STUDY OF FIVE-AXIS COMMERCIAL SOFTWARE POST-PROCESSOR CONVERSION APPLIED TO A PARALLEL FIVE-AXIS MACHINING MACHINE

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International Journal of Mechanical Engineering and Technology (IJMET)
Volume 10, Issue 05, May 2019, pp. 179-186, Article ID: IJMET_10_05_018
Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=5
ISSN Print: 0976-6340 and ISSN Online: 0976-6359
© IAEME Publication
STUDY OF FIVE-AXIS COMMERCIAL
SOFTWARE POST-PROCESSOR CONVERSION
APPLIED TO A PARALLEL FIVE-AXIS
MACHINING MACHINE
Yuan-Ming Cheng*
Associate Professor, Computer and Intelligent Robot Program for Bachelor Degree, National
Pingtung University, Pingtung 90004, Taiwan, Republic of China
Mu-Sheng Lin
Graduate Student, Department of Mechanical & Automation Engineering, Kao-Yuan
University, Kaohsiung City 821, Taiwan, Republic of China
*Corresponding Author E-mail: chengym@mail.nptu.edu.tw
ABSTRACT
This study developed a five-axis machine center that integrates two mechanical
models: a three-degree-of-freedom parallel platform and traditional computer
numerical control (CNC) X–Y table. In the design of the mechanism, the three
actuator axes are parallel to each other, and the two platforms are installed in
parallel. The positions of the moving platform are changed by extending and
shortening the three axes.
To verify the machining precision and usability of this machine, this study used the
post processing program to transfer the numerical control code using five-axis
machining software to determine the processing path; the Z, α, and β values of the
numerical control program are used to convert each axis value of a three-axis motion
platform through inverse kinematics. Finally, this study used two machining methods
in the design: actual concentric roughing and actual spiral roughing. Machining
experiments were conducted to verify the accuracy of the proposed method.
Keywords: Parallel mechanism, motion platform, five-axis machine tool, post-
processing.
Cite this Article: Yuan-Ming Cheng and Mu-Sheng Lin, Study of Five-Axis
Commercial Software Post-Processor Conversion Applied to a Parallel Five-Axis
Machining Machine, International Journal of Mechanical Engineering and
Technology 10(5), 2019, pp. 179-186.
http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=10&IType=5

Study of Five-Axis Commercial Software Post-Processor Conversion Applied to a Parallel Five-
Axis Machining Machine
1. INTRODUCTION
A reconfigurable parallel five-axis machine center comprises a three-degree-of-freedom
parallel platform and an X–Y table (Fig. 1). The three-degree-of-freedom parallel platform
can be divided into three types according to how the actuator axes are installed. In the first
type, the actuator axes are installed vertically [1]; in the second type, three actuator axes are
parallel to each other[2]; in the third type, the actuator axes are placed horizontally on the
base plate [3]. Fan et al. [2] used the second type of three-axis platform to conduct inverse
kinematics derivation and then analyzed the sensitivity model for the spindle platform that
was influenced by structural parameters. Cheng et al. [4] used the third type of three-axis
platform combined with an X–Y platform to investigate the calibration of the three-axis
platform and apply it to concentric drilling with multiple surfaces and angles. Lue et al.[5]
proposed system structure and contour tracking for a hybrid motion platform. The
reconfigurable parallel five-axis machine center can be applied to machining for various
purposes [2–5].
To enable the application of the parallel five-axis machining center to more machining
situations, this study was conducted using the commercial CAM software Siemens NX.
Specifically, the illustration software Autodesk Inventor was employed to illustrate 3D
machining workpieces, which were then input into Siemens NX. A suitable machining cutting
tool was selected, and the five-axis NC machining codes for the complex surfaces were
calculated. The derived five-axis NC codes were then input into the programmed graphical
monitoring software LabVIEW to convert the five-axis postprocessor data. Subsequently, the
X, Y, and Z values of the output NC codes of the parallel five-axis machining center were
extracted and input into the Autodesk Inventor for verification. After the values were verified,
the machining point was converted into the drive value for each axis of the reconfigurable
parallel five-axis machining center and then input into the five-axis simultaneous machining
center to finish the machining.
Figure 1. Parallel five-axis machining center

Yuan-Ming Cheng and Mu-Sheng Lin
2. MECHANISM ANALYSIS
2.1. Inverse kinematics of mechanism
First, the inverse kinematics of the three-axis mechanism were derived to control the
trajectory, namely to control the extension from the center point of the movable platform (U)
to the three-axis drive shaft. The inverse kinematics can be used to convert the attitude of the
movable platform into the amount of extension of the three actuator axes. The locations of the
various connection points on the base and the movable platform are presented in Fig. 2.
T
iii
U
1]0sin[cosrU  ; i=1~3 (1)
T
iii
B
1]0sin[cosRB  (2)
Here, and should be separately defined. Superscripts U and B denote the
coordinate system of the movable platform and the base platform; U and B denote the
movable platform and the base platform, and the subscript i is the number of each drive shaft.
Here, is the radius of the circumcircle of the movable platform; R is the radius of the
circumcircle of the base platform;
3~1i1);-(i
3
2



(3)
The coordinate values of all points on the movable platform and the base ( ) are
presented as follows:
3~1i];U][T[U i
U
U
B
i
B
 (4)
Where













1000
0
0
Z
R
T U
B
U
B
(5)
The coordinate points on the movable platform were converted into the coordinate system
of the base (B) using the roll, pitch, and yaw angles, and . Therefore, the rotation
coordinate is presented as follows:

















coscossincossin
sin-cos0
cossinsinsincos
,, xyU
B
RRR
(6)
According to Eq. (4), the coordinate values of the connection points on the movable
platform that had been converted into the coordinate system of the base are
i
U
U i
B
B
r
0
BBB Z,Y,X

Figure 2. Parallel three-axis mechanism




























sinsinrsincos
cossin
sinsinsinrcoscos
i
i
i
i
i
iz
B
iy
B
ix
B
i
U
U
B
i
B
rZ
r
r
U
U
U
UTU
(7)
The connecting rods were expressed in the form of vectors:
iii BUD 

(8)
The length of each connecting rod was
(9)
where iD signifies the length of the connecting rod (fixed value), and 0Biz
B

2
iz
B
iz
B2
iy
B
iy
B2
ix
B
ix
B2
i )B-U()B-U()B-U(D 
(10)
where
2
iz
B2
iy
B
iy
B2
ix
B
ix
B2
i U)BU()BU(D 
(11)
Square expansion of Eq. (11) was then performed.
2
iy
B
iy
B2
ix
B
ix
B2
iiz
B
iz
B
)B-U()B-U-(D-UB 
(12)
Based on the aforementioned parallel three-axis control equation, this study wrote a
LabVIEW program that was then used as the final output to control the spindle.
2.2. Parallel five-axis post processing equation
The five-axis post processing equation was derived from Fig. 3 and is presented as follows:
[ ] (13)
Incorporate Eq. (13) into Eq. (14):
i
B
i
B
i BUD 

[ ] (14)
where TL indicates the total length of the cutting tool, which is expressed as
[ ] (15)
The current turning platform was added onto the surface of the cutting tool, and was
multiplied by to obtain
[ ] [ ] (16)
Expand Eq. (16).
[ ] (17)
The derived equations were integrated to obtain the following parallel five-axis
postprocessing equations:
X→
Y→
Z→
3. EXPERIMENTAL SETTING
3.1. Experiment framework
Figure 3 displays a flowchart of the experiment. Autodesk Inventor was used to illustrate a 3D
machining workpiece, which was then input into Siemens NX CAM software to obtain a five-
axis NC code. The code was subsequently incorporated into the postprocessing equation,
which was generated using LabVIEW, to determine the NC code for the parallel five-axis
machining center. Two PCI-8134 four-axis servo motor control cards were used to drive the
servo motor controller. One card was to control the 3-PRS parallel three-axis motion platform,
and the other was to control the X–Y motion table. The linkage mechanism was driven to
perform machining. The servo motor encoder transmitted a pulse back to the PCI-8134 four-
axis servo motor control card, and LabVIEW was used for monitoring.

Figure 3. Experimental system architecture
3.2. Five-axis postprocessor conversion
Five-axis NC codes (X, Y, Z, A, and B) were obtained from the CAM software, and a
program was written using LabVIEW to read the source NC codes. We used the sequence
number N in the NC codes to read X, Y, Z, A, and B at each line and input the total length of
the cutting tool and height of the Z-axis for postprocessing calculation. Z, A, and B were used
for inverse kinematics calculation to determine L1, L2, and L3, which were then input into the
PCI-8134 cards to control the parallel three-axis platform. After angle calculation, X and Y
were input into the other PCI-8134 card to control the X–Y platform.
4. RESULTS AND DISCUSSION
The five-axis machining center comprised three translational axes and two rotational axes.
The R5 ball knife was selected as the cutting tool, and the toward point was chosen. The
shank swung on a point 150 mm above the Z-axis for reciprocating machining to meet the
requirement for the machining center workspace based on the rotation angle .
4.1. Actual concentric roughing
Figure 4a displays the 3D model for the machining experiment. The cutting tool path was set
to concentric circles in the Siemens NX software. Figure 4b was illustrated by employing
Autodesk Inventor, in which the values of the machining points X, Y, and Z extracted from
the five-axis NC codes were used, and the NC codes were calculated using the Siemens NX
software on the basis of an isometric view. Figure 4c presents the figure illustrated by
Autodesk Inventor, in which the machining points X, Y, and Z produced from the five-axis
postprocessor conversion based on the isometric view were used. Figure 4d displays
successive concentric circles produced by outward machining on the actual finished product.

Figure 4a. Concentric tool path produced
by the Siemens NX software
Figure 4b. Three-dimensional concentric
coordinate system before conversion
(isometric view)
Figure 4c. Three-dimensional concentric
coordinate system after post
processing conversion
Figure 4d. Finished product of concentric
machining (top view)
4.2. Actual spiral roughing
Figure 5a displays the 3D model for the machining experiment. The cutting tool path was set
to spiral in the Siemens NX software. Figure 5b was illustrated by employing Autodesk
Inventor, in which the values of the machining points X, Y, and Z extracted from the five-axis
NC codes were used, and the NC codes were calculated using the Siemens NX software on
the basis of an isometric view. Figure 5c presents the figure illustrated by Autodesk Inventor,
in which the machining points X, Y, and Z produced from the five-axis postprocessor
conversion based on the isometric view were used. Figure 5d displays successive spira
produced by outward machining on the actual finished product.
Figure 5a. Spiral tool path produced by the
Siemens NX software
Figure 5b. Three-dimensional spiral
coordinate system before conversion (isometric
view)

Figure 5c. Three-dimensional spiral
coordinate system after postprocessing
conversion (isometric view)
Figure 5d. Finished product of spiral
machining (top view)
5. CONCLUSION
With advancements in technology, the machining of part surfaces has become increasingly
complex. The demands for five-axis machining have increased substantially. This study
derived the inverse kinematics and calculated the five-axis postprocessing equations for a
parallel three-axis platform of a parallel five-axis machining center. The experiment results
(Figs. 4–5) demonstrate that the equation derivation and calculations were correct. After the
values were verified, the machining point was converted into the drive value for each axis of
the reconfigurable parallel five-axis machining center and then input into the five-axis
simultaneous machining center to finish the machining.
In this study, five machining methods were used in the experiment design, namely actual
concentric roughing and actual spiral roughing. This study determined that the parallel five-
axis postprocessor developed using LabVIEW can convert the NC codes generated by the
Siemens NX CAM software into codes suitable for the parallel five-axis machining center
used in this study to conduct actual machining. The experiment results (Figs. 4d–5d) were
actual machining finished products that were almost the same as the 3D models. Therefore,
this study verifies that the proposed method possesses high accuracy.
REFERENCES
[1] Yuan-Ming Cheng and Yu-Song Chen, “An Angle Trajectory Tracking for a 3-DOF
Pneumatic Motion Platform by the NI Compact RIO Embedded System”, Journal of
Mechanics Engineering and Automation. 3 (2013) 14-21.
[2] Kuang-Chao Fan, Hai Wang, Jun-Wei Zhao, Tsan-Hwei Chang” Sensitivity analysis of
the 3-PRS parallel kinematic platform of a serial–parallel machine tool” International
Journal of Machine Tools & Manufacture 43 (2003) 1561–1569
[3] Yuan-Ming Cheng,”An Investigation of a 3-PRS Parallel Motion Mechanism with
Intersecting Rails”, Applied Mechanics and Materials. 2011, Vols. 52-54, pp 517-522.
[4] Yuan-Ming Cheng, Wei-Xiang Peng and An-Chunand Hsu “Concentric hole drilling in
multiple planes for experimental investigation of 5-axis reconfigurable precision hybrid
machine” The International Journal of Advanced Manufacturing Technology .2015,
Volume 76, Issue 5-8 , pp 1253-1262.
[5] Chih-Wei Lue, Yuan-Ming Cheng and Jih-Hua Chin, “System Structure and Contour
Tracking for a Hybrid Motion Platform”, The International Journal of Advanced
Manufacturing Technology . 26 ,November 2005, pp.1388 - 1396

STUDY OF FIVE-AXIS COMMERCIAL SOFTWARE POST-PROCESSOR CONVERSION APPLIED TO A PARALLEL FIVE-AXIS MACHINING MACHINE

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