Presentation for Hmt Workshop3

7/31/2019 Presentation for Hmt Workshop3

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HMT MACHINE TOOLS LIMITED

MACHINE TOOLS DIVISION

AJMERInception 1967


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HMT AJMER UNIT PROFILEThe unit was established at Ajmer as MACHINE

TOOL CORPORATION OF INDIA LIMITED agovernment of India undertaking in January,1967bin collaboration with M/s. WMW, GDR, thethen east Germany, for the purpose of makingIndia self-reliant in manufacture of precisiongrinding machines. This unit was merged withM/s.HMT Limited in 1975.

From 1.4.2000 it became a unit of HMTMACHINE TOOLS LTD., a wholly ownedsubsidiary of HMT Limited.


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FOUNDARY

WORKSHOP

GRINDING

PROCESS


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SILICA SAND

BY FILTERNET

HOSE

BYELEVATOR

HOPER

BY

STRAINER

STRAINER

COOLINGSYSTEM

SHOOTERBOX

HOPERS

MIXERTOWER

NO BACKSAND


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CORE SECTION

CORE IS A PART OF FOUNDARY

WORKSHOP WHICH IS MADE BY THESAND AND USED TO GET THEHOLLOW PORTION , HOLES, SHAPES

WHICH CANT GET BY THE PATTERNIN THE CASTING.


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MOULD SECTION

Mould Is A Cavity Which Is Made By ThePattern .The Process Of Making Cavity OrMould Is Called Mould.


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PROCESS OF MOULD MAKING SELECTION OF PERFECT IRON BOX.

SET THE PATTERN ON BOTTOM BOARD

KEEP IRON BOX ON PATTERN

POUR THE SANDOVERTURN THE IRON BOX

SET THE SECOND PART OF PATTERN WITH HELPOF DOVEL PINS

POUR THE SANDUNPLUG THE COPE

REMOVE THE PATTERN

NOW MOULD IS READY IN TWO PARTS..


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GRINDING PROCESS

GRINDING IS AN ABRASIVE MACHININGPROCESS THAT USES A GRINDING WHEEL ASTHE CUTTING TOOL.

GRINDING IS A PROCESSING TO REMOVINGMETAL IN SMALL VOLUME FROM WORKPIECE.

GRINDING IS A FINISHING PROCESS FOR ACHIEVING

:- Close size tolerances- Better Geometrical Accuracies- Better Surface Roughness


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GRINDING PROCESS Cutting speed of Grinding Wheel. =3.14xDxN/

60x1000 m/sec.

Surface speed of job

=3.14x dn/ 1000 m/min Grinding ratio= GW speed/Work speed

= 60-100 (Rough-Finish)


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REMOVE SMALL METERIAL

CLOSE DIMENSIONAL TOLERANCE

SURFACE FINISH

SHARPING OF CUTTING TOOLS

MACHINING HARD SURFACES

SOME TIMES HIGHER METAL REMOVALS


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NO FEED MARKS

LESS CUTTING FORCE

REMOVING METAL FROM COMPLEX SHAPES

ITS ONLY MATHOD OF MACHINING AFTER

HARDNING

ACCURACEY ACHIVE 0.02MM

SURFACE FINISH 0.1 MICRON


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GRINDING WHEEL

GRINDING WHEEL IS ROTATING AT VERY HIGH

SPEED. GRINDING WHEEL IS A MULTI-POINT CUTTING

TOOL.

CUTTING IS ACHIEVED BY RELATIVE ROTATION OF

JOB w.r.t. GRINDING WHEEL..


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BONDINGMETERIAL

ABRASIVE

METERIAL

GRINDINGWHEEL


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SPEED RELATIONSHIP

OF

GRINDING WHEEL AND

WORK


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Increase in GW speed

Chip thickness decrease

Cutting forces decreases

Better MRR can be achieved Wheel act HARDER.

Surface Roughness improves.

Centrifugal forces due to unbalance of GW increases.


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INCREASE IN WORK SPEED

Chip thickness increases.

Wheel wear increases.

Cutting ability of wheel decreases. Surface finish deteriorates.

Wheel acts softer.


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WHEEL SIZE V/S WORK SIZE

BIGGER SIZE OF WHEEL

-More cutting particle per wheel rev.

-Better cooling of wheel .

- Cooler cutting action.-Less wheel wear.

-Better size controls.

-Inertia forces increases.

-Centrifugal forces due to unbalance ofwheel increases .

- Therefore optimum wheel size to beselected.

BIGGER SIZE OF WORK

- -Material removal increases.

- -Wheel wear increases.

- -Size variation increases.- -Contact area increases so lesser

feed

- to be used.

- -Therefore optimum work size tobe

- selected for EFFICIENTGRINDING.


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.

Thank you

Presentation for Hmt Workshop3

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