NC verification and simulation software has been used by aerospace manufacturers for more than 20 years, yet some NC programmers do not take advantage of the benefits it can offer. Given the expense of each part machined, NC simulation is generally regarded as an important step in the machining process. Simulation checks each machining operation as it is programmed, or as a final check after the programming is finished and post-processed for the specific machine. It’s typically a quality checking process that ensures the part is cut as expected from the generated NC programs,without the risk of a machine collision.
These are valuable uses that justify software cost, often many times over. However, some resourceful companies have discovered that simulation software can be used to benefit their shop in ways that others overlook, sometimes even in ways that were unintended by the software developer.
Evolving strategies and techniques
One of the easiest ways to get more from simulation software is to simply use it.Test new, unproven, machining strategies virtually as an analysis laboratory. Other than the time required to virtually create and test new methods, there is no physical cost. An NC programmer can try and fine-tune radical new ideas several times over. A few hours spent trying out different methods could potentially save many hours of machine time, reducing tool and machine wear, wasted materials, energy costs and human fatigue.
CAM vendors are developing new 5-axis strategies which are more complex; they are also developing new 5-axis roughing strategies that are improving the process of machining. New processes and new techniques must be employed and 5-axis machine simulation software that accurately represents each 5-axis machining cut in great detail will provide the necessary confidence to succeed.This also allows for new invention, experimentation and success with new techniques.
Removing the fear of multi-axis machining
CGTech, the developer of VERICUT software, has encouraged its customers to push the software to its limits. This can be well described using an example involving a creative NC programmer for a large aerospace engine manufacturer. They were looking for a faster way to make the leading edge of a titanium fan blade, and the NC programmer theorised that a new machining method could make the difference they needed.
Traditionally the process for making the part took many hours using a grinding technique. The NC programmer believed the part could be created using a 5-axis mill, but he knew he would need to convince his management before tying up the expensive machine for many hours cutting a test part. By using VERICUT to simulate the process, the programmer was able to create a video and review file to prove the process would work.
According to the association for manufacturing technology, 5-axis mills and mill/turn machines have increasingly become popular, for a good reason. They enable the manufacturer to drastically reduce machining time and the number of set-ups required to complete a job. Simulation software takes the fear out of programming a multi-axis machine. When an NC program can be simulated, from the same code that will be sent to the machine, there is no excuse for not taking full advantage of a 5-axis machine’s capabilities.
Machining before machine arrival
Even today, with ups and downs in machine tool sales, there is still considerable time between the date when the machine is ordered, and the date that it is installed and ready to cut the parts. With simulation software, the manufacturer can be ready to create parts on the first day the machine is installed.
CGTech has partnerships with many of the leading machine tool companies and they will often supply the CAD geometry for its joint customer’s machines – before the machine is even shipped. The manufacturer can then be proving out programs right away. Some of the customers can discover the efficiency and suitability of the machine configuration ordered even before the machine is delivered. By catching the machine specification mistake early, the customer can change the order before the machine is delivered.
Opting for the right machine using virtual simulation
The aerospace manufacturer working on the leading edge took the idea a step further. After proving the 5-axis milling process could work, they were ready to order production machines. Rather than simply picking the machine from a catalog, they designed the machine in their simulation software, where they had already proven the process would work. These files were then sent to the machine tool builder who built the machine exactly to their specifications as described in a virtual machining simulation.
Another leading aerospace company created programs for more than 200 parts and proved them using virtual simulation software even before the arrival of machines on their shop floor. All the machines ordered were built using virtual simulation software and all NC programs were proved on a virtual machine. The machine loading plan was also prepared, thanks to accurate cycle times provided by simulation software. Once the machines arrived, they cut the parts without any further delay.
By maximising the use of simulation software, shop floors don’t need to wait for NC programs. There are always opportunities to improve an existing process, and simulation software can help by giving the NC programmer the freedom to try practically any machining technique in a virtual world. Only creativity and a good virtual platform are required to accomplish the job!
Photo Caption: VERICUT CNC machine simulation, verification and optimisation software simulates all types of CNC machining. The software operates independently, but can also be integrated with leading CAM systems.