Aero Components getting up to speed
New CAM software reduces programming and machining time for USA-based subcontractor Aero Components
Aero Components is an advanced subcontract machining firm that uses mill-turn machines to produce complex and precision components for the aerospace, medical, semi-conductor, and oil field industries. The company’s machinists, who produce their own CNC programs, were less than satisfied with the previous CNC software because its milling strategies were limited and programs ran at less than optimal speed. The company switched to ESPRIT Mold from DP Technology because of its much broader range of milling strategies and ability to optimize the speed at which the resulting code runs on the machine. This new CAM software has helped to substantially reduce the amount of time required for programming while increasing the productivity of the company’s CNC machine tools.
Most of the parts produced by Aero Components are for surgical instruments. For example, the company produces aluminum housings and most other components for a number of different models of bone and tissue shavers. The company uses 13 multitasking Mazak Integrexes and two Mazak Multiplex mill-turn machines, as well as several lathes, horizontal and vertical mills and two EDMs. The CAM software previously used by the company offers only two types of toolpaths, Z-level and planar machining. In Z-level machining, the cutter starts at the top of the part and goes around it while stepping down each revolution. In planar machining, the cutter goes back and forth in parallel lines to - for example - rough out a pocket.
Another concern with the previous software was that it did not address the full capabilities of the 5-axis Integrex machines, such as the ability to rotate the mill spindle and the part at different angles. This meant that all but the simplest programs required manual editing before they could be run. The programs produced by the previous CAM software also ran considerably slower than speeds appropriate to the capability of the machine.
The problem was that the software would generate paths with a large number of intermediate points spaced very closely together. The machine’s control could not process the points fast enough, resulting in very large programs and more machine wear. These calculations often could not be processed before the last motion was completed, with the result that the cutting tool idled while the calculations were being completed, effecting the finish quality. 
‘We were impressed with ESPRIT Mold from DP Technology because it makes it easy to program complex toolpaths,’ says Keith Woodhouse, machinist for Aero Components. ‘ESPRIT Mold is built to take full advantage of the capabilities of 5-axis mills and the latest mill-turn machines, particularly with its 3+2 feature, which makes it easy to rotate the tool and or workpiece to accommodate milling in up to five axes. This CAM software also offers a much wider range of milling strategies than I have seen in other software, which helps to improve the productivity of machining options.
"Finally, the CAM software package generates programs that run substantially faster than programs created with conventional software because they waste much less time cutting air, advancing and retracting, and idling while the machine control is calculating moves.’
The initial stage of the implementation process was challenging because ESPRIT Mold was a relatively new product to North America and posts were not yet available for their Integrex machines with the 640MTPro and the new Matrix controls used by Aero Components. ‘DP Technology pulled together a team of software developers and application engineers that went to work immediately in developing the posts,’ says Woodhouse. ‘We were very impressed at how quickly they were able to develop the posts and get them working.
Programming example
Woodhouse cites the housing for a camera used in laparoscopic surgery as an example of how the new software has improved CNC programming at Aero Components. This application provides a platform for comparing the company's previous and current CNC programming methods since the company made similar parts using the previous CAM system. It should be noted that the part described here is more complex than those machined in the past.
ESPRIT Mold software is used only for milling, so Woodhouse first used the conversational programming on the Integrex to execute turning, drilling and boring functions. Tony Lugard, a fellow Aero Components machinist, then used CAD to patch unnecessary geometry before importing the resulting geometry, in the form of an IGES file, into Esprit Mold. Next, Lugard refined the CAD model to display the few simple required turning operations done on the machine controller. He then created an STL file of the lathe work and returned it to Woodhouse. Woodhouse imported the resulting geometry into ESPRIT Mold, along with the finished part geometry and, by overlaying the two models, could easily see what metal needed to be removed from the workpiece.
Woodhouse then created toolpaths to mill out the inside of the part. For each toolpath, he selected a tool and defined its diameter, length, tool holder and speeds and feeds. He selected a 3/8 conventional end mill and used the Z-level roughing toolpath. The software automatically created a path that roughed out as much of the inside as the tool could reach without cutting areas that had been drilled and bored previously as defined by the STL file. Woodhouse then switched to a 1/4-inch ball nose-end mill. The software generated a routine that roughed out the rest of the part. While nearly all CAM software packages would have created a toolpath that followed the entire contour of the part, ESPRIT Mold first determined which areas required further roughing by looking at the current rest material after previous operations and moved the tool rapidly between these areas without cutting air, providing a substantial reduction in cycle time.
The inside of the part had several undercuts that required tilting the tool with the B axis and the part with the C axis to reach. The previous CAM software was not capable of accessing the B and C axes, so it was necessary to move these axes by manually editing the G-code program produced by the old software. This process was time consuming and prone to errors because the toolpath could not be verified graphically.
ESPRIT Mold, on the other hand, enables the programmer to create workplanes that involve rotating either the tool or part and then generates code to move the machine into the workplane as required for machining. The programmer sees the tool, tool holder and part in the proper orientation on the screen and can graphically generate the toolpath. This saves time and makes it much easier to ensure that the program is correct. Woodhouse moved the rotational axes into position, tried out the cut and was quickly able to see if there was any interference between the part and toolholder.
Woodhouse created 10 different toolpaths to rough out the part, using most of ESPRIT Mold’s wide range of machining strategies. Z-plane concentric roughing optimizes the toolpath based on the results of the previous machining cycle, eliminating air cutting and minimizing retract movements. Roughing re-machining enables the re-machining of previously cut areas of the model, resulting in a constant volume of remaining material. High-speed Z-level finishing cycles generate passes of variable height in support of a constant scallop height to produce a high-quality finish.
Planar zone re-machining provides zigzag or concentric toolpaths and the clearance distance from walls is independently controlled and may be different from clearance used with respect to the stock. In concentric milling with constant stepover strategy, ESPRIT Mold produces a toolpath inside a closed curve, avoiding any number of islands. Multiple machining strategies can also be combined. For example, radial or spiral strategies combined with constant 3D step concentric milling provide higher machining speed, superior surface quality, longer tool life and optimizing of cutting parameters.
The program generated by ESPRIT Mold produces the camera housing in 53 minutes, a reduction of 27% from the 73 minutes that was required with the program produced with the previous CAM software. These savings were achieved in spite of the fact that the newer version of the part has more complicated geometry. The time savings substantially reduce the cost of machining the part by reducing the amount of time and labor required to produce each part.
The savings were achieved because of the more efficient roughing operations generated by ESPRIT Mold, which take previous operations into account and avoids cutting air, and by the more efficient code generated by the software that reduces the number of intermediate points without affecting surface finish.
The surface finish of the parts produced with the new CAM software is even better than that produced with the old software because the tool moves continuously rather than hesitating while the machine control makes unnecessary calculations. ‘ESPRIT Mold has helped us substantially reduce our machining costs and take on complex jobs that would have been impossible in the past,’ Woodhouse concludes.
