Let the chips fly: fast, 5-axis machining
TruePath software from CAMplete Solutions Inc. runs full five-axis CAM programs in a unique fashion, accommodating all machine kinematics to maintain tool path integrity.
“We perceived a market need for five-axis machining, where we could offer customers a complete turnkey package from engineering to application, software to machining programs, prototype to production runs, on a variety of complex parts,” explains Rob Bujeaud, vice-president of manufacturing for Turbocam.
“We began with a single machine and a vision in 1985,” he says. “We believed that with ongoing integrity, investment and innovation, we could be successful in the market for the long run. Today, we make that scenario happen for our aerospace, automotive and commercial business partners, every day.”
The Chiron FZ08KSM machine used in this application features a small (2.3 sq m) footprint, fast chip-to-chip time of 1.9 s or less, rapid feed rate of 75 m/min, acceleration up to 2g, typical spindle rate up to 27,000 rpm, tool changes in 0.8 s and, in this application, a two-axis NC rotary/tilt table—an ideal combination for the aluminum workpieces processed at Turbocam Automated Production Systems (TAPS), according to Turbocam engineering manager, Andrew Hussey.
The associated Siemens Sinumerik 840D CNC system offers a wide range of specialized functions for milling, drilling, turning, grinding, and materials handling technologies. Its open architecture is said to increase productivity on the manufacturing floor, especially in the challenging segments of high-speed and five-axis machining.
Impellers machined on these work cells measure approximately 4-in. dia. x 4-in. high and load/unload at the rotary table fixture via robot. Many passes are required to machine the impeller blades, so the speeds of the spindle, toolchanger and rotary table are all critical for optimum cycle time. Hussey also noted the advantages of the Siemens CNC and drive package, Simodrive 611U, in this process. Says Hussey, “The high speeds and five-axis movement can create nonlinear machine motion that affects cutting accuracy and the CNC/drive package helps to smooth out those kinematics. This is also an area where the CAMplete TruePath software compensates for nonlinear machine motions.”
TruePath takes APT or CL data as well as native CAM data, such as MasterCAM .nci and OpenMind .pof and creates the CAM program-compensating tool path and communicating design intent in a manner comparable to a typical post-processor, with the added advantage of factoring machine motions into the sequence. According to the developer, CAMplete Solutions Inc., it provides everything needed to modify, analyze, optimize, simulate, and post-process five-axis tool paths in a seamless five-view 3D environment. Tool path editing, vectoring, vector modification to avoid collision, and machine overtravel monitoring help to further reduce time to first part.
While actual run time per cycle is proprietary between TAPS and its customer, a diesel engine builder, Hussey comments that reduction in run time exceeded 20%, compared to the production method and machines previously utilized for this application. He explains, “We track production on every machine in the facility and compare output by machine, by cell, and by product produced. Since the materials we run vary considerably, it’s critical that we maintain these data, to facilitate proper selection of machines for target projects. In the case of these impellers, we knew Chiron machines that we first saw at IMTS in 2004 and again at the 2005 EMO show were the answer, compared to other five-axis vertical milling centers on the market and even those brands in our shop.”
Despite the speeds involved, typical tolerances are better thanion essential for process integrity.
The Siemens 840D with onboard ePS network server also monitors tool wear and overall machine maintenance, with Wi-Fi email capability directly from the controller to Chiron America in North Carolina as well as the machine builder’s factory in Germany.
Parts are checked on an in-house five-axis CMM (coordinate measuring machine) at TAPS, before they are released to the customer.
As a unique collateral benefit to work cell design at TAPS, there are heat exchangers on the fluid-processing system that feeds into evaporative coolers outside the building. The captured energy is also used to heat walkways during cold New England winters. Company personnel did the design and engineering work on this system.
Tool path software can help decrease time to create the first part and reduce production time after that.
Regarding the overall operation of the machine controls, Hussey notes his operators and application engineers like the speed and flexibility of the Siemens CNC. Hussey further notes that the open architecture of the CNCs onboard Chiron machines make them extremely adaptable to changes, auxiliary equipment add-ons and the attendant monitoring/tracking of data required thereby. “The CNC has a great ability to process data and remain flexible enough to accommodate our various automation set-ups. In conjunction with Chiron machine technology, we’re getting the best possible combination available for this application.”
Hussey and Bujeaud detail how a typical job flows through the TAPS engineering department. “We take design data, Pro-E model, or IGES file, then create our engineering model. It rarely happens that we get a machinable model from our customer, unless we’ve created it at our parent company (Turbocam). We analyze the customer model to determine proper surface integrity and curvature to reduce surface deviation, designing the three-axis tool path, as well as the two-axis rotary table movements. Tool path placement is the result of our TruePath software and internal Turbocam coding. With these‘clean data,’ we determine tool position and tool axis vectors in an APT format with XYZ positions in 3D space. The approaches and retracts are automatically determined in the TruePath software, which is a real time saver. We are able to do the first runout on the actual production machine much sooner than in the past and with much more predictable results. We’re even able to simulate program execution on different materials, using our existing performance databases. The Traori (transformation orientation) feature of Sinumerik 840D also gives us great control over the entire process, because it’s based on workpiece orientation rather than tool position in a predetermined program. This results in a more consistent finish and less chatter on the material surface, an absolutely critical factor in these turbocharger components.”
Hussey and Bujeaud cited the onsite training provided by Chiron, as well as update seminars offered by Chiron and Siemens, as factors in determining their selection as vendors on this project. “The training on the application, software, and servicing of the machine were all first-rate.”
Turbocam processes a variety of aerospace, automotive, and medical-grade materials, including aluminum, magnesium, nickel-based alloys, titanium, 304, 416, 17-4 and 15-5 stainless steel, HP1318 surgical and various tool steels, as well as plexiglass impellers for the medical industry.
Rob Bujeaud and Andrew Hussey of Turbocam/TAPS, Karamarie Gerbracht and Marty Demers of Chiron America, and Jim Rodgers of Siemens Machine Tool Business provided information for this article.