epetitive multiaxis manufacturing of complex parts poses a special challenge to CAM software manufacturers. Examples include Swiss-machined medical components, cylinder-head ports, and multiblade parts used widely in aerospace, energy conversion, and other fluid movement applications. When considering the possible alternative approaches, Mastercam’s multidiscipline teams at CNC Software Inc. (Tolland, CT) came to the conclusion that the CAM software should be simple yet highly intelligent. It should be able to automatically analyze the model and create the most efficient and safe manufacturing process with only a minimal amount of intervention from the end user.
"Multibladed parts are difficult to machine because orientation of the tool must be continually adjusted to reach all the surfaces that require machining," explains Karlo Apro, Mastercam multiaxis product manager. "Programming a complex multiblade part, even with full-featured CAM software, must be done thoughtfully and carefully to avoid crashes and ruining an expensive part. It’s common for programming to take a couple of days. One approach blade manufacturers have relied on is the 3:2 programming technique in which the part is rotated to a new angle and then a three-axis program is used to clear out as much material as possible from that orientation. Then the part is moved to a new position and more material is cleared. These programs are tedious to write, and they result in very long machining cycles because there are many overlaps where the tool is doing nothing but air cutting."
Some blade manufacturers have sidestepped this problem by opting not to manufacture the blade out of a mono material but instead to manufacture blade segments and assemble them into a special manifold. This can result in a heftier design; however the problem of machining hard-to-access material is substituted for the problem of aligning and balancing blade components in a multiblade assembly.
Multiblade parts come in a variety of shapes and sizes, but there is a significant amount of similarity in the way they are machined. The workflow is almost always the same: rough out excess material between the blades; semifinish the blades; finish the blades; and finish the base. "The initial iteration of our blade program makes it possible to apply this one workflow process to a wide variety of multibladed parts. All the user is required to do is identify the features on the part. After bringing in the blade model, the user is prompted to provide basic manufacturing information from selecting the tool, toolholder, and tooling-related data to choosing the cut pattern and setting collision avoidance and noncutting gap motions," Apro explains.
Program simulation using Vericut software enables the user to visualize all of the complex machine movements. "Blade Expert reduces what would have taken two days with conventional programming techniques down to an hour," says Apro. "We evaluated the expert blade program by dipping into a library of blade models that had been collected over decades. Once we had worked our way through our own library of nasty blades, we also began benchmarking the expert blade program against blade models sent to us by several five-axis machine tool builders. By the time this simulation process was finished, the program was tested on more than 50 different blade designs."
After extensive benchmarking, Blade Expert is being released along with Mastercam X6, which is available now. Users are able to purchase a seat of the product as is and use it specifically for blade manufacturing or in conjunction with a full five-axis seat of Mastercam with a broad range of "big toolbox" capabilities. Postprocessor modifications have been developed so that the expert blade programming works cleanly with a wide range of five-axis manufacturing systems.
Before blade manufacturers can begin using their Blade Expert seat, however, they will be required to go through a qualification process to verify that their five-axis machine tool is calibrated and that their postprocessor is capable of precise code generation for blade manufacturing. Mastercam application specialists will modify the posts if necessary, train the programmers, write the first part program for the user, and manufacture it on the customer’s own five-axis equipment to assure that the process works. ME
For more information from Mastercam/CNC Software,
go to www.mastercam.com or phone 860-875-5006.
Aerospace Alloy Machining HMCs
Thermal stress and wear at the cutting edge in milling high-strength materials like titanium and nickel alloys continue to challenge aerospace manufacturers. The solution is found in machines that provide high torque delivered at low speed.
The latest machine development from Heller Machine Tools LP (Troy, MI), the F Series HMC for five-axis simultaneous machining, features three high-performance spindle options for different cutting conditions and part configurations.
The F2000 HMC with swivel head offers a large working area of 800 × 800 × 1000 mm, (X, Y, Z) and can accommodate a 630-mm pallet and a 3080-lb (1397-kg) workpiece. The high-performance spindles offer options to machine smaller, lighter parts, frequently made from tough materials like titanium, and aluminum parts that require high-speed machining.
The swivel-head provides a fifth axis that delivers a constantly high-cutting performance in horizontal and vertical position, as well as any spatial angle, especially important for aerospace applications. Five-axis machining is provided by the tool in X, Y, C or A axes and two axes provided by the workpiece in the Z and B axes.
Machine structure and axis design are tailored to the special requirements of five-axis machining. Heller determined that the most flexible, robust, and efficient way to do five-face and five-axis machining is to have one of the axes in the workhead. Using a B-axis table in combination with a universal or tilting workhead allows greater table loads, larger working envelopes and greater accessibility than five-axis machines that have two axes of motion under the workpiece, such as a tilt/rotary table or C-over-B type.
HSK63 spindle choices include the PCU 63 for high-performance cutting with speeds up to 10,000 rpm, power up to 44 kW and torque up 244 N•m. Two other spindles go up to 16,000 rpm with 40 kW of power and 80 N•m of torque: the SCU 63 and the SCT 63 Tilt spindle. The SCT-63 is an A-axis head, in contrast to the others that are C-Axis. The A-axis provides even more flexibility in cutting complex shapes. ME
For more information on Heller
Machine Tools, go to www.heller-us.com, or telephone: 248-288-5000.
CNC Ties Machine
Data to Enterprise
Integrating machine tool and production data into company-wide information systems—right down to the chip level—can uncover weak spots, eliminate them, and develop an effective basis for a continual improvement process. In that sense, integration of machine tools into corporate processes is a vital step toward the achievement of lean production. Machine tools can be commissioned more effectively, made more productive, and are easier to customize and optimize over their entire lifecycle within the complete PLM process chain.
Sinumerik Integrate from Siemens Industry Inc. (Elk Grove Village, IL) offers machine tool OEMs the opportunity to optimize Sinumerik CNCs in terms of improved technology, programming, and operation. Builders can integrate their machines quickly, simply and efficiently into customer production and communication processes. However, machine tool users can also use Siemens Integrate to successfully integrate their machines into complex existing corporate IT systems. Benefits include improved productivity and overall reduction in manufacturing costs.
Integrating machine tool data quickly and reliably into other company processes allows managers, machine operators, part programmers, maintenance engineers, and machine tool builders to be inter-connected with each other and integrated into the overall system by means of defined processes. IT-related functions are integrated into the network using a single process suite of six different available modules that cover every aspect of the machine tool integration process.
The "Create-it!" module is used to group solutions for the generation and configuration of user-specific functions in the Sinumerik Operate user interface. The programming of interfaces to machine tools and to company servers also falls within the scope of this module. Extensive function libraries facilitate the use of NC, PLC, and HMI functions across the entire network. Proprietary technological expertise in the machine tool is protected against unauthorized access using the function of the "Lock-it!" module.
The "Run-it!" module encompasses the entire runtime system for execution of the individual screen interfaces and of internal compile cycles at the NC kernel. Drive control and also the workflow of the virtual numerical controller kernel (VNCK) are also part of this module. "Manage-it!" is used for the organization and management of NC programs and tools, comprising solutions related to tool, data and program management to enable the fast, overarching availability of production information. The rapid availability of NC programs over the network, central NC program management and storage are also key functions of this module, as is an overview of actual tool data.
The standardized communication interface used throughout the Sinumerik CNC family is made available by the "Access-it!" module, which allows remote accessing for machine diagnostics. This module helps reduce machine downtime, enhances machine availability by allowing fast online access and cuts maintenance costs. It also allows backups to be automatically initiated by the higher-level data backup software overnight, or decentrally-generated information such as local NC programs to be collected automatically. "Access-it" has the additional benefit of reducing standstill periods and preventing data loss in the event of component failure.
The "Analyze-it!" module makes a number of functions for condition-based maintenance and key indicator-based analysis available. The continuous evaluation of information within the production process allows machine run-times to be increased, while condition-oriented maintenance reduces machine downtime and standstill periods. ME
For more information about CNC solutions and services from Siemens Industry Inc., go to www.usa.siemens.com/cnc, or telephone 847-640-1595.
TechFront is edited by Senior Editor James Lorincz.
He can be reached at firstname.lastname@example.org.
This article was first published in the May 2012 edition of Manufacturing Engineering magazine. Click here for PDF.