西门子SIPLACE HS 60-设备参数_EN - 第23页

21 Vision Sensor Technology: PCB Position Recognition Reference Mark Criteria Locate 2 marks Locate 3 marks in addition X-/Y-position, rotation angle, mean distortion Shear, distortion in X- and Y-direction Mark shapes S…

Vision Sensor Technology:

PCB Vision Module

Technical Data

Reference marks

Local marks

Library memory

Recognition of bad boards

up to 3 (subpanels and multiple panels)

up to 2 per component

(may be of different type)

up to 255 types of reference marks

per subpanel

Image analysis Correlation principle (geometric

alignment) based on gray-scale values

Lighting method Front lighting

Recognition time fiducial/

bad board marks

0.4 s

Camera’s field of view 5.7 x 5.7 mm

Description

The SIPLACE HS-60 has a number

of vision modules and a central vi-

sion system to evaluate the re-

corded image data ensuring high

placement accuracy.

At the machine´s X-gantry the PCB

vision module is mounted. It is

used to find the PCBs´ positioning-

offsets within the conveyor sys-

tem.

This vision module is also required

to measure the machine origin

and/or the feeder positions on one

side of the table. It consists of a

single CCD camera with integrated

lighting and optics.

The offsets in the position of the

PCBs are determined with the

help of at least two but generally

three reference fiducial marks on

the PCB. When the PCB arrives at

the placement area the positioning

system with its PCB vision module

moves to the programmed mark

position.

Using the Geometrical Alignment

allows to choose predefined

marks from a menu (e.g. cross,

circle, square). The size of the

mark is programmed at the Station

Computer. From this time on form

and size of the mark is defined and

known.

With this data the PCB vision

module is able to search and rec-

ognize the mark at the predefined

position on the PCB or ceramic

substrate without further assis-

tance. For this reason it places

several small evaluation windows

at the assumed border of the

mark. Within these evaluation win-

dows the vision system looks for

contrast transitions between

bright and dark. After finding such

contrasts the actual position of the

mark can be assigned by compari-

sion with the predefined – and

thus known – form and size.

Camera’s field of view

Pixel

Ink spot, e.g. square

Evaluation operations calculate

possible PCB offsets against given

values of X-, Y- and Theta-axis.

Saving the mark by teaching is not

necessary any more.

Additional functions of the PCB

vision module are recognition of

the position of the feeders and

ceramic substrate (optional) and

recording of the machine data in-

cluding mapping.

Geometrical Alignment

Evaluation window

In addition, the bad board recogni-

tion unit handles “ink spots” with

the aid of the PCB vision module.

Vision Sensor Technology:

PCB Position Recognition

Reference Mark Criteria

Locate 2 marks

Locate 3 marks in addition

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

Shear, distortion in X- and Y-direction

Mark shapes Synthetic marks e.g., circle, cross, square,

rectangle, rhombus, circular ring, square

ring, octagonal ring (choose from menu)

Mark surface:

Copper

Tin

Without oxidation and solder resist

Warp ≤ 1/10 of structure width,

both with good contrast to environment

Mark dimensions

Circle

Cross

Rectangle/square

Rhombus

Diameter: 0.3 - 3 mm

Length and width: 0.3 - 3 mm

Line thickness: 0.1 - 1.5 mm

Edge length: 0.3 - 3 mm

Transversal length: 0.3 - 3 mm

Mark environment Clearance around reference mark not

necessary if there is no similar mark

structure in the search area

Description

Different reference mark shapes

prove to be optimal depending on

the condition of the surface.

Particularly advisable for bare cop-

per surfaces with little oxidation is

the single cross. Maximum recog-

nition reliability is achieved due to

the high information content. Rec-

tangle, square and circle are less

“informative” but save space, are

rugged, 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 mark dimen-

sions to the presolder thickness is

particularly favorable.

Fiducial Editor

Teach Synthetic Fiducial

Vision Sensor Technology:

Bad Board Recognition

Position Recognition of Feeder

Ink Spot Criteria

Evaluation method

for fiducials

for structures

brightness method

contrast method

Shapes and sizes of

fiducials/structures for

brightness method

contrast method

square or circular forms

edge length/diameter 0.3 - 5 mm

rectangular forms

edge length 0.3 - 5 mm

Masking material mat dark (light-absorbing)

not recommended: white or shiny

Ink spot recognition time 0.3 s for each method

Description

In the cluster technology each

subpanel is assigned an ink spot.

If this is present during the meas-

urement via the PCB vision mod-

ule, the corresponding subpanel is

populated. It is also possible to ac-

complish the population of the

subpanel when the ink spot is

missing. With this function it is

possible to eliminate costs due to

unnecessary population of faulty

subpanels.

Global Ink Spot

Each bad board evaluation needs

time, so naturally the consumed

time increases with the number of

subpanels per PCB. Using a 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 fiducial. In case of recogni-

tion there is no following evalua-

tion of subpanels. The system al-

lows the customer to choose also

the opposite interpretation.

Position Recognition of Feeder

The pick-up position of the com-

ponents can be determined pre-

cisely with the aid of the position

recognition of the feeder. It is acti-

vated each time after a change of

feeder or component table. The

offset in position relative to the

stored ideal position is determined

on the basis of fiducials on the

feeder modules using the PCB vi-

sion module. This provides a very

high pick-up reliability even for the

very first component. This is par-

ticularly important with small com-

ponents.