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Machine Tool Automation 48.3 NC Part Programming 845

48.3.1 Manual Part Programming

This is the simplest way to generate a part program. Ba-

sic numeric data and alphanumeric codes are entered

manually into the NC controller. The simplest com-

mands example is shown as follows:

N0010 M03 S1000 F100 EOB

N0020 G00 X20.000 Y50.000 EOB

N0030 Z20.000 EOB

N0040 G01 Z−20.000 EOB

Each code in the statement has a meaning to deﬁne

a machining operation. The “N” code shows the se-

quence number of the statement. The “M” code and

the following two-digit number deﬁne miscellaneous

functions; “M03” means to spindle on with clock-

wise rotation. The “S” code deﬁnes the spindle speed;

“S1000” means that the spindle speed is 1000rpm. The

“F” code deﬁnes the feed speed; “F100” means that the

feed is 100mm/min. “EOB” stands for “end of block”

and shows the end of the statement. The “G” code

and the following two-digit number deﬁne preparatory

functions; “G00” means rapid positioning by point-to-

020

LN4

LN1

CIR

LN3

LN2

40 60 80

PARTNO TEMPLET

REMARK PART TYPE KS-02

MACHINE/F 240, 2

CLPRT

OUTTOL/0.002

INTOL/0.002

CUTTER/10 $$ FLAT END MILL DIA=10mm

$$ DEFINITION

LN1=LINE/20, 20, 20, 70

LN2=LINE/(POINT/20, 70), ATANGL, 75, LN1

LN3=LINE/(POINT/40, 20), ATANGL, 45

LN4=LINE/20, 20, 40, 20

CIR=CIRCLE/YSMALL, LN2, YLARGE, LN3, RADIUS, 10

XYPL=PLANE/0, 0, 1, 0 $$ XYPLANE

SETPT=POINT/-10, -10, 10

$$ MOTION

FROM/SETPT

FEDRAT/FO1 $$ RAPID SPEED

GODLTA/20, 20, -5

SPINDL/ON

COOLNT/ON

FEDRATE/FO2

GO/TO, LN1, TO, XYPL, TO, LN4

FEDRAT/FO3 $$ CUTTING SPEED

TLLFT, GOLFT/LN1, PAST, LN2

GORGT/LN2, TANTO, CIR

GOFWD/CIR, TANTO, LN3

GOFWD/LN3, PAST, LN4

GORGT/LN4, PAST, LN1

FEDRAT/FO2

GODLTA/0, 0, 10

SPINDL/OFF

COOLNT/OFF

FEDRAT/FO1

GOTO/SETPT

END

PRINT/3, ALL

FINI

Start statement

Comment

Selection of post processor

Outer tolerance

Inner tolerance

Cutting tool

Definition of geometry

Motion of machine tool

Start point

Feed rate

Tool motion

Spindle on

Coolant on

Feed rate

Tool motion

Feed rate

Tool motion

Feed rate

Tool motion

Spindle off

Coolant off

Feed rate

Tool motion

Stop

Print out

End statement

Fig. 48.17 Example program list in APT

point control. The “X” and “Y” codes indicate the x-

and y-coordinates. The cutting tool moves rapidly to

the position x =20mm and y = 50mm with the sec-

ond statement. Then, the cutting tool moves rapidly

again to the position z = 20mm with the third state-

ment. “G01” means linear positioning at controlled

feed speed. Then the cutting tool moves with the feed

speed, deﬁned by “F100” in this example, to position

z =−20mm.

The positioning control can be classiﬁed into two

types, (1) point-to-point control and (2) continuous path

control. “G00” is a positioning command for point-to-

point control. This command only identiﬁes the next

position required at which a subsequent machining op-

eration such as drilling is performed. The path to get

to the position is not considered in point-to-point con-

trol. On the other hand, the path to get to the position is

controlled simultaneously in more than one axis to fol-

low a line or circle in continuous path control. “G01” is

a positioning command for linear interpolation. “G02”

and “G03” are positioning commands for circular in-

terpolation. These commands permit the generation of

two-dimensional curves or three-dimensional surfaces

by turning or milling.

Part F 48.3

846 Part F Industrial Automation

48.3.2 Computer-Assisted Part

Programming: APT and EXAPT

Automatically programmed tools is the most impor-

tant computer-assisted part programming language and

was ﬁrst used to generate part programs in produc-

tion around 1960. EXAPT contains additional functions

such as setting of cutting conditions, selection of cut-

ting tool, and operation planning besides the functions

of APT. APT provides two steps to generate part

programs: (1) deﬁnition of part geometry, and (2) spec-

iﬁcation of tool motion and operation sequence. An

example program list is shown in Fig.48.17. The fol-

lowing APT statements deﬁne the contour of the part

geometry based on basic geometric elements such as

points, lines, and circles:

LN1 =LINE/20, 20, 20, 70

LN2 =LINE/(POINT/20, 70), ATANGL, 75, LN1

LN3 =LINE/(POINT/40, 20), ATANGL, 45

LN4 =LINE/20, 20, 40, 20

CIR =CIRCLE/YSMALL, LN2,

YLARGE, LN3, RADIUS, 10

where LN1 is the line that goes through points (20, 20)

and (20, 70); LN2 is the line that goes from point (20,

70) at 75

◦

to LN1; LN3 is the line that goes from point

(40, 20) at 45

◦

to the horizontal line; LN4 is the line

that goes through points (20, 20) and (40, 20); and CIR

is the circle tangent to lines LN2 and LN3 with radius

10. Most part shapes can be described using these APT

statements.

On theother hands,tool motionsare speciﬁed by the

following APT statements:

TLLFT, GOLFT/LN1, PAST, LN2

GORGT/LN2, TANTO, CIR

GOFWD/CIR, TANTO, LN3

where “TLLFT, GOLFT/LN1” indicates that the tool

positions left (TLLFT) of the line LN1, goes left

(GOLFT), and moves along the line LN1. “PAST, LN2”

indicates that the tool moves until past (PAST) the line

LN2. “GORGT/LN2” indicates that the tool goes right

(GORGT) and moves along the line LN2. “TANTO,

CIR” indicates that the tool moves until tangent to

(TANTO) the circle CIR. GOFWD/CIR indicates that

the tool goes forward (GOFWD) and moves along

the circle CIR. “TANTO, LN3” indicates that the tool

moves until tangent to the line LN3.

Additional APT statements are prepared to de-

ﬁne feed speed, spindle speed, tool size, and toler-

ances of tool paths. The APT program completed by

the part programmer is translated by the computer

to the cutter location (CL) data, which consists of

all the geometry and cutter location information re-

quired to machine the part. This process is called

main processing or preprocessing to generate NC

commands. The CL data is converted to the part

program, which is understood by the NC machine

tool controller. This process is called postprocessing

to add NC commands to specify feed speed, spin-

dle speed, and auxiliary functions for the machining

operation.

48.3.3 CAM-Assisted Part Programming

CAM systems grew based on technologies relating to

APT and EXAPT. Originally, CAM stood for computer-

aided manufacturing and was used as a general term

for computer software to assist all operations while re-

alizing manufacturing. However, CAM is now used to

indicate computer software to assist part programming

in a narrow sense.

The biggest difference between part programming

assisted by APT and CAM is usability. Part program-

ming assisted by APT is based on batch processing.

Therefore, many programming errors are not detected

until the end of computer processing. The other hand,

part programming assisted by CAM is interactive-mode

processing with a visual and graphical environment.

It therefore becomes easy to complete a part program

after repeated trial and error using visual veriﬁca-

tion. Additionally, close cooperation between CAD

and CAM offers a signiﬁcant beneﬁt in terms of

part programming. The geometrical data for each part

path generation, such as surface proﬁling, contouring,

and pocket milling, in CAM through software rou-

tines. This saves signiﬁcant programming time and

effort for part programming. Recently, some simu-

lation technologies have become available to verify

part programs free from machining trouble. Optimiza-

tion of feed speed and detection of machine crash

are two major functions for part program veriﬁcation.

These functions also save signiﬁcant production lead

time.

Part F 48.3

Machine Tool Automation 48.4 Technical Innovation in NC Machine Tools 847

48.4 Technical Innovation in NC Machine Tools

48.4.1 Functional and Structural

Innovation by Multitasking

and Multiaxis

Turning and Milling Integrated Machine Tool

Recently, a turning and milling integrated machine tool

has been developed as a sophisticated turning center.

It also has a rotating cutting tool which can perform

milling operationbesides turning operation, as shown in

Fig.48.18. The beneﬁts ofthe useof turningand milling

integrated machine tools are

1. Reduction of production time

2. Improved machining accuracy

3. Reduction of ﬂoor space and initial cost.

As the high performance of these machine tools

was accepted, the conﬁguration became more and

more complicated. Multispindles and multiturrets are

integrated to perform multitasks simultaneously. The

machine tool shown in Fig.48.18 has two spindles: one

milling spindle with four axes and one turret with two

axes. Increasing the complexity of these machine tools

causes the risk of machine crashes during machining

operation, and requires careful part programming to

avoid machine crashes.

Five-Axis Machining Center

Multiaxis machining centers are expanding in practical

applications rapidly. The multiaxis machining center is

applied to generate a workpiece with complex geome-

try with a single machine setup. In particular, ﬁve-axis

machining centers have become popular for machining

aircraft parts and complicated surfaces such as dies and

molds. A typical ﬁve-axis machining center is shown in

Fig.48.19. Beneﬁts to the use of multiaxis machining

centers are

1. Reduction of preparation time

2. Reduction of production time

3. Improved machining accuracy.

Parallel Kinematic Machine Tool

A parallel kinematic machine tool is classiﬁed as a mul-

tiaxis machine tool. In the past years, parallel kinematic

machine tools (PKM) have been studied with inter-

est for their advantages of high stiffness, low inertia,

high accuracy, and high-speed capability. Okuma Cor-

poration in Japan developed the parallel mechanism

machine tool COSMO CENTER PM-600 shown in

Fig.48.20. This machine tool achieves high-speed and

high-degrees-of-freedom machining operation for prac-

tical products.Also, high-speedmilling of a free surface

is shown in Fig.48.20.

Ultraprecision Machine Tool

Recently, ultraprecision machining technology has ex-

perienced major advances in machine design, perfor-

mance, and productivity. Ultraprecision machining was

successfully adopted for the manufacture of computer

memory discs used in hard-disk drives (HDD), and also

Fig. 48.18 Milling and turning integrated machine tool (courtesy of

Yamazaki Mazak Corp.)

B axis

C axis

B axis

Fig. 48.19 Five-axis machining center (courtesy of Mori Seiki Co.

Ltd.)

Part F 48.4

848 Part F Industrial Automation

Cross groove

V-angle : 90°

Pitch : 0.3 µm

Height : 0.15 µm

Material : Ni-P plate

0.3µm

Fig. 48.21 Ultraprecision machine tool (courtesy of Fanuc Ltd.)

Fig. 48.20 Parallel kinematic machining center (courtesy

of OKUMA Corp.)



photoreﬂector components used in photocopiers and

printers. These applications require extremely high geo-

metrical accuracies and form deviations in combination

with supersmooth surfaces.

The FANUC ROBONANO α-0iB is shown in

Fig.48.21 as an example of a ﬁve-axis ultraprecision

machine tool. Nanometer servo-control technologies

and air-bearing technologies are combined to realize

an ultraprecision machine tool. This machine provides

various machining methods for mass production with

nanometer precision in the ﬁelds of optical electronics,

semiconductor, medical, and biotechnology.

48.4.2 Innovation in Control Systems

Toward Intelligent CNC Machine

Tools

The framework of future intelligent CNC machine tools

is summarized in Fig. 48.22. A conventional CNC con-

trol system has two major levels: the servo control

(level 1 in Fig.48.22) and the interpolator (level 2) for

the axial motion control of machine tools. Certainly, the

conventional CNC control system can achieve highly

sophisticated motion control, but it cannot achieve

sophisticated cutting process control. Two additional

levels of control hierarchy, levels 3 and 4 in Fig. 48.22,

are required for a future intelligent CNC control system

to achieve more sophisticated process control.

Machining operations by conventional CNC ma-

chine tools are generally dominated by NC programs,

and only feed speed can be adapted. For sophisticated

cutting process control, dynamic adaptation of cutting

parameters is indispensable. The adaptive control (AC)

scheme is assigned at a higher level (level 3) of the

control hierarchy, enabling intelligent process monitor-

ing, which can detect machining state independently of

cutting conditions and machining operation.

Level 4 in Fig.48.22 is usually regarded as a super-

visory level that receives feedback from measurements

of the ﬁnished part. A reasonable index to evaluate the

cutting results and a reasonable strategy to improve cut-

ting results are required at this level. For this purpose,

the utilization of knowledge, knowhow, and skill related

to machining operations has to be considered. Effec-

tive utilization of feedback information regarding the

cutting results is very important.

Additionally, an autonomous process planning strat-

egy, which can generate a ﬂexible and adaptive working

Part F 48.4

Machine Tool Automation 48.4 Technical Innovation in NC Machine Tools 849

Future intelligent CNC machine tools with adaptive and process control

Current CNC machine tools with/without adaptive control

Computer

• Process planning

• Tool path

generation

(CAPP, CAM)

CNC controller

• Tool path

• Cutting conditions

• Tool position

• Tool velocity

Actuator

• Servo-amplifier

• Servo-motor

• Ball screw

Machine tool

Deformation/vibration/

noise

Servo-control (Level 1)

Interpolation (Level 2)

Cutting process information (Level 3)

Cutting results (Level 4)

: Key issues for future intelligent CNC machine tools

Temperature/vibration

• Relative motion

between tool and

workpiece

• Cutting operation

Cutting process

• Knowledge

• Knowhow

• Skill

• Cutting force

• Temperature

• Vibration

• Noise

• Machining accuracy

• Surface roughness

• Tool condition

Database

Fig. 48.22 Framework of intelligent machine tools (CAPP – computer aided process planning)

plan, is required as a function of intelligent CNC ma-

chine tools. It must be responsive and adaptive to

unpredictable changes, such as job delay, job insertion,

and machine breakdown on machining shop ﬂoors. In

order to generate the operation plan autonomously, sev-

eral planning and information processing functions are

needed. Operation planning, cutting tool selection, cut-

ting parameters assignment, and tool-path generation

for each machining operation are required at the ma-

chine level. Product data analysis and machining feature

recognition are important issues as part of information

processing.

48.4.3 Current Technologies

of Advanced CNC Machine Tools

Open Architecture Control

The concept of open architecture control (OAC)was

proposed in the early 1990s. The main aim of OAC

was easy implementation and integration of customer-

speciﬁc controls by means of open interfaces and

conﬁguration methods in a vender-neutral standardized

environment [48.2]. It provides the methods and utili-

ties for integrating user-speciﬁc requirements, and it is

required to implement several intelligent control appli-

cations for process monitoring and control.

Altintas has developed a user-friendly, reconﬁg-

urable, and modular toolkit called the open real-time

operating system (ORTS). ORTS has several intelligent

machining modules, as shown in Fig.48.23. It can be

used for the development of real-time signal process-

ing, motion, and process control applications. A sample

tool-path generation using quintic spline interpolation

for high-speed machining is described as an applica-

tion, and a sample cutting force control has also been

demonstrated [48.3].

Mori and Yamazaki developed anopen servo-control

system for an intelligent CNC machine tool to mini-

mize the engineering task required for implementing

custom intelligent control functions. The conceptual de-

sign of this system is shown in Fig.48.24. The software

model reference adaptive control was implemented as

a customintelligent function, and a feasibility study was

conducted to show the effectiveness of the open servo

control [48.4]. Open architecture control will reach the

level of maturity required to replace current CNC con-

trollers in the near future. Thecustom intelligent control

functions required for an intelligent machine tool will

be easy to implement with the CNC controller. Ma-

chining performance in terms of higher accuracy and

productivity will thereby be enhanced.

Feedback of Cutting Information

Yamazaki proposed TRUE-CNC as a future-oriented

CNC controller. (TRUE-CNC was named after the

following key words. T: transparent, transportable,

transplantable, R: revivable, U: user-reconﬁgurable,

and E: evolving.) The system consists of an informa-

tion service, quality control and diagnosis, monitoring,

control, analysis, and planning sections, as shown in

Part F 48.4

850 Part F Industrial Automation

Tacho generator

and encoder

DSP

I/O board

I/O

box

Motor

Servo-

amplifier

Motor power

Velocity feedback

Position feedback

PC/Windows NT-ORTS

- Man machine, communication, CAD/CAM functions, ...

DSP-board 1

Motion control module

NC-code decoding

DSP-board n

Intelligent machining

module

Interpolation

- Linear, circular, spline, ...

- Sensor data collection

- Filtering

- FFT, FRF

- Adaptive control

- Tool wear monitoring

- Tool breakage detection

- Chatter avoidance

- Thermal deformation

compensation

- Probing

- Manipulate machine tool

operating functions

MT operating functions

- Fedd, speed, offsets, ...

Axis control functions

- PID, PPC, CCC,

ZPETC, ...

Sensor functions

- Velocity, torque,

position, force, ...

Fig. 48.23 Application of ORTS on the design of CNC and machining process monitoring (after [48.3]) (DSP – digital

signal processor, FFT – fast Fourier transform, FRF – frequency response function, PID – proportional–integral–

derivative controller, PPC – pole placement controller, CCC – cross coupling controller, ZPETC – zero phase error

tracking controller, I/O – input/output, MT – machine tool)

Program

decode

and

analysis

Preprocess

accel/decel

control

Multiaxis

interpolator

Postprocess

accel/decel

control

program

Display

control

Display

data

program

data

Analised

results

Interpolated

results

Position

command

Axis servo-control

parameters and data

Accl./dcl.

data

Accl./dcl.

parameters

Dual port memory (RAM)

Servo-

control

timing

flag

Position

control

Intelligent control application

Velocity

control

Current

control

Conventional CNC control logic unit

CNC non-real-time processing section

CNC real-time motion control section

Custom real-time execution section

Custom non-real-time execution section

Intelligent control engine

Fig. 48.24 Conceptual design of open servo system (after [48.4])

Fig.48.25 [48.5]. TRUE-CNC allows the operator to

achieve maximum productivity and highest quality

for machined parts in a given environment with au-

tonomous capture of machining operation proﬁciency

and machining knowhow. The autonomous coordinate

measurement planning (ACMP) system is a compo-

nent of TRUE-CNC, and enhances the operability of

coordinate measuring machines (CMMs). The ACMP

generates probe paths autonomously for inline mea-

surement of machined parts [48.6]. Inspection results

Part F 48.4

Machine Tool Automation 48.4 Technical Innovation in NC Machine Tools 851

Blank shape

Product mode

Progressive

product model

Machined

workpiece

Machining

process

Monitoring

system

General-

purpose robot

system

Vision

capture

system

Machine

tool

system

Inspection

result

Hole XYZr#1

CAD based

design

Product mode

Report

Recommendation

Planning section Analysis section Monitoring sectionControl section

Selected

tools

Selected

jigs

Process & operation

planning

Real-time machining

simul. & machining

condition optimization

Machining

environment

recognition

General-

purpose robot

control

Tool wear

recognition

Autonomous

measurement

planning

Real-time machine

motion dynamics

simul. & process

optimization

In-process

& quick

dynamic

calibration

Process analyzer

database generator

Main CNC

control

Autonomous

measurement

Evolving information

provision &

consultation service

Quality control &

Machining process

diagnoser

Information service section

QC & diagnosis section

Resource

database

Machine tool

spec. data

Available

tool data

Available jigs

& fixture file

Machining

know-how

database

Operation

sequence

record

Tool

utilization

record

Machining

element

record

Cutting

condition

record

Result

database

Machining

history

Product quality

control

Machining

process

diagnosis

Workpiece

orientation

Operation

procedure list

CNC

program

Tool

data

1. Fix workpiece

2. Setup tools

3. Measure tools

Fig. 48.25 Architecture of TRUE-CNC (after [48.5])

Part F 48.4

852 Part F Industrial Automation

Experimentally obtained

stability lobe diagram

Database

Real-time controller

3-Dimensional

modeler

Design

specification

Tool path generation

with machining

condition information

CAD system

Machining

efficiency

evaluation

Machining

condition

determination

Real-time machining

condition controller

Machining

state judgement

Machining center

NC data interpreter

Modification

of database

(depth of cut,

spindle speed)

Depth of cut,

actual spindle speed

and actual feed speed

Depth of cut,

spindle speed

and feed speed

Geometrical

information

to be machined

Reference

information

Multiaxis force

information

Modified spindle speed

and modified feed speed

Tool path, initial spindle

speed and initial feed speed

Geometrical

information for

a mechanical part

Override value

NC data

Fig. 48.26 Software system conﬁguration of open architecture CNC (after [48.8])

or measurement data are utilized to evaluate the ma-

chining process to be ﬁnished and to assist in the

decision-making process for new operation planning.

The autonomous machining process analyzer (AMPA)

system is also a component of TRUE-CNC. In order to

retrieve knowledge, knowhow, and skill related to ma-

chining operations, the AMPA analyzes NC programs

coded by experienced machining operators and gathers

machining information. Machining process sequence,

cutting conditions, machining time, and machining

features are detected automatically andstored inthe ma-

chining knowhow database [48.7], whihc is then used to

generate new operation plans.

Mitsuishi developed a CAD/CAM mutual informa-

tion feedback machining system which has capabilities

for cutting state monitoring, adaptive control, and learn-

ing. The system consists of a CAD system, a database,

and a real-time controller, as shown in Fig. 48.26 [48.8].

The CNC machine tool equipped with a six-axis force

sensor was controlled to obtain the stability lobe dia-

gram. Cutting parameters, such as depth of cut, spindle

speed, and feed speed, are modiﬁed dynamically ac-

cording to the sequence for ﬁnding stable cutting

states, and the stability lobe diagram is obtained au-

tonomously. The stability lobe diagram is then used to

determine chatter-free cutting conditions. Furthermore,

Mitsuishi proposed a networked remote manufacturing

system which provides remote operating and monitor-

ing [48.9]. The system demonstrated the capability to

transmit the machining state in real time to the operator

who is located far from the machine tool. The operator

can modify the cutting conditions in real time depend-

ing on the machining state monitored.

Five-Axis Control

Most commercial CAM systems are not sufﬁcient to

generate suitable cutter location (CL) data for ﬁve-axis

control machining. The CL data must be adequately

generated and veriﬁed to avoid tool collision with

the workpiece, ﬁxture, and machine tool. In general,

ﬁve-axis control machining has the advantage of en-

abling arbitrary tool posture, but it makes it difﬁcult

to ﬁnd a suitable tool posture for a machining strategy

without tool collision. Morishige and Takeuchi applied

the concept of C-space to generate tool-collision-free

CL data for ﬁve-axis control [48.10, 11]. The two-

dimensional C-space is used to represent the relation

between the tool posture and the collision area, as

Part F 48.4

Machine Tool Automation 48.4 Technical Innovation in NC Machine Tools 853

Tool

radius

Local

coordinate

system

Surface to

be machined

Boundary of definition area

(limit of inclination angle)

Collision

surface

Collision

area

Collision

area

Free area

Collision

surface

φ =

φ = 0

θ = 0

φ = 2π

φ = π

φ =

Fig. 48.27 Conﬁguration space to deﬁne tool posture (af-

ter [48.11])

shown in Fig. 48.27. Also, three-dimensional C-space

is used to generate the most suitable CL data which

satisfy the machining strategy, smooth tool movement,

good surface roughness, and so on. Experimental ﬁve-

axis-control collision-free machining was performed

successfully, as shown in Fig.48.28.

48.4.4 Autonomous and Intelligent

Machine Tool

The whole machining operation of conventional CNC

machine tools is predetermined by NC programs. Once

the cutting conditions, such as depth of cut and stepover,

are given by the machining commands in the NC pro-

grams, they are not generally allowed to be changed

Collision-free tool posture

Fig. 48.28 Five-axis control machining (after [48.11])

during machining operations. Therefore NC programs

must be adequately prepared and veriﬁed in advance,

which requires extensive amounts of time and effort.

Moreover, NC programs with ﬁxed commands are not

responsive to unpredictable changes, such as job de-

lay, job insertion, and machine breakdown found on

machining shop ﬂoors.

Shirase proposed a new architecture to control

the cutting process autonomously without NC pro-

grams. Figure 48.29 shows the conceptual structure

of autonomous and intelligent machine tools (AIMac).

AIMac consists of four functional modules called

management, strategy, prediction, and observation. All

functional modules are connected with each other to

share cutting information.

Digital Copy Milling

for Real-Time Tool-Path Generation

A technique called digital copy milling has been de-

veloped to control a CNC machine tool directly. The

Part F 48.4

854 Part F Industrial Automation

Machining process

Cutting force

Machining error

Chatter vibration

Cutting temperature

Tool wear, etc.

Feed rate

Spindle speed

Spindle load

Cutting force

Vibration

Temperature

Tool wear, etc.

Machining status

Machining trouble

(chatter vibration,

tool breakage), etc.

Machining sequencePlanning

Cutting condition

maintenance

Real time process stimulation

Tool path generation

Monitoring

Process diagnosis

Database

generation

Database

maintenance

Workpiece model/CAD data

Design

Management

Prediction

Observation

Real machining

Strategy

Tool list

Raw material

Resource

Machining

knowhow

Resource

and

machining data

Machine tool data

Tool data

Machining feature

Cutting condition

Process

---, T2, ---, T5, ---

OP1

T1Face

T2, T3Pocket

T5, T6, T7Hole

T2, T4Step

OP2

--- --- ---

Depth of cut

Stepover

Feed rate

Spindle speed

CL data

Fig. 48.29 Conceptual structure of AIMac

digital copy milling system can generate tool paths in

real time based on the principle of traditional copy

milling. In digital copy milling, a tracing probe and

a master model in traditional copy milling are repre-

sented by three-dimensional (3-D) virtual models in

a computer. A virtual tracing probe is simulated to fol-

low a virtual master model, and cutter locations are

generated dynamically according to the motion of the

virtual tracing probe in real time. In the digital copy

milling, cutter locations are generated autonomously,

and an NC machine tool can be instructed to perform

milling operation without NC programs. Additionally,

not only stepover, but also radial and axial depths of

cut can be modiﬁed, as shown in Fig.48.30. Also, dig-

ital copy milling can generate new tool paths to avoid

cutting problems and change the machining sequence

during operation [48.12].

Furthermore, the capability for in-process cutting

parameters modiﬁcation was demonstrated, as shown in

Fig.48.31 [48.13]. Real-time tool-path generation and

the monitored actual milling are shown in the lower-

left corner and the upper-right corner of this ﬁgure.

The monitored cutting torque, adapted feed rate, and

radial and axial depths of cut are shown in the lower-

right corner of this ﬁgure. The cutting parameters can

be modiﬁed dynamically to maintain the cutting load.

Part F 48.4