MANUFACTURING PRODUCTS

MECHANICAL DEPARTMENTINDUSTRIAL CASE STUDY BY ADITYA ITWARE A-13 AJAY LEDADE A-14 AJINKYA INGOLE A-15 AJITESH SORTE A-16 AKASH INGOLE A-17 GUIDED BY: PROF.D.J.TIDKE

Contents:Company profile and information

Manufacturing products and procedure of the production.

Machines used in the company & their features and limitations.

Problem identification.

Causes of the tool wear.

Analysis of the different tools and features.

Development of the new tool material.

General Remarks

future possibilities.

Company Name: Kinetic GearsChief Executive Officer : Mr. Vishram Jamdar.Raw Material Source: Manish ForgingCOMPANY PROFILE:Business Type: Supplier, manufacturerYear Of Establishment: 1980Ownership Type: Sole ProprietorshipAnnual Turnover: Rs.50 Lakhs 1 Crore.Total Number Of Employees: 11-25 People.

MANUFACTURING PRODUCTSHeavy Duty Industrial GearsMechanical GearsPrecision Gears Cutting ToolsGear BoxesAutomobile Gears Reduction Gears.Images of the manufactured products:

Mechanical gear gear box precision gearGear fanReduction gearGENERAL PROCEDURE DESIGN DRAWING OF PRODUCTRAW MATERIAL RAW MATERIAL INSPECTIONJOB DIMENSIONSOPERATIONSFINALPRODUCTOPERATIONS MATERIALSIZESTURNINGSLOTTINGHOBBINGSHAVINGMILLINGDRILLINGHARDENINGGRINDINGPOLISHINGFINALPRODUCTMachines Used: MillingLathe(cylindrical & turret lathe)Polishing (surface polishing machine)Hobbing machineGrinding machineSpecial Purpose machines(CNCs, VMCs)CNC MACHINESIn modern CNC systems, end-to-end component design is highly automated using computer-aided design (CAD) and computer-aided manufacturing (CAM) programs. The programs produce a computer file that is interpreted to extract the commands needed to operate a particular machine via a postprocessor, and then loaded into the CNC machines for production. It can be operated by single human or robotic operator that moves the component from machine to machine.The complex series of steps needed to produce any part is highly automated and produces a part that closely matches the original CAD design.Normal working temperature is 33C.Cutting tool used in cncs is generally of cemented carbides.HSS and high carbon steel are used at high speed.Features of CNC MachineConsistency of workpieces produced Faster workpiece machining Complexity of workpieces to be machined Flexibility, faster turn-around, and smaller lotsEasy to handle & safe too. LIMITATIONS OF CNC MACHINES In CNC, a "crash" occurs when the machine moves in such a way that is harmful to the machine, tools, or parts being machined. This results in bending or breakage of cutting tools, accessory clamps, vices, and fixtures, or causing damage to the machine itself by bending guide rails, breaking drive screws, or causing structural components to crack or deform under strain. If anything in input changes (workpiece, raw material hardness or shape), there will be problems the next time the job is run.It requires a great deal of duplicated effort since 3 CNCs are used.Reduced gripping force due to inadequate lubrication can cause malfunction.Moisture can occur in CNC controlling machine.

SIMONS CNC(15- 20LAKHS) FANUC CNC(20-25 LAKHS)HOBBING MACHINESHobbing is machining process for making gears spinles and sprockets on a hobbing machine, which is a special type of milling machine.Also called as hobbers fully automated machines can come in different sizes.Uses: cycloid gears, helical gears, worm gear spur gear, involute gear etc.

FEATURESIt is relatively quick and inexpensive.They are fully automated.Lubrication is required.

HOBBING MACHINE USED IN KINETIC GEARS.POSSIBLE LIMITATIONSSize changes during hob shifting.Size changes from part to partRigidity of gear system and accuracy is reduced due to long parts in gear trains.Stability of machine tool is adversely affected due to large openings and spaces required for gear boxes.Breaking of gears is possible due to high speed of operation.Thread deformation due to interruption in operation may occur.TURRET LATHESThe turret lathe is a form of metalworking lathe that is used for repetitive production of duplicate parts, which by the nature of their cutting process are usually interchangeable.

The general minor problems are like gear wear, improper electric supply due to which job gets damaged and affect the production rate.Turret lathe used in KINETIC GEARS.

20LIMITATIONSRate of tool feeding is slow in turret lathe providing more fatigue to operators hand. Turret tooling is heavy, cumbersome, and slow to change out. Turning between centers is difficult due to absence of tailstock, compound rest, lead screw.Electric failure may result in reduced output quality.SURFACE GRINDING MACHINEA surface grinder is a machine tool used to provide precision ground surfaces, either to a critical size or for the surface finish.The typical precision of a surface grinder depends on the type and usage, however +/- 0.002mm (+/- 0.0001") should be achievable on most surface grinders.

EFFECTS ON WORKING MATERIALThe high temperatures encountered at the ground surface create residual stresses and a thin martensitic layer may form on the part surface; this decreases the fatigue strength. In ferromagnetic materials, if the temperature of the surface is raised beyond the Curie temperature then it may lose some magnetic properties. Finally, the surface may be more susceptible to corrosion.

VMC

Fully tooled up solutions to meet the customer needs & Tool life management.Chip ConveyorHigh speed spindle up to 12000 rpm with chillier Flood Coolant System.Coolant through Spindle.Centralized & Programmable LubricationCarbide tool is generally used.FEATURES:PROBLEM IDENTIFIED:

The machines like different lathes ,hobbing machine,CNCs have the general minor problems like gear wear in the lathes etc.

Since the machining work is more in the industry ,we have selected the TOOL WEAR as major problem for the ICS(Industrial Case Study).

So, considering this problem we have given the solutions for that.

Causes of the tool wear:Macro transfer type mechanical wear process like abrasion and adhesion.Micro transfer type therrmochemical process like diffusion electrochemical process like galvanic action, oxidation.Chemical wear is due to interaction between tool and work material in the cutting fluid environment,Mechanical wear is also produced due to : abrasion due to ploughing into softer matrix by hard constituents & segregated carbides etc

adhesion and formation of metallic bonds formed over rubbing surface under load. Requirement of cutting tools materials:

to prevent failure of cutting tool, the material must posses certain essential requirements

The tool material should be strong & hard enough to withstand the high pressures without having brittle fracture(RBF=resistant to brittle fracture)

The tool material should be able to retain its strength and hardness at high operating temperature.

The tool material must have sufficient wear resistant i.e. Resistant to adhesion or diffusion at high temperaturesANALYSIS OF CUTTING TOOL MATERIALSCUTTING TOOL MATERIALS USED GENERALLY:

Carbon tool steels Medium alloy steelsHigh speed steelsCast alloy toolsCemented carbide toolsCeramics.Carbon tool steels:Up to 1870, tools are all of this type only..

Characteristics of the carbon tool steels are, low hot hardness and poor hardenability.

Compositions of carbon tool steel would have, carbon=0.8-1.3% silicon=0.1-0.4% manganese=0.2-0.4%

Higher the carbon content higher the hardness and high the wear resistance.

Medium alloy steels:Differ from the plain carbon steel due to addition of alloy element to improve hardenability used for drills ,taps and reamers. Typical Medium Alloy Tool Steels,%

CSMnCrMoWFe1.20.30.60.5--balance1.20.30.70.50.5-balance1.20.30.30.70.31.5balanceHIGH SPEED STEELS:

COMPOSITIION: (M-2 HSS) 0.8 % CARBON2 % V6 % W4% Cr5% Mo (invented in 1993)

Features:Steel has high hot hardnessSteel can operate at high cutting speed.

HSS tools Cast Alloy Tools:These are non-ferrous high temp. Alloys containing significant amount of cobalt, chromium & tungsten . number of such non-ferrous alloys have been used in cutting tools called as stellites. these cant be heat-treated are used for a cast from a temperature of about 1300*c.Composition: Co=40-50% Cr=27-32% W=14-29% C=2-4%CEMENTED CARBIDE TOOLS:In early stages the material was brittle, so difficult to grind & have tendencies of adhesion while machining, But in 1938 it was found that the addition of Tic & TaC which reduces the adhesion properties in machining with steelTHREE GROUPS OF METAL CUTTING CEMENTED CARBIDES:WC+Co(for use in machining cast irons and nonferrous metals)WC+Co+(WC-TiC-TaC-NiC) (for steels)TiC+Ni+Mo(for high temp high strength metals)GENERAL CHARACTERISTICS OF CARBIDE TOOLS:High hardness over a wide range of temperature(900*c).

Where, WC=tungsten carbide. Co= cobalt TiC=titanium carbide TaC =tantalum carbide(a kind of carbide ceramic)

Ceramics:

Also Called As Oxide Tool Materials. E.g.: aluminium oxide alumina(Al2O3).

Since oxides are relevant to heat and do not soften at elevated temperatures.

Oxide cutting tools reflect the high hardness and good wear resistant too.

Firstly introduced in the USA in 1955 and after that its properties are improved a bit till 1964.

Images of some ceramic tools as shown:

Comparison between different tools according to there strength

According to the hardness value:General remarks :Materials having high young's modulus are more refractory (more hot hardness character).In an example , the hardness & strength oh the HSS fall rapidly above 500*cBut cast cobalt alloys are softer than HSS at room temperature are harder at temp. Above 500*cWide range of carbide characteristic is due to the variation in cobalt content which may vary between 3%-12%.When cobalt content increased, the carbide becomes more ductile and shock resistant but less refractory.Still some materials recover there hardness value on cooling,The ceramics,carbides,cast cobalt alloys recover there hardness completely but HC steel soften irreversibly (above 500*c for HSS).This is the one reason why HSS tools are limited to operations having working temperature below 500*c.Difference b/w tools :

After attaining 500*c Recovery of the hardness value after cooling.Development of new tool materials:During the machining of high strength temp. Resistant (HSTR)alloys commonly known as AERO-SPACE material. so its essential to improve mechanical & thermal strength .

Development in HSS involves ,atomization of pre alloyed HSS followed by consolidation into shanks by powder metallurgy technique, which gives uniform distribution of the carbide.(smaller size =for better grind inability.)

To increase the wear resistance of HSS, a hard layer contain upto 15%-20% V or Ti may be deposited on tough substrata.Extremely hard but very thin surface layers have also been developed by VAPOUR DEPOSTION OF CARBIDES.

FORD motor company uses improved TiC(titanium carbide) tools for cutting purposes because of there LOW density HIGH oxidation resistance ,which is having FOUR TIMES TOOL LIFE THAN other grades of carbides.

Mixture of Al2O3+TiC gives CERMETS, used in high speed machining of hard cast irons& hard steels too.

One of successful combination is (60%TaN+40%ZrB2)=new refractory material.DevelopmentExistingModify com[position (increase hard phase content)High speed steelsCast cobalt alloysHigh tungsten, high carbon atomized Co-Cr-W-CCarbide with high melting matricesNew refractory materials (TaN-ZrB2)Cemented carbidesCeramicsDevelopment of new tool material:Development in potentialities of tool material.ZrB2=zirconium diboride, highly covalent a refractory ceramic material,used for wear protection and antioxidants (zirconium diboride powder)TaN=tantalum nitride.43Some Advanced Tool Materials During Development:

Coated carbides: When a thin film of TiC was deposited on the steel cutting grade of carbide by vapour phase deposition.

A coating of 0.005 mm reduced the tendency of cemented carbide tool to crater.

Coatings are form TiC,TiN,&Al2O3.while TiC & Al2O3 appear to have most stable layer between the chip and tool. TiN=lowest tool friction.

TiN=due to the strengthening character of the nitrogen.44Coating can be done by physical methods or sputtering BUT for better bonding we should use the CHJEMICAL VAPOUR DEPOSITION where gas like TiCl4 & CH4 is reached on hot surface about 650*c.

Multilayer coatings can also be used .The layer next to TiC which gives stable diffusion barrier(C leaving prevented) and outer layer TiN gives low interface friction.

Coated carbides are more brittle than carbides but used when crater is to be removed.CUBIC BORON NITRIDE(CBN)Coating of polycrystalline diamond or cubic boron nitride(CBN) is introduced on the surface of sintered tungsten carbide having Co binder.CBN coated tools are used primarily to machine stainless steel,HSS, and HSTR alloys.Tool life of the CBN tool is EXCELLENT for machining quenched alloy steel for dies.

Tool life of CBN sintered=method of creating objects from powders & ceramic powders .it is based on atomic diffusion.46NOBIUM BASED UCON:Union carbide developed UCON based on COLUMBIUM(NIOBIUM)consisting of 50% COLUMBIUM, 30% titanium & 20% tungsten .These are casst, rolled and slit into blanks.Nitrogen is finally diffused intpo the surface at 1650*c to produce hard surface layer.These blanks are usde for machining steel at high speeds and feeds and are not suitable for cast iron or stainless steel or HSTR alloy.47FUTURE POSSIBILITIES: From the above discussion it is considered that continuous interest in developing new cutting tools may have following new ideas:Thermo-mechanical treatments to produce textural hardening.Internal oxidation to produce very small(10 nm)hard particles that strengthen by precipitation or dispersion hardening.Directional solidification of cast tool materials& casting techniques that eliminate the embrittling action of micro shrinkage cracks.Application of cooling techniques to produce materials of very fine grain size approaching amorphous structure. It is seen that there are many exciting new possibilities for further development in cutting tool materials.Thank you !!!