西门子SIPLACE S25 HM-设备性能参数_EN - 第29页

27 Description In addition to correct positi oning, placement reliabi lity is import ant. On the SIPLACE S-25 HM this is ensured through a number of con- trol functions, such a s vacuum checks and compo nent vision testi…

Description

Various factors contribute to the

placement accuracy of the

SIPLACE S-25 HM machine, e.g.,

the stationary PCB during the

placement process. As no accel-

erations are acting on the placed

components, their position contin-

ues unchanged. The PCB moves in

and out at a coordinated speed

which is automatically reduced just

before the nominal position is

reached.

A further guarantee for long-term

high placement accuracy is the

position recognition of the axes of

the gantry and placement head by

means of optical scanning by in-

cremental encoders. Revolving

star and segments of the Collect

& Place Head are positioned by

means of high-resolution glass in-

cremental panels. The X- and Y-

axes are positioned with the help

of the metal scales on each gantry

axis.

To determine the placement accu-

racy on SIPLACE machines, highly

precision glass components with

mounted structures are placed on

a dimensionally accurate glass

mapping plate. The results are sta-

tistically evaluated and presented

as a Gaussian standard distribu-

tion. In the case of the 6-Nozzle

Collect & Place Head at the

SIPLACE S-25 HM the placement

accuracy is ± 80 µm at a statistical

reliability of 4 sigma. In other

words, of one million placed com-

ponents, 60 are outside the speci-

fied tolerance (= 60 dpm). If the

accuracy value ± 80 µm is divided

by the sigma value 4, the result is

the standard deviation S of 1

sigma = ± 20 µm.

A machine capability analysis is

conducted for each machine ac-

ceptance test.

Machine Criteria:

Placement Accuracy

Technical Data Gantry

Drive Brushless AC Temperature

Controlled Motor

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

Placement Accuracy see table on page 6

Standard Deviation - dpm

-4

-3

-2

2700 dpm

60 dpm

P Point o

lection

Description

In addition to correct positioning,

placement reliability is important.

On the SIPLACE S-25 HM this is

ensured through a number of con-

trol functions, such as vacuum

checks and component vision

testing during the placement se-

quence.

Out of tolerance components are

rejected, placed on the repair list

and automatically processed dur-

ing a repair cycle. An offset in the

position of the PCB relative to the

conveyor system (PCB vision) and

an offset of the X-axis, Y-axis or ro-

tation of the component relative to

the midpoint of the nozzle (com-

ponent vision) trigger an immedi-

ate correction to ensure placement

accuracy.

Since the PCB is fixed, the com-

ponents remain in the exact posi-

tion they are placed. The stationary

component table ensures a pre-

cise pick up. Options, such as the

component bar code scanner, can

be added to further enhance reli-

ability.

Placement errors

Placement errorsPlacement errors

Placement errors

Errors that occur after the compo-

nent has been placed on the PCB.

They include:

§ Component is missed on PCB

§ Too many components on PCB

§ Components not placed prop-

erly on PCB

§ Components placed while

standing on edge

Machine Criteria:

Placement Reliability

Placement Principle of SIPLACE S-25

➀ 6-Nozzle or 12-Nozzle

Collect & Place Head

➁ X-/Y-Gantry System

➂ Fixed Component Supply

➃ Fixed PCB

Description

Despite the highly stable machine

frame, slight distortions of the gan-

try axes cannot always be avoided.

With the aid of the mapping proc-

ess the high placement accuracy

of the machine is preserved

throughout its entire service life.

With this calibrating procedure,

which can be conducted quickly

and easily, the PCB camera recog-

nizes the fiducials on a mapping

calibration plate placed in its oper-

ating area. Any distortions are re-

vealed by comparing the nominal

grid on the glass plate with the ac-

tual grid “drawn” by placement

head. These distortions are taken

into account during all further posi-

tioning of X-/Y-axes and thus com-

pensated for.

Machine Criteria:

Mapping (Option)

Technical Data

Dimensions of the mapping

test plate

520 x 460 mm

(for single conveyor)

520 x 215 mm

(for dual conveyor)

Number of measurement

points

13 x 11 (standard resolution)

26 x 21 (high resolution)

Ambient temperature during

calibration + 20° ± 3°C

Components of the option Test plate (special glass)

Calculation data (disk)

Case for secure storage

Nominal Grid of Mapping Plate and Actual Grid with

Deviations Due to Gantry

Corrected

Position