The Weakest Link

The 5-axis post processor provides controller syntax and language commands to the machine tool. Fanuc, Siemens and Heidenhain compose the large predominance of 5-axis machine tool controls. Others emulate Fanuc language. Though the devil is in the details, and most post processors have unique requirements, 5-axis post processors can be developed with high confidence.

http://youtu.be/z05uHib8tYw

So the 5-Axis Demo remains a possible procurement option for the purchaser, depending on the confidence and support of the software vendor. As with the 3-Axis Demo in days of yore, a strong 5-axis demo with live cutting is very impressive to the shop owner. Many software vendors backpedal quickly at the thought of a live 5-axis demo, without the ability to prepare every step to reduce their risk. Many software vendors also backpedal when offered the chance to actually cut a part on the customer’s 5-axis machine.

The customer should pursue these demos, even if a consulting fee is required. Marketing departments print colorful brochures and good engineers can guide a demo to produce the desired results. But a live test cut tells a story clear to all – interaction with the machine tool, cutting times, and surface finish.

5-AXIS POST PROCESSOR SOURCING
When purchasing 5-axis milling software, the prospect should understand the impact of the source of their post processor, since there are many ways to obtain one. Machine shops should carefully consider these options as it may be a strong determinant of their success not only with the CAM software, but also the fundamental performance of their machine tool.

One way to source a 5-axis post processor is through a technical chat room or user forum. Users in different locations posting under nicknames that hide their affiliation come together to share information used to connect 5-axis CAM software to expensive 5-axis machines.

Compare this to the 5-Axis Demo, where the prospective software and post processor are used and proven before purchase. Some end-users believe that post processors should be free and that a chat room connects the user to a community of like-minded peers. But are such post processors documented? Is there technical support? How wise is it to obtain a free post processor if the typical 5-axis post processor sells for approximately one percent of the cost of the milling machine?

Other users want a toolkit so that they can build and adapt their post processors, as the customer gains control with this process. The counter-argument is that machine shops and their employees should be primarily focused on making parts for their customers and not being software developers.

Today’s machines have many options and correspondingly complex logic – tool center point programming, tilted work plane, multiple coordinate systems, and invoking axis brakes. Professional software development companies should have experience and available libraries (from the same or similar machine types) to quickly implement a stable post processor, and the customer can then focus on programming, metal cutting and productivity.

Some machine vendors offer post processors with their machine tools, presenting these solutions as proven. True, the machine vendor has intimate knowledge of their machine, so the output commands from the post processor can be confirmed to be compatible.  But the input to a post processor comes from the CAM software tool path processor. There are many CAM software products, and each has unique intermediate file formats that are rarely published for outside post processor companies.

Further, the intermediate file format specifications frequently change with new software versions to enable new CAM software capabilities. Accordingly, post processor utilities supplied by a machine tool vendor (or a third party through a machine tool vendor), may not be compatible with every CAM software product or each new product release. Too often, a customer may stumble with this approach after new software releases, until the “formatter” is reverse-engineered to meet the standards of the new software version.

The remaining and commonly used option is to obtain a post processor from the CAM software company. In this approach, it is easy for the CAM software vendor to assure compatibility between the CAM software release and the post-processor.The potential open-end in this approach is for the CAM software to ensure compatibility to the machine tool. Here, the CAM software vendor can rely on similarities between machines that share a common controller or use a standard requirements document to obtain specific commands for key machine functions. And, of course, the syntax requirements for a machine control do not change year-by-year.

Not only should there be a defined protocol to obtain post processor requirements, there should also be a standard process to test a post processor. In only rare cases should a post processor be considered plug-and-play. Even with the same software (post processor input) and machine tool/controller (post processor output), there may be many controller options or user preferences that require adaptation or configuration to the post-processor.

Multi-axis post processors often do not get high visibility during the selling process, but they should. Customers that overlook details about post-processors, such as sourcing, service, and testing, often question those same details after the purchase. In today’s high-efficiency world, it is reckless to make capital purchases of machine tools and software, without having defined a clear plan for post-processor implementation.