D4操作手册.pdf - 第23页

23 Vision Sensor Technology Bad Board Recognition Position Recognitio n for Feeder Modu les Description In the clus ter te chnol ogy each subpanel is assig n ed an ink spot. If this is p resent dur- ing the m easurement …

Vision Sensor Technology

PCB Position Recognition

Description

Different fiducial shapes

prove to be optimal depend-

ing on the condition of the

surface. Particularly advis-

able for bare copper surfaces

with little oxidation is the

single cross.

Maximum accuracy is

achieved due to the high in-

formation content. Rectan-

gle, square and circle are less

“informative” but save space

and can even be used when

oxidation is at an advanced

stage. Advisable for tinned

structures are circle or square

because in this case the ratio

of the fiducial dimensions to

the presolder thickness is

particularly favorable.

Fiducial criteria

Locate 2 fiducials

Locate 3 fiducials

X-/Y-position, rotation angle, mean PCB distortion

in addition: shear, distortion in X- and Y-direction separately

Fiducial shapes Synthetic fiducials: circle, cross, square, rectangle, rhombus,

circular, square, and rectangular contours, double cross

any pattern

Fiducial surface:

copper

tin

without oxidation and solder resist

Warp ≤ 1/10 of structure width, both with good contrast to

environment

Dimensions of synthetic fiducials

min. X/Y size for circle and rectangle: 0.25 mm

min. X/Y size for annulus and rectangle: 0.3 mm

min. X/Y size for cross: 0.3 mm

min. X/Y size for double-cross: 0.5 mm

min. X/Y size for lozenge: 0.35 mm

min. frame width for annulus and rectangle: 0.1 mm

min. bar width / bar distance for cross, double-cross: 0.1 mm

max. X/Y size for fiducial shapes: 3 mm

max. bar width for cross / double-cross: 1.5 mm

min. tolerances, general: 2% of nominal dimension

max. tolerances, general: 20% of nominal dimension

Dimensions of patterns

min. size

max. size

0.5 mm

3 mm

Fiducial environment Clearance around reference fiducial not necessary if there is

no similar fiducial structure in the search area

Vision Sensor Technology

Bad Board Recognition

Position Recognition for Feeder Modules

Description

In the cluster technology

each subpanel is assigned an

ink spot. If this is present dur-

ing the measurement via the

PCB vision module, the corre-

sponding subpanel is popu-

lated.

It is also possible to accom-

plish the population of the

subpanel when the ink spot is

missing. With this function it

is possible to eliminate costs

due to unnecessary popula-

tion of faulty subpanels.

Global Ink Spot

Each GOOD/SCRAP scan takes

some time, and the time re-

quired is even greater if there

are a large number of sub-

panels on a PCB. Using the

global ink spot can result in a

significant reduction of these

secondary times.

The PCB vision module

searches at positions taught

before for the defined fidu-

cial. In case of recognition

there is no following evalua-

tion of subpanels. The sys-

tem allows the operator to

choose also the reverse inter-

pretation.

Recognition of the position

of the feeder modules

The pick-up position of the

components can be deter-

mined precisely with the aid

of the position recognition

for the feeder. The offset in

position relative to the stored

ideal position is determined

on the basis of fiducials on

the feeder modules using the

PCB vision module.

This provides very high pick-

up reliability even for the

very first component, which

is particularly important for

small components.

Ink Spot Criteria

Methods • Synthetic fiducial recognition method

• Mean grayscale value

• Histogram method

• Template matching

Shapes and sizes of fiducials/structures for

synthetic fiducials

other methods

for dimensions of synthetic fiducials, see page 22

min. 0.3 mm, max. 5 mm

Masking material good coverage

Recognition time depends on the method: 20 ms - 0.2s

Technical Data

Siemens Signal Interface

Connector Assignment

Signal interface (20-pole ribbon cable connector)

Upstream station X1 Downstream station X2

Pin 1 Reserved Pin 1 Reserved

Pin 2 GND 24 VDC Pin 2 Reserved

Pin 3 + 24 VDC Pin 3 Reserved

Pin 4 Reserved Pin 4 Reserved

Pin 5 Reserved Pin 5 GND 24 VDC

Pin 6 Reserved Pin 6 + 24 VDC

Pin 7 Reserved Pin 7 Reserved

Pin 8 Reserved Pin 8 Reserved

Pin 9 Reserved Pin 9 Reserved

Pin 10 Reserved Pin 10 Reserved

Pin 11 Interfering signal loop Pin 11 Interfering signal loop

Pin 12 Interfering signal loop Pin 12 Interfering signal loop

Pin 13 GND 24 VDC Pin 13 GND 24 VDC for permission /

arrived (galvanic isolation)

Pin 14 Arrived Pin 14 Arrived

Pin 15 Permission Pin 15 Permission

Pin 16 Reserved Pin 16 Reserved

Pin 17 Reserved Pin 17 Reserved

Pin 18 Transferred Pin 18 Transferred

Pin 19 Request Pin 19 Request

Pin 20 GND 24 VDC for request / trans-

ferred (galvanic isolation)

Pin 20 GND 24 VDC