Control operation features are a crucial aspect in the design of any control, but the bottom line is machine speed and performance. Namely, how fast a machine cuts, how accurate the cut is, and the surfacing profile.
Using the Legacy as a benchmark, we are measuring critical performance improvements by a factor of 10x or more.
Watch and see a detailed video demonstration.
This performance is possible because the NXGEN control combines the power of Windows, a 64-bit Intel Core processor and a powerful RISC processor dedicated to motion control. Enabling the most advanced software to achieve that “State-Of-The-Art” performance.
A platform design that’s truly a Next Generation CNC!
Below is list of some the new features behind our speed and performance.
Program Memory – Gigabytes!
Instead of measuring program storage in Megabytes, we are now offering Gigabytes! Using the latest Windows Embedded operating system provides tremendous possibilities of data storage management. Currently, we are using Solid State Disks (SSD) with no moving parts and 160 GB of storage. Concerns of program size are a thing of the past!
High Resolution – 10 Millionths!
The Legacy, as with most controls, has a minimum resolution of .0001″ (1 tenth), while the NXGEN has .000010″ (10 millionths) programmability for both input and output, all the time, even in Jog Mode. Having 10x the resolution provides better finishes and accuracy.
The heart of the NXGEN servo system is the motion control board. The control board uses a high-speed RISC-processor which has a servo response time of 0.062 ms (16 kHz) — 32x faster than the Legacy servo controllers. This speed greatly increases the servo reaction time. The difference is even audible. For example, on any machine with the Legacy control paired with Glentek brushless motors and amplifiers, the servos generate a “whining” buzz when not in motion.
Now with our control, using the same servos, that “whine” is significantly reduced, in fact almost gone. The combination of .00001 resolution and the 16 kHZ position loop is one of the many benefits to our high performance servo system.
High Speed Block Processing
The ability to process small moves and not become buffer bound, causing the machine to pause or stop, is termed “Block Per Second Throughput” and it is measured by how many moves the control can process within one second. With the Legacy control, the fastest speed was 250 blocks per second in G90, 1000 blocks per second in G91.1 mode.
With the NXGEN we have three modes for Advanced Surfacing:
1) NO RAMPS – like the standard Legacy G8 contouring, but we can achieve a blocks per second rate 3x faster than the original Legacy CNC. This feature is comparable to Fanuc G8 P00 function.
2) BUFFER – turns on the 511 block look-ahead with motion data pre-buffering, this doubles the performance to +6x faster. This feature is comparable to Fanuc Advanced Preview Control mode.
3) HIGH SPEED – contouring is designed for XYXAB mold data points and currently we are testing 20x faster (5,000 blocks per second). This feature is comparable to Fanuc High Speed Cycle Machining.
The ability to hold position under load and is measured by motor rotation: deflection (error) from desired position. To measure the performance improvement, we performed a static torque test.
The test compared the original Legacy system with our new CNC system, using the same brushless motors and amplifiers while applying a 20 inch pound load at the motor shaft.
1) The Legacy control measured .0003” position deflection as a baseline.
2) With the NXGEN control, we measured .00002” deflection.
The result: NXGEN is 30x stiffer! This directly relates to the ability of the servos to accurately control the machine slides while standing still or during motion; resulting in more accurate and better finishes.
Also, this higher stiffness is one of the features that enables us to achieve a true zero following error!
Servo Stability – Zero Following Error
Normally with CNC controls, you will see the position “dither” back and forth +-.0001” while “servoing” to hold position. With our new designs we achieve a stability of +-.000010, a factor of 10x better!
The combined features previously described: High Resolution, Servo Stiffness and Servo Stability, greatly contribute to the reduction of following error and in most cases the servo system operation has zero following error. Without the normal servo lag with most machines, now your parts with be consistently more accurate, even as you speed up the feed rates. Our goal is reducing your part cycle time without sacrificing accuracy!
While others worry about saving seconds during tool change time, we look to saving all the minutes during machining time!
iSMOOTH – Intelligent Smooth Servo Motion
Smooth Acceleration and Deceleration during Before with the Legacy and most other controls, in G9 ramp mode, the machine would “bang” during a starting move or stopping move (N1 and N5). The G9 ramp was limited to one move and was especially a problem with small moves when a longer ramp is more desirable. This was also the case when applying a change in velocity that requires ramping during profile motion.
With our newly developed iSMOOTH servo control, we can ramp up/down, during multiple moves, regardless of the number and size of the moves. The above velocity graph shows in red the acceleration taking place while making N1,N2 and N3 moves, then decelerating N3,N4 and N5 moves. This results in a much smoother velocity during acceleration and deceleration as shown above. Even during G8 mode with ramping turned off, changes in velocity are automatically ramped up or down to maintain smooth motion regardless of the move length or feed rate. It automatically maintains the proper acceleration and deceleration profiles.
Using the latest advanced velocity algorithms reduces the “bumps and bangs” for G1, G2 and G3 feed moves as well as with rapid moves. We now can make it much simpler to maximize performance and reduce part time without damaging the machine.
The velocity ramp profiles are selectable and adjustable on-the-fly! While other high end controls might have similar features, most are very complicated and almost impossible to use. We’ve strived to make it as easy as possible. To make it as simple as possible, this feature has only two settings; it’s either ON or OFF and the other is how much velocity ramp to apply.
iRAMP – Intelligent Feed Forward Ramp Control
Automatic Acceleration and Deceleration Before InterpolationYou can easily turn on our iRAMP control feature that uses a 511 block look-ahead buffer to determine when it needs to slow down for a direction change. The look-ahead will automatically generate at G9 ramp when needed then switch back to G8 mode. In the diagram below, the red dots show where the control would automatically generate a ramp. This allows maximum high speed machining to be easily achieved by automatically ramping without slamming to a stop and banging at the start. Also relieving the programmer from the normal complication of adding G9 and G8 in the program. The iRAMP feature automatically ramps for functions such as a tool change, G28, G0, Fixture Offsets… etc.
Again, unlike other controls, we have made it very simple to use. The programmer can easily turn it on or off in the middle of the program and modify settings on-the-fly.
This mode creates a Bi-Cubic Parametric Spline through the original programmed points. Using this mode requires less data points (linear moves) to achieve a smooth finish. The motion control board interpolates in-between the original programmed points as it cuts the part. Requiring less linear moves simplifies the programming while actually providing the best possible finish.
The diagram above shows typical shape before and after the Smoothing function.
Comparable to Fanuc Smooth Interpolation.
Non-Uniform Rational B-Splines provide free-form surface machining more integrated to the CAD system instead of line segment limitations. Using NURBS retains the closes possible mathematical definitions of the part, providing better accuracy and smoother reproduction of the CAD surface. Now your not restrained to using only XYZ data points that typically have .0001″ rounding limitations. Accuracy has a direct relationship to surface finish, improving the part finish and accuracy on the machine reduces the hand polishing operation off the machine resulting in less cost plus a better and more accurate part.
Comparable to Fanuc NURBS Interpolation.