Designed for developers of small to medium-sized machine tools with four or five axes, the Flexium+ 8 CNC provides machine operators with a cost-effective control solution that in many cases eliminates the need for a second CNC kernel. NUM introduced the technology to the U.S. market at IMTS, where it also launched a new version of its 3D simulation software -- now including kinematic equations to support advanced five-axis machining applications.

The Flexium+ 8 CNC kernel offers two CNC channels and accommodates up to five axes, four of which may be interpolated. At any time, either CNC channel may be used to control a spindle motor and four axes, instead of the full complement of five axes.

This control flexibility helps machine designers to lower the cost of machines with complex synchronization requirements. For example, on a grinding machine, one channel could control two X/Z axes and a spindle to perform the grinding functions while the other channel controls two rear mounted U/W dressing axes.

Each channel can run either its own part program asynchronously and operate autonomously (as if it had a dedicated CNC kernel), or the two channels can be synchronized. Control of one to five axes, or a spindle, can be passed on-the-fly from one channel to the other, to maximize use of available hardware resources.

Flexium+ 8 firmware (and all NUM CNC systems) includes “rotation around tool center point” (RTCP) and Inclined Plane functions. Pioneered by NUM, the RTCP function provides advantages for precision five-axes machining applications. By very accurately controlling the machine’s rotary axes, such as a dual rotary tool-head or a table and cradle holding the part, the function enables the tool to be held in contact with the part, and at a constant angle, throughout the machining process.

RTCP also is beneficial if the part is not flat; it automatically computes all the offsets due to factors such as tool head mechanics and tool length that are needed to maintain accurate tool contact.

As its name implies, the reference point for all RTCP calculations is the tool’s center, or contact point, not the tool-head position, which would require the contact point to be determined mechanically. The difference between these two methods has a major impact on machining.

For example, if the distance between the tool tip and the center of the rotary head is 600 mm, a head positioning error of just one-hundredth of a degree will cause a tool tip error of 0.1 mm. Without the RTCP function, this may result in tool or part damage.

Another advantage of the RTCP function is that the programmed coordinates are those of the part contour, not the machine, which makes the programs machine-independent, and means that tool offsets can be applied without program modification. The RTCP function is implemented as part of the Flexium+ CNC post-processor, which further helps to ensure part program portability.

NUM recently integrated the complex coordinate transformation algorithms of the RTCP function into its Flexium+ 3D simulation software. Users can now analyze and optimize the kinematic performance of part programs for four- and five-axis machines easily and accurately by employing advanced 3D visualization techniques. The software includes comprehensive collision monitoring and detection to guard against tool, part or machine damage.