ACT - Accuracy Check Tool.pdf - 第215页
ACT with SSW 7xx / User Manual 07/2017 Edition 107 As of the 707.x station software ver sion, an error me ssage with Best ück - Index: Nummer (Placement index : number) is displ ayed together with each error meas urement…
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7.3 Measuring Errors
7.3.1 Several Components Cannot be Measured
The ACT measurement is performed with front-light.
I.e. the illumination of the board camera is used to illuminate the component on the plate.
To keep the contrast in the image constant, the so-called light plate (black protective plate) is used
at the bottom side of the ACT glass plate.
Possibly, this light plate was not inserted or it is scratched or dirty.
See section 4.2.3.
7.3.2 Dirty Components / Foil
In principle, the double-sided adhesive foil can be used several times until (too many) measuring
errors or runaway values occur.
"Runaway values" are often caused by dirt on the adhesive foil.
E.g.: crumbs, lint, hair, rubbed-off parts from the scraping equipment (e.g. board edges), locally
concentrated adhesive/scraps, etc.
These particles may interfere with the optical measurement of the fiducials or cause the
components to slip, tilt or rotate during placement, which must not be charged to the placement
process.
► Check the foil after each scraping with sufficient illumination from several angles.
If the number of error measurements exceeds a certain limit, the overall result is statistically
doubtful or an indication of another problem.
Until station software 707.x there is no output which features were not detected.
Examples of error measurements
From the video view at the station – up to 10 (part of) images of the buffer are visible:
In the second of 4 part images of a glass component (image in the middle) the upper two fiducials
are clearly covered by the used adhesive foil.
However, this error measurement will first be output with the last part image and is not integrated in
the calculations of the placement accuracy.
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As of the 707.x station software version, an error message with Bestück-Index: Nummer
(Placement index: number) is displayed together with each error measurement.
By clicking on the icon to the left of the error message a window opens in which the details of the
optical (error) measurement are displayed.
Cleaning the glass components
The CC02-05 glass components must not be cleaned in an ultrasonic bath.
► Clean the glass side of the components with a lint-free cloth and glass cleaning agent (alcohol).
► Brush the holes at the top (with the fiducials) carefully with a fine brush.
NOTICE
The glass disk is glued into the plastic housing. The disk is only 0.2 mm thick.
► Therefore, when cleaning the fiducial holes, be careful not to pressure the brush on
the glass.
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7.3.3 Others
As first step when the ACT measurement is started the grid on the edge gets measured or is
approached.
Example: dirty grid
Cleaning the glass plate
► Clean the glass plate when replacing the adhesive foil.
► Use a lint-free cloth and glass cleaning agent (alcohol) for this.
► Also remove the light plate and clean the glass plate on both sides.
NOTICE
Applying the adhesive foil
► Make sure that the foil (as described in section 3.1
) is only applied up to the
boundary line and that the grid is not covered!