FLEXLINE-CAD_INM.pdf - 第119页
B-3 3.2 T ransforming Flex line CA D coordinate s y ste m to machine coordi nate sy stem Again, machines use different way s to transform t he PCB reference coordinate (positioning hole positions or PCB layout of fset) b…
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2. Overview
Computer Aided Design (CAD) software packages use different coordinate systems to describe
the location and orientation of components (ICs) placed on a PCB. On the other hand, JUKI's
SMT machines use the said four systems in the transport direction. The PCB reference
coordinate is interpreted by the PCB transport reference (Front, or Rear) and PCB transport
direction (“Right to Left,” or “Left to Right”). Thus, the need for geometric transformation
between coordinate systems is significant.
Flexline CAD provides a mechanism to transform both top and bottom CAD coordinate system
to the Flexline CAD coordinate system. Furthermore, Flexline CAD can transform from Flexline
CAD coordinate system to any of the four possible machine coordinate systems. As a result of
the two-stage transformation (CAD coordinate system / Flexline CAD coordinate system then
Flexline CAD coordinate system / machine coordinate system), Flexline CAD is capable of
transforming any CAD coordinate system to any of the machine coordinate systems. This
document describes the techniques that Flexline CAD adapts in transforming between different
coordinate systems.
3. Transforming CAD coordinate system to machine coordinate system
CAD coordinate system transforms to the Flexline CAD coordinate system, then Flexline CAD
coordinate system transforms to machine coordinate system.
3.1 Transforming CAD coordinate system to Flexline CAD coordinate system
Transforming CAD coordinate system to Flexline CAD coordinate system is implemented by
taking the following two operation steps:
1. Unit conversion
When each of the CAD coordinate system and the Flexline CAD coordinate system uses a
different unit system related to dimensions and angle, unit conversion is executed.
2. CAD top PCB perspective \ Flexline CAD coordinate system or CAD bottom PCB
perspective \ Flexline CAD coordinate system
Flipping the X-axis around the Y-axis is a transformation that produces a mirror image of the
X-axis about the Y-axis. Flipping the Y-axis around the X-axis is a transformation that
produces a mirror image of the Y-axis about the X-axis.
Translating CAD coordinate system is done by repositioning its origin point along a straight
line path from one coordinate location to another by adding the translation distance.
However, Flexline CAD uses the origin point of Flexline CAD coordinate system ((0, 0) point
of Flexline CAD coordinate system) to be the destination point of translation.
The following two equations transform (X, Y) point to (X', Y') where (c, b) is a translation
distance from the CAD coordinate system to the Flexline CAD coordinate system.
(Ox, Oy): Offset point.
a = 0, +1 or -1. b = 0, +1 or -1.
% is a remainder, and
θ ′ is the angle of rotation for the top components.
X ′ = a X + b Y + (X+ OX)
Y
′ = b X + a Y + (Y+ OY)
θ ′ = (k θ + j 360 °) % 360 °
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3.2 Transforming Flexline CAD coordinate system to machine coordinate
system
Again, machines use different ways to transform the PCB reference coordinate (positioning hole
positions or PCB layout offset) based on the PCB transport reference (front or rear) and PCB
transport direction (right to left or left to right).
The equations used in each transformation are as follows:
KSx
Hx
Hy
KSy
Transportation direction
Tx
Y
X
Positionong hole
Ty
Positioning hole coordinate
Figure B-2: Machine coordinate system where transport direction is
(“Left to Right”) and front reference
The following symbols are used in expressing transformation equations as described later:
• X X-coordinate of PCB.
• Y Y-coordinate of PCB.
• KSX X-dimension of PCB.
• KSY Y-dimension of PCB.
• LX X-layout offset of PCB (before transformation).
• LY Y-layout offset of PCB (before transformation).
• LX ′ X-layout offset of PCB (after transformation).
• LY ′ X-layout offset of PCB (after transformation).
• HX See figure shown above.
• HY See figure shown above.
• PX X-coordinate of PCB pin or edge reference point (before transformation).
• PY Y-coordinate of PCB pin or edge reference point (before transformation).
• PX ′ X-coordinate of PCB pin or edge reference point (after transformation).
• PY ′ Y-coordinate of PCB pin or edge reference point (after transformation).
• TX constant = 5 MM if pin reference is used (PCB X-margin) or constant = 0 if
edge reference is used.
• TY constant = 5 MM if pin reference is used (PCB Y-margin) or constant = 0 if
edge reference is used.
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Transformation takes place when any of the following parameters changes:
1. PCB Transport direction
“Left to Right” is changed to “Right to Left.”
2. PCB transport reference
“Front” is changed to “Rear.”
• PCB layout offset changes according to the following equations:
• Transport direction is changed to “Right to Left”
LX ′ = LX - KSX
• Reference is changed to “Rear reference”
LY ′ = KSY + LY
1. Changing PCB transport direction:
• PCB pin or edge reference changes according to the following conditions and equations:
Front reference:
Left to Right transport direction is changed to Right to Left transport direction:
PX ′ = - ((KSX - HX) - TX)
Right to Left transport direction is changed to Left to Right transport direction:
PX ′ = + ((KSX - HX) - TX)
Rear reference:
Right to Left transport direction is changed to Left to Right transport direction:
PX ′ = + ((KSX - HX) - TX)
Left to Right transport direction is changed to Right to Left transport direction:
PX ′ = - ((KSX - HX) - TX)
2. Changing PCB transport reference:
• PCB pin or edge reference changes according to the following conditions and equations:
Left to Right direction:
Front reference is changed to Rear reference:
PY ′ = + ((KSY - HY) - TY)
Rear reference is changed to Front reference:
PY ′ = - ((KSY - HY) - TY)
Right to Left direction:
Front reference is changed to Rear reference:
PY ′ = + ((KSY - HY) - TY)
Rear reference is changed to Front reference:
PY ′ = - ((KSY - HY) - TY)