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Bretschneider, J. and Menzel, T.

Development Report:

Virtual Optimization of Machine Tools and Production Processes

Jochen Bretschneider and Thomas Menzel

Siemens AG, A&D MC MT P

Frauenauracher Strasse 80, 91056 Erlangen / Germany[Received February 28, 2007; accepted June 1, 2007]

Faster development of innovative machine tools,

shorter processing times, improved surface quality of

workpieces, higher machine productivity – these are

just a few of the wishes and demands of machine man-

ufacturers and end-users. Time-to-market is decisive;

in some industries, six months too late on the market

can already be decisive in losing the race for market

leadership. The key to success lies in virtual tech-

niques. These are an extremely cost-effective way toincrease productivity in all phases of the machine tools

life cycle. Siemens AG, the leading provider for con-

trol and drive technology, sees itself as a partner for

the whole machine tool industry and offers four phases

of simulation support which cover the entire life cy-

cle of a machine: Mechatronic Support for simulation

for machine development, Machine Simulator for sup-

porting commissioning, Virtual Production for the op-

timization of production and, finally, Virtual NC Ker-

nel (VNCK) for the testing of NC part programs at the

end-user.

Keywords: machine tool, mechatronic, simulation, de-

velopment

1. Introduction

Manufacturers of machine tools have come under in-

creasing pressure to introduce their innovative machines

into the market at ever shorter intervals and at ever lower

costs. In addition to these market realities, user demands

for high precision, dynamic and flexible machines with

low life-cycle costs continue to increase. One of the keysto success for machine manufacturers lies in the area of

machine and machining simulation. Simulation has come

to be regarded as an extremely cost-effective approach to

increasing productivity in all phases of a machine tool’s

life cycle.

In fulfilling its role as a partner to machine manufac-

turers and users, Siemens offers four phases of simula-

tion support that encompass the entire life cycle of a ma-

chine (see Fig. 1). This phase-based simulation support

includes the innovative services Mechatronic Support and

Virtual Production and the products Sinumerik Machine

Simulator and Virtual NC Kernel.

Fig. 1. Simulation activities at Siemens for machine manu-

facturers and users.

2. Mechatronic Support

Mechatronic Support involves the simulated design of

a machine to be developed in the form of a virtual mecha-

tronic machine. The machine’s properties can be tested,

modified, and optimized in the simulation before the ma-

chine is actually built. This can even make the time-

consuming and costly construction of a prototype entirely

superfluous. The virtual mechatronic machine consists of

a dynamic machine model (e.g. a FE model), an electronic

control and drive system and a machining model for the

milling technology. The virtual mechatronic machine al-

lows to analyze and to enhance the essential performance

specifications of a new machine already in simulation.As a service within the scope of Mechatronics Support,

the corresponding virtual mechatronic machine is created

for the customer machine to be developed (see Fig. 2). To

do so, the machine manufacturer provides Siemens with

the CAD data of the machine. Ideally this is done in the

design phase or at an early stage in the construction – so

that construction variants can be verified at very little ex-

pense. This enables a machine concept to be optimally

utilized. All analyses that are normally only possible on

a physical prototype of a new machine tool are now per-

formed on the virtual mechatronic machine on a PC.

Simulation with the virtual mechatronic machine can

be used to analyze and improve the main performance pa-

rameters that are expected with the new machine, for ex-

136 Int. J. of Automation Technology Vol.1 No.2, 2007

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Virtual Optimization of Machine Tools and Production Processes

N10 G0 Z20N20 X-23.883 Y-1.858N30 Z11.298N40 G1 Z6.298 F5000N50 G1 Y-1.865 Z5.76N60 G1 X-23.875 Z5.61

compressor

Interpretation

Preparation

fine-

interpolator

Fine

Interpolation

motion control

+ i nterpolator

Motion ControlInterpolation

drives+

mechanics

Encoder MechanicsFoundation

controllers

Position ControlSpeed ControlCurrent Control

CNCSimulation

DrivesSimulation

MechanicsSimulation

MachiningSimulation

MotorsServo-Drive

Elementsfine-

interpolator

SurfaceQuality

F i ni t e - E l e me nt - M o d e l b ui l d up b y Si e me nsM e c hat r o ni c Sup p o r t

Validate already in Simulation: Maximum Dynamicof Machine Tool (kv and Jerk)

Resonance Frequencies f 0 / DynamicStiffness

Influence of Machine Placement and Foundation

Virtual Mi lling of Workpieces (Time and Quality)

Fix Weak Points in Machine Concept and overcome it

NC Part Program

N10 G0 Z20N20 X-23.883 Y-1.858N30 Z11.298N40 G1 Z6.298 F5000N50 G1 Y-1.865 Z5.76N60 G1 X-23.875 Z5.61

compressor

Interpretation

Preparation

fine-

interpolator

Fine

Interpolation

motion control

+ i nterpolator

Motion ControlInterpolation

drives+

mechanics

Encoder MechanicsFoundation

controllers

Position ControlSpeed ControlCurrent Control

CNCSimulation

DrivesSimulation

MechanicsSimulation

MachiningSimulation

MotorsServo-Drive

Elementsfine-

interpolator

SurfaceQuality

F i ni t e - E l e me nt - M o d e l b ui l d up b y Si e me nsM e c hat r o ni c Sup p o r t

Validate already in Simulation: Maximum Dynamicof Machine Tool (kv and Jerk)

Resonance Frequencies f 0 / DynamicStiffness

Influence of Machine Placement and Foundation

Virtual Mi lling of Workpieces (Time and Quality)

Fix Weak Points in Machine Concept and overcome it

NC Part Program

Fig. 2. Virtual mechatronic machine.

BodeDiagram

Frequency(Hz)

P h a s e ( d e g )

M a g n i t u d e ( d B )

100

101

102

-720

-540

-360

-180

0

T o : Y ( 1 )

-80

-60

-40

-20

0

20

From:OUT

T o : Y ( 1 )

X:98 Hz Y:-68.789 deg1Hz 400Hz AVG: 10

A:F1 DJOM(FRES2 X:98 Hz Y:-64.866 dB-50dB

-150dB

dB Mag10dB

/div

B:F1 DJOM(FRES2180deg

-180deg

Phase36

deg/div

1Hz 400Hz AVG: 10

Slide Tilting: 90 HzSlide Tilting: 90 Hz

Axial Stiffness: 50 HzAxial Stiffness: 50 Hz

Machine Base: 10 HzMachine Base: 10 Hz

Measurement Simulation(with Accelerometer

mounted at TCP*)

* Tool Center Point

BodeDiagram

Frequency(Hz)

P h a s e ( d e g )

M a g n i t u d e ( d B )

100

101

102

-720

-540

-360

-180

0

T o : Y ( 1 )

-80

-60

-40

-20

0

20

From:OUT

T o : Y ( 1 )

X:98 Hz Y:-68.789 deg1Hz 400Hz AVG: 10

A:F1 DJOM(FRES2 X:98 Hz Y:-64.866 dB-50dB

-150dB

dB Mag10dB

/div

B:F1 DJOM(FRES2180deg

-180deg

Phase36

deg/div

1Hz 400Hz AVG: 10

Slide Tilting: 90 HzSlide Tilting: 90 Hz

Axial Stiffness: 50 HzAxial Stiffness: 50 Hz

Machine Base: 10 HzMachine Base: 10 Hz

Measurement Simulation(with Accelerometer

mounted at TCP*)

* Tool Center Point

Fig. 3. Frequency response of the Y axis measured between

the velocity of the motor and the Tool Center Point.

ample under the following aspects:

Maximum axis jerk (relevant for machining time)

Positioning response

Control response / disturbance response

Possible controller gains

Static stiffness

Dynamic stiffness (compliance frequency responses)

Circularity test Analysis of the relevant natural oscillation forms

Influence of the machine mounting and the machine

bed

Influence of the measurement system connection

Chatter forecast for milling (determination of the

cutting depth)

Machining times for a specific acceptance part or

Machining quality.

As an example, Fig. 3 shows the frequency response of

the Y axis, measured between the velocity of the motor

and the tool center point (TCP) of a milling machine –

after the machine tool has been built up. Simulation and

Measurement Simulation


4

m



4

m

Fig. 4. Positioning response of the Y axis measured at the

TCP. Top: soft isolation pads. Bottom: hard isolation pads.

Fig. 5. CNC connected with Machine Simulator at PC for

virtual commissioning.

Simulation System (Collision,Material Removal) Source:

Unigraphics Solutions GmbH

NC User Program

Third-Party Product ofan IndependentSystem House

e.g.:

CGTech

UGS

Tecnomatix

“Einfache” Steuerungsnachbildung

NC Axis Positions

Virtual NCK of SINUMERIK

X100.5 Y300

X33.1 Y15.8

X5.88 Z100

....

Simulation System (Collision,Material Removal) Source:

Unigraphics Solutions GmbH

NC User Program

Third-Party Product ofan IndependentSystem House

e.g.:

CGTech

UGS

Tecnomatix

“Einfache” Steuerungsnachbildung

NC Axis Positions


NC Axis Positions


X100.5 Y300

X33.1 Y15.8

X5.88 Z100

....

Fig. 6. Simulation with Virtual NC Kernel.

measurement show a high level of conformity in ampli-

tude and phase. The mechatronic simulation model can

be used to find the places where natural oscillations oc-

cur in the machine. This provides valuable information to

help improve the construction of the machine.

Int. J. of Automation Technology Vol.1 No.2, 2007 137

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