Airbus is selling so well that the demand to increase build rate has never been higher. BAE Systems (Filton, UK) needed a simple way toimprove throughput — it found the answer in VERICUT.
Modern high-speed machine tools are equipped with digital control systems incorporating very elaborate algorithms to ensure the machine does not shake itself to pieces when contouring at feeds in excess of 20m/min. These features, more commonly known as the acceleration/ deceleration curves, work extremely well in most applications.
However, BAE Systems Filton found them to be an inhibiting factor when trying to optimize the production of key components for the wing structures of Airbus planes. It wasn’t straightforward at first; you cannot simply switch such control parameters off and hope for the best. That would have lead to some very unpredictable situations. So instead, BAE Systems set about contacting tooling and software companies for a solution. The result was a very successful project involving CGTech and Kennametal.
Both companies set about optimizing the setup on Cell F, comprised of Mori Seiki SH-50 machining centers and mainly used to cut aluminum A-Frames for the A330/340 Airbus. These come in 60 variations and are situated along the leading edge of the wings. There was no need to change the fundamental setup; material already arrived on a JIT basis pre-blocked, skimmed, and drilled ready for fixtures. So it was back to optimizing feeds and speeds. OptiPath® was used to override various control parameters, while Kennametal’s tooling allowed efficient cutting at higher feeds and speeds.
VERICUT’s OptiPath reads the NC tool path file and divides motion into a number of smaller segments. Because VERICUT mathematically subtracts the material cut away from the model, the software always knows the depth/ width/angle of cut, and the amount of material removed. Where necessary, based on the amount of material removed in each segment, OptiPath assigns the best feed rate for each cutting condition encountered. It then outputs a new tool path, identical to the original but with improved feed rates. The principle is simple – the shallower the cut, the faster the feed rate. In order to keep material cutting rather than just tearing at these accelerated feed rates, the spindle speed is ramped up accordingly. For deeper cuts the reverse is applied.
"CGTech got involved helping us to get the best out of our NC programs and changing the mind set at Filton," said Matt Godfrey, EIT team leader. "We swapped tools for ones with longer flute lengths and took greater depths of cut – and got better finishes. We didn’t have to change the part programs whatsoever. OptiPath took care of feed rates for us – we just capped the programs at 7m/min. feed rate to stop thin cuts ramping up to 16m/min. This would have given us unacceptable surface finishes for aerospace work. The original program was set up to cut at around 1m/min. We now have improved accuracy and better tool utilization."
Filton experimented with two optimization methods: ‘Constant Volume’ and ‘Constant Chip’ thickness. Operators found the constant volume method was more suited to the A-Frames. Using this method run time was cut by 25% and throughput was in increased by 15% – with the largest savings on roughing.
To ensure the master programs are never altered, subdirectories were set up to handle the optimized versions of each program. These are downloaded over the shop floor DNC system just as any NC program. They are standard programs – the only difference is they contain optimized feeds and speeds. An attempt to do this manually would more than likely result in hours of programming time for very little benefit.
They also use OptiPath to optimize part programs for Airbus ribs which run on Cell G, equipped with the older type Marwin Automax II machining centers. These machines do not run using normal G-code. Instead they use the direct CL output from the CAM system. The CL data is processed by the machine tool itself using tool diameter, length data measured by a tool probing system. "To get around this we had a ‘reverse post’ written," says Godfrey. The CL file is run through Expertec software to turn it into a G-code file, then it’s optimized using OptiPath and turned back into a CL file. Godfrey is currently concentrating on roughing where the savings are the greatest. So far the results have been excellent. In fact, the roughing procedure has improved so much that the swarf removal capability of the machines had to be upgraded.
A special project team is currently being assembled to roll the benefits seen on cells F and G across all five cells at the Filton plant. One cell that will particularly benefit is Cell W, a new £8 million Forest-Line installation. Cell W is comprised of three large high-speed machining centers fed by an automatic pallet system, designed to machine 330/340 Airbus ribs. "Once the programmers for this cell have finished training on OptiPath we’ll start using it," says Godfrey.
Another Cell destined for OptiPath is cell E – Mori Seiki machining centers exclusively used in machining titanium components.
Airbus is selling so well that the demand to increase build rate has never been higher. BAE Systems (Filton, UK) needed a simple way to improve throughput - it found the answer in VERICUT.
With VERICUT, engineers at Stellex Monitor modeled the Sidewinder and Spar Mill machines.
Tell Tool of Westfield, Mass., has integrated VERICUT CNC simulation software into its numerical control program prove-out process.
VERICUT enabled us to start ordinary production after a minimum of time. Since this product is new for Volvo Aero Norge and our company had never before had parts with similar machining complexity, it is difficult to estimate the amount of cost saving.
Before implementing VERICUT, the company experienced the usual time-consuming and expensive manufacturing problems related to NC program prove-outs such as scrap loss, broken tooling, and a danger of occasional machine crash.
Over the last two years, GE Aviation (formerly Aerostructures Hamble) has used Machine Simulation to speed the implementation of several new 5-axis machine tools.
VERICUT showed the NC programmers leftover or heavy stock." And the software detected a couple of places where the depth of cut was too large and tools were shanking out," said Collings. They then went back and corrected the errors in the tool path before
Dassault, Seclin initially purchased VERICUT in order to reduce the number of manual prove-outs using polystyrene material, which represented a significant expense in terms of time and money.
VERICUT enabled the designers and programmers see exactly what they were building as and in-process model in different stages of the machining cycle.
We utilized VERICUT to verify the CNC programs for cutting the tooling before they were sent to the machine control,
To protect their investment, they have been using VERICUT since 1996. They have two people to verify the accuracy of their G-code files.
"When we first started using OptiPath we concentrated on the feed rate option; now we use the constant chip thickness capability. With jobs up to 200 hours long, 50% saving is significant – like having another machine tool."
The entire process took less than two hours and no manpower was required, whereas, creating the same pattern manually (the old way), would have taken one of our designers several days.
The verification process stays ahead of the actual machine position in the NC code being verified. Opera-tors can see errors before they occur.
The bottom line? Using VERICUT has made Supreme's existing machine tools more productive. Enthusiasm is up, delivery times have been reduced, and pricing is more competitive.delivery times have been reduced, and pricing is more competitive.
Using VERICUT to compare the electrode burn with the mold cavity ensures that we have all the correct clearances in the electrodes and that we have 100% clean-up." says Allen.
If I was using VERICUT at the time I would've caught the problem, and had a chance to fix it before it damaged the part.
Now I rarely see the potential crashes because the students find and correct them before I review the work. Catching those costly problems is a non-event now!
VERICUT can change speeds and feeds according to cutting conditions including difference in material and tooling. It is done automatically; the programmer does not have to make even one manual insert into the code."
Flying shrapnel from shattered cutting tools and components is avoided by using VERICUT to test student programs before they are run on NC machines.
The NC programmers at Ingersoll also rely on the simulation software to prevent mistakes when programming complex, five-axis parts.
After creating the NC programs in Mastercam, they began simulating the machining process in VERICUT by simulating the G-code data. There often can be a difference between the motion as programmed and the code after it's run through the post processor
After selecting VERICUT for third-party verification, each NC programmer attended two days of basic training where they experienced first-hand the type of results they could expect to achieve.
The program simulates milling, drilling, turning, wire EDM, and mill/turn machining operations using both G-codes and CAM output.
VERICUT provides simulation capabilities for the all the 3-5 axis and wire EDM parts, with focused control over the orientation of our 5-axis machine tool including the cutters used on that machine.
The inspection probe is created as a tool in VERICUT so the complete in- cycle gauging sequence is checked for collisions.
The bottom was machined first. This effort took about 24 hours from start to finish. By using VERICUT software from CGTech, Elliot was able to test the NC program for any problems before it was ever cut on the machine.
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With data exported from NX, Vericut simulates the cutting process on the shop floor utilizing the machine G-code to detect any issues prior to NC Program release.
VERICUT software removes this potentially hazardous stage by allowing ReedHycalog to do all of their prove-outs on a computer.
VERICUT verification detects errors such as: inaccurate programming, incorrect tool path motions, rapid motion contact, collisions with fixtures and clamps, tool shank and holder collisions, & CAD/CAM and post processor bugs.
VERICUT Machine Simulation supports G-codes and Multi-axis (5-axis or more) support for milling, drilling, turning, grinding & EDM machines
However, BAE Systems Filton found them to be an inhibiting factor when trying to optimize the production of key components for the wing structures of Airbus planes. It wasn’t straightforward at first; you cannot simply switch such control parameters off and hope for the best. That would have lead to some very unpredictable situations. So instead, BAE Systems set about contacting tooling and software companies for a solution. The result was a very successful project involving CGTech and Kennametal.
"CGTech got involved helping us to get the best out of our NC programs and changing the mind set at Filton," said Matt Godfrey, EIT team leader. "We swapped tools for ones with longer flute lengths and took greater depths of cut – and got better finishes. We didn’t have to change the part programs whatsoever. OptiPath took care of feed rates for us – we just capped the programs at 7m/min. feed rate to stop thin cuts ramping up to 16m/min. This would have given us unacceptable surface finishes for aerospace work. The original program was set up to cut at around 1m/min. We now have improved accuracy and better tool utilization."