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during the controlled welding trials. More consistent bead appearances were observed to be produced from the dip transfer trials (see Figures 7.23 and 7.25). Reduced levels of spatter were also observed to occur. In the spray transfer trials, a considerable reduction in the levels of defects was obtained. The porosity was eliminated completely and the undercut largely reduced (see Figures 7.27,7.29,7.31). Also, consistent penetration levels were obtained through-out the welds. The stand-off was controlled to ±2.5 mm in all welding trials. Table 7.5 shows the bead geometry measured from the weld beads produced in the voltage and stand-off controlled trials. Table 7.5 - Bead geometry along the welds produced in the voltage and stand-off controlled flat position fillet welding trials Run Measured feature Position alon the weld mm Geometry feature mm 30 65 100 135 170 Min. R uired Expected SV2 4.85 4.56 4.58 4.78 4.59 4.00 4.46 Pen,, 0.58 0.63 0.53 0.56 0.55 0.32 0.57 Max. Undercut 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SV3 Le 5.95 5.87 5.91 6.03 5.83 6.00 6.41 peng 1.00 1.14 1.07 0.93 1.01 0.32 1.21 Max. Undercut 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SW Le 4.08 4.11 3.98 4.07 4.19 4.00 4.54 Pen., 1.32 1.25 1.40 1.27 1.33 0.32 1.26 Max. Undercut 0.37 0.25 0.37 0.32 0.30 0.0 0.0 SV5 Le 5.73 5.39 5.55 5.63 5.53 5.00 5.40 Pen., 1.70 1.90 1.92 1.85 2.08 0.32 1.70 Max. Undercut 0.0 0.0 0.0 0.0 0.0 0.0 0.0 SV6 Le 4.82 4.73 4.99 5.21 5.12 5.00 5.43 Pen., 2.22 2.31 2.12 2.20 2.14 0.32 1.86 Max. Undercut 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Note the improvement on the penetration profile obtained in the spray transfer trials. The finger-like penetration was greatly reduced and in some cases even eliminated. Some bead misalignment was observed to occur in some welds, even though the robot was carefully programmed on-line to ensure good alignment. This was believed to occur due to some joint movement allowed in the welding jig (see Figure 5.1) during the joint fit-up. Also, the cast of the wire together with differences in the heat sink characteristics provided in both sides of the joint were believed to affect the symmetry of the bead profiles relative to the joint bisection plane. These observations confirm the already mentioned necessity of a means to ensuring the alignment of the wire relative to the joint line, which could be provided by a proper seam tracking facility. 169
ö a2 ., u" u,.., g .,. aucyuaac VI-UN VUIL1I V WI uIc upp uwur vi uIVIiI u 4113IcI. 20-- 19-- 18-- > 17 16 15 60 ß_Z40 30 20 > 10 ^170 a 150 c130 110 90 0 0.3 0.2 0.1 0 0 0 ab 0-- 0 257 257 257 2579 11 13 Vi_nc 1 Figure 7.2 - Welding data of the non-controlled (nc) and the controlled (c) welding trials shown in Figure 7.1 Time [s] 170 9 11 13 9 11 13 9 11 13 --1 Vmean nc Vmean c Imean-nc Imean c PR_nc PVP R-c
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CRANFIELD UNIVERSITY GC CARVALHO AN
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ABSTRACT The aim of this work was t
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I dedicate this work to the memory
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FIGURES TABLES APPENDICES NOTATION
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3.3.2.1 Welding parameters generato
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References Further reading Appendic
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Figure 3.12 Offsets for weld start
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Figure 6.31 Voltage step input test
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Figure J. 2 Plot of stand-off varia
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Table A. 1 Welding extended entity
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NOTATION A, Electrode sectional are
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Pr(ign) Possibility measure of proc
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1. Introduction Welding is the thir
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Chapter 4 describes the on-line pos
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In pulse transfer, the welding curr
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Pd = Pv - pzh-s (2.1) where Pd is t
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the bridge. Another factor that ind
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establish the stable conditions for
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Philpott [ref. 21] developed an on-
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current peak at the moment the tip
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obot on the line must be individual
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collision detection capabilities wh
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cause dynamic variation in the seam
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Another type of robot static calibr
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spatter the gas nozzle is particula
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Table 2.1: Joint positioning tolera
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In order to minimise the undesirabl
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c) Ultrasonic sensors; d) Through-t
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where K,, K2, K3 and K4 are constan
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Philpott [refs. 21,131], based on t
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centre. This is attributed to the m
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technique must be employed to preve
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" digital hardware, which is basica
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" Maximum value, W.: Wmý = max(W )
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process studied over a small range.
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In-process welding control is a muc
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volume caused by the presence of a
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SHIELDING GAS IN CONSUMABLE ELECTRO
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Arc voltage Anode Arc length I Anod
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computed ideal procedure optimisnti
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CONSTANT CURRENT POWER SOURCE `j' O
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Original Surface New Surface Electr
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otating welding wire direction weld
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3.1.1.1 Robot errors A robot arm is
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3.2.2 Programming error correction
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3.3.2 Off-line programming module I
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Pen is the weld penetration (side p
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a. 2) Geometrical constraints from
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Step 11 Step 12 Step 13 Step 14 Ste
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Step 21 Step 22 If the wire feed sp
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the Y'-axis results in a positive "
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_ p1e0a - pORoba m31 Ilp! - poll (3
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of a robot in its zero position12 w
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frame points to the front of the ro
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CAD Off-line (AutoCAD) programming
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Z Surface 4 A Y 7 M2 Open Edge Join
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WCF World Co-ordinates Frame 2a = J
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x Torch Co-ordinates Frame o Indica
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vo Ö 't7 Y7 't O m O 'S O O S O S
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ýý aý 0 oA aW ö A O Zt A OO 't
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Ti 9ý-! i4 *Tx t ap31 jx ý- ymin
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errors', (i. e. joint positioning,
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was considered to be outside the sc
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Table 4.3 - Linguistic representati
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The introduction of such a reduced
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Table 4.8 - Final welding process c
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the collection of welding data corr
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Step 4- Calculate the confidence of
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Z Table Co-ordinates Frame Y X Robo
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5.3 Monitoring system The monitorin
Page 143 and 144: the torch end. Only one degree of f
Page 145 and 146: Current: 500 Position: 234.5 5.7.3
Page 147 and 148: I" va JI ºr ö C 3 r" r" rl f_ £-
Page 149 and 150: IgurC a. H -I UI qur vCiSUJ JpCCU C
Page 151 and 152: 126
Page 153 and 154: Table 6.1 - Welding trials carried
Page 155 and 156: Table 6.3 - Coefficients of Ogunbiy
Page 157 and 158: Note that the calibration model sho
Page 159 and 160: Table 6.6 - Welding parameters used
Page 161 and 162: constant set-up welding parameters
Page 163 and 164: stickout lengths and the temperatur
Page 165 and 166: of the dip mode of metal transfer.
Page 167 and 168: which would become active by settin
Page 169 and 170: In section 4.2.5 it has been mentio
Page 171 and 172: 300 280 260 240 rd 35- 3D 25 20 15
Page 173 and 174: Figure 6.5 - Measured "versus" Pred
Page 175 and 176: i S 0 -0.1 -0.2 -0.3 -0.7- 68 10 12
Page 177 and 178: 32.0 E 31.5 y 31.0 30.5 30.0 j 29.5
Page 179 and 180: 35 - 30 p 15 10 0.00 2.60 5.42 8.23
Page 181 and 182: 40 35 30 25 20 15 10 A+iIII+F0.17 2
Page 183 and 184: 30 28 26 24 22 SO_act [mm] DipR [mo
Page 185 and 186: 22 20 18 SO_act [mm] DipR [ohm/100]
Page 187 and 188: !: 30 25 20t 10 5-- 0 Dip Transfer
Page 189 and 190: 0.430- - 0.380- - :r 0.330 fPR L- 0
Page 191 and 192: 7.2 Tests with varying stand-off an
Page 193: Table 7.3 - Bead geometry along the
Page 197 and 198: 0 24-- 22-- 18 210 1 90 0 v 170 mm
Page 199 and 200: Q 34 32 3o mIm Viewing direction Fl
Page 201 and 202: ýa 34 mm JO a .. ý nn ýr "u 00 M
Page 203 and 204: 22 20 18 Viewing direction Flange W
Page 205 and 206: 36 33 31 o 29 t 350 310 o 290 U due
Page 207 and 208: I C, x -i 23 21 j 19 Q 240c WFS =10
Page 209 and 210: en 34 32 - vsec 30- 26- 24 + .. ++
Page 211 and 212: 186
Page 213 and 214: " to design and build the hardware
Page 215 and 216: Although only linear joints were im
Page 217 and 218: for predicting possibility of bad a
Page 219 and 220: 8.4 Process monitoring and control
Page 221 and 222: satisfy the required quality criter
Page 223 and 224: 198
Page 225 and 226: types of joints and multi-pass weld
Page 227 and 228: [14] NEMCHINSKY, V. A. The effect o
Page 229 and 230: [38] D1LTHEY, U. , REICHELL, T. , S
Page 231 and 232: [64] KING, F-J. and HIRSCH, P. Seam
Page 233 and 234: [86] CARGNELLI, M. and ROGOWSKI, A.
Page 235 and 236: [109] KURKIN, N. S. and DRIKKER, V.
Page 237 and 238: [130] USHIO, M. , LIU, W. , MAO, W.
Page 239 and 240: [151] DAVIS, A. R. Orr-line gap det
Page 241 and 242: [177] COOK, G. E. Feedback and adap
Page 243 and 244: [201] WON, Y. J. and CHO, H. S. A f
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220
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222
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wnum: local variable which defines
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Table A. 1 - continuation List item
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Imean = a2 + b2*WFS + c2*SO + d2*SO
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TCP2 number are also defined. The o
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f ROBSET. DAT: This file is created
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Figure C. 3 - Main dialogue box of
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Choose the set of welding parameter
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Water Cooling optic fibre bundle 0
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Figure E. 1 - Main graphical screen
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242
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Table G. 2 - Interface box external
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Robot ii Controller +24W CO . +24Vd
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248
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Table 1.1 - continuation Run Vpk M
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10- y =0.001ac 0 r. dSO [mm] $0 '10
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5.00- 0.00 y=0.0019x 1000 1500 2000
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Table J. 7 - Welding data collected
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Table J. 10 - Welding data collecte
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20.00- 15. M y=0.0047x - 1.7922 10.
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266
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Table K. 1- continuation Set-up par
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Table K. 1 - continuation Set-up pa
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Table K. 2 - continuation Set up pa
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Table K. 2 - Continuation Set-up pa
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Table K. 3 - Continuation Set-up pa
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Table K. 3 - Continuation Setup par
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