This page contains a Flash digital edition of a book.
TechView CAD/CAM Developments:


What is Required?


Te aerospace industry has always been an early adopter of CAD/CAM tech- nologies for designing and manufactur- ing of the components necessary for its industry. Milling of aerospace compo- nents, while sharing similarities to mill- ing of other parts, also presents its own set of unique challenges, oſten related to the intended use and long-term safety requirements of those components. Because of this, many CAD/CAM de-


velopers collaborate with engineers from the aerospace industry when determin- ing future development directions. Oſten, what is requested is not new cutterpath algorithms, but rather complementary functions to make existing functions work more reliably and efficiently. Large Parts: It has become neces-


sary for CAM systems used in aero- space applications to utilize an internal database capable of working with large data sets. Aerospace parts with curved details, such as an airfoil, are oſten tessellated so that point-to-point CNC output can be generated. Tighter the tolerance used during tessellation, the more points generated. It is not uncom- mon for CNC files for large parts to have tens of millions of individual CNC points defined in them. Calculating these large parts can


be time consuming: Fortunately, new developments in CAM have shortened these calculation times. CPUs and work- stations with multicore technology have replaced older workstations. Addition- ally, CAM developers have implemented multithreading into their algorithms, allowing for faster calculations. With some aerospace parts, you have a very large part with slight curvature,


such as an airfoil. Tis presents a chal- lenge in the finish of the part, where one may see the use of tessellations. Although using tighter tolerances is beneficial due to the large curvature of the part, it may not be enough. Some CAM systems also utilize a “Maximum Segment Length,” such that no two points in an NC file will be more than a set distance apart regardless of the tolerance, and additional points will be placed on the 3D data as needed to fill in the gaps.


The milling of aerospace components presents its own set of unique challenges.


Accurate Stock Representations: Dur-


ing the milling process, there are oſten multiple operations performed prior to the completion of the final part. Main- taining an accurate representation of the remaining stock, before, aſter and dur- ing cutter-path calculations is important for reliable milling. Knowing stock thicknesses during


calculations in a dynamic environment allows CAM algorithms to create more efficient cutterpaths. It also allows cut- terpaths to consider the cutter load and make adjustments as necessary. Creating trochoidal, or similar adaptive move- ments is necessary to maintaining the cutter load. Accurate stock representa- tions are necessary for the collision checking process, not just the tool, but for the toolholder and machine tool. Machine Simulations: Although


the aerospace industry was an early adopter of five-axis technology, en- hancements to this technology have


Jeff Jaje


Business Development Manager, Vero Software Wixom MI


improved the CAM process. Previously, third-party programs have been used to accurately simulate the five-axis cutterpaths to ensure there were no col- lisions or catastrophic events with the machine tool, tooling, and part. Ma- chine simulation and collision check- ing has since been integrated into the CAM soſtware—allowing programmers to fine-tune their five-axis programs without changing soſtware products. Tis ensures programmers are us- ing the shortest tool lengths possible, and the stiffest tool and toolholder combinations allowed. Tis minimizes tool deflection, which allows for faster cutting speeds, allowing programmers to optimize their toolpaths for cutter forces and chip loads. 3D Printing: While the scope of this


article was CAM focused, we would be remiss to not mention the growth of 3D printing in the aerospace industry. Besides its use in prototyping, there


are 3D-printed parts used in production airplanes. Te Boeing 787 currently has approximately 30 different parts that are manufactured through 3D print- ing. Tese parts in use are in noncritical areas, however, it has been stated by the major aerospace manufacturers that they would like to see this technology evolve into creating structural parts. When this happens, many 3D-print-


ed parts may still need some form of milling, drilling, tapping or grinding to bring them to a finished state. It will be- come important for CAD/CAM soſtware to work with 3D printing soſtware and algorithms, allowing these parts to be created seamlessly through a hybrid of 3D printing and milling operations. ✈


Aerospace & Defense Manufacturing 2013 57


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150  |  Page 151  |  Page 152  |  Page 153  |  Page 154  |  Page 155  |  Page 156  |  Page 157  |  Page 158  |  Page 159  |  Page 160  |  Page 161  |  Page 162  |  Page 163  |  Page 164  |  Page 165  |  Page 166  |  Page 167  |  Page 168  |  Page 169  |  Page 170  |  Page 171  |  Page 172  |  Page 173  |  Page 174  |  Page 175  |  Page 176  |  Page 177  |  Page 178  |  Page 179  |  Page 180  |  Page 181  |  Page 182  |  Page 183  |  Page 184  |  Page 185  |  Page 186  |  Page 187  |  Page 188  |  Page 189  |  Page 190  |  Page 191  |  Page 192  |  Page 193  |  Page 194  |  Page 195  |  Page 196  |  Page 197  |  Page 198  |  Page 199  |  Page 200  |  Page 201  |  Page 202  |  Page 203  |  Page 204  |  Page 205  |  Page 206  |  Page 207  |  Page 208  |  Page 209  |  Page 210  |  Page 211  |  Page 212  |  Page 213  |  Page 214  |  Page 215  |  Page 216  |  Page 217  |  Page 218  |  Page 219  |  Page 220  |  Page 221  |  Page 222  |  Page 223  |  Page 224  |  Page 225  |  Page 226  |  Page 227  |  Page 228  |  Page 229  |  Page 230  |  Page 231  |  Page 232  |  Page 233  |  Page 234  |  Page 235  |  Page 236  |  Page 237  |  Page 238  |  Page 239  |  Page 240  |  Page 241  |  Page 242  |  Page 243  |  Page 244  |  Page 245  |  Page 246  |  Page 247  |  Page 248  |  Page 249  |  Page 250  |  Page 251  |  Page 252  |  Page 253  |  Page 254  |  Page 255  |  Page 256  |  Page 257  |  Page 258  |  Page 259  |  Page 260  |  Page 261  |  Page 262  |  Page 263  |  Page 264  |  Page 265  |  Page 266  |  Page 267  |  Page 268  |  Page 269  |  Page 270  |  Page 271  |  Page 272  |  Page 273  |  Page 274  |  Page 275  |  Page 276  |  Page 277  |  Page 278  |  Page 279  |  Page 280  |  Page 281  |  Page 282  |  Page 283  |  Page 284  |  Page 285  |  Page 286  |  Page 287  |  Page 288  |  Page 289  |  Page 290  |  Page 291  |  Page 292  |  Page 293  |  Page 294  |  Page 295  |  Page 296  |  Page 297  |  Page 298  |  Page 299  |  Page 300  |  Page 301  |  Page 302  |  Page 303  |  Page 304  |  Page 305  |  Page 306  |  Page 307  |  Page 308  |  Page 309  |  Page 310  |  Page 311  |  Page 312  |  Page 313  |  Page 314  |  Page 315  |  Page 316  |  Page 317  |  Page 318  |  Page 319  |  Page 320  |  Page 321  |  Page 322  |  Page 323  |  Page 324  |  Page 325  |  Page 326  |  Page 327  |  Page 328