High Speed Machining (HSM) is a concept that began to come into use in the late 1990s. Simply put, increasing the effective material removal rate is the primary consideration as an increased removal rate translates to reduced machine cycle times. As HSM began to gain popularity, it became clear that changes to CNC Machine Design and CNC Control Systems would need to be made to achieve greater material removal rates.
The existing machine designs of the time were dominated by the use of box way systems. The inherent problem with box way systems is that while they are very rigid, that rigidity is provided by the very significant mass and surface area of those ways.
Enter Sir Isaac Newton and his Laws of Motion.
More specifically, Newton's First & Second Laws of Motion.
Newton's First Law of Motion deals with Inertial Force.
Inertia is the resistance of any physical object to a change in its state of motion or rest, or the tendency of an object to resist any change in its motion.
Newton's Second Law of Motion deals with Acceleration.
It can be summarized as follows: The acceleration of a body is parallel and directly proportional to the net force acting on the body, is in the direction of the net force, and is inversely proportional to the mass of the body. This can be expressed as the equation, Force = Mass x Acceleration (F = ma). More mass also requires more energy to achieve the acceleration required for HSM.
Since we can't change the laws of physics, machine design has changed to reduce the mass and allow for higher rates of acceleration. Linear Guides are now preferred for machines that will be using high speed machining.
Higher acceleration rates also create another problem related to inertial force, changes in direction. Rapid changes in direction are inherent in HSM so any CNC Control System capable of supporting HSM must be able to adjust acceleration AND deceleration to achieve the smoothest, most accurate, continuous motion on the machine.
CNC control systems have also been improved as they are now capable of handling this issue and provide users with the ability to balance speed and accuracy as needed.
FANUC's original High Speed Mode was called HPCC,
(High Precision Contour Control). It was built upon the RISC (Reduced Instruction Set Computing) Chip Architecture of the time. With significant advancements in Microprocessor technology, The original HPCC became obsolete. The newer microprocessors allowed significantly more complex processing at significantly faster speeds.
FANUC's latest High Speed modes are AICC and AIAPC- AI Contour Control and AI Advanced Preview Control. AI does not refer to 'Artificial Intellegence'. AI represents FANUC's Alpha I Series Servo System. There are differences between the two AI modes. However, the syntax for using them is exactly the same. (For detailed data on the two specifications, contact FANUC directly.)
Note:
All Machine Tool Builders can modify the syntax from the default FANUC.
Consult your Machine Tool Dealer if the AICC/AIAPC syntax has been modified by your Machine Tool Builder.
AICC/AIAPC Format:
Enable: G05.1 Q1 Rx
Where:-Rxx provides the user with the option of selecting from 10 fixed settings (R1 -R10) which contrast Tool Path Speed (feedrate) with Positioning Accuracy,
G05.1 Q1 R1 - Toolpath Speed has priority over Positioning Accuracy
G05.1 Q1 R2
G05.1 Q1 R3
G05.1 Q1 R4
G05.1 Q1 R5 - Tool Path Speed and Positioning Accuracy have Equal Priority
G05.1 Q1 R6
G05.1 Q1 R7
G05.1 Q1 R8
G05.1 Q1 R9
G05.1 Q1 R10 - Positioning Accuracy has priority over Tool Path Speed
R1-R2: Smoother Axis Motion and Improved Accuracy.
R3-R5: Die & Mold - Roughing.
R6-R8: Die & Mold - Semi-Finish.
R9-R10: Best Accuracy, Finish, Form & smooth axis motions.
R1 = Rough Machining
R10 = Finish Machining
(Using R1, a 90° corner produced at a feedrate of 10,000 mm/min will produce an approximate deviation of 0.15mm.)
Cancel: G05.1 Q0
NOTE:
G05.1 Q2 is the FANUC Smooth Interpolation Function.
AICC is simultaneously activated when Smooth Interpolation is activated.
G05.1 Q3 is the FANUC Nano Smoothing Function.
AICC is simultaneously activated when Nano Smoothing is activated.
FANUC Smooth Interpolation and NANO Smoothing are Optional Functions.
Consult your Machine Tool Dealer for requirements and pricing.
Practical Application
Application Case 1: 2D Contouring
AICC/AIAPC Addresses the typical corner rounding or overshoot problems when feedrate is high or feature is small.
Applications Case 2: 3D Surfacing
AICC/AIAPC will keep the contouring profile more accurate.
There are 4 Simple rules that should be followed for successful use of AICC/AIAPC.
1. Make sure G49 is called before the execution of G05.1 Q1 Rx
2. G05.1 Q1 Rx should be engaged BEFORE G43-Tool Length Comp
3. AICC and AIAPC need to be turned on and off for each tool
4. AICC and AIAPC does not apply to canned drilling cycles
Example:
The existing machine designs of the time were dominated by the use of box way systems. The inherent problem with box way systems is that while they are very rigid, that rigidity is provided by the very significant mass and surface area of those ways.
Enter Sir Isaac Newton and his Laws of Motion.
More specifically, Newton's First & Second Laws of Motion.
Newton's First Law of Motion deals with Inertial Force.
Inertia is the resistance of any physical object to a change in its state of motion or rest, or the tendency of an object to resist any change in its motion.
Newton's Second Law of Motion deals with Acceleration.
It can be summarized as follows: The acceleration of a body is parallel and directly proportional to the net force acting on the body, is in the direction of the net force, and is inversely proportional to the mass of the body. This can be expressed as the equation, Force = Mass x Acceleration (F = ma). More mass also requires more energy to achieve the acceleration required for HSM.
Since we can't change the laws of physics, machine design has changed to reduce the mass and allow for higher rates of acceleration. Linear Guides are now preferred for machines that will be using high speed machining.
Higher acceleration rates also create another problem related to inertial force, changes in direction. Rapid changes in direction are inherent in HSM so any CNC Control System capable of supporting HSM must be able to adjust acceleration AND deceleration to achieve the smoothest, most accurate, continuous motion on the machine.
CNC control systems have also been improved as they are now capable of handling this issue and provide users with the ability to balance speed and accuracy as needed.
FANUC's original High Speed Mode was called HPCC,
(High Precision Contour Control). It was built upon the RISC (Reduced Instruction Set Computing) Chip Architecture of the time. With significant advancements in Microprocessor technology, The original HPCC became obsolete. The newer microprocessors allowed significantly more complex processing at significantly faster speeds.
FANUC's latest High Speed modes are AICC and AIAPC- AI Contour Control and AI Advanced Preview Control. AI does not refer to 'Artificial Intellegence'. AI represents FANUC's Alpha I Series Servo System. There are differences between the two AI modes. However, the syntax for using them is exactly the same. (For detailed data on the two specifications, contact FANUC directly.)
Note:
All Machine Tool Builders can modify the syntax from the default FANUC.
Consult your Machine Tool Dealer if the AICC/AIAPC syntax has been modified by your Machine Tool Builder.
AICC/AIAPC Format:
Enable: G05.1 Q1 Rx
Where:-Rxx provides the user with the option of selecting from 10 fixed settings (R1 -R10) which contrast Tool Path Speed (feedrate) with Positioning Accuracy,
G05.1 Q1 R1 - Toolpath Speed has priority over Positioning Accuracy
G05.1 Q1 R2
G05.1 Q1 R3
G05.1 Q1 R4
G05.1 Q1 R5 - Tool Path Speed and Positioning Accuracy have Equal Priority
G05.1 Q1 R6
G05.1 Q1 R7
G05.1 Q1 R8
G05.1 Q1 R9
G05.1 Q1 R10 - Positioning Accuracy has priority over Tool Path Speed
R1-R2: Smoother Axis Motion and Improved Accuracy.
R3-R5: Die & Mold - Roughing.
R6-R8: Die & Mold - Semi-Finish.
R9-R10: Best Accuracy, Finish, Form & smooth axis motions.
R1 = Rough Machining
R10 = Finish Machining
(Using R1, a 90° corner produced at a feedrate of 10,000 mm/min will produce an approximate deviation of 0.15mm.)
Cancel: G05.1 Q0
NOTE:
G05.1 Q2 is the FANUC Smooth Interpolation Function.
AICC is simultaneously activated when Smooth Interpolation is activated.
G05.1 Q3 is the FANUC Nano Smoothing Function.
AICC is simultaneously activated when Nano Smoothing is activated.
FANUC Smooth Interpolation and NANO Smoothing are Optional Functions.
Consult your Machine Tool Dealer for requirements and pricing.
Practical Application
Application Case 1: 2D Contouring
AICC/AIAPC Addresses the typical corner rounding or overshoot problems when feedrate is high or feature is small.
Applications Case 2: 3D Surfacing
AICC/AIAPC will keep the contouring profile more accurate.
There are 4 Simple rules that should be followed for successful use of AICC/AIAPC.
1. Make sure G49 is called before the execution of G05.1 Q1 Rx
2. G05.1 Q1 Rx should be engaged BEFORE G43-Tool Length Comp
3. AICC and AIAPC need to be turned on and off for each tool
4. AICC and AIAPC does not apply to canned drilling cycles
Example:
For those who may like to see the effects of AICC/AIAPC first hand, Please download the test file from the link below. You can then run the program in air above the machine table and see what the motion is like. Also record your cycle time.
Try running the program again with the Block Skip enabled and monitor the motion and cycle time again. It will prove beyond a doubt that AICC/AIAPC are valuable tools for achieving greater material removal rates and producing accurate parts.
http://dl.dropbox.com/u/82220297/GASKET-3X.NC
In either case the machine will continue in the reverse direction, processing block after block for up to about 100 blocks During reverse e xecution, if the retrace switch is turned off, the reverse execution is stopped (after completion of the block if not in single block or feed hold) and forward execution is then restarted.