CHARTWeightage

ConceptsOption # 1 Option #2 Option #3 Option #4 Option

#5

Use of Pneumatic Cylinder

Use of shear blades instead of scissor blades

Electronic sensor for air flow regulation

FRL regulating switch for air flow

Use less base area for sheet cutting

CRITERIA

Efficient Cutting 4 1 1 S S S

Reduced Human effort 3 S S 1 1 1

Less space to occupy 3 S S 1 S 1

Portability 4 S S S S 1Low cost 3 1 -1 -1 1 S             ∑+   2 1 2 2 3

∑-   0 -1 -1 0 0

∑   2 0 1 2 3

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Part Models

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Assembly

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Mathematical Equations and numerical calculation for Sheet metal cutter

For Aluminum Sheet of Thickness “1mm”

Thickness = 1 mmLength of cut = 30mmMaximum Shear Strength of Aluminum = 30 N/mm2

Force Calculation:

Force required to cut the sheet =

This is the force required to cut the sheet. However, initially the force required will be 140-150 % of calculated value.(We have taken this from reference)

Hence, required force

The Compressor pressure should be max 10 bar.But our Base structure is made up of wood, so it can’t withstand such pressure when applied continuously.

So we have taken iterations of 8 bar, 6 bar and 4 bar respectively. Out of which 8 bar pressure gives us the cylinder diameter of minimum size.

Design of cylinder:Since max force required to cut the sheet= 1350N Applied Max pressure= 10bar, we will let the pressure at 8 bar.Converting the unit 1 bar= So, Force applied by the cylinder,

Therefore, diameter of the cylinder is ~50mm (This is taken basing upon the dimensions available in the market)

maxtL

30130 FN900

1350%150900 mmd

d

35.46

1084

1350 12

PdF 2

4

1260%140900

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Solid Works Simulation

Fixtures and Load

Fixture name Fixture Image Fixture Details

Fixed-1

Entities:3 face(s)

Type:Fixed Geometry

Resultant Forces

Components X Y Z ResultantReaction force(N) -0.490486 5.69331 1.44239 5.89362

Reaction Moment(N.m) 0 0 0 0

Load name Load Image Load Details

Force-1

Entities:1 face(s)Type: Apply normal forceValue: 675 N

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Dynamic Analysis of stress

Name Type MinMax

Stress1 VON: von Mises Stress at Step No: 100(1 Seconds)

2.20596 N/m^2Node: 6434

7.90995e+007 N/m^2Node: 1727

Assembly3-Dynamic 3-Stress-Stress1

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Displacement analysis

Name Type Min

Max

Displacement1 URES: Resultant Displacement at Step No: 100(1 Seconds)

0 mmNode: 1725

0.373107 mmNode: 10603

Assembly3-Dynamic 3-Displacement-Displacement1

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FMEA of Sheet metal cutter productProduct Name: Pneumatic sheet metal cutterMetal Cutting System

Devel. Team: Ansita, Jyoti, Basundhara, Shubhendu, Rohit, Smruti

Page No. 1 of 1 Date: 21.03.2016

Part No & Functions

Potential Failure Mode

Potential Effect(s) of Failure

SEVERE(S)

Potential Cause(s)/ Mechanism(s) of Failure

OCCUR(O)

Current Design Controls/ Tests

DETECT(D)

Recommended Actions

RPN

Blade Tool breakage and edge breakage

Deteriorated cutting operation

8 Incorrect clearance angle and blade angle during manufacturing Misalignment of lower blade and upper blade 

3 Prototype test and analysis

7 Regular maintenance and checking for contact surface erosion

168

Cylinder Decrease of air pressure within the cylinder

Insufficient cutting force to the blade

4 Leaks in tubing and connections

6 Prototype test and analysis

8 Secure the valves and check the tubing regularly

192

Piston  Damage in Piston head

 In appropriate motion

6  Maximum usage and mfg. defects

5  NA 8  Maintenance service 240

Connecting Rod

Fracture of connecting rod

Disengagement of blade w.r.t. pneumatic cylinder

9 Failure due to sudden change in pressure of inlet air

2 Check for material strength during prototype simulation

9 To maintain a near constant pressure output from the compressor

162

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Material selection for pneumatic sheet metal cutter

• Base frame: To choose the material for the ‘Base frame’ would be ‘Wood’. The kind of wood available in local area is mostly Teak.The Base of the frame would be made up of ‘Plywood’ as it provides High strength and it is available in large sheets.

• Shearing Blade: To choose the material for ‘Shearing blade’ would be ‘High speed steel (H 13)’.This type of hot work steel provides better Toughness and resistance to Thermal Fatigue cracking.

• Connecting Link: The material for ‘Connecting Link’ would be ‘Mild steel’. The connecting link should provide high strength during to and fro motion of the connecting rod.Also the connecting Link needs to be welded properly with the Upper blade to make a linkage as shown in the figure.

• Pneumatic cylinder: The material for ‘Pneumatic Cylinder’ would be ‘High carbon steel’. As we are not manufacturing this cylinder, we don’t focus on what material it is based on.

Component Manufacturing process

Shearing blade

(1 )Milling, (2) Hardening and tempering, (3) Surface grinding. (4) Drilling, (5) Welding

Base Frame (1)Ply cutting, (2) Wood cutting, (3) Fastening, (4) Drilling

Connecting Link

(1)Drilling, (2) Filing, (3) Welding

Manufacturing Process

Pneumatic Cylinder-Frame: Assembled by Drilling.

Upper Blade and Lower Blade: Bolt and nut tightening at the hinge point so that Upper blade can rotate smoothly.

Connecting Link-Upper Blade: They were Joined by welding and bolt nut tightening.

Connecting Link-Cylinder: There was a threading at the end of Connecting Rod of Cylinder. So The connecting Link was tightened with Nuts and Bolts to the Connecting Rod.

Assembling Process

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Our Fabricated Model

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Merits and Demerits

Hydraulics present certain advantages over pneumatics, but in a given application, pneumatic powered equipment is more suitable, particularly in industries where the factory units are plumbed for compressed air.

Moreover, to avoid corrosive actions, oil or lubricants are added so that friction effects can be reduced.

Compressed air is used in most of the machines and in some cases compressed carbon dioxide, whereas cutting process is become easy.

Fast cutting action is carried out.

Cutting without bending is achieved.    

Sheet more than 1 mm thickness cannot cut easily.

Compressed air is

must.

Foundation is required also safety measurer must be taken.

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Conclusion

Now we know that Pneumatic Shearing machine is very cheap as compared to hydraulic shearing machine.  The range of the cutting thickness can be increased by arranging a high pressure compressor and installing more hardened blades. This machine is advantageous to small sheet metal cutting industries as they cannot afford the expensive hydraulic shearing machine.

Thus we can say that our Product was up to the mark and it hold a good running condition for a sheet of 1 mm thickness.

The Team performed in all activities in the project and gave their optimum values in dedication. We learnt the basics and established a well capable model that can fulfill our customer demand and satisfy their needs.

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References

Ajit Kumar Singh, Harpreet Singh and Dharmendra Sharma, “Design and Fabrication of Pneumatic Auto Sheet Metal Cutting Machine Using Solar Energy”, International Journal of Engineering Research & Technology (IJERT): ISSN: 2278-0181: Vol. 4 Issue 03, March-2015

A.S. Aditya Polapragada & K. Sri Varsha , “Pneumatic Auto Feed Punching, cutting and Riveting Machine “, International Journal of Engineering Research & Technology (IJERT) Vol. 1 Issue 7, September - 2012 ISSN: 2278-0181.

P.M.Pradhan, “Experimental Investigation and Fabrication of Pneumatic Cutting tool”, International Journal of Innovative Research in Science, Engineering and Technology, Vol. 2, Issue 6, June 2013.