proceedings of the fourth us water jet conference - Waterjet ...

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For very specific applications, these technologies may have certain advantages over abrasive-waterjets. In general, the abrasive-waterjet technology appears to provide greater benefits. A comparison of the various machining methods is made in Table 5. Data given for abrasive-waterjets were obtained from cutting tests and would be improved with optimization and further nozzle development. Table 5. Typical volume removal rates and surface finish for different non-traditional machining techniques. Electrical discharge machining, which is suitable only for electricity-conducting materials, uses a pulsating electrical discharge to melt the metal that is to be removed. Because of short tool life and high cost, ordinary EDM techniques are seldom competitive with other metal removal techniques. The EDM process increases the surface hardness and reduces the fatigue strength. Among the other disadvantages of EDM are the need to shape electrodes (tools) for every new machining task and the slow rate of metal removal. Electrochemical machining is used for odd-shaped cavity machining or marking. Slow material removal rates and high cost of equipment are among the disadvantages of 17
this technique. The technique is also limited to materials that conduct electricity. Pilot testing is often required before the parameters are selected for cutting. ECM machines must also be rigid enough to withstand the pressures caused by the electrolyte. Chemical machining utilizes chemical attack or etching to remove layers of metal. Nearly all metals can be chemically machined at very low rates of metal removal. Maximum blanking depth is about 1.5 mm. This process requires highly skilled operators. Ultrasonic machining uses abrasive slurries in a gap between an oscillating tool and the workpiece to cause metal removal. It is used chiefly for hard and brittle materials that do not conduct electricity. It is suitable for producing relatively shallow irregular cavities. The main disadvantages of USM are the high cost and low rates of material removal. Abrasive jet machining uses air to accelerate and entrain abrasives. Its primary use is in the cleaning and deburring of very hard, brittle materials. AJM is not really suitable for rapid machining operations because of the low power and low volume removal rates associated with this method. However, it does have the advantage of being able to cut hard, brittle materials without inducing thermal stresses. Electron beam machining requires a vacuum chamber in which workpieces are placed. It is suited for drilling holes and making slots of a millimeter fractions in size. This process has the disadvantages of high cost, limited applicability (to a 6 mm depth), slow production rates and thermal distortions of produced surfaces. Laser beam machining, while applicable to any known material, Is not suitable for thin workpieces and the removal of small amounts of material. Precise alignment is required, which slows the production rate. Also, the resulting cuts are nonuniform and thermally damaged. Plasma arcs are suitable for machining any metal. In spite of the high equipment and operating costs, rapid cutting rates make plasma cutting economical for straight cuts. Although the plasma cuts are smooth, the top surfaces are rounded. A second problem with this thermal cutting technique is the distortion of surface characteristics. CONCLUSIONS As a result of this study, the feasibility of machining with abrasive-waterjets has been successfully demonstrated. Specific conclusions are listed below. • Abrasive-waterjet nozzles typically used for slotting are adequate for machining operations such as milling. • Reasonable rates of material removal can be obtained with the abrasive-waterjet technique with relatively low power levels. • A full economic analysis and comparative studies with other techniques need to be conducted for a full economic assessment. The results of this preliminary testing, however, have been very encouraging. 18
Page 1 and 2: PROCEEDINGS OF THE FOURTH U.S. WATE
Page 3 and 4: FOREWORD The U.S. Water Jet Confere
Page 5 and 6: FIELD APPLICATIONS- MINING Water Je
Page 7 and 8: Figure 1. Abrasive-Waterjet Nozzle
Page 9 and 10: N2 = ⋅ 2 d 2 j mav N = 3 N 4 Sett
Page 11 and 12: • Although reasonable correlation
Page 13 and 14: Effect of Traverse Speed Increasing
Page 15 and 16: Table 3. Material removal rate and
Page 17 and 18: Abrasive flow rate 7.5 g/s (maximum
Page 19 and 20: where u is the traverse rate in mm/
Page 21: Table 4 shows the results of additi
Page 25 and 26: 12. Preece, C., editor, "Treatise o
Page 27 and 28: experiment was carried out to exami
Page 29 and 30: of changes in jet pressure, nozzle
Page 31 and 32: D = 0.0911 P 1.42 n 1.37 V −0.39
Page 33 and 34: Figure 8. Average Specific Energy V
Page 35 and 36: with the density of the material, o
Page 37 and 38: PERCUSSIVE JETS—STATE-OF-THE-ART
Page 39 and 40: This process of discharge modulatio
Page 41 and 42: has been demonstrated on all types
Page 43 and 44: 500 psig and 6,000 psig. Compressiv
Page 45 and 46: Figure 6. STATIC IMPACTS ON COMMERC
Page 47 and 48: not pursued because frequency, ampl
Page 49 and 50: 12. Ponchot, W.D., "Hydrodynamic Mo
Page 51 and 52: THEORETICAL ANALYSIS AND EXPERIMENT
Page 53 and 54: D.Rockwell, E.Naudascher, Thomas an
Page 55 and 56: Fig. 3 Flow model Hence we can comp
Page 57 and 58: amplitude decreases suddenly when c
Page 59 and 60: Where T: wave function period If we
Page 61 and 62: Fig.14 Variation of dimensionless r
Page 63 and 64: EXPERIMENTAL RESULT ANALYSIS (1) Th
Page 65 and 66: Fig.19 Amplification factor versus
Page 67 and 68: DYNAMIC CHARACTERISTICS OF WATERJET
Page 69 and 70: A piezoelectric transducer (Kistler
Page 71 and 72: From the data obtained, it is clear
Page 73 and 74:
conjectured that this optimum signa
Page 75 and 76:
difference of impact forces with an
Page 77 and 78:
The pressure of the jet is not an i
Page 79 and 80:
near the nozzle exit in the mixing
Page 81 and 82:
etween 0.5 mm and 1.5 mm. Full- fie
Page 83 and 84:
earlier observations that cavitatio
Page 85 and 86:
Obstructed Conical Nozzle The nozzl
Page 87 and 88:
CONSIDERATIONS IN THE DESIGN OF A W
Page 89 and 90:
An experimental mechanism was desig
Page 91 and 92:
horn and the modification of the st
Page 93 and 94:
ased on more detailed examination o
Page 95 and 96:
DEVELOPMENT OF CAVITATING JET EQUIP
Page 97 and 98:
hole, a total 23 minutes was requir
Page 99 and 100:
from 1.5 to 4 ft to be cut. Other f
Page 101 and 102:
Table 2 Summary of CCPC Pavement Cu
Page 103 and 104:
All of the experimental modules wer
Page 105 and 106:
Figure 10. Effect of CAVIJET R cutt
Page 107 and 108:
HYDRO DEMOLITION - TECHNOLOGY FOR P
Page 109 and 110:
Figure 1. Air entrained concrete pr
Page 111 and 112:
TABLE II used a mean rating because
Page 113 and 114:
As work loads grew and costs escala
Page 115 and 116:
inches deep of deteriorated bridge
Page 117 and 118:
Figure 6. Atlas Copco Conjet removi
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6. Total Ownership Cost Per Day $ 9
Page 121 and 122:
ABRASIVE-WATERJET AND WATERJET TECH
Page 123 and 124:
Commercial nuclear power plant deco
Page 125 and 126:
Figure 3. Components of rotating no
Page 127 and 128:
shroud and catching system designed
Page 129 and 130:
Figure 9. Effect of abrasive size.
Page 131 and 132:
alternative abrasive material. The
Page 133 and 134:
four arms leading to nozzle holders
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surrounding grout, they tended to r
Page 137 and 138:
12. Hashish, M. “Steel Cutting wi
Page 139 and 140:
Figure 1 Kerf test stand pressure v
Page 141 and 142:
Figure 3 Kerf area versus standoff
Page 143 and 144:
The ratio of kerf depth to width or
Page 145 and 146:
where: x c = u o d o ( ) (1) 4v e l
Page 147 and 148:
Depending on the rock type γ can v
Page 149 and 150:
CONICAL WATER JET DRILLING W. Dicki
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feed line. A conical cutting fluid
Page 153 and 154:
A second series of tests at the ful
Page 155 and 156:
Figure 8. 6061-T6 aluminum cut with
Page 157 and 158:
serves to reduce tool wear (8). It
Page 159 and 160:
Traverse speed is the velocity of t
Page 161 and 162:
Figure 4: Diagram illustrating the
Page 163 and 164:
The picture changes dramatically wh
Page 165 and 166:
Analysis of the residuals of these
Page 167 and 168:
5. Hood, M., "Cutting Strong Rock w
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hundred feet-per-second. At these v
Page 171 and 172:
Figure 1. Typical Nozzle Configurat
Page 173 and 174:
Figure 5. Expanded Signal from an I
Page 175 and 176:
where: V w = water velocity F = mea
Page 177 and 178:
HYDRO-ABRASIVE CUTTING HEAD—ENERG
Page 179 and 180:
Figure 3. Percentage of initial abr
Page 181 and 182:
Figure 6. Location of optimum recei
Page 183 and 184:
WATER JET ASSISTED LONGWALL SHEARER
Page 185 and 186:
• reduction of the proportion of
Page 187 and 188:
The conversion set for the shearer
Page 189 and 190:
into account. As far as possible no
Page 191 and 192:
gal/yd 3 ). Another important influ
Page 193 and 194:
At approximately 2 m/s (393 fpm), a
Page 195 and 196:
Proceedings of the 8th Internationa
Page 197 and 198:
κ = permeability of rock at atmosp
Page 199 and 200:
operating parameters (P. V tr , etc
Page 201 and 202:
κ = permeability at 1 atm. pressur
Page 203 and 204:
was substantial gain in the depth o
Page 205 and 206:
Figure 9. Plot of exposure rate aga
Page 207 and 208:
For nozzle C2, a = 0.5 x 10 4 and b
Page 209 and 210:
204
Page 211 and 212:
Deep drilling or slotting requires
Page 213 and 214:
imparted by an air motor coupled to
Page 215 and 216:
Conventional rotary or percussive r
Page 217 and 218:
A RELATIVE CLEANABILITY FACTOR A. F
Page 219 and 220:
Relation [6] was used to derive the
Page 221 and 222:
which has been observed for much of
Page 223 and 224:
As part of a project to develop the
Page 225 and 226:
Figure 1. Cost per square foot clea
Page 227 and 228:
Abrasive Feed Rate The effect of ab
Page 229 and 230:
Figure 4. Total cost per square foo
Page 231 and 232:
3. Barker, C. R.; Mazurkiewicz, M.
Page 233 and 234:
For our purposes here, we will lump
Page 235 and 236:
Surface condensers can be cleaned b
Page 237 and 238:
Some Powerlance customers have 20,0
Page 239 and 240:
system could be designed that was o
Page 241 and 242:
236
Page 243 and 244:
ROTARY WATERBLAST LANCING MACHINES
Page 245 and 246:
Motors and Gearing An advantage of
Page 247 and 248:
The DuPont Company in LaPlace, Loui
Page 249 and 250:
Fig 3 Heavy duty Rotary Lancing Mac
Page 251 and 252:
D L - lower diameter of through hol
Page 253 and 254:
Figure 1. A - single-pass, rough ke
Page 255 and 256:
The erosion process is stochastic i
Page 257 and 258:
three dimensional controlled erosio
Page 259 and 260:
This can only be regarded as a simp
Page 261 and 262:
approximately zero. Time constant T
Page 263 and 264:
Figure 12. Transients of HAJM cycli
Page 265 and 266:
T A = (f, h o, p, s o, f o, c, . .
Page 267 and 268:
SURFACE FINISH CHARACTERIZATION IN
Page 269 and 270:
FIG. 2 Force Sensor Designed for Cu
Page 271 and 272:
system can be used in the developme
Page 273 and 274:
Figure 8 Cutting Force versus Cutti
Page 275 and 276:
nearly at the center of the ceramic
Page 277 and 278:
ABRASIVE WATERJET CUTTING OF METAL
Page 279 and 280:
Figure 1. Experimental setup, inclu
Page 281 and 282:
Figure 3. Scanning microphotograph
Page 283 and 284:
Figure 8. Effect of cutting speed o
Page 285 and 286:
a. Scanning microphotograph, lOOOx
Page 287 and 288:
c. Silicon image 1000x Figure 16. S
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