Taking a data RISC

By eliminating the risk of data starvation, the RISC processor added to a feature-rich vertical machining center makes it an even more attractive option for precision cutting applications.

Sold by Methods Machine Tools Inc. in Sudbury, Massachusetts, the VB53α VMC from OKK USA Corp. in Glendale Heights, Illinois, offers a variety of features aimed at minimizing vibration and maximizing accuracy for high-end die and mold components, as well as other precision applications.

The VB53α “is fully loaded for die/mold (machinists) or anybody else who wants to make very accurate parts,” said Bob Meier, technical product manager at Methods Machine Tools.

The VB53α is a compact machine with a footprint of 2,495 mm × 3,050 mm (98.2"×120.1"). The table work surface measures 1,260 mm × 600 mm (49.6"×23.6") and has a load capacity of 1,200 kg (2,645.5 lbs.). Designed with operators in mind, he said the machine’s workspace requires 50% less reach to get to the workpiece and spindle than its predecessor does.

The VB53α is a high-accuracy VMC. Image courtesy of Methods Machine Tools

To improve part quality, the oil cooler is located externally.

“All OKK machines have chillers for thermal stability, but in this case it isn’t mounted to the machine,” Meier said. “It is sitting on the floor because chillers vibrate and you don’t want that in the machine.”

The machine offers x, y and z travel of 1,050 mm, 530 mm and 510 mm (41.3", 20.9" and 20.1"), respectively. Fine-pitch, high-resolution ballscrews for travel along the machine axes increase machining precision, as does a 0.05 µm resolution linear scale.

“An encoder on the ballscrew motor is not reading the position of the table,” Meier said. “It’s just assuming where it is located. But a linear scale along a rail actually reads the position of the table, so it is the most accurate (type of) position feedback.”

He said linear scales are optional for some machines but come standard with the VB53α.

The VB53α also includes Soft Scale Cube technology that monitors and compensates for temperature-related displacement in real time. Meier said data from thermal sensors is fed to the controller, which is programmed with the knowledge of how the VB53α reacts to temperature changes. The controller also knows how to make corresponding adjustments so the machine stays accurate.

The machine’s Fanuc F31i-B control gets an assist from Hyper HQ control technology that features the RISC processor, a 64-bit, high-speed unit separate from the Fanuc control. Machining programs are sent through a high-speed Ethernet connection to the RISC processor, which does calculations to determine upcoming machine movements. This data is stored in a 1GB server, so the VB53α never is starved for data as it goes through a machining routine. Without this “look-ahead” system, he said the machine simply would stop whenever it runs out of data and wait for the calculations that determine its next move. Like linear scales, he said this system is normally a machine option but comes standard with the VB53α.

The system also includes a machining mode selector with accuracy options ranging from 1 to 10, with 10 being the most accurate but slowest and 1 being the fastest but somewhat less accurate. Meier said users can select 1 for roughing, 5 for semifinishing and 10 for the most precise machining.

Although he describes the VB53α as “very fast in the cut,” he emphasizes that it is not meant for short-cycle part production but rather high-accuracy, longer-runtime components.

“If your cycle time is 30 minutes or less and you can get away with lower tolerances, I would sell you something else,” Meier said. “But if the cycle time is over 30 minutes, then it is a good machine to have.”