5-Axis Machining – Some Best Practices
Longxiang Yang
FANUC America
IMTS 2018 Conference
September 11, 2018
Full Utilization of 5-axis Machines
• 5-axis machines were developed and
used in production more than 50
years
• Because of limitation of computing
hardware, the compensation
functions were not available in early
use. FANUC developed tool length
compensation for Ingersoll 5-axis
machines in late 80s.
• Many advanced 5-axis functions have
been developed in the last 20 years.
These functions greatly enhanced the
application of 5-axis machines.
Full Utilization of 5-axis Machines
• However, in many machine shops, these functions are not used due to
unawareness or lack of understanding.
• A story about a job shop in Seattle area
– 5-axis machines with table-table configuration from OKK, Matsuura and GROB
– Customer used some 5-axis functions like TCP and WSEC but has stopped using them
since the NC programmer left
5-axis Machining Process
Positional (3+2) 5-axis Machining Applications
Rotary axes do not move in a cutting block. Only X, Y and Z-axis
are commanded in a cutting block.
1. Cutting multi-sided parts
• Rotate tool/table to be perpendicular to part surface
• Establish new program coordinate using Tilted Working
Plane Command
• Machining is done in 2.5D or 3D milling
2. Roughing 3D surface parts
• Mainly used in 3D surface roughing
• Rotate tool to a vector position that provides optimum
cutting results
5-axis Machining Process
Simultaneous 5-axis Machining Applications
Rotary axes move in a cutting block. All five axes X, Y, Z, A and C
are commanded in a cutting block
1. Part Cutting
• Thin wall structure, such as turbine blades, rib and spar of
airplanes
• Both tool side and tool tip are used in cutting
2. Mold Cutting
• 3-D sculptured surface, such as die and mold
• Only tool tip is used in cutting
Use of 3+2 Machining vs Simultaneous Machining
•
•
A small sampling of machine shops in Seattle area shows that
about 40%-50% of 5-axis machines are used in 3+2 machining
Mainly on table-table machines for smaller parts
Advantages of 5-axis Machining
Easy Setup for Machining
3-axis machine
5-axis machine
Use of Short Tool
3-axis machine
5-axis machine
• Reduce setup time and setup error
• Reduce fixture cost
• Reduce machining time by about 20-30%
• Increase machining speed
• Better surface
• Increase tool life
Advantages of 5-axis Machining
Machining Cavity
• Increase part surface accuracy
Optimization of Tool Cutting Point
• Increase surface accuracy
• Increase tool life
3-axis machine
5-axis machine
3-axis machine
5-axis machine
Advantages of 5-axis Machining
Efficient Machining with Tool Side
• Increase surface accuracy
• Reduce machining time significantly
3-axis machine
5-axis machine
Factors that Limited Application of 5axis Machines in the Past
•
•
•
•
•
Higher cost of machines
More complex operations
Difficult to program
Lack of good CNC 5-axis functions
Not easy to understand and use 5-axis
functions
CNC Functions for 5-axis Machining
CAD/CAM
Simulation
Setup
CNC/Servo
Z
Actual Cutting
Part Inspection
Y
X
Servo Guide
3D Viewer
Good CNC Functions for 5-axis machining
• Compensation for tool length and radius
• Choice of programming coordinate for
simultaneous 5-axis machining
• Compensation for workpiece
• Easy and flexible programming for 3+2
machining
Fine surface finish
Easy setup and calibration
Real time interference check
Volumetric machine error compensation for
linear and rotary axes
• Optimization of post processor
•
•
•
•
CNC Functions for 5-axis Machining
Tool Center Point Control (TCP) – Tool Length Compensation
Features need to be considered:
• Control tool center point (TCP): control point is tool center point not pivot point
• Control tool vector: tool posture control
• Use of different types of tool: cutting point command
• Choice for programming: physical rotary angles such as B/C or A/B and tool vector in I/J/K
TCP with physical rotary axes
G43.4 H1
Xx Yy Zz Aa Bb
Control point is pivot point
Control point is TCP
TCP generates more accurate surface
TCP with tool vector I/J/K
G43.5 H1
Xx Yy Zz Ii Jj Kk
CNC Functions for 5-axis Machining
Tool Center Point Control (TCP) – Tool Length Compensation
Without Tool posture control:
Two rotation axes are linearly interpolated and tool posture may not be on a plane
With Tool posture control:
Two rotation axes are controlled so that tool posture is on a plane
Posture Control OFF
Posture Control ON
CNC Functions for 5-axis Machining
Tool Center Point Control (TCP) – Tool Length Compensation
Cutting point command
Same program can be used with different
types of tools
Cutting point command
G43.8 H1
Xx Yy Zz Aa Bb L2 Ii Jj Kk
CNC Functions for 5-axis Machining
3D Cutter Compensation (3DCC) – Tool Cutter Compensation
Features need to be considered:
• Tool side offset
G41.2 (G42.2) D1 ;
• Leading edge offset
G41.3 D1 ;
Tool axis
Offset plane
Tool axis
Offset plane
Offset vector
Offset path
Programmed path
Tool side offset
Programmed path
Offset path
Offset vector
Leading edge offset
TCP and 3DCC are the most important compensation functions for 5-axis machines
CNC Functions for 5-axis Machining
Choice of Programming Coordinate
Two program coordinate systems:
• Workpiece-based coordinate (WBC) – fixed on machine coordinate, not rotate
• Table-based coordinate (TBC) – fixed on table, rotate with table rotary axes
Background
• Part is designed in modal space in CAD/CAM without machine type information
• Postprocessor outputs programs for tool type, or table type, or mixed type, and program
coordinate needs to be selected
• Without TCP, program is always posted in workpiece coordinate (rotation centerline) for
table type
Advantages of Table Coordinate
• Easier to understand program
• Both physical angles and tool vector in TCP can be applied
Recommendation:
• Use table-based coordinate for table and mixed type
CNC Functions for 5-axis Machining
Choice of Programming Coordinate
How does it work
• Program X, Y and C so tool
moves along the edges of
rectangle
• X/Y/Z – workpiece
coordinate
• X’/Y’/Z’ - table coordinate
• G54 = (10, 50, 0)
Move to Point 1:
In table coordinate: X0 Y0 C0
ABS X=0, Y=0, MACH X=10, Y=50
In workpiece coordinate: X0 Y0 C0
ABS X=0, Y=0, MACH X=10, Y=50
Move to Point 2:
In table coordinate: X10 Y0 C90
ABS X=10, Y=0, MACH X=0, Y=30
In workpiece coordinate: X-10 Y-20 C90
ABS X=-10, Y=-20, MACH X=0, Y=30
CNC Functions for 5-axis Machining
Workpiece Setting Error Compensation – Dynamic Compensation for Workpiece
• Apply on top of conventional workpiece coordinate such as G54-G59 and dynamically
compensate any misalignment in TCP and 3DCC
• Significantly reduce setup time for 5-axis machining
• Workpiece setting errors: translational Δx, Δy, Δz and rotational (in R-P-Y) Δa, Δb, Δc
• G code format
G54;
G54.4 P1;
G43.4 H1;
CNC Functions for 5-axis Machining
Workpiece Setting Error Compensation – Dynamic Compensation for Workpiece
• How does it work
C
Z
Y
X
G54 at table
rotation center
Y’
X’
G54.4 P1
C=90
C=90
C=0
Y
Z’
Y’ 4
G54
1
3
X
10
Y
Y
10
X
2 X’
G54
G54
1
4
table coordinate
G54.4 P1
2
Y’
3
Work coordinate
G54.4 P1
1
X
Y’
X’
2
4
3
X’
Table coordinate
Workpiece coordinate
CNC Functions for 5-axis Machining
Tilted Working Plane Command – Flexible and Easy Programming for 3+2
Machining
• A method to establish new program coordinate
system so that
– 2.5D or 3D milling can be done in a slanted surface
– Canned cycles or custom cycles can be used
– Same feature on different planes can be machined
using the same program
• Similar to 3D Coordinate Conversion, but more
comprehensive.
• In the past, it was limited to 3-axis compensation, i.e.,
only G43 and G41/G42 can be used.
• Now, it allows 5-axis compensation, such as TCP and
3DCC with Workpiece Setting Error Compensation
CNC Functions for 5-axis Machining
Tilted Working Plane Command – Flexible and Easy Programming for 3+2
Machining
Flexible Command Formats
• Euler’s Angle
• Roll-Pitch-Yaw Angles
• Three Points
• Two Vectors
• Projection Angles
• Tool Axis Direction
Program Format (Euler’s angle)
G68.2 Xx Yy Zz Ii Jj Kk
G53.1 (automatically position
rotary axes to make tool
perpendicular to the
slanted plane)
Easy Programming on CNC
Euler’s Angle Transformation
z
y’
y
α
x
z’’
β
x’
z
y’’
β
y’
X’
Yc
Zc
y’’
γ
Xc
γ
x’
CNC Functions for 5-axis Machining
Fine Surface Finish
High Speed Smooth TCP:
• Smoothing rotary axes
• Smoothing tool center point
• Great for cutting with both tool side
and tip such as airplane parts
Smooth Tolerance+ Control:
• Smoothing tool center point
(different algorithm)
• Great for cutting 3D free surface
CNC Functions for 5-axis Machining
Fine Surface Finish
High Speed Smooth TCP cutting example:
• Facets with High Speed Smooth TCP is OFF
• Facets is gone with High Speed Smooth TCP is ON
• Many customers like Boeing Portland and PMW in Seattle are using this functions
HS Smooth TCP OFF
Faceted surface
HS Smooth TCP ON
Smooth surface
CNC Functions for 5-axis Machining
5-axis Probing – Easy Setup and Calibration
• Measurement of features on a slanted surface: inspection
• Rotary axis calibration: check offset of rotation centerlines
• Measurement of Workpiece Setting Error
• By three spheres
• By a feature in TWP
Spindle Probe
Tooling ball
CNC Functions for 5-axis Machining
5-axis Probing – Easy Setup and Calibration
Easy input screens are developed
• Programming Screen: measurement
• Programming Screen: WSEC calculation and setting
CNC Functions for 5-axis Machining
Built-in 3D Interference Check
• Real time interference check during program
execution and manual operation
• Before collision occurs, CNC generates
interference alarm and movement is stopped
• Interference objects: tables, jigs, tool holders,
tools and workpiece
• This is particularly useful in 5-axis manual setup
• User can add multiple interference objects to a
machine for more accurate checking
CNC Functions for 5-axis Machining
3D Linear and Rotary Volumetric Error Compensation
• ISO 230-1: 21 errors for 3-axis mill and 6 errors for each rotary
• These errors are measured by laser tracker or interferometer
• The measured data is converted to FANUC data: δX, δY, δZ, δA,
δB and δC for 3D grid for linear axes and 2D grid for rotary
axes
• 3D linear and rotary volumetric compensation greatly
improves the machining accuracy
CNC Functions for 5-axis Machining
Servo Guide 3D Viewer
• 3D display of TCP path error and tool
posture by SERVO GUIDE
• Position data displayed
– Part program command
– CNC command
– Feedback
• Surface finish defects can be analyzed
in 3D viewer and minimized by servo
tuning
• Part program error can be easily found
in 3D view
SERVO GUIDE
3D tool path
Z
Y
X
C
B
Impeller
CNC Functions for 5-axis Machining
Servo Guide 3D Viewer
• Surface defect can be visually inspected and eliminated using Servo Guide
Magnified display of 3D error between
command and feedback
Before tuning
After tuning
Feedback path
Command path
Color-coded display of 3D path error
color scale
Large deviation
Small deviation
Before tuning
After tuning
CNC Functions for 5-axis Machining
Servo Guide 3D Viewer
(All in one screen: 2D/3D position and waveform in time domain)
CNC Functions for 5-axis Machining
Servo Guide 3D Viewer (Display of NC program position, CNC command and feedback position)
CNC Functions for 5-axis Machining
CAM Development
• PC software that will extract CNC configuration, option contents and parameter setup
• Assist CAM/Post software to generate proper G code programs and fully utilize 5-axis
machining functions
Parameters
Proper G code
Configuration
CNC
PC software
Some Best Practices
1. TCP and 3DCC – Tool compensation
• G code:
– TCP: G43.4 H1
– 3DCC: G41.2 D1
• Obviously, these two functions are the
most important for 5-axis machining
• Most other 5-axis functions are working
together with TCP and 3DCC
• Without TCP and 3DCC, either “qualified
tooling” has to be used for certified
programs, or programs have to be
generated for different tools
• Lower tooling cost
• Save programming time
• Widely applied on 5-axis machines
2. HSTCP/ST+C – Surface finish
• G code:
– HSTCP: G43.4 H1 P3
– ST+C: G5.1 Q3
• Combination with AICC (high speed
machining) provides better results
• These two functions are enabled by G
codes, but a lot of customers are not
aware of this.
• Many customers have used these two
functions and got very good results
(Boeing, PWM etc.)
Some Best Practices
3. WSEC – Dynamic workpiece offset
• G code:
G54.4 P1
• Dynamically compensate workpiece offset
setting error in translations and rotations
• Work for both table-based program
coordinate and machine-based program
coordinate
• Reduce setup time
• Reduce fixture cost
• Many customers have used this function
(Flow, Boeing, PWM, GKN/Six Digma, Line
etc.)
4. TWP – 3+2 machining
• G code:
G68.2
• 6 formats of command to establish feature
coordinate, very flexible
• A lot of 5-axis machines are mainly used
for 3+2 machining in industry
• Reduce programming time
• All 5-axis compensation functions such as
TCP can be used in TWP
• Many customers have used this function
(Boeing, Exotic Metal, Primus etc.)
Some Best Practices
5. 5-axis test part
• NAS 979 Uniform Cutting Tests in 1969.
• The cone is used for testing 5-axis
machining. However, the uniform shape
does not reflect the complexity of in
production parts.
• Some customers like Boeing Portland
developed their own acceptance test
parts. These parts are designed to
– reveal more defects on a machine
– setup issues for servo and CNC
• For large users, custom part can used for
acceptance test for all machines.
NAS 979 part
Boeing RR part
Some Best Practices
6. 5-axis probing part
• Check probing cycle setup on CNC as part
of machine acceptance test
• Used for measuring WSEC offset
• Good training tool for TWP
7. Program verification in NCG
•
•
•
•
Boeing R2D2 part
NCGuide is CNC simulator on PC
Configure same as CNC on a machine
More realistic program verification, such
as cutter comp interference check etc.
More realistic estimate for cycle time
Summary
• 5-axis machining has been widely used in manufacture because it provides many
advantages
• Many advanced CNC functions have been developed to support better utilization of 5-axis
machines
• A lot of end users are either unaware of the latest development or afraid of taking
advantage of the development due to lack of understanding
• The past development was mainly focused on tool/work compensation and high speed
machining
• The future development need to be focused on
– fine surface technology
– Easy of use/application
– AI application (machine/tool/machining condition/programming/CNC/Servo)
• As a leading CNC manufacturer FANUC, we will closely work with OEM, CAM companies,
NC programming community and end users to promote 5-axis machining technology
Global Machine Tool Consumption
Machine Tool
• Global: $80 Billion (2015)
• US: $8 Billion (2015)
CNC Machine
• Global: about $50 Billion
(2015)
• US: about $7.25 Billion
(2015)
• Global growth to $55
Billion by 2021
(Technavio)
Gardner 2016World Machine Tool Survey
Global 5-axis Machine Consumption
Wise Guy Reports
• In 2014-2017, 5-Axis CNC
machining centers market
size to maintain the average
annual growth rate of 6.22%
• $1.26 billion in 2014
• $1.51 billion in 2017
• $2.13 billion by 2022
Technavio Forecast