Advances in Motion Control

Introduction

Developments in hardware and software improve motion control performance. Motion control improvements usually follow this evolution:
  • Higher accelerations
  • Higher resolution servo motors
  • Andvanced engineering analysis

G187 Smoothness Level

G187, Accuracy control for high speed machining ("smoothness level"), was introduced in 2005 with software version M13.14.

G-187 can change both the smoothness and the maximum corner rounding in a program.

G-187 can change the accelerations of the axes to match the needs of the application.

G187 runs in three modes:

  • P1, Rough - doubles the acceleration and corner rounding values.
  • P2, Medium - default acceleration and corner rounding values.
  • P3, Finish - halves the acceleration and corner rounding values.

Running G187 in the P3, Finish mode increases cycle time on long-running programs.

G-187 can override the values in Setting 191, DEFAULT SMOOTHNESS, and in Setting 85, MAX CORNER ROUNDING:

G187 P3 E0.0125

P is the smoothness level mode, 1, 2, or 3, and E is the maximum corner rounding setting.

 

G187 Performance Example

1: G187 P3, FINISH

2: G187 P1, ROUGH

Sigma 5 Servo Motors

 

Servo Motors

  • 1 - Sigma 1 motor
  • 2 - Sigma 5 motor

Sigma 5 servo motors, the next generation of brushless servo motors, were phased into service during 2010 and 2011.

Features that make the Sigma 5 motors more efficient:

  • Serial data connection, for communication speeds faster than the Sigma 1 motors.
  • 8 times the resolution of the previous motors. While this does not improve absolute positional accuracy, it does improve dynamic motion control.
  • Higher acceleration rates than servo motors we used before.
  • The smaller design gives more room for future use.

FIR Filter

The FIR (Finite Impulse Response) filter is a Haas software feature that uses the Sigma 5 servo motor to achieve these results:

  • higher acceleration rates with smoother transitions
  • reduced cycle times
  • reduced vibration from machine motion

 

Acceleration Rate and Velocity

  • A: "Corner rounding" of the acceleration profile
  • B: Higher acceleration rate
  • 1: Velocity with FIR
  • 2: Velocity without FIR
  • 3: Acceleration with FIR
  • 4: Acceleration without FIR

Notice that the example axis in this illustration did not have a higher rapid speed: it simply accelerated fast to the maximum speed with the FIR filter.

With the shorter time to maximum speed, the axis arrived at the commanded position faster. This gives a shorter cycle time.

FIR filters offer faster acceleration/deceleration (the steeper curve) with smoother transitions.

FIR filters are standard on all machines.

They are always active. You do not need to adjust parameters.

FIR Performance Example

1: FIR active

2: FIR inactive

Both surfaces run at G187 P2, MEDIUM, 75 ipm (1.9 m/min).

Notch Filter

Commanded movement causes the machine to vibrate. The notch filter is a Haas software feature that adjusts the acceleration rates of the axes to compensate for the machine's vibration.

The amount of adjustment is based on the natural vibrations inherent in each frame size and does not affect cycle time. The machine still achieves the commanded axis speeds.

The notch filter is always active. Do not change the factory-set parameters for the notch filter.

The notch filter is available only in mills. It is not necessary in lathes.

 

To measure the machine's natural frequency, engineers "shake" it with an out-of-balance tool [1].

VF-7 Notch Filter Example

1: Notch filter inactive

2: Notch filter active

Advancements in Motion Control - Examples

Improvements in Machine Performance

1: VF-SS from 2006

2: The same program from a VF-SS in 2011

The current VF-SS machine's surfacing capabilities are similar to a VM, which is suitable for demanding mold applications that require minimal to no bench work.

Improvements in Surface Finish

1: VF-SS from 2006

2: The same program from a VF-SS in 2011

Improvements in Circular Interpolation

1: VF-SS from 2006

2: The same program from a VF-SS in 2011

Revised Test Cut

1: Old test cut

2: The revised test cut forces the machine through transitions to expose known issues:

  • G2 to G03
  • Obtuse angles
  • 45 degree angles
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Be aware: Many service and repair procedures should be done only by authorized personnel. The service technicians at your Haas Factory Outlet (HFO) have the training, experience, and are certified to do these tasks safely and correctly. You should not do machine repair or service procedures unless you are qualified and knowledgeable about the processes.

Danger: Some service procedures can be dangerous or life-threatening. DO NOT attempt a procedure that you do not completely understand. Contact your Haas Factory Outlet (HFO) and schedule a service technician visit if you have any doubts about doing a procedure.