Programmed in ESPRIT, this finished part is a template for knee-replacem
Programmed in ESPRIT, this finished part is a template for knee-replacement
RD Machine, Inc., Hutchinson, Minnesota, is a machining job shop that works for the process control, medical and aerospace industries, among others. Over the last few years, the company has purchased a number of 4- and 5-axis CNC machining centres with the goal of increasing productivity by reducing the number of setups required to produce complex parts. “Our previous CNC programming software worked well in 2- and 3-axis machining, but we discovered that it was not the right tool for 4- and 5-axis machining centers and mill-turn lathes,” said Jeff Laway, president of RD Machine. Based on the recommendation of a machine-tool manufacturer, RD Machine switched to ESPRIT CNC programming software from DP Technology Corp., which provides a wide range of features designed especially for 4- and 5-axis machining, as well as mill-turn machines. “ESPRIT is designed specifically for today’s latest machine tools and provides a wide range of features that help us get the most out of these machines while simplifying the programming task,” Laway said. “The end result is that we can now take full advantage of the power of newer machine tools while reducing programming time by about 25percent.”
RD Machine sets itself apart by investing in the latest technology to provide its customers with the highest possible levels of quality, competitive pricing and fast delivery times. For example, the company recently purchased a Makino PS95 vertical machining center with 4-axis simultaneous machining plus one additional positioning axis. The key advantage of the additional axes is the ability to move the part so that the tool can access it from nearly any angle to machine surfaces at compound angles, drill holes at angles, access hidden surfaces, etc. So a complicated part that might have taken up to 15 setups and many custom fixtures in the past can now often be machined with only one or two setups with no need for custom fixtures. This substantially reduces the amount of time required to machine the part, which in turn enables the company to offer more competitive pricing and faster delivery times. Quality is also improved because reducing the number of setups makes it possible to more closely control the relationships between different features than was possible in the past. The company’s mill-turn machines offer similar advantages by completely machining parts that would normally require operations on both a turning centre and a machining centre.
Challenges of Programming the Latest Machine Tools
When RD Machine began using 4- and 5-axis and mill-turn machines, the company began to experience the limitations of the CNC programming software that it used in the past. “The programming complexity is much greater with the newer generation of machines,” Laway said. “We found that we were unable to access many of the capabilities of these machines through our previous software. In many cases we had to write manual code in an effort to take full advantage of these machines. This substantially increased the amount of time required for programming and created the potential for errors, which took additional time to resolve. In a number of cases, we also had difficulty getting the code produced by our old software to run on the newer machines.” Laway spoke to the manufacturers of several of his newer machines and received a recommendation to try ESPRIT. ESPRIT is specifically designed to meet the challenges of programming for 2–5 axis milling, 2–22 axis turning, 2–5 axis wire EDM, multitasking mill-turn machining and B-axis machine tools, and high-speed 3- and 5-axis machining. For example, it offers a wide range of milling strategies designed especially for 5-axis milling, such as composite milling, ruled swarf miling, surface swarf milling, contour milling and impeller milling.
RD Machine purchased one seat of ESPRIT and later a second seat as the advantages of the new software became clear. “ESPRIT provides an excellent platform for programming 4- and 5-axis and mill-turn machines,” Laway concluded. “It can import a solid model from nearly every CAD program and nearly always gets the geometry right the first time. Feature recognition saves a substantial amount of time by quickly and accurately adding the intelligence back to the model that is inevitably lost when the geometry leaves the proprietary environment of the CAD system. ESPRIT offers a wide range of milling strategies that are specifically designed to take advantage of the capabilities of 4- and 5-axis machines, as well as many others designed for 3-axis machines. The powerful simulation capabilities in ESPRIT help to ensure that, in spite of the complexities of 5-axis machining, our programs work right the first time we try them. ESPRIT also does a much better job in supporting the capabilities of advanced machines with their posts. We almost never have to write manual code anymore.”
Example of a Medical Device Part
As an example of the programming improvements that RD Machine has achieved with ESPRIT, Laway cited the case of a class of medical device parts the company programs on a regular basis. In the past, these parts required considerable amounts of manual code to access the machine’s fourth and fifth axes. Problems were often experienced with this code, which required extra time to resolve. The programming process was greatly simplified with ESPRIT. Laway began programming the latest part by importing the customer’s solid model, which contained the geometrical definition of the part. He then used ESPRIT’s automatic feature recognition capability to restore the intelligence to the geometry by organising it into features such as holes, bosses, pockets, chamfers, fillets, etc. He checked over the features recognized by the software and made a few changes.
The next step was defining the machining operations. The ESPRIT KnowledgeBase helps a programmer or operator determine the best method to machine a given part or feature by automatically selecting the most appropriate machining cycles, cutting tools and machining parameters based upon best practices saved by the company. Laway used ESPRIT’s 5-axis composite milling function to independently define the machining patterns and tool orientation strategies to be used when creating the toolpath. This function includes 20 different machining strategies so it can handle nearly any geometry. Laway also used the 5-axis contour milling strategy, in which the tool follows a curve while keeping its axis perpendicular to the part surface.
Realistic Simulation and Visualisation
For each toolpath, Laway selected a tool and defined its diameter, length, tool holder and speeds and feeds. After the toolpath was generated, he used ESPRIT’s simulation functionality to visualise the cutting process. The realistic simulation and visualisation generated by ESPRIT rendered the complete cutting process with lifelike realism, including all toolpath, inclined or indexed, from 2 to 5-axis. The simulation is not limited to a simple graphical effect, but provides the advance detection of any unreachable axis position, or collision of the machine’s moving parts, the tool and its holder, and the part being produced. Laway also viewed a presentation of the part that would be produced by the program and compared the as-machined workpiece to the original design. He spotted a few areas where improvements were possible and made tweaks to the program.
Just like the majority of programs produced by RD Machine, the resulting program worked perfectly the first time it was run on the Makino PS95 5-axis machine. Laway estimates that the time required to program the part was about 25 percent less than what was required to produce similar parts in the past. Laway also said that the machining cycles designed specially for 5-axis machining provide significant reductions in machining time on many parts. “By utilizing ESPRIT to generate CNC programs for our 4- and 5-axis and mill-turn machines, we have substantially increased our capabilities to deliver high quality parts to our customers at a competitive price with fast delivery times,” Laway concluded. “Our 5-axis machines are inherently faster because of their ability to produce parts with fewer setups, but ESPRIT generates additional productivity gains with its strategies designed especially for 5-axis milling and ability to support the full functionality of these machines. Finally, the excellent technical support provided by ESPRIT makes it easy for us to take full advantage of the software’s capabilities.”