Specification_SIPLACE_S23HM_eng - 第22页

21 Description The component vision module in- tegrated into the placement head signific antly contributes to plac e- ment precis ion and reliabilit y. It dependably recognizes all package forms (= geometric dimensions o…

Description

The component vision module is

directly integrated into the revolver

head and it takes a picture of the

pertinent component. This image

is analyzed by the central vision

system while the component is

cycling into the next station, where

the position of the component is

corrected in accordance with the

offsets in position discovered.

Vision Sensor Technology:

Component Vision Module on the 12-Nozzle Revolver Head

Technical Data

Maximum component size 18.7 x 18.7 mm

Recognizable spectrum

of components

0402 to PLCC44

incl. BGA, µBGA, Flip Chip, TSOP,

QFP, PLCC, SO to SO32, DRAM

Lead pitch

min. ≥ 0.5 mm

Camera’s field of view 24 x 24 mm

Type of lighting Front lighting

(3 freely programmable planes)

Description

The component vision module in-

tegrated into the placement head

significantly contributes to place-

ment precision and reliability. It

dependably recognizes all package

forms (= geometric dimensions of

the component) which are illumi-

nated at various angles from three

planes in the case of the 12-nozzle

revolver head. For optimal illumina-

tion of each component, the

brightness of the lighting of the

planes can be adjusted individually

in 256 increments.

Aside from the dimension of the

SMD module, the vision system

determines the number of leads

and their pitch (lateral IC lead bend)

as well as the offset of the place-

ment angle and the X-/Y-axis. Un-

suitable components are rejected

and automatically added later in a

repair cycle. Offsets in placement

angle and X-/Y-axis are corrected at

the turning station of the revolver

head or via the gantry axes. From

the positions of a number of com-

ponents in one track a relevant

offset in the pick-up position on

the X-/Y-axis is calculated. This off-

set is taken into account during

subsequent component pick-up

steps due to the self-learning prin-

ciple.

Prior to placement, the required

geometric dimensions of a com-

ponent type are entered into the

GF editor, creating a synthetic

model of the SMD chip. This task

is facilitated by the extensive on-

line information and help system.

The central SIPLACE vision sys-

tem, to which the other vision

modules are also connected, sub-

sequently analyzes the gray-scale

value of the component vision

module. Algorithms suitable for

the specific package form are used

for this purpose. Due to the com-

bination of algorithms, the vision

system also functions reliably un-

der the most difficult conditions,

e.g., in case of different reflection

behavior on the part of the leads or

interference from outside.

Vision Sensor Technology:

Algorithms to Determine the X-/Y-Position and the

Placement Angle

Algorithm Component Analysis based on

Size Driven Chip the component contour (pro-

file/gradient)

Row Driven IC Several component leads (correla-

tion method)

Corner Driven IC all component leads

(correlation method)

Lead Driven Complex IC Each component lead (High-

Accuracy-Lead-Extraction method)

Grid/Ball

BGA, µBGA,

Flip Chip

all defined balls

(gradients/ball centering)

Description

Various factors contribute to the

placement precision of the

SIPLACE S-23 HM system, for ex-

ample the PCB which is stationary

during the placement process.

Components previously placed are

not affected by any forces of ac-

celeration, therefore their position

remains stable. The PCB is moved

in and out at a coordinated speed

which is automatically reduced just

before reaching the target position.

A further guarantee of long-term

high placement precision is the

position recognition feature of the

gantry and placement axes by op-

tical scanning of increment encod-

ers. Revolving star and segments

of the revolver head are positioned

by means of high-resolution glass

incremental panels. The X- and Y-

axes are positioned with the aid of

metal scales on each gantry axis.

In order to ascertain the placement

precision on SIPLACE machines,

high-precision glass components

with applicated structures are

placed on a dimensionally accurate

glass mapping calibration board.

The results are analyzed statisti-

cally and represented as a Gaus-

sian standard distribution. In the

case of the 12-nozzle revolver

head the placement precision is

± 90 µm at a statistical reliability of

4 sigma. In other words, out of one

million placed components 60 may

be outside the specified tolerance

(- 60 dpm). If the accuracy value

± 90 µm is divided by the sigma

value 4, the result is the standard

deviation S of 1 sigma =

± 22.5 µm.

A machine capability analysis is

conducted for each machine ac-

ceptance test.

Machine Criteria:

Placement Accuracy

2700 dpm

60 dpm

Standard Deviation - dpm

P Point of Inflection

Technical Data Gantry

Drive AC servomotors

Position measuring system (X/Y) Linear scales

Resolution of X-/Y-axis

2.5 µm

Speed of X-axis max. 2.5 m/s

Speed of Y-axis max. 2.5 m/s

Accuracy

X-/Y- and D-axis offset in optical component and PCB centering

Angle accuracy ± 0.525° / 3 σ

± 0.70° / 4 σ

± 1.05° / 6 σ

Placement accuracy

± 67.5 µm/ 3 σ

± 90 µm/ 4 σ

± 135 µm/ 6 σ

-4

-3

-2

σσ