Job shop cuts CNC programming time

Honeycutt Manufacturing Inc.’s CNC programming system was showing its age. It was difficult to use and presented particular difficulties in programming mill-turn machines. Company engineers selected Delcam’s FeatureCAM CNC programming system because it is more intuitive and does a better job of addressing mill-turn and other advanced machining methods. The new CNC programming software has automated many tasks that used to have to be done manually, saving time and virtually ensuring that the program will run correctly the first time. The end result: typical parts that used to be programmed in 12 to 16 hours can now be programmed in 3 to 4 hours.

Sophisticated machining

Honeycutt’s forte is its ability to produce parts with complex geometries to demanding tolerances in relatively short delivery times utilizing sophisticated CNC machine tools such as a Tsugami SS-26 mill-turn, Nakamura Tome WT-300 mill-turn, Mori Seiki SH-50 horizontal machining center, Hitachi Seiki HG-400 III horizontal machining center, and Matsuura VX-1000 vertical machining center. As the company upgraded its machines, the original CNC programming software had difficulty in fully taking advantage of their capabilities.

“Another shop in the area recommended FeatureCAM as being particularly good for mill-turn machines,” says Steven Honeycutt, manufacturing engineer for Honeycutt Manufacturing. “We demoed the software and found that it greatly simplified the task of mill-turn programming. So we purchased one seat and began using it to program our mill-turn machines. Later we tried using FeatureCAM to program our milling machines and found that it was better for these machines as well. So we bought two more seats of FeatureCAM and now use it for all of our programing.”

FeatureCAM automatically handles many aspects of programming that used to be manual. For example, the company’s mill-turn machines have a sub-spindle with a chuck that feeds bar stock and then grips it while a series of operations are performed, Honeycutt adds.

Programming how far to pull the bar out and where to grip it has been changed from a complex code-writing exercise to just a few mouse clicks. Milling operations on a mill-turn machine are programmed with exactly the same interface used to program milling operations on a milling machine. The common user interface simplifies the programming process, and the common functionality enables the milling spindle of a mill-turn machine to do everything that a conventional milling machine can do.

Programming the multiple spindles of a mill-turn machine is easier. New features enable the programmer to drag an operation from one spindle to the other to accommodate a change in programming strategy. FeatureCAM also calculates the time required for each machining operation. When operations are performed simultaneously on different spindles, it inserts the wait codes needed so that the spindle that is done first waits until the other is finished.

As an example of how FeatureCAM improves milling machine programming, Honeycutt points to a large family of parts that the company builds on a regular basis for checking printed circuit boards. Usually built one at a time, the parts are circular or rectangular and up to 26" in length or diameter. Each has many holes that need to be held to very close tolerances for absolute position, and many of them need to be tapped as well. The parts also often have multiple pockets with varying depths.

“In the past we had to manually define each of these holes and also spend a lot of time checking to be sure that each was in the proper position, had to the right diameter, was tapped with the right thread, etc.,” Honeycutt says. “It was easy to make mistakes with the old software and the result sometimes was that the tap went beyond the depth that the hole was drilled which would break the tap.”

Honeycutt Manufacturing programmers have set up standards in the software configuration that automatically set the tap size and depth based on the hole size and depth. The software performs additional checks that help avoid errors such as ensuring that tapping depth does not exceed drilling depth. The software also automatically recognizes the various pockets on the part. The programmer typically begins by performing a roughing operation that leaves perhaps 0.050" of stock on the walls and floor of the pocket which is removed in a subsequent finishing pass. CNC programming is kept simple to minimize programming time. With similar parts that are produced in larger lots, more sophisticated programming techniques are used to reduce cycle time.

“We have reduced the time required to program the typical part by 75% and also reduced the cycle time by 10% to 20%,” Honeycutt concludes. “Compared to other CNC programming systems that I have used, FeatureCAM is much easier to learn. I enjoy using it and teaching it to others. The program is continually improved with updates being released every three to six months.”

Delcam
www.delcam.com
IMTS 2014 booth #E-3222