Manufacturing Machines ETME-206drravinderkumar.com/wp-content/uploads/2016/10/Shaper-Grinding.pdfPlaner m/c tool •Inplaningmachine ... •The quick return persists ... In planing

Manufacturing Machines

ETME-206

Dr. Ravinder Kumar

SHAPER

28-Mar-16 2:51 PMDr.Ravinder Kumar

Shaper

•The cutting motion is provided by the linear forwardmotion of the reciprocating tool.

•The intermittent feed motion is provided by the slowtransverse motion of the job along with the bed resultin producing a flat surface by gradual removal of excessin producing a flat surface by gradual removal of excessmaterial layer by layer in the form of chips.

•The vertical in feed is given either by descending thetool holder or raising the bed or both.


Shaper

•Straight grooves of various curved sections are alsomade in shaping machines by using specific form tools.

•The single point straight or form tool is clamped inthe vertical slide which is mounted at the front face ofthe reciprocating ram whereas the work-piece isdirectly or indirectly through a vice is mounted on thebed.


Shaper


Kinematic system and working principles of Shaper


Machining of flat surfaces in shaping machines

(a) horizontal surface (b) vertical surface (a) horizontal surface (b) vertical surface

Inclined surfaces (dovetail slides and guides) 28-Mar-16 2:51 PMDr.Ravinder Kumar

ShaperShaperShaperShaper


SHAPING OPERATION


Major parts of Shaping M/C TOOL

Major parts of Shaping M/C are:

� Ram: it holds and imparts cutting motion to the tool through reciprocation

� Bed: it holds and imparts feed motions to the job (blank)

� Housing with base: the basic structure and also accommodate the drive mechanisms

� Power drive with speed and feed change mechanisms.

� Shaping machines are generally used for producing flat surfaces, grooving, splitting etc. Because of poor productivity and process

� Capability these machine tools are not widely used now-a-days for production.


Shaping machine SpecificationsShaping machine SpecificationsShaping machine SpecificationsShaping machine Specifications

� Length, breadth and depth of the bed

� Maximum axial travel of the bed and vertical travel of the bed / tool

� Maximum length of the stroke (of the ram / tool)

� Range of number of strokes per minute

� Range of table feed

� Power of the main drive

� • Space occupied by the machine


PLANNING M/C TOOLPLANNING M/C TOOLPLANNING M/C TOOLPLANNING M/C TOOL


Planer m/c toolPlaner m/c toolPlaner m/c toolPlaner m/c tool

•In planing machine, instead of the tool, the work piecereciprocates giving the fast cutting motion and instead of thejob, the tool(s) is given the slow feed motion(s).

•Compared to shaping machines, planing machines are muchlarger and more rugged and generally used for large jobs withlarger and more rugged and generally used for large jobs withlonger stroke length and heavy cuts.

•In planing machine, the workpiece is mounted on thereciprocating table and the tool is mounted on the horizontalrail which, again, can move vertically up and down along thevertical rails.


PlanerPlanerPlanerPlanerPlaning machines are more productive (than shaping machines) for longer and faster stroke, heavy cuts (high feed and depth of cut) possible and simultaneous use of a number of tools. As in shaping machines, in planing machines also;

•The length and position of stroke can be adjusted •Only single point tools are used •Only single point tools are used •The quick return persists •Form tools are often used for machining grooves of curved section •Both shaping and planing machines can also produce large curved surfaces by using suitable attachments.


PlaningPlaningPlaningPlaning


Planing action


Difference between Shaper and Planner

� Planing machine The general configuration is schematically shown in Fig. This machine tool also does the same operations like shaping machine but the major differences are:

� In planing the job reciprocates for cutting motion and the tool moves slowly for the feed motions unlike in shaping machine.

� Planing machines are usually very large in size and used for large jobs and heavy duty work.


Slotting MachineSlotting MachineSlotting MachineSlotting Machine

•Slotting machines can simply be considered as vertical shapingmachine where the single point (straight or formed)reciprocates vertically (but without quick return effect) and theworkpiece, being mounted on the table, is given slowlongitudinal and / or rotary feed .

•In this machine also the length and position of stroke can beadjusted. Only light cuts are taken due to lack of rigidity of thetool holding ram for cantilever mode of action.

•Unlike shaping and planing machines, slotting machines aregenerally used to machine internal surfaces (flat, formedgrooves and cylindrical). 28-Mar-16 2:51 PMDr.Ravinder Kumar

Slotting MachineSlotting MachineSlotting MachineSlotting Machine


Slotter in ActionSlotter in ActionSlotter in ActionSlotter in Action


Kinematic system of a slotting machineKinematic system of a slotting machineKinematic system of a slotting machineKinematic system of a slotting machine


GrindingGrindingGrindingGrinding

� Grinding is the most common form of abrasive machining.

� It is a material cutting process which engages an abrasive toolwhose cutting elements are grains of abrasive material known asgrit.

� These grits are characterized by sharp cutting points, high hot


� These grits are characterized by sharp cutting points, high hothardness, chemical stability and wear resistance.

� The grits are held together by a suitable bonding material to giveshape of an abrasive tool.





Grinding


Advantages

� Dimensional accuracy

� Good surface finish

Good form and locational accuracy

Major advantages and applications of grinding


� Good form and locational accuracy

� Applicable to both hardened and unhardened material

ApplicationsApplicationsApplicationsApplications

� Surface finishing

� Slitting and parting


� Descaling, deburring

� Stock removal (abrasive milling) finishing of flat as well as cylindrical surface •

� Grinding of tools and cutters and resharpening of the same.

Grinding Machines Grinding Machines Grinding Machines Grinding Machines

� Grinding Machines are also regarded as machine tools. Adistinguishing feature of grinding machines is therotating abrasive tool. Grinding machine is employed to


rotating abrasive tool. Grinding machine is employed toobtain high accuracy along with very high class of surfacefinish on the work piece.

Conventional grinding machines can be Conventional grinding machines can be Conventional grinding machines can be Conventional grinding machines can be

broadly classified as: broadly classified as: broadly classified as: broadly classified as:

� Surface grinding machine

� Cylindrical grinding machine


Cylindrical grinding machine

� Internal grinding machine

� Tool and cutter grinding machine

Surface grinding machineSurface grinding machineSurface grinding machineSurface grinding machine

� This machine may be similar to a milling machine usedmainly to grind flat surface. However, some types of surfacegrinders are also capable of producing contour surface withformed grinding wheel.

� Basically there are four different types of surface grindingmachines characterized by the movement of their tables and


machines characterized by the movement of their tables andthe orientation of grinding wheel spindles as follows:� Horizontal spindle and reciprocating table

� Vertical spindle and reciprocating table

� Horizontal spindle and rotary table

� Vertical spindle and rotary table

Horizontal spindle reciprocating table surface

grinder


Surface grinding (a) traverse grinding (b) plunge

grinding


Vertical spindle reciprocating table surface

grinder


Cylindrical grinding machine Cylindrical grinding machine Cylindrical grinding machine Cylindrical grinding machine

� This machine is used to produce external cylindrical surface.The surfaces may be straight, tapered, steps or profiled.Broadly there are three different types of cylindrical grindingmachine as follows:

� 1. Plain centre type cylindrical grinder


� 1. Plain centre type cylindrical grinder

� 2. Universal cylindrical surface grinder

� 3. Centreless cylindrical surface grinder

Plain centre type cylindrical grinder Plain centre type cylindrical grinder Plain centre type cylindrical grinder Plain centre type cylindrical grinder


Centreless grinding

� This grinding machine is a production machine in whichout side diameter of the work piece is ground. The work


out side diameter of the work piece is ground. The workpiece is not held between centers but by a work supportblade. It is rotated by means of a regulating wheel andground by the grinding wheel.

External centreless grinding


Internal grinding machine

� This machine is used to produce internal cylindrical surface. The surface may be straight, tapered, grooved or profiled.

� Broadly there are three different types of internal grinding machine as follows:

� 1. Chucking type internal grinder


� 1. Chucking type internal grinder

� 2. Planetary internal grinder

� 3. Centreless internal grinder

Chucking type internal grinder


Internal grinding in planetary grinder


Centreless internal grinder


Tool and cutter grinder machine Tool and cutter grinder machine Tool and cutter grinder machine Tool and cutter grinder machine


Truing and dressing of grinding wheel Truing and dressing of grinding wheel Truing and dressing of grinding wheel Truing and dressing of grinding wheel

� Truing

� Truing is the act of regenerating the required geometry onthe grinding wheel, whether the geometry is a special formor flat profile. Therefore, truing produces the macro-geometry of the grinding wheel.


geometry of the grinding wheel.

� Truing is also required on a new conventional wheel toensure concentricity with specific mounting system. Inpractice the effective macro-geometry of a grinding wheel isof vital importance and accuracy of the finished work piece isdirectly related to effective wheel geometry.

Application of single point diamond Application of single point diamond Application of single point diamond Application of single point diamond

truing tool truing tool truing tool truing tool


DressingDressingDressingDressing

� Dressing is the conditioning of the wheel surface whichensures that grit cutting edges are exposed from the bondand thus able to penetrate into the work piece material.Also, in dressing attempts are made to splinter the abrasivegrains to make them sharp and free cutting and also toremove any residue left by material being ground.


remove any residue left by material being ground.

� Dressing therefore produces micro-geometry. The structureof micro-geometry of grinding wheel determine its cuttingability with a wheel of given composition. Dressing cansubstantially influence the condition of the grinding tool.

Dressing of super abrasive wheelDressing of super abrasive wheelDressing of super abrasive wheelDressing of super abrasive wheel

� Dressing of the super abrasive wheel is commonly donewith soft conventional abrasive vitrified stick, whichrelieves the bond without affecting the super abrasive


relieves the bond without affecting the super abrasivegrits.

Need of Super Finishing Processes

� To ensure reliable performance and prolonged service life ofmodern machinery, its components require to bemanufactured not only with high dimensional andgeometrical accuracy but also with high surface finish. The


geometrical accuracy but also with high surface finish. Thesurface finish has a vital role in influencing functionalcharacteristics like wear resistance, fatigue strength,corrosion resistance and power loss due to friction.Unfortunately, normal machining methods like turning,milling or even classical grinding can not meet this stringentrequirement.

Gradual improvement of surface roughness


Lapping Lapping Lapping Lapping

� Lapping is regarded as the oldest method of obtaining a fine finish.Lapping is basically an abrasive process in which loose abrasivesfunction as cutting points finding momentary support from thelaps.

� Material removal in lapping usually ranges from .003 to .03 mmbut many reach 0.08 to 0.1mm in certain cases.


� Characteristics of lapping process:

� Use of loose abrasive between lap and the work piece.

� Usually lap and work piece are not positively driven but areguided in contact with each other

� Relative motion between the lap and the work should changecontinuously so that path of the abrasive grains of the lap is notrepeated on the work piece.

Scheme of lapping process Scheme of lapping process Scheme of lapping process Scheme of lapping process


� Cast iron is the mostly used lap material. However, soft steel, copper, brass, hardwood as well as hardened steel and glass are also used.

� Abrasives of lapping:

� Al2O3 and SiC, grain size 5~100µm

� Cr2O3, grain size 1~2 μm

Characteristics of lapping process:


� B4C3, grain size 5-60 µm � Diamond, grain size 0.5~5 V

� Vehicle materials for lapping

• Machine oil

• Rape oil

• grease

Characteristics of lapping process:

� Technical parameters affecting lapping processes are:

• unit pressure

• the grain size of abrasive

• concentration of abrasive in the vehicle

• lapping speed


� Lapping is performed either manually or by machine. Handlapping is done with abrasive powder as lapping medium,whereas machine lapping is done either with abrasive powderor with bonded abrasive wheel.

Production lapping on (a) flat surface (b) cylindrical surface Production lapping on (a) flat surface (b) cylindrical surface Production lapping on (a) flat surface (b) cylindrical surface Production lapping on (a) flat surface (b) cylindrical surface


Honing Honing Honing Honing

� Honing is a finishing process, in which a tool called honecarries out a combined rotary and reciprocating motionwhile the work piece does not perform any working motion.

� Most honing is done on internal cylindrical surface, such asautomobile cylindrical walls. The honing stones are heldagainst the work piece with controlled light pressure.


against the work piece with controlled light pressure.

� The honing head is not guided externally but, instead, floatsin the hole, being guided by the work surface.

� It is desired that

1. honing stones should not leave the work surface

2. stroke length must cover the entire work length.

Honing tool and Lay pattern produced by combination Honing tool and Lay pattern produced by combination Honing tool and Lay pattern produced by combination Honing tool and Lay pattern produced by combination

of rotary and oscillatory motion of rotary and oscillatory motion of rotary and oscillatory motion of rotary and oscillatory motion


Honing Honing Honing Honing

� The honing stones are given a complex motion so as to prevent every single grit from repeating its path over the work surface. The critical process parameters are:

1. Rotation speed

2. Oscillation speed


3. Length and position of the stroke

4. Honing stick pressure

Documents

Manufacturing Machines ETME-206drravinderkumar.com/wp-content/uploads/2016/10/Shaper-Grinding.pdfPlaner m/c tool •Inplaningmachine ... •The quick return persists ... In planing