5-Axis Machining – Some Best Practices

Longxiang YangFANUC America

IMTS 2018 ConferenceSeptember 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

Positional (3+2) 5-axis Machining ApplicationsRotary 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 ApplicationsRotary 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

5-axis Machining Process

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

3-axis machine 5-axis machine

Advantages of 5-axis MachiningEasy Setup for Machining• Reduce setup time and setup error• Reduce fixture cost• Reduce machining time by about 20-30%

Use of Short Tool • Increase machining speed• Better surface • Increase tool life

3-axis machine 5-axis machine

Machining Cavity• Increase part surface accuracy

3-axis machine 5-axis machine

Advantages of 5-axis Machining

Optimization of Tool Cutting Point• Increase surface accuracy• Increase tool life

3-axis machine 5-axis machine

Efficient Machining with Tool Side• Increase surface accuracy• Reduce machining time significantly

3-axis machine 5-axis machine

Advantages of 5-axis Machining

Factors that Limited Application of 5-axis 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

• 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

Good CNC Functions for 5-axis machining

Actual CuttingCAD/CAM Setup

X

YZ

Part InspectionSimulation CNC/Servo

Servo Guide 3D Viewer

Tool Center Point Control (TCP) – Tool Length CompensationFeatures 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

CNC Functions for 5-axis Machining

TCP with physical rotary axesG43.4 H1Xx Yy Zz Aa Bb

TCP with tool vector I/J/KG43.5 H1Xx Yy Zz Ii Jj Kk

Control point is pivot point Control point is TCP

TCP generates more accurate surface

CNC Functions for 5-axis Machining

Posture Control OFF Posture Control ON

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

CNC Functions for 5-axis MachiningTool Center Point Control (TCP) – Tool Length Compensation

Cutting point commandG43.8 H1Xx Yy Zz Aa Bb L2 Ii Jj Kk

Cutting point commandSame program can be used with different types of tools

CNC Functions for 5-axis Machining3D Cutter Compensation (3DCC) – Tool Cutter CompensationFeatures need to be considered:• Tool side offset

G41.2 (G42.2) D1 ;• Leading edge offset

G41.3 D1 ;

Tool axis

Offset path Programmed path

Offset vector

Offset plane Tool axis

Offset plane

Offset vectorOffset pathProgrammed path

Tool side offset Leading edge offset

TCP and 3DCC are the most important compensation functions for 5-axis machines

CNC Functions for 5-axis MachiningChoice 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 axesBackground• 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 typeAdvantages of Table Coordinate• Easier to understand program• Both physical angles and tool vector in TCP can be appliedRecommendation:• Use table-based coordinate for table and mixed type

CNC Functions for 5-axis MachiningChoice 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=50In 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=30In workpiece coordinate: X-10 Y-20 C90

ABS X=-10, Y=-20, MACH X=0, Y=30

CNC Functions for 5-axis MachiningWorkpiece 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 MachiningWorkpiece Setting Error Compensation – Dynamic Compensation for Workpiece• How does it work C

G54 at table rotation center G54.4 P1

X’

Z’Y’

Z Y

X

10

10X’

Y’

1 2

34

X

Y

G54

C=0 C=90

X’

Y’

1

2 3

4table coordinate

G54.4 P1

G54 X

Y

C=90

1

2 3

4Work coordinate

G54.4 P1

X

Y

X’

Y’G54

Table coordinate Workpiece coordinate

CNC Functions for 5-axis MachiningTilted 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

Flexible Command Formats• Euler’s Angle• Roll-Pitch-Yaw Angles• Three Points• Two Vectors• Projection Angles• Tool Axis DirectionProgram Format (Euler’s angle)

G68.2 Xx Yy Zz Ii Jj KkG53.1 (automatically position

rotary axes to make tool perpendicular to the slanted plane)

CNC Functions for 5-axis MachiningTilted Working Plane Command – Flexible and Easy Programming for 3+2 Machining

Easy Programming on CNC

x

z

y

x’

y’

α

β

X’

z y’’

z’’ y’ β

γ

Zc

Yc

Xc

x’

y’’

γ

Euler’s Angle Transformation

High Speed Smooth TCP: • Smoothing rotary axes• Smoothing tool center point• Great for cutting with both tool side

and tip such as airplane parts

CNC Functions for 5-axis MachiningFine Surface Finish

Smooth Tolerance+ Control:• Smoothing tool center point

(different algorithm)• Great for cutting 3D free surface

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

CNC Functions for 5-axis MachiningFine Surface Finish

HS Smooth TCP OFF

Smooth surfaceFaceted surface

HS Smooth TCP ON

• 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

CNC Functions for 5-axis Machining5-axis Probing – Easy Setup and Calibration

Spindle Probe

Tooling ball

• Programming Screen: measurement

• Programming Screen: WSEC calculation and setting

Easy input screens are developed5-axis Probing – Easy Setup and Calibration

CNC Functions for 5-axis Machining

CNC Functions for 5-axis MachiningBuilt-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 Machining3D 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 MachiningServo 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

Y

Z

X

BC

3D tool path

Impeller

CNC Functions for 5-axis MachiningServo Guide 3D Viewer• Surface defect can be visually inspected and eliminated using Servo Guide

Before tuning After tuning

Command path

Feedback path

Magnified display of 3D error between command and feedback

Color-coded display of 3D path error

Large deviation Small deviation

color scale

Before tuning After tuning

CNC Functions for 5-axis MachiningServo Guide 3D Viewer (All in one screen: 2D/3D position and waveform in time domain)

CNC Functions for 5-axis MachiningServo Guide 3D Viewer (Display of NC program position, CNC command and feedback position)

CNC Functions for 5-axis MachiningCAM 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

CNC PC software

Parameters

ConfigurationProper G code

Some Best Practices1. 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 Practices4. 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.)

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.)

Some Best Practices5. 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

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

Some Best Practices7. Program verification in NCG• 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

Boeing R2D2 part

• 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

Summary

Global Machine Tool ConsumptionMachine 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 ConsumptionWise 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