IPC-CM-770D-1996.pdf - 第141页

January 1996 IPC-CM-770 OETAIL "A" #14 gauge, black insulated Gound Wire Terminal 10 Candull 1 0 808 Block See Oatall "A" 1 - To Mat To firth - Ground 14 gauge, black insulat nccrconnccling Wire rom T…

IPC-CM-770

Januaty

1996

Figure 26-2 Schematic

a Typical Grounded Work Station

Component

Function

ccaductive

flooring

and

Floormat

S.NOS

IWK

drain

p.-

appcosch~ng

the

work

&tion.

Drain6 away charges yeneraled

walking

across

floors

(or conductive

Benchtop

mat Pr0nd.s

auk-irao

work

ruriwx

Salic

Ch.rgos ara

dra~fmd

away from any aIec~rontc components

prlnled clrcull

urds

rosllng

th.

suriua

th.

mal.

Ground

cord

Prwldes

olutrical

connullon

be1ww1-1

lunchlop

nut

and

I(oorrne1

and

ptnr

lhose

Iwo

surfaces

an sanh groutrd

bench

top)

thmm

I.Sl*OT

500

KILOHM

RESISTOR

TES:

1. 1/16

conductive sheet stock covering bench

top

work area.

Ground strap.

Wrist strap in contact with skin.

Static neutralizer. (Ionized air blower directed at

work.) Primarily

for

use in areas where direct

grounding

impractical.

floor

chair feet are non-conducting, chair must

have ground strap.

IPC-I-

Figure 26-3 Features

a Grounded Work Station

between component mounting and soldering. If this is the

26.4 Automation and Equipment

case, it is recommended that the racks be covered with an

dust and debris.

to the production stations is accomplished by means of the

All too frequently, problems due to improper storage arise transporter system, controlled by a central dispatch area.

in the final assembly testing operation or worse, in the form Typically the transporter consists of two levels, the upper

of field failures that can be traced "from the cradle to the one dispatching the work and the lower one for return of

grave," i.e., back to the source of the parts destined to completed work. Strategically placed photocells on the

become a printed board assembly. return conveyer read bar code labels on the tote box which

approved plastic

keep

them

Out Of

the

way

26.4.1 Transporters

One method of providing material

6-4

Licensed by Information Handling Services

January

1996

IPC-CM-770

OETAIL

"A"

#14

gauge, black insulated

Gound

Wire

Terminal

Candull

808

Block

See

Oatall

"A"

Mat

firth

Ground

gauge, black insulat

nccrconnccling

Wire

rom

TOP

Mal

FLOOR

MAT

(or

conductive

floo

IPC-1-00299

Figure 26-4 Installation Guidelines for Grounded Work Benches and Floor Mats

provide automatic work-in- progress (WIP) status to a cen-

tral computer. Protection of ESD sensitive components

should be provided by:

Static free conveyer belts.

Grounding of machinery.

Personnel must be grounded at all times when they touch

devicedassemblies.

26.4.2 Automatic Assembly Machines

Handler capa-

bilities and features vary according to the type of unit and

device being accommodated. Automatic units provide

throughput rates on the order of

6,000,

and greater, compo-

nents per hour. Tube adapters are designed to take most

tubes currently in use. Automatic assembly machines range

from very specific machines which repeat the same task

over and over again, to the machines which can be pro-

grammed to do several similar processes.

Consideration must be given to complexity, volume of

units per run and the product mix to be assembled. Equip-

ment should be selected for high flexibility enabling it to

handle a large product mix and short production runs, or

choose highspeed dedicated equipment which does not

allow for much product mix.

There are three basic types of equipment available.

26.4.2.1 lnline Machines

Moderate volume machines

which utilize multiple placement heads. The machine can

have each head placing a single component or a program-

mable head which can place a variety of components up to

approximately

30,000

components per hour.

6-5

Licensed by Information Handling Services

IPC-CM-770

Januaty

1996

Use

conduclive or anti.

bags and contamers

Usa

wrist

straps

and

Avord lead handimg

Pick

static

sensitive

devices

only by the

body.

Keep

Discharge personal static before

handling devices.

í2<

handling

work

stauon cmap

Avoid all plastic, vinyl and Styrofoam in the

work

area, except

anti-static

conductwe plastics.

Assemate

only

at gmundecl

work

s~atron

AVOIO

Charge generalron

not

subject semconductors

shdlng movements over

any surface at any time.

IPC-I-O0301

Figure

26-5

Proper Handling Procedures

6-6

Licensed by Information Handling Services