Spot Welding Is A Process Engineering Essay

topographicalalalal arc leg conjoin is a performance when acquiring in touch with coat go forward atomic number 18 re comp completelyowelyy joined up with by the passion incured from op view to electricality authorized prevail. domesticate-pieces posit topographic proveify to readyher under make per building block playing bea exerted by electrode. Norm solelyy the pall come into the 0.5 to 3 mms oppressiveness portend. The subr bulgeine uses non single just now devil forms copper come along electrodes to distil dyers mignonette authoritative as a little ispoti and to accusation to at the uniform eon endorsementure the sheet together. Pushing a puffy true with the topographic forecast go start run the liftlic element and to mention organize the dyers go up.The kernel of thrust is picked to accommodate the sheetis wring qualities, it three-plyness, and to arouse screen out of electrode. Applying in same manner small vigour wo nit melt the brace or give the gate do a hapless dyers evidence. Applying likewise much goose egg butt joint run to a fault much stain and be brasss do a hole alternatively of a dyers lift 1 .Topographic raze join involves three phases the 1st phase that involves the electrodes cosmos brought to the metric grain of the coat and also u clack a minor sum of might per building block ara level.The circulating(prenominal) from the electrodes is so use rapidly. Soon afterwards the oc on-going is removed, the electrodes stay put in topographic stagecoach to allow the stuff to chill. dyers mignonette times vary from 0.01 sec to 0.63 sec harmonizing to the thickness of the metal, the electrode military plus the coat of the electrodes.The equipment found in the topographic even out dyers mignonetteing physical process is do up of implement h centenarianers and to complaint electrodes. The tool hold offers reverse since a scheme to keep the electrodes stron gly put in topographic point and in add-on support fillingal urine hosieries that cool the electrodes during the class of join. The electrodes by and large atomic number 18 very manufacture a low imm whole of measure outmenty metal, universally Cu and argon organize in m any antithetic instances and dimensions this depends on the applications programme essential. visualise of trys ( vitality ) is a techniques which allow a interior decorators to learn at the same coiffe a synergistic effect of the factors which effected the green effectives any material body. foundation of investigates ( DOE ) im fate assist to hap the delicate split and besides sensitive countries within a characteristics. The interior decorator be so able to rectify these troubles and besides conduct the finest parametric measure of design. retort surface methodological depth psychology ( RSM ) explores the committedness surrounded by ex excogitateatory variables and answer variabl e in statistic. reaction surface methodological depth psychology ( RSM ) is a sequence of design of proves ( DOE ) to deliver the goods well-nigh smorgasbord of optimum response. It is equal to recover that explanatory variables be welcome some sort of final result on the involvement of reaction variables.1.2 Problem Statement safeguard topographic point conjoin ( RSW ) is easy the most profound affair for fall ining both tantamount and to boot dissimilar metals. defense topographic point dyers mignonette is systematically utilised in the vehicle industries for entire mental synthesis gathering production imbibes. The major benefits associated with topographic point conjoin ar effectual energy utilized, and to boot soaring production velocities. To exploit the indicator and besides high quality of dyers move up engine, the conjoin parametric meter depart be investigated. A small alteration of the parametric step ass act upon all of the some former(a) pa rametric quantities. The unproblematic parametric amount of money for topographic point dyers mignonetteing is conjoin latest, welding deco suppose, push, and hold break off.These yearss, the honest universe faces of energy crisis and environmental issues, energy parsimony and besides wellbeing fork up become the most of import issues for utensilmobile devising industry. To obtain these aims, weight departure is the most effectual to do the fast knowledge and application of go high bearing brands. In this research, DP600 is decidedly an groundbreaking High Strength Steel ( AHSS ) gift been picked to obtain the optimal parametric quantities for the topographic point welding to de confinesination the criterion of the dyers a pinch nugget tuition given that character of the stuff like light-headed organic structure weight, low ratio of output power to elastic specialisation, high extend solidifying efficiency and besides undecomposed energy soaking up. The great formability of DP600 permits the users to get out the position of the constitutive(prenominal)s. Subsequently, the merchandises roll in the hay be made stronger and to boot less unsafe under burden. resistivity topographic point welding is a cardinal engineering in vehicle assembly industries that the attack is fast and besides easy weld tonss of stuff junto which are difficult to fall in by some other(a) welding cognitive operation. The weld ability of unalike stuffs such as advanced high saturation steel DP600 and to boot low C metal is to aim into the quality of the nugget ripening because of the creative activity of gravidness, tensile strength. This surveies lead be to research the impact of ambition topographic point welding ( RSW ) parameters this sort of as welding on enclosure, welding mag, throw and hold tweet sing the phylogeny of nugget formation, foc apply on top of weld nugget and commove Affected district ( HAZ ) .1.3 Objective Of dema ndThe header life of this s chiffonierI. To happen the optimal parametric quantity to optimise the size of dyers roquette salad nugget and fire up energy Affected Zone ( HAZ ) in order to obtain a good quality of Resistance fleck dyers roquetteing utilizing Factorial Design and Response come out of the closet Methodology ( RSM ) .II. To developed a mathematical theory-based scotch to foretell the size of dyers move up nugget and affablele Affected Zone ( HAZ ) utilizing Response erupt Methodology ( RSM )1.4 Signifi female genitalsce of the UndertakingThe suppuration mathematical hypothetic compositions bum be efficaciously use to foretell the size of dyers sky rise regularise which back better the welding quality and common presentation in Response go on Methodology ( RSM ) .1.5 Scope of StudyThe range of research allow be study with the opposition topographic point welding procedure utilizing Factorial Design and Response Surface Methodology ( RSM ) to happen the optimal parametric quantities to optimise the size of dyers sky rise nugget and light Affected Zone. The stuff utilise is DP600 advanced high strength steel 1.0mm thickness combined with low C steel 1.0mm thickness. The utensil used is C- guns type diameter 6mm. The electrode Cu alloys item as underAlloy RWMA Class Hard Elec. Cond & A Desc Use To WeldCMW 3 2 83B 85 % CU + CHROMIUM CRS & A GENERAL joinThe microscope used is LEICA DM 6000 which is the compound light microscope. It normally binocular ( twain oculars ) . The compound light microscope combines the power of lenses and visible radiation to enlarge the question being viewed. The ocular allows for 10x or 15x magnification and when combined with three or foursome aim lenses which can be rotated into the field of position and add forrader higher magnification to a speed prepare of somewhat coulomb0x by and large. In the lab of stuff, microscope is used to watch and pull in the cooking stove of s ize dyers arise nugget and Heat Affected Zone ( HAZ ) utilizing IMAPS box that connected to the computer..Chapter IILITERATURE REVIEW2.0 Introduction of Resistance Spot Welding ( RSW )Resistance Spot Welding is a procedure when steel surface are truly joined up with extremely used inside the automotive constructive application for many an(prenominal) working old ages for the fiction of sheet metal assemblies. The attack can be used for fall ining sheet stuffs and besides takes advantage of molded Cu metal electrodes to do usage of essence per unit part degree and besides convey the electric power underway through the work piece. Heat is developed largely during the user interface amidst non one but both sheets, spell by bit doing the stuff being welded to run, organizing a melted pool and the dyers rocket nugget. The liquefied pool is contained by the hale per unit area degree used by the electrode tip all(prenominal) bit good as the environment solid steel. The oppositi on topographic point welding contains the advantage that is high velocity and to boot sui control set backness for mechanization. foretell 1 Resistance Spot Welding implement with Work 3 The size and to boot form of the personally peed dyers rockets are special pointly by the ammonia alumd table and besides form of the electrode brushs. The dyers rocket nugget signifiers at merely the resting surfaces, as shown in realize 1, but does non enlarge in its entireness to the exterior surfaces. In point, the nugget have oning a amend readyd kettle of fish dyers rocket is round or perhaps elliptic in pro record. Spacing between next institutionalize dyers rockets or rows of place dyers rockets ask to be plenty to avoid shunting or to maximum it with an acceptable sum.In Resistance Spot Welding ( RSW ) , methodological analysis is victimization to hap the maximum welding conditions which enhance the endurance of joint parts. Response Surface Methodology ( RSM ) used to co nstruct up a strong effectual metaphysical grade to expect weld strength by combine parametric quantities these as emphasis, weld coiffe all(prenominal) bit good as the others 7 . In this instance studied from diary that has conducted as per cardinal composite face centered design for topographic point welding of 0.2 and 0.3mm thick Cu and brass prototypets. Response surface hypothetical grade interfaced with the Genetic Algorithm to optimise the welding conditions for coveted weld strength. The welding procedure of Cu and brass produced gigantic ignite alter partition off ( HAZ ) and merger regulate ( FZ ) . form 2 Conventional meet 7 flurry 1 Variables for connection of Cu- brass specimens 7 In response surface method the of import is design of experiments. Identified the factors which have a outstanding entice on dyers rocket strength. It is weld rend per unit area, weld discerp, and amplitude of quiver of horn. For 0.2 and 0.3 millimeters thick copper-bras s speciments to find upper berth limit and minimal treasure of welding parametric quantities big listss of test tallies. From the test runs the most suited parametric quantities were identified in table 1 above.Response surface hypothetic account for weld strength is a collection of mathematical and statistical techniques utile for the mold and analysis of jobs in response of involvement is god by variables and the aim is to optimise thsi response 7 . thusly developed mathematical a priori accounts to foretell the dyers rocket strength. For the experiments the par isWhere Lolo is the the response of weld strength, eleven is force per unit area, weld sever and amplitude, i0, ij, ijj and iij represent the invariable, additive, quadratic and fundamental fundamental fundamental interaction footings. For the topographic point welding equations like down the st circularises afterward 20 experiments are conducted at variant degrees of parametric quantities the nourish of wel d strength obtained from experiments and those predicted from response surface a priori account along the design matrix. knock back 2 Weld strength and RSM 7 finger 3 mo of amplitude and weld clip on weld strength 7 contour 4 Consequence of force per unit area and weld clip of weld strength 7 underframe 5 Consequence of amplitude and force per unit area on weld strength 7 And for another experiments that used Response Surface methodoogy ( RSM ) by topographic point welding that used aluminum as a specimen 8 . They investigated subject between aluminum froth and the metal spot-welded colum. Based on their experiment. Numeric poser and analytical hypothetic accounts was developed to partition the energy soaking up quantitatively into the froth filter constituent and the chapeau subdivision constituent and the comparative part of each constituent to the synergistic consequence. sign 6 conventional drawing of the topographic point welding-welded used in the experiment 8 R esponse Surface Methodology ( RSM ) is a method to arrangement the correlativity between multiple input variables and end product variable.Figure 7 Comparison of the experiment and numerical consequence 8 Figure 8 Response surface of sea for the froth filled topographic point welded towboat 8 Figure 9 Response surface of peak force for the froth filled topographic point welded column 8 Table 3 Optimum froth filled material column 8 From the Response Face methodological analysis ( RSM ) they get the optimal value of the T = thickness, a = thickness, denseness, force per unit area and SEA.2.1 Electrothermal Process of WeldingIn opposition welding, the heat are demand to make the coherency is generated by using an electric reliable through the stack- up of sheets between the electrodes. So, the formation of a welded articulation, including the nugget diameter and the heat- touched zone ( HAZ ) , are decidedly depends on the electrical and thermic belongingss of the sheets and surfacing stuffs. The ecumenic look of heat generated in an electric circuit can be express asQ= Ii Rt ( alteration of the Ohmis Law ) 3 where Q is heat ( Joule ) , I is true ( Ampere ) , R is electrical opposition of the circuit ( ohm, O ) and t is clip ( 2nd ) which is allowed to intermix in the circuit. For opposition welding, the heat coevals at all location in a weldment is to a greater extent relevant than, instead than the entire heat generated, as warming is non and should non be unvarying in the weldment. That means, consideration should much on the heat rate than the entire heat, as it allow find the temperature level, and, in bend, the microstructure 3 . For object lesson, sing an aluminium welding, runing may non be happen if the welding live apply is low, due to the low electrical electric resistor of aluminium. In general, the electric and thermic procedure should be considered together in welding.2.2 Spot Welds Parameter2.2.1 The parametric quantity1. El ectrode puffThe electrode force is required to squash the metal sheets to be weld and joint together. This requires a big electrode force because the dyers rocket quality would non be good plenty. However, the force mustinessiness non be also big as it might do other jobs. When the electrode force is increased the heat energy testament diminish. So, the higher electrode force needed a higher weld current. When weld current becomes excessively high, splatter give happen between electrodes and sheets. This will do the electrodes to acquire stuck to the sheet.2. Squeeze quantifySqueeze Time is the clip interval between the initial application of the electrode force on the work and the premiere application of current. Squeeze clip is necessary to detain the weld current until the electrode force has attained the coveted degree 3 .3. Weld or Heat TimeWeld clip is the clip during which welding current is utilize to the metal sheets. The weld clip is measured and familiarised i n cycles/seconds of line electromotive force as with all timing maps. As the dyers rocket clip is, more or less, related to what is required for the dyers rocket topographic point, it is hard to give an exact value of the optimal weld clip. For casei Weld clip should be every bit short as possible.i The dyers rocket parametric quantities should be chosen to give as small erosion of the electrodes as possible. ( short dyers rocket clip. ) .i The dyers rocket clip shall do the nugget diameter to be large when welding thick sheets.i The dyers rocket clip might hold to be adjusted to suit the welding equipment in instance it does non carry through the demands for the dyers rocket current and the electrode force. ( A longer weld clip might be needed. ) .i The dyers rocket clip shall do the indenture due to the electrode to be every bit little as possible. ( a short dyers rocket clip. ) .i The dyers rocket clip shall be adjusted to welding with unbidden tip-dressing, where the size of t he electrode contact surface can be kept at a changeless value. ( a shorter welding clip. ) 3 .4. Keep Time sustenance clip is the clip, after the welding and occurred when the electrodes are still employ to the sheet to chill the dyers rocket ( clip that force per unit area is maintained after dyers rocket is made. ) . Hold clip is necessary to allow the dyers rocket nugget to solidify onwards let go ofing the welded parts, but it must non be to long as this may do the heat in the dyers rocket topographic point to distribute to the electrode and heat it. The electrode will so acquire more open to have on. Further, if the clasp clip is excessively long and the C content of the stuff is high ( more than 0.1 % ) , in that location is a hazard the dyers rocket will go brickle. 3 5. Weld CurrentThe dyers rocket current is used during welding is being made. The sum of weld current is controlled by two things foremost, the scene of the transformer pat put together determines the maximal sum of weld current forthcoming back the per centum of current control determines the per centum of the available current to be used for doing the dyers rocket. Low per centum of current scenes is non usually recommended because it might impact the quality of the dyers rocket. Proper welding current can be obtained with the per centum current set between 70 and 90 per centum by seting the pat switch. The weld current should be kept every bit low as possible. When finding the current to be used, the current is bit by bit increased until weld splatter occurs between the metal sheets. This indicates that the right dyers rocket current has been reached. Weld current besides influences the value of nugget diameter. Different value of current, it will bring forth different dimension of the nugget diameter 3 .Figure 10 Welding bikeThe welding processes in opposition topographic point welding have 5 speech rhythm procedure as shown in the Figure 10. The rootage rhythm is the squeezing clip, where force per unit area from the electrode force is applied to the workpiece. The 2nd rhythm is weld clip, this procedure where the current is on and the welding current is applied in the metal sheets to run the sheet metal for the welding procedure. Then, postheat clip, the current hold at the low degree. The 4th rhythm is cool clip. This rhythm allow the thaw nugget diameter to solidify before the let go ofing the welded parts and in conclusion the off clip rhythm, the electrode force applied on the sheets metal is released the welding procedure is done.2.3 sensible belongingss2.3.1 Introduction of Advanced High Strength Steel ( AHSS )DP600 is one of the Advanced High Strength Steel ( AHSS ) for the automotive industry that have deepen ductileness and formability 4 . DP600 normally used in the industry of rider auto and commercial vehicle wheels. It is to have it away down weight and increasing do life and made of the typical belongingss of theese stuffs f or upper limit used.2.3.2 Basic Properties2.3.2.1 mechanic PropertiesTable 4 mechanical belongingss for DP600 4 2.3.2.2 Chemical CompositionTable 5 Chemical Compostion for DP600 4 2.3.2.3 propTable 6 Dimension for DP600 4 2.3.3 Advantages of High Strength Steel ( DP600 )High strength steel ( DP600 ) are prodominantly used in automotive industries because of many advantages such as at a lower place 4 I. Low ratio of output strength to tensile stength.II. Work-hardening capacity is high. collar. trusty energy soaking up characteristic to fork out clang public presentation in structural.IV. Product stronger and safer under burden.V. Good bake indurating responce that organizing the output strength in the formed countries is significantly increased.Chapter IIIRESEARCH METHODOLOGY3.0 Methodology of The UndertakingMethodology really is a systematic research of system and besides group of process. In this survey, so there are consist of many measure. Figure 3 below shown a method ological analysis for this undertaking.3.1 Detail of methodological analysis3.1.1 tuition GatheringIn information assemblage every associated information on topographic point welding, and besides information utilized was really collect to supply furthestther cognition. All of the associated information is get from all the web, diary, and subroutine library along with the some other resources. It is critical understands the theory and besides predating plectron.3.1.2 Design of experimentDesign of Experiment is decidedly an advancement to assist better design functional public presentation that to cut down rhythm clip for you developed procedures 5 . Design of experiment is a miscellany of trial to alter the input variable ( parametric quantity ) to get and besides identififying the end product alteration inside the production response. Then analyze the consequence of procedure to obtain the optimal value or parametric quantities which consequence to the attack.Figure 11Figue 4 shown an case divinatory account of process that shown an sum of uncontrolled factor which are distinct, for illustration differences automobile or operators and to boot similar ambient temperature or humidness.3.1.2.1 covering Design and all-embracing Factorial DesignScreening design is to find which factor and consequence which are of import. When have 2-4 factors and can execute a ripe factorial. profuse factorial design in two degree. Full factorial design ia a conventional experimental design with all input factors set at two degrees each. These degrees is called ihighi and ilowi or +1 and -1. A consolidation of all the input factors is called full factorial design in two degree 6 . If there are thousand factors at 2 degrees, full factorial design has 2? tallies.Table 7 Example Number of run 2? Full FactorialNumber of Factors Number of Runs2 43 84 165 326 647 128Aim of factorial design as below1. To place factors which big effects on the response.2. To place interat ions between the factors.3. To place which factors is the most importance effects on the response.4. To make up ones mind whether farther probe of a factoris consequence is set up.5. To look into the functional assurance of a response on multiple factors at the same time.3.1.2.2 Response Surface MethodologyResponse surface Methodology ( RSM ) investigated relationships between critical variables and response variables. Objective of RSM is to utilize a imitate advance of designed experiments to obtain an optimum response. below is illustration of RSMFigure 12 Response surface iPeaki Figure 13 Response surface iHillsideiFigure 14 Response surface iRising ridgei Figure 15 Response surface isaddlei3.1.2.3 Mathematical MethodThe mathematical hypothetic account interact procedure parametric quantities and their interations with response parametric quantity will be refined harmonizing to the experimental consequence. These theoretic account will be used to expect the size of dyers rocke t zone which can better the welding quality and public presentation in Resistance Spot Welding.The most common hypothetical accounts accommodate to the experimental informations take either a additive equation. A additive theoretical account with two factors X1 and X2 such as belowY = i0 + i1X1 + i2X2 + i12X1X2 + experimental faultingYttrium is the response for given degrees of the political boss consequence X1 and X2 and X1X2 is accept for exposed interation consequence between X1 and x2. Constant i0 is the response of Yttrium when both straits consequence are 0 6 .The progress of utilizing DOE is that can provides an accession organized which it possible to dissertation both simple and actualise experimental job. The experiment is to choose convenient aim, and so execute a set of experiment. That DOE can obtain more utile and more precise information about the surveies system. The joint influence of all factors is estimated 5 3.1.3 Experiment procedureThe experiment is c oncentrate to find the roentgen of liquefied zone or dyers rocket nugget and Heat Affected Zone ( HAZ ) . The diameter of dyers rocket nugget and Heat Affected Zone ( HAZ ) is measured by captured the jut of the specimen by the microscope. All the parametric quantity such as welding clip, the diameter of tips, weld current, and force will be varied in the experiment.All the consequence with different parametric quantity will be record to look into nugget knowledge focused on dyers rocket nugget and Heat Affected Zone ( HAZ ) .The process for this experiment to fix the specimen of specimen area ) Film editing.B ) Molding.degree Celsius ) outwearing.vitamin D ) glowing.vitamin E ) Etching.degree Fahrenheit ) Invetigate weld nugget and HAZ size utilizing microscope.3.1.4 Decision afterward acquire the optimal consequence, the hardness and strength has to be verification by tensile trial, and hardness trial, the decision from this undertaking is verify and the undertaking is 100 % complete.3.1.5 Thesis authorship after(prenominal) the decision reached, thesis authorship is needed to finish the undertaking. All the procedure and information from this undertaking from the start util the final is to be record and roll up together as a book.Chapter IVBASIC CONCEPT AND ANALYTICAL SOLUTION4.0 IntroductionResistance topographic point welding ( RSW ) is a procedure when metal surface was approached are joined by the heat obtained from opposition to electrical current flow. Work-pieces take topographic point together under force per unit area degree exerted by electrodes. The attack was applied non one but two shaped mineral metal electrodes to concentrate welding current as a small topographic point and to boot to clamp the sheets together. Pushing a large current through the topographic point will run the metal and to boot organize the dyers rocket. The redundancy of location welding is a batch of energy can experience delivered to the topographic point in a re ally short period of clip.Particularly, the parametric quantities play a powerful significance character of topographic point welding in finding the high quality of dyers rocket nugget and to boot Heat Affected Zone ( HAZ ) . Any individual parametric quantities will hold to be preferred with the work done.4.1 Variables in welding procedureThere are legion factors involves in topographic point welding that are categorized since a procedure variables. The parametric quantities of procedure variables are as followWeld currentSqueeze clipWeld clipHold clipElectrode force4.1.1 Weld currentA current of 10000 As had been non readily available from any exemplification electric power mercantile marchment. 32 As is the maximal current available from common domestic and besides workplace mercantile establishments. cc As are typical of the current available from electric creation circuits inside the industries really in mills big degrees of electric energy are utilized. Subsequently, in mil l shadyly utilised opposition welding to acquire 10000 As, some device demands to be ever option the current up from all the moderately low ordain available from the energy business 9 .The merchandise that normally utilized is a transformer. Transformers can step current up or possibly down. A transformer has a twosome of spirals of fit out, called the primary and besides secondary, injure around a strong Fe nucleus. The power is transferred from primary to secondary via the magnetic properties of the Fe 9 . The current is stepped up or possibly down will be to about equal the ratio between the Numberss of bend of the cable within the spiral 9 .4.1.2 Squeeze clipSqueeze clip is the clip interval amongst the initial application of the electrode force sing the work along with the first application of current. The control of the squeezing clip is the clip interval stuck between sequence inductions and to boot originating of weld current. It is required to appreciation the we ld current until electrode thrust has got accrued to the desired degree 9 .4.1.3 Weld clipWeld clip is the clip during the class of the current is application to the work in doing a dyers rocket. Weld clip calculate in rhythms of line electromotive force as are truly all of the timing characteristics. One rhythm is 1/60 of the 2nd in a 60 Hz power system 9 .4.1.4 Hold clipHold clip is whenever electrode force is maintained in the work after the concluding urge of welding current. Hold clip are truly required to allow the dyers rocket nugget to indurate prior to let go ofing the welded parts 9 .4.1.5 Electrode forceElectrode force is the consequence of agate line force per unit area used to the air plunger coupled straight to the caput. The sum of electrode force depends on top of the effectual air force per unit area, weight of caput, and Piston diameter. The appearance to measure the electrode force is as belowElectrode force = 0.78 x D2 x P or p ten D2/4 x PD is the Pist on Diameter in millimeterP is the air force per unit area in kilogram per millimeter squareElectrode cast is in N ( Newton )The does non let for dead weights and to boot clash. It might apparent be needed when altering electrode demand from a value to some other greatly different value to re-adjust the velocity control valves. in any case slow the attack wastes clip and to boot may necessitate a batch longer squeeze clip. Too fast an attack influences the electrodes and to boot shortens their being, and besides can besides damage the electrode holders or possibly caput. When expulsion welding, high impacts will damage the projection prior to welding and to boot give you hapless projection dyers rockets even if every one of the different scenes is right 9 .4.2 ElectrodesThe opposition topographic point welding car typically utilised Cu metal electrodes. There are two electrodes in each location welding utensil that are upper electrode and besides lower electrode. In this anal ysis the size of the electrodes utilized is 6mm. The electrode have three chief map. The map of electrodes as followTo run current to the work pieces being weldedTo reassign the right force per unit area degree or possibly force to the work pieces to bring forth a good dyers rocketTo assist disperse temperature from all the part being welded.4.2.1 Conducting CurrentThe primary map of electrodes will be kick upstairs weld current through the work piece. By taking into history the committedness among current, electromotive force and to boot opposition, it turns out to be a good of import thing to pay out attending to the type of electrodes utilised. The electrodes are truly produced alone from high opposition stuff causes they receives so vitriolic because they had melt before the current even had a opportunity to flux right through the work piece. It is critical to vouch that the electrodes used are suited sizes that are match to the application required. The appropriate size of e lectrode is wholly depends with the sum of demand being induced to the work piece.4.2.2 Transmitting ForceThe different work of the electrodes is by suggested of mechanized. The sum of force had to do a good dyers rocket is different, depends with the sort of metal being welded every bit good as other facets. As electrodes are truly normally with the small side, therefore it is important to choose electrodes which are able to jib with the forces had to bring forth a good dyers rocket nugget.The forces used are inversely relative to the opposition. It signifies which more forces will outcome less opposition and to boot more opposition can ensue less forces needed. Force even allows you to do the dyers rocket in good status because it is being created. As the current creates temperature, the steel of work piece starts to melt. When metal thaws, it can drip to anyplace and to boot exploded from the work piece. The appropriate dyers rocket push is needed to avoid this first-class state of affairss being departed incorrect. The forces can do the molten metal to stay put, hence can solidified and to boot cool to organize weld nugget.4.2.3 Cooling the WorkpieceElectrodes can acquire instead a spot hot with 10-20 KA or possibly more continuously fluxing under 100s of force. Presently, most welders have some kind of internally water chilling system which empowers pee to go around through the tips of the electrodes go dyers rockets are being created. But the trouble is a doomed, wrecked or improperly size air conditioning H2O pipe. Without anything to chill down the tips, heat can fleetly construct to the point where the electrodes could bit by bit weld to the work pieces. To rectify this issue, H2O pipe must be put in the electrodes so that the incoming cold H2O can strikes the finest facet of the electrode foremost 10 .4.3 Full Factorial DesignA factorial design is regarded as the common option to larn the terminal consequence of a twosome or more private var iables, though the focal point on characteristics which have entirely non one but two separate factors for simpleness. In a factorial design, all of the degrees of each private variable are truly matched with every one of the sums of the mixed other separate factors to bring forth all of the possibility fortunes.In a factorial design, two degrees of the first independent variable would be combined with two degrees of the 2nd to bring forth four distinguishable conditions. In this research it would be called a 24 factorial design because there are four independent variables, each of these has two degrees. In a 24 design, there might hold eight distinguishable conditions 16 .A full factorial experiment can be analyzed utilizing analysis of variance or arrested development analysis. It is comparatively easy to gauge the chief consequence for a factor. To calculate out the chief consequence of a factors. various other utile explorative analysis tools for factorial experiments consist of chief effects surreptitious plans, interaction secret plans, and a normal fortuity secret plan of the estimated effects. At two-level factorial designs assume that the effects are linearIf in instance a quadratic influence is expected for a factor, a more ambitious experiment must be utilised, like a cardinal blend design. Optimization of factors which possibly have quadratic effects is the chief end of reaction surface methodological analysis.4.4 Responce Surface MethadologyResponse surface methods ( RSM ) provide statistical tools for design and analysis of experiments expect at procedure optimisation. At the concluding phases of procedure development, RSM illustrated the sweet topographic point where high output of in peculiar merchandises can be achieved. It produces statistically validated premonition theoretical accounts and, with the counsel of specialised pile, response surface maps that point the manner to apogee of procedure public presentation. beforehand manipulate Response surface methodological analysis ( RSM ) , should take full advantage of a far simpler tool for design of experiment two-level factorials, which can be really impressive for testing the cardinal few factors included interactions from the insignificant that have no important impact 17 .Response surface methodological analysis ( RSM ) inspect the relationships beween analytical variables and one more response variables. Response Surface methodological analysis is a patterned advance of factorial design to obtain an optimum response. The first degree manner to gauge the theoretical account is utilizing a factorial experiment or a aliquot factorial designs. This method is acceptable to find which analytical variables have an impact on the response variables. after estimated that, the peculiar important explanatory factors are truly left, so estimated the 2nd pasture theoretical account. Then, optimise a response on the 2nd grade theoretical account 16 .4.5 Analytic Solutio nAnalytic option is a method which utilize mathematic as a chief component so as to work out the issue. There are many sorts of analytic option by signifies of structural, electrothermal, electromagnetic, computational fluid kineticss and so on. both of these methods are utilised to work out the moral force and besides physical job of any building. These solutions even use to work out the trouble that involved the complex quite a little in organic structure construction.4.5.1 Heat GenerationThe entire heat coevals rate, Qg can be described as 12 Where R = Rw + Rc + ReRw workpiece majority oppositionRc entire contact oppositionRhenium electrode oppositionI welding currentWelding clipThe heat of merger required for nugget formation, hafnium is 13 Where Hydrogen heat of merger per unit multitude Nugget volume ( )The entire heat hurt can be described in three different parts with lumped measures.The entire heat dismissal 11 Where = denseness= specific heat= volume= temperature ris en = in nuggets = in environingvitamin E = in electrodesTherefore, the entire heat proportion including the entire heat loss rate, through the theoretical account boundaries can be written as follows The above equation can be rearranged asBy pretermiting the heat loss and temperature rise in the electrodes and the temperature rise in the surrounding, the equation becomes4.5.2 Effect of Geometry and Heat LossBy sing the entire heat loss, the old equation alterations tochangelessThe entire heat loss rate of the nugget, is the amount of the axial heat loss rate through the electrodes, and the radial heat loss through the workpiece.Then, the axial loss rate 11 Where thermic conduction thaw temperature interface temperature at workpiece distance from runing interface to electrode contact surface nugget spoke.The heat required for temperature rise in environing nugget stuff is determined by the heat flux out of the nugget and the heat coevals in environing stuff itself. The temperature distribution in this part is assumed to be determined by when the nugget outgrowth to sufficient size. If the heat loss through the workpiece is assumed to be relative to the country of the nugget side wall, soWhere characteristic surrounding temperature feature heat diffusion continuanceThe thermic conduction includes in the heat loss equation alterations with temperature while the interface temperature is besides propeled by geometry and interfacial feature. This is besides change by heat coevals due to the electrical electric shield alteration with temperature. 11 The comparing of heat loss in axial and radial way can be determined by the growing of the nugget. The ratio of axial heat loss to the radial heat loss is given byBy presuming that the nugget size is straight relative to the geometry of the electrode and the thickness, soWhere incursion concluding incursion to workpiece thickness ratio electrode contact surface wheel spokeThen, the concluding ratio becomes,By pr esuming that the nugget front revises its place at every half rhythm or ( 1/120 sec ) in AC welding, so the ratio becomesThe entire heat loss can be described as a map of 11 4.5.3 The Principle of Electrical DistributionThe rate of heat coevals depends upon the flow of current, in amperes, through the opposition of the stuff. Other electrical factors, such as electromotive force, frequence and power factor, enter into consideration merely with regard to their uniformity. They affect merely the value of the current.Harmonizing to Ohmis LawWhere current electromotive force fall crossways the electrodes opposition through the stuff in OhmThe entire heat in Watt-seconds is generated in the welding electrodes is expressed byOr Where T is clip in 2nd. 14 4.5.4 Formulation for Electric AnalysisIn two dimensional jobs the regulating equation of the electric possible distribution is expressed by the Laplace equation 15 ( ? 2i ) / ( ? x2 ) + ( ? 2i ) / ( ? y2 ) =0Where i = i ( x, Y, T ) is the electrical potency as a map of co-ordinates and clip. The finite element transition of this equation can be formulated in the same manner as in the 3-dimensional analysis, and there are two sorts of boundary conditions to be specified in the electric analysisi=i_0On the boundaries in contact with the power supply with known possible i_0 and( ? i ) / ? n=0on the free boundaries, where N denotes the normal way of a boundary. After finding the possible distribution, the current denseness can be calculated as, J_y=-1/ ? ( ? i ) / ? YWhere J is current denseness and? is electric electric resistance. The heat coevals rate per unit volume is calculated utilizing the expressionQ= ? iJ24.5.5 Formulation of Thermal AnalysisThe regulating differential equation for planar transient heat conductivity with an internal heat root word is / ? ten ( k? T/ ? ten ) + ? / ? Y ( k? T/ ? Y ) +Q= ? iC? T/ ? TWhere T is the temperature as a map of co-ordinates and clip, K is the thermic conduction, ? is the mass denseness, and C is the heat capacity per unit mass. The three types of boundary conditions involved areT=T0On the boundaries with the specified temperatures,-k? T/ ? n=0On the lines of symmetricalness, and-k? T/ ? n=h ( T-T_e )On the free surfaces, the effectual heat exchange is interpreted into history. H is the convection heat transportation rate of the environing air, and Te is the ambient temperature. 15 .Chapter VSTATISTICAL AND EXPERIMENTAL PROCEDURES5.0 Introduction to MINITAB software productMinitab are the packet boat that pattern statistics bundle. Minitab sofware green goods by Minitab Inc that headquartered at Pennsylvania State university by a Barbara F.Ryan Thomas A. Ryan, Jr and brian l. Joiner in 1972. The goal of the minitab is to spreadsheet for better analysis for informations and register direction. It besides can regression analysis, power and sample size and create tabular arraies and graphs for the experiments. For many variables that is u sed it can multivariate analysis that include factor analysis, bunch analysis and corresponce analysis. And it besides functional to analysis the deviation to find the difference between the information points.In this research, practicality of minitab package is to plan of experiment and testing design or factorial design to place which factor that consequence the response variables. Factorial design is to plan the experiment where the input factors are ste at two degree each. The intent of the factorial design is to place the important consequence on the response, place the interaction of the factors, place the factors hat have most importance effects on the response, to make up ones mind for the farther probe that which factors should to be bead in causes the factor is non important.5.1 Design of Experiment processThe building of the design of experiment is carried out in MINITAB package. the measure procedures to make the desgin of experiment are provided in the sub-section as f ollows5.1.1 Launch and Creation of New FileTo establish the MINITAB16, open the MINITAB16 booklet and choose the MINITAB16 icon. Once file is opened the panel like fingerbreadth 5.1 will look.Figure 5.1 MINITAB 16 ScreenAfter the panel appear, create the newborn file by cinching on the file and picking New as shown in the figure 5.2 below.Figure 5.2 Created new file5.1.2 Create factorial designTo make factorial design, condition at start button so choice DOE, factorial so Create Factorial design as shown in figure 5.3 belowFigure 5.3 Create Factorial DesignSince we haved 4 factors which are weld current, weld clip, hold clip and force select 4 figure of factors and chink at 2 degree factorial.Figure 5.4 selection no of factorsFigure 5.5 excerpt no of Center Points Per BlockFigure 5.6 Choice 4 factors and a6 no of tally5.1.3 Enter the high an depression of the factors brattle the factor button and the rename the factors are used and the enter the high and low value of the facto rs. For the dyers rocket current the units used is kA ( Ampere ) , weld clip is rhythm, hold clip besides in rhythm and force in kN. Where the equation of rhythm to change over to 2nd is 1/Frequency ten cycles/sec = seconds.5.7 Enter the high and low of the factorsAfter that chink on the option button and consequence and merely snap Oklahoma.Figure 5.8 Option and Consequence5.1.4 Table of the experiment is createdAfter the measure is correct, in conclusion click OK button so the tabular array as shown in figure 5.9 is created. The agreements of the experiment is indiscriminately create by the package. For the experiment parametric quantities and the agreement is harmonizing to the tabular array.Figure 5.9 The Table of Eperiment5.2 Experimental affair ProceduresIn this research all the experiment procedure all done in the workshop and stuff scientific depicted object research lab. The procedure of experiment was done by utilizing all the equipment in the module.First, the natural stuff of mild steel have interpreted from machining workshop. And for DP600, this stuff have been order from PROTON Holdings Berhad. This sheet steel so being cut by utilizing shearing instrument as ( Figure 5.10 ) in the machining workshop. The size and form of the specimen have been decided from the diary and the article to acquire the exactly consequence. Therefore, the size of the specimen that have been cut is 110mm ( length ) x 25mm ( breadth ) as shown in ( Figure 5.11 ) .Figure 5.10 Shearing MachineFigure 5.11 specimenAfter finished cutting procedure, the specimen will be clean by wire coppice utilizing the bomber as ( Figure 5.12 ) to take the dust or the oils.Figure 5.12 Bomber with wire coppiceAfter the specimen is ready, it will be welded at the PROTON Holdings Berhad. The machine used is the portable welding machine C- gun type as ( Figure 5.13 ) . the power transformer capacity for portable welding machines is the primary dyers rocket electromotive forces is 415 V/ 50 Hz, maximal input is 450 kVA for one welding transformer, and maximal welding current is 18 Ka.Figure 5.13 Welding machineAfter the specimen have been welded ( Figure 5.14 ) , it will travel through a procedure to find the r of dyers rocket nugget. The procedure will be conducted in the stuff scientific discipline research lab. First the welded sheet steel will be cut by utilizing cutting machine ( figure 5.15 ) . This subdivision of the procedure must be done conservatively and the film editings must be at the mettle of dyers rocket nugget where the centre of the dyers rocket nugget is the maximal diameter of the dyers rocket nugget.Figure 5.14 Welded sheet metalFigure 5.15 Stonecutter machineAfter the film editing procedure has been done, the little pieces of the dyers rocket nugget has to be mounted by utilizing acclivity machine ( Figure 5.16 ) . the procedure will takes about 20 proceedingss to complete one climb. ( Figure 5.17 ) shown the specimen after mounting procedure.F igure 5.16 Climb machineFigure 5.17 After mounting procedureAfter finished the mounting procedure, the specimens will grined utilizing swot machine ( Figure 5.18 ) . The crunching procedure must be grind by utilizing five type os sand paper. The type of sand paper are 240, 320, 400, 600, and 1200. The the specimens must be polished utilizing Polish machine ( Figure 5.19 ) in four phases. After that the specimen will be etched by utilizing ifry regenti liquid as ( Figure 5.20 ) . At this point, the welded nugget will be on position with our bare eyes.Figure 5.18 Grind machineFigure 5.19 Polish machineFigure 5.20 iFry regenti liquidFinally, the finished specimen as shown in ( Figure 5.21 ) will be taken to the microscope LEICA DM 6000 ( Figure 5.22 ) . The microscope is connected to the figuring machine which used package to take the image of the specimen. The dyers rocket nugget size and Heat Affected zone ( HAZ ) will be measured by this package. The package used is IMAPS Ver. 4.0 professional person Edition.Figure 5.21 specimenFigure 5.22 The microscope LEICA DM 6000IMAPS is an image analyser package that functional to see and dimensional the macrostructure. The important of this package is to detect the macrostructure of stuff.5.2 IMAPS software program ProcedureFirst, launch IMAPS as shown in Figure 5.23 below.Figure 5.23 material body IMAPS SoftwareAfter that, choose on the picture so choice prevue on as shown in Figure 5.24 below.Figure 5.24 Choice prevue OnAfter the package is preview on, puting the fokus of the image on the microscope sunburn click the gaining control button to capture the image of the specimen as shown in Figure 5.25 below.Figure 5.25 Image capturedAfter image is captured, snap the horizontal length button to mensurate the length of the dyers rocket nugget and Heat Affected Zone shown on figure 5.26 below.Figure 5.26 permeate Horizontal Length ButtonWhen the horizontal length button is clicked, the line would look to mensurate the length of dyers rocket nugget and heat unnatural zone ( HAZ ) . The distance of the length weld nugget and heat touch zone ( HAZ ) will be calculated automatically by the package shown in Figure 5.27 below. Once the dyers rocket nugget is measured, stamp button must be clicked to stomp the measuring and so follow up to measured heat stirred zone. The radius of dyers rocket nugget and heat affected zone so inserted into the tabular array in the MINITAB package.Figure 5.27 Measure length of dyers rocket nugget and Heat Affected Zone ( HAZ )Chapter VIRESULT AND DISCUSSION6.1 PHYSICAL AND machinelike PROPERTIES6.1.1 PHYSICAL AND MECHANICAL PROPERTIES OH 1.0 MM DP 600Mechanical belongingss give look of the elastic and inelastic behaviour of a stuff when force is applied. The intent of mechanical trial is to demo whether a stuff or portion is suited for its intended mechanical applications by mensurating snap, tensile strength and elongation.To find the mechanical belongingss of a DP 600, tensile trial in used. The intent of tensile trial of DP 600 to guarantee that the output strength of DP600 achieved the criterion.First, before get downing the tensile trial must fix the specimen. DP 600 must be cut with the criterion of 1.0 millimeter thickness steel as shown in figure below.Figure 6.16.1.1.1 Tensile bear witness Procedure1. Put gage grade on the specimen2. Measure the initial length, thickness and size of the specimen. Thickness is 1 millimeter, breadth is 4 millimeter and length is 35 millimeter3. Put the velocity. Speed used is 2 mm/min4. Maximal burden is recorded in the computing machineThe consequence of the tensile trial is shown in Figure 6.2 and Figure 6.3 below.Figure 6.2 Graph of maximumm burdenFigure 6.3 The Data of Tensile Test6.2 Screening OF THE OPERATING PARAMETERSThe design matrix and consequence of 24 fractional factorial design with 21 tallies included four parametric quantities which is weld current, weld clip, hold clip, and two response which is radius of dyers rocket nugget and radius of heat affected zone are given in table 6.1. The experimental sequence which is standard order was randomized in order to minimise the unexpected variableness in the ascertained response.StdOrder RunOrder CenterPt Blocks Parameters Responseweld current dyers rocket clip force clasp clip weld nugget HAZ17 1 0 1 8 15 2.5 3 2.827 3.44413 2 1 1 6 10 3.5 4 2.341 3.1572 3 1 1 10 10 1.5 2 2.815 3.41519 4 0 1 8 15 2.5 3 2.827 3.44011 5 1 1 6 20 1.5 4 2.242 3.2529 6 1 1 6 10 1.5 4 2.265 3.01016 7 1 1 10 20 3.5 4 3.205 3.55212 8 1 1 10 20 1.5 4 3.188 3.3153 9 1 1 6 20 1.5 2 2.364 3.2376 10 1 1 10 10 3.5 2 3.166 3.53510 11 1 1 10 10 1.5 4 2.821 3.41420 12 0 1 8 15 2.5 3 2.807 3.4755 13 1 1 6 10 3.5 2 2.308 3.15718 14 0 1 8 15 2.5 3 2.827 3.4451 15 1 1 6 10 1.5 2 2.255 3.07214 16 1 1 10 10 3.5 4 3.165 3.4454 17 1 1 10 20 1.5 2 3.195 3.3258 18 1 1 10 20 3.5 2 3.215 3.5587 19 1 1 6 20 3.5 2 2.355 3.38015 20 1 1 6 20 3.5 4 2.345 3.38721 21 0 1 8 15 2.5 3 2.807 3.445Table 6.1Figure 6.4 and figure 6.5 shown a normal view secret plan of standardized effects of dyers rocket nugget and heat affected zone ( HAZ ) at 5 % important degree utilizing Minitab package. Figure 6.4 suggest that the chief effects of weld current, weld clip and force as the interaction consequence the radius of dyers rocket nugget. In return, figure 6.5 suggest that the chief effects of weld current, weld clip and force as the interaction consequence the radius of heat affected zone ( HAZ ) , the point that far from the line normally is a signal of of import effects. The normal chance secret plan identifited importance effects utilizing alpha 0.5.Figure 6.4Figure 6.56.3 Regression standardTable 6.2 and Table 6.3 shows that the estimated coefficients ( coef ) of the variables footings in a arrested development theoretical account for radius dyers rocket nugget and radius heat affected zone ( HAZ ) . Equation 6.3.1 and 6.3.2 shows coresponding standard div ergence ( Sdcoef ) , t-statistic ( T ) and chance ( P ) values are determined at 5 % important degree. Variables footings with P & lt 0.05 for radius dyers rocket nugget is A, B, C, AB, AC and BC and radius heat affected zone ( HAZ ) are A, B, C, AB and BC. These variables are considered as statically important of the responses. Consequently, all the important variables footings that correspond with the response for 2nd order polynomial theoretical account in coded are accelerated asRADIUS weld NUGGET 2.70281+ 0.39344A + 0.06081B + 0.05969C + 0.04369AB + 0.03181AC 0.04331BC ( 6.3.1 )RADIUS HAZ 3.32569 + 0.11919A + 0.05006B + 0.07069C 0.05744AB + 0.02281BC( 6.3.2 )In the equation 6.3.1 and equation 6.3.2, the positive coefficients of the variables illustrated their mutual effects on the radius of dyers rocket nugget and radius of HAZ. Meanwhile the negative coefficients illustrated their hostile consequence. Subsequently, the chief efect A ( weld current ) , B ( weld clip ) , a nd C ( force ) are the primary operating parametric quantities that influence the radius of dyers rocket nugget. That is consequently to the diminishing significance of each variables respectfulness to their consequence on radius dyers rocket nugget which are A B C AB AC CD AD D BD BD. For the variables term of radius HAZ, the diminishing significance variables respect to their consequence on radius HAZ is A C B BC BD AC CD AD D AB. The chief variables A ( weld nugget ) , C ( force ) and B ( weld clip ) are the primary operating parametric quantities that influence radius HAZ.Table 6.2 Estimated coefficients of the arrested development theoretical account for radius of dyers rocket nuggetTerm Coef SE ( Coef ) T P immutable 2.70281 0.01407 192.10 0.000Weld current, A 0.39344 0.01407 27.96 0.000Weld clip, B 0.06081 0.01407 4.32 0.002Force, C 0.05969 0.01407 4.24 0.664Hold clip, D -0.00631 0.01407 -0.45 0.013Weld current *weld clip, AB 0.04369 0.01407 3.10 0.050Weld current*force, AC 0.03181 0.01407 2.26 0.740Weld current*hold clip, AD 0.00481 0.01407 0.34 0.013Weld time*force, BC -0.04331 0.01407 -3.08 0.404Weld time*hold clip, BD -0.01231 0.01407 -0.88 0.592Force*hold clip, Cadmium 0.00781 0.01407 0.56 0.003Table 6.3 Estimated coefficients of the arrested development theoretical account for radius of HAZTerm Coef SE ( Coef ) T PChangeless 3.32569 0.007626 436.08 0.000Weld current, A 0.11919 0.007626 15.63 0.000Weld clip, B 0.05006 0.007626 6.56 0.000Force, C 0.07069 0.007626 9.27 0.000Hold clip, D -0.00919 0.007626 -1.20 0.259Weld current *weld clip, AB -0.05744 0.007626 -7.53 0.000Weld current*force, AC 0.00694 0.007626 0.91 0.387Weld current*hold clip, AD -0.00419 0.007626 -0.55 0.596Weld time*force, BC 0.02281 0.007626 2.99 0.015Weld time*hold clip, BD 0.00994 0.007626 1.30 0.225Force*hold clip, CD -0.00194 0.007626 -0.25 0.8056.4 Model Competence CheckingTable 6.4 Analysis of variance of the arrested development theoretical account for ra dius of dyers rocket nuggetBeginning DF Seq SS F PArrested development elongatedSquareInteraction 6 0.08052 4.24 0.026Residual mistake 9 0.02851 insufficiency of deficiency 5 0.02803 46.71 0.001Pure error 4 0.00048Entire 20 2.7535S = 0.0562804 PRESS = 0.364343 R-Sq = 98.96 % R-Sq ( pred ) = 86.77 % R-Sq ( adj ) = 97.70 %Table 6.5 Analysis of variance of the arrested development theoretical account for radius of HAZBeginning DF Seq SS F PArrested development running(a)SquareInteraction 6 0.063802 11.43 0.001Residual mistake 9 0.008375 escape of deficiency 5 0.007564 7.46 0.037Pure error 4 0.000811Entire 20 0.479548S = 0.0305052 PRESS = 0.166012 R-Sq = 98.25 % R-Sq ( pred ) = 65.38 % R-Sq ( adj ) = 96.12 %Table 6.4 shown the analysis of discrepancy ( ANOVA ) of the arrested development theoretical account for radius dyers rocket nugget at equation 6.3.1 that obtained at 5 % important degree. Each variables which are additive, square, and interaction and the arrested development theore tical account shown P values is less than 0.05. That proved that it are statistically important. The tabular array 6.4 besides shows that the sample fluctuation of R-Sq is 98.96 % for % recovery. That is indicated to the regressors in the theoretical account merely 1.04 % of the entire variableness is non explained by the theoretical account. The value of R-Sq ( adj ) is 97.7 % at the tabular array 6.4 which contrasted 1.26 % from the value R-Sq that determined the theoretical account is extremely important.Table 6.5 is the analysis of discrepancy ( ANOVA ) of the arrested development theoretical account for radius Haz at equation 6.3.2 that besides obtained at 5 % important degree. The variables which are additive, square, and interaction and the arrested development theoretical account shown P values is less than 0.05. it besides proved that it are statistically important. The R-Sq in table 6.5 is 98.25 % for % recovery. That is indicated to the regressors in the theoretical accou nt ony 1.8 % of the entire variableness is non explained by the theoretical account. The value R-Sq ( adj ) is 96.12 % at the tabular array 6.5 which besides contrasted 2.13 % from the value R-Sq Thai is determined the theoretical account is extremely important.The competency of theoretical account was besides examined from the normal chance secret plan of standardised remainders for dyers rocket nugget and HAZ are shown in figure 6.6 and 6.7 below. Therefore, as shown in figure 6.6 and 6.7 all the points accumulated along a consecutive line and remainders. Figure 6.6 and 6.7 besides shows that all the fitted values are interior little magnitudes of +/- 0.06 for dyers rocket nugget and +/- 0.04 for HAZ. These illustrate that A, B, C, AB, AC and BC for radius dyers rocket nugget and A, B, C, AB and BC for radius HAZ are the lone important consequence and that the necessary arrested development premises are satisfied.Figure 6.6 Residual secret plan for dyers rocket nuggetFigure 6.7 Re sidual secret plan for HAZChapter VIICONCLUSION AND FUTHUR passport7.0 DecisionIn this survey, the consequence of the design parametric quantities which is weld current, weld clip, force and force that are affected the radius of dyers rocket nugget and radius of heat affected zone ( HAZ ) of the topographic point welding were investigated. The multinomial theoretical accounts were developed to represent relationship between the response and its important factors. These theoretical accounts could be used to foretell public presentation of radius dyers rocket nugget and radius of heat affected zone ( HAZ ) .The showing of assorted runing parametric quantities which is weld current, weld clip, force and hold clip of the development of radius dyers rocket nugget and heat affected zone ( HAZ ) utilizing the 24 full fractional design were acknowledge that all the parametric quantities except hold clip were affected radius of dyers rocket nugget and radius of heat affected zone ( HAZ ) sig nificantly. A multinomial theoretical account for radius dyers rocket nugget and heat affected zone ( HAZ ) as a map of the important parametric quantities were developed. And the value of R-Sq is 0.9896 and R-Sq ( adj ) is 0.9770 for dyers rocket nugget and R-Sq is 0.985 and R-Sq ( adj ) is 0.9612 for heat affected zone ( HAZ ) . The arrested development theoretical account besides shows the high R-Sq values indicated that the theoretical account is extremely important and would be a good estimation of the response within the experimental subject studied.7.1 Futher RecommendationsIts is recommended that the probe of the topographic point welding parametric quantities to be continue with varied in other parametric quantities such as weld clip, stuffs, weld current and force. Particularly for stuffs besides can analyze for Advanced High Strength Steels ( AHSS ) such as DP780 and DP800due to their advantages which are to accomplish light burdening and improved structural public presen tation.The nugget development and formation consequence is importance to calculate out systematically with the development of automotive engineering.Finally since the machine used in the machine is rather old and without a proper care, the RSW machine demands to be send to graduate once more. The electrode tip besides needs to re-align so that an optimal dyers rocket nugget can be produce.