Pneumatic Punching Machine

BATCH MEMBERS A.SULTANUL ARIBEENK.SURAYAL.THANGA PANDIANN.TIRUMALAIS.TAMILSELVAN

PNEUMATIC HOLE PUNCHING HELPS TO MAKE THE HOLE IN SHEET METAL   BY USING COMPRESSED AIR. 

PNEUMATIC ACTUATORS CONTROLLED ENERGY TO THE PUNCH, SO THE OPERATOR NEEDS TO PROVIDE ONLY MODEST EFFORT REGARDLESS OF CONDITIONS.

PNEUMATIC PUNCHING MACHINE HELPS TO MAKE HOLE IN VARIOUS SIZE BY CHANGING TOOL.

AS WELL, PNEUMATIC PUNCH PROVIDES SOME FEEDBACK OF FORCES ACTING ON THE SHEET AND HOLE CAN MADE IN SHEET METAL.

INTRODUCTION

TYEPE OF  PUNCHING MACHINE

FLYWHEEL DRIVE

MECHANICAL PUNCH PRESS

PNEUMATIC PUNCHING MACHINE

HYDRAULIC PUNCH PRESS

SERVO DRIVE TURRET PUNCH PRESS

ABSTRACT             HYDRAULIC PUNCH PRESSES, WHICH POWER THE RAM WITH A HYDRAULIC CYLINDER RATHER THAN A FLYWHEEL, AND ARE EITHER VALVE CONTROLLED OR VALVE AND FEEDBACK CONTROLLED. VALVE CONTROLLED MACHINES USUALLY ALLOW A ONE STROKE OPERATION ALLOWING THE RAM TO STROKE UP AND DOWN WHEN COMMANDED. CONTROLLED FEEDBACK SYSTEMS ALLOW THE RAM TO BE PROPORTIONALLY CONTROLLED TO WITHIN FIXED POINTS AS COMMANDED. THIS ALLOWS GREATER CONTROL OVER THE STROKE OF THE RAM, AND INCREASES PUNCHING RATES AS THE RAM NO LONGER HAS TO COMPLETE THE TRADITIONAL FULL STROKE UP AND DOWN BUT CAN OPERATE WITHIN A VERY SHORT WINDOW OF STROKE THIS PROJECT WORK DEALS WITH THE DESIGN OF PNEUMATICALLY CONTROLLED SMALL SCALE PUNCHING MACHINE TO CARRY OUT PIERCING OPERATION ON THIN SHEETS (1-2 MM) OF DIFFERENT MATERIAL (ALUMINUM AND PLASTIC). REDUCTION IN PUNCHING FORCE REQUIREMENT BEING THE MAIN AIM OF THIS PROJECT WORK IS OBTAINED BY MODIFICATION IN PUNCH TOOL DESIGN

DESCRIPTION OF VARIOUS PARTS Pneumatic Cylinder.

5/2 Flow control Hand Lever Valve. 

Pipe connector and push.

Punch and die.

Air Hoes.

IN A DOUBLE ACTING CYLINDER, AIR PRESSURE IS APPLIED ALTERNATELY TO THE RELATIVE SURFACE OF THEPISTON, PRODUCING A PROPELLING FORCE AND A RETRACTING FORCE AS THE EFFECTIVE AREA OF THEPISTON IS SMALL, THE THRUST PRODUCED DURING RETRACTION IS RELATIVELY WEAK. THE IMPECCABLE TUBES OFDOUBLE ACTING CYLINDERS ARE USUALLY MADE OF STEEL. THE WORKING SURFACES ARE ALSO POLISHED ANDCOATED WITH CHROMIUM TO REDUCE FRICTION.

Double acting cylinder

THE DIRECTION CONTROL VALVE IS USED TO CONTROL THE DIRECTION OF FLOW OF COMPRESSED AIR.

USUALLY CLASSIFIED INTO NORMALLY OPEN (NO)AND NORMALLY CLOSED (NC)VALVES.

THE NORMALLY OPEN VALVES WILL PERMIT FLOW FROM INLET PORT OF VALVE TO OUTLET PORT NORMALLY THE FLOW WILL BE CUT BY CHANGING THE POSITION OF THE VALVE.

THE NORMALLY CLOSED VALVES WILL NOT PERMIT FLOW FROM INLET PORT OF VALVE TO OUTLET PORT NORMALLY THE FLOW WILL BE PERMITTED ONLY BY CHANGING THE POSITION OF THE VALVE.

IN GENERAL VALVES ARE DESIGNATED AS 5/2 DCV ETC. IN WHICH THE FIRST NUMERICAL INDICATES NUMBER OF

PORTS AND SECOND NUMERICAL INDICATES NUMBER OF POSITIONS.

5/2 FLOW CONTROL HAND LEVER VALVE

PUNCH TOOLING (PUNCH AND DIE) IS OFTEN MADE OF HARDENED STEEL OR TUNGSTEN CARBIDE. A DIE IS LOCATED ON THE OPPOSITE SIDE OF THE WORK PIECE AND SUPPORTS THE MATERIAL AROUND THE PERIMETER OF THE HOLE AND HELPS TO LOCALIZE THE SHEARING FORCES FOR A CLEANER EDGE. THERE IS A SMALL AMOUNT OF CLEARANCE BETWEEN THE PUNCH AND THE DIE TO PREVENT THE PUNCH FROM STICKING IN THE DIE AND SO LESS FORCE IS NEEDED TO MAKE THE HOLE. THE AMOUNT OF CLEARANCE NEEDED DEPENDS ON THE THICKNESS, WITH THICKER MATERIALS REQUIRING MORE CLEARANCE, BUT THE CLEARANCE IS ALWAYS LESS THAN THE THICKNESS OF THE WORK PIECE. THE CLEARANCE IS ALSO DEPENDENT ON THE HARDNESS OF THE WORK PIECE. THE PUNCH PRESS FORCES THE PUNCH THROUGH A WORK PIECE, PRODUCING A HOLE THAT HAS A DIAMETER EQUIVALENT TO THE PUNCH, OR SLIGHTLY SMALLER AFTER THE PUNCH IS REMOVED. ALL DUCTILE MATERIALS STRETCH TO SOME EXTENT DURING PUNCHING WHICH OFTEN CAUSES THE PUNCH TO STICK IN THE WORK PIECE. IN THIS CASE, THE PUNCH MUST BE PHYSICALLY BACK OUT OF THE HOLE WHILE THE WORK IS SUPPORTED FROM THE PPULLED UNCH SIDE, AND THIS PROCESS IS KNOWN AS STRIPPING. THE HOLE WALLS WILL SHOW BURNISHED AREA, ROLLOVER, AND DIE BREAK AND MUST OFTEN BE FURTHER PROCESSED. THE SLUG FROM THE HOLE FALLS THROUGH THE DIE INTO SOME SORT OF CONTAINER TO EITHER DISPOSE OF THE SLUG OR RECYCLE IT.

PUNCH AND DIE

WORKING PRICIPLE   THE COMPRESSED AIR FROM THE COMPRESSOR IN THE PRESSURE RANGE OF 7-10 BAR IS PASSED THROUGH A PIPE CONNECTED TO THE SOLENOID VALVE WITH ONE INPUT.

THE SOLENOID VALVE IS ACTUATED BY THE TIMER UNIT. THE SOLENOID VALVE HAS 2 OUTPUTS AND ONE INPUT. THE AIR ENTERING THE INPUT GOES OUT THROUGH THE TWO

OUTPUTS WHEN THE TIMING UNIT IS ACTUATED. AS THE AIR PRESSURE IS HIGH AT THE BOTTOM OF THE

PISTON, THE AIR PRESSURE BELOW THE PISTON IS MORE THAN ABOVE IT.

THE MATERIAL IS PLACED ON THE DIE, WHICH IS FIXED ON THE BASE OF THE MACHINE AND THE PUNCH.

AS THE EXHAUST VALVE IS OPENED, THE PRESSURIZED AIR PUSHES THE PISTON DOWNWARDS WHICH IN TURN IS CONNECTED TO THE PUNCH.

DUE TO THIS THE PUNCH TRAVELS DOWN ON THE METAL SHEET KEPT OVER DIE, PUNCHING THE HOLE.

ADVANTAGESSIMPLICITY OF DESIGN AND CONTROLMACHINES ARE EASILY DESIGNED USING STANDARD CYLINDERS & OTHER COMPONENTS. MACHINES OPERATE BY SIMPLE ON - OFF TYPE CONTROL.

RELIABILITYPNEUMATIC SYSTEMS TEND TO HAVE LONG OPERATING LIVES AND REQUIRE VERY LITTLE MAINTENANCE.BECAUSE GAS IS COMPRESSIBLE, THE EQUIPMENT IS LESS LIKELY TO BE DAMAGED BY SHOCK. THE GAS IN PNEUMATICS ABSORBS EXCESSIVE FORCE, WHEREAS THE FLUID OF HYDRAULICS DIRECTLY TRANSFERS FORCE.

STORAGE COMPRESSED GAS CAN BE STORED, ALLOWING THE USE OF

MACHINES WHEN ELECTRICAL POWER IS LOST.

SAFETY VERY LOW CHANCE OF FIRE (COMPARED TO HYDRAULIC

OIL). MACHINES CAN BE DESIGNED TO BE OVERLOAD SAFE

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