YSD_Users_E.pdf - 第213页
5-24 5 Creating the board data 4.4.3 Local fiducial functions T here are three kinds of local fiducial functions relating to mount data: “point fiducial”, “local fiducial” and “4-point fiducial” functions. T hese are gen…
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Creating the board data
4.4.1 Board fiducial function
The board fiducial function corrects the positioning error of the entire board by using a pair of fiducial marks.
This function is particularly effective in correcting the positioning error caused by board clamping mechanism
fluctuations. As shown in the figure below, a pair of fiducial marks must be diagonally located on the entire
board.
Mark 1 (X1, Y1)
Mark 2 (X2, Y2)
Board fiducial marks
Board origin
63509-N7-00
4.4.2 Block fiducial function
The block fiducial function corrects the positioning error of each block on a multi-block board, by using a pair
of fiducial marks provided in the block. This function is also effective in correcting the positioning error caused
by board clamping mechanism fluctuations.
As shown in the figure below, a pair of fiducial marks must be diagonally located in each block.
Mark 1 (X1, Y1)
Mark 2 (X2, Y2)
Reference block origin
Block fiducial marks
Block repeat No.2
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c
CAUTION
The block fiducial function can only be used for board data (i.e. multi-block board data that uses the block offset
function) for which block fiducial of the offset information has been set.
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Creating the board data
4.4.3 Local fiducial functions
There are three kinds of local fiducial functions relating to mount data: “point fiducial”,
“local fiducial” and
“4-point fiducial” functions. These are generally called the local fiducial functions.
The local fiducial functions are used to enhance the local mounting position accuracy of individual mount
data, rather than improving the mounting position accuracy on an entire board or block as is done by the board
fiducial or block fiducial function.
1. Point fiducial function
The point fiducial function is used to enhance the mounting position accuracy only of a specific component. In general,
as the board size becomes larger, the land pattern layout tends to become inaccurate due to flexing, twist and expansion/
shrinking of the board. Therefore, the point fiducial function is effective when mounting QFP components with a fine
lead pitch on a large board. (Note that the board and block fiducial functions are not effective in this case, although they
are useful in correcting a positioning error caused by the board clamping fluctuations.) The point fiducial function uses a
set of two fiducial marks diagonally located across the land patterns on which you want to improve mounting position
accuracy. It is okay if these two marks are different in shape, but use the same marks for the same type of component.
Mounting center
Point fiducial marks
Mark 1 (X1, Y1)
Mark 2 (X2, Y2)
63511-N7-00
2. Local fiducial function
The local fiducial function improves the mounting position accuracy of two or more components within a specified area,
by using a pair of fiducial marks. This function is also effective in correcting the mounting position errors when two or
more different types of boards are supplied on the same transfer pallet. The local fiducial marks must be arranged
diagonally across the specified area, but can be different in shape from each other.
Board origin or block offset
Mark 1 (X1, Y1)
Local fiducial marks
Mark 2 (X2, Y2)
63512-N7-00
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Creating the board data
3. 4-point fiducial function
The “4-point fiducial” function is used to enhance the mounting position accuracy by recognizing 4 fiducial marks
provided on a board. This function is effective in the following cases.
• boards with 4 or more fiducial marks which meet the conditions
• Large boards
• boards made of materials which tend to expand, flex or warp. (paper phenol, paper, glass epoxy, other flexible
materials)
The 4-point fiducial data settings are basically the same as those for point fiducial and local fiducial marks. However,
because the 4-point fiducial function requires 4 XY coordinate points, you must use two data lines (“4Local-M” and
“4Local-S”) on the Offset tab screen in order to register one set of 4- point fiducial marks.
(50, 10)
(200, 10)
(50, 150)
(0, 0)
(200, 200)
Mark 3
Board origin
4-point fiducial marks
Mark 2
Mark 4
Mark 1
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