IPC-CM-770D-1996 - 第91页

IPC-CM-770

Januaty

1996

I

IPC-1-00268

I

Figure 17-1

6

Terminal Installation, Single-Sided Board,

Soldered on Flared Flange Side

IPC-1-00269

I

L

Figure 17-17 Installation of Terminal in Plated-through

Hole

r-""

30"160"

swaging

tool

r--

-

"1

I

\

\"",I

on swagmg

tool

Grind or.mlll flats

I

Plated-thru

hole

IPC-I-O0270

L

Figure 17-1

8

Elliptical Swaging

B. Pins

Pins should be soldered in plated-through-holes,

and the standard requirements for minimum annular ring

(0.13

mm minimum) apply.

C. Wires

Wires, when soldered to printed boards, utilize

the same land configurations as through-the-board mounted

components.

D. Bus Bars

Bus bars utilize the same land configurations

as through-the-board mounted components.

E. Test Points

Test points utilize the same land configu-

ration as through-the-board mounted components.

17.2.3 Lead Configuration After Assembly

17.2.3.1 Soldered Assemblies

A. Placement of Heat Sensitive Components

Where a

number of different types of components are mounted on a

turret terminal, the most heat sensitive components should

be placed at the top (see Figure 17-19). The sequence of

installation from top to bottom should be as follows:

Semiconductors and diodes

Resistors

Relays

Capacitors

Coils

Hookup wires

Jumpers

B. Component Lead and Wire Attachment to Terminals

There should be no more than the three leads or wires

attached to a terminal, lug or any section of a multisection

turret terminal. However, each lead or wire must be in inti-

mate contact with the terminal and they should be

mechanically secure prior to soldering (see Figure 17-19).

C. Lead and Wire Placement on Double-Ended Terminals.

(See Figure 17-20.) The component lead should be attached

to the terminal on one side of the board and the bus and

jumper wire should be placed on the same side. Hookup

wires should only be connected to the terminal opposite the

component's side of the board.

V

IPC-I-O0271

Figure 17-19 Placement of Terminal-Mounted

Components

D. Terminal Wire Wrapping Prior to Soldering

The wrap

of the wire or component lead before soldering should be

sufficient to hold the wire in place without movement dur-

ing the solder operation. Minimum requirements to assure

mechanical security should be one half or

180

of wire

4-22

COPYRIGHT Association Connecting Electronics Industries

Licensed by Information Handling Services

COPYRIGHT Association Connecting Electronics Industries

Licensed by Information Handling Services

January

1996

IPC-CM-770

wrap. The maximum wire wrap should not overlap (see

Figure 17-21).

I I

W

Hook-up

Figure 17-20 Double-ended Terminal

(a)

Mlnlmum

Wrap

I

Blfurcated

(SPllt)

lug

Turret

lug

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(b)

Maxlmum Wrap

Hook

lug

\

IPC

-1-00095

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Figure 17-21 Terminal Wrap Prior to Soldering

E.

Jumper Wires

Component leads should not be used for

the purpose of jumper wires, bus wires or for interfacial

connections on printed boards. Jumper wires should be as

direct and as short as possible, without being taut, and

should not be routed over or under other components.

Where continuity between the two sides of a printed board

is desired, a short piece of unsleeved bus wire is used

either in a “C” or “Z” shape to conform to pattern

restrictions.

F. Point to Point Connections

The following rules should

be adhered to in selecting point to point jumper wires.

Bus wire over

1

inch long should be sleeved, and secured

to the board at one- inch intervals.

Bus wire crossing conductors should be sleeved.

Bend radii will conform to normal component bend

requirements.

The shortest route will be used unless design consider-

ations dictate otherwise.

Sleeving will be of sufficient length that slippage to either

end will not result in a gap between the insulation and

solder joint or bend of more than 3.2 mm. Sleeving

should not show damage caused by the soldering opera-

tion. (See Figure 17-22.)

3.2 mm 1.5 mm

-

,

[0.125”] max.

,

[0.060”] min

-

(al

Supported

Holes

-~

PTH

or

Eyelet

1.5 mm[0.060”] min.

r3i; mm [0.125”] max

Terrnlnal

post

i-

v///////a///A

(b)

Termlnals

IPC-1-00272

Figure 17-22 Methods

of

Mounting Jumpers

G. Jumper Wires or Leads Crossing Conductors

All

jumper wires crossing printed wiring conductor or conduc-

tors should be insulated with insulation sleeving. Compo-

nent leads should be insulated if they are within 1.27 mm

of the conductor surface, or over 9.52 mm in length from

the component body to bend radius. Large, supported, or

anchored components may not fall in this category.

H.

Insulation Clearance

The clearance between the end of

the insulation and the solder of the connection should be as

follows:

Minimum Clearance

The insulation should not be

embedded in the solder connection or touch the terminal.

The contour of the conductor should not be obscured at

the termination end of the insulation.

Maximum Clearance

Clearance should be less than two

wire diameters including insulation, or

0.15

mm, which-

ever is larger, but should not permit shorting to adjacent

conductors or terminals.

1.

Wire Bending Tools

Wire bending tools should be used

to form component lead and wires when preforming is

required. Round nose or protected long nose pliers may be

used as a bending tool. Bending tools, manual or auto-

matic, should not nick the wire. Other deformation should

not reduce the wire cross sectional area more than ten

percent.

17.2.3.2 Solderless (Wire) Wrap Assemblies

A. Wire Wrapping Guidelines

The following material is

provided to explain various types of solderless wrapped

connections. Figure 17-23 shows the common terminology

of this type of interconnection.

Conventional solderless wrapped connection consists of a

helix of continuous, solid, uninsulated wire tightly

wrapped around a suitable wrapost to produce a mechani-

cally and electrically stable connection (see Figure

4-23

COPYRIGHT Association Connecting Electronics Industries

Licensed by Information Handling Services

COPYRIGHT Association Connecting Electronics Industries

Licensed by Information Handling Services

IPC-CM-770 Januaty 1996

17-24). The number of turns required will depend on the

gauge of the wire used.

Wrapost

Apex

Wrapost

2

3

Level

Wrapper Turn

Insulated Wire

2

Level

-

2

1

Level

IPC-1-00273

Figure 17-23 “Wrapping Terminology”

Modified solderless wrapped connection is shown in Fig-

ure 17-25. In addition to the length of uninsulated wire

wrapped around the wrapost as defined for the conven-

tional solderless wrapped connection, an additional mini-

mum wrap of insulated wire in intimate contact with three

comers of the wrapost should be wrapped around the

wrapost to help insure better vibration characteristics.

Turn Requirement. (Table 17-3.) Each connection should

have the minimum number of complete turns given in

Table 17-3 in order to be acceptable.

Wire Size. (Table 17-4.) Unless otherwise specified, the

wire size in Table 17-4 will be used for all wire wrapping.

Wire wrapping tools may be manual, pneumatic, battery,

or electrically operated. To assure consistent results, only

pneumatic or electrically powered wire wrapping tools

should be used on Class 3 equipment.

Insulated or

Uninsulated Wire

Reference Corner

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IPC-1-00274

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Figure 17-24 Conventional Solderless Wrapped

Connection

Insulated Wire

I’

4

Corners

of

Contact

of

Insulated Wire

t

”2

Turn or

3

Corners

of

Contact

of

Insulated Wire

(2

IPC-1-00275

Figure 17-25 Modified Solderless Wrapped Connection

Table 17-3 Turns Requirement

Wire Gage

Insulated Wire* Uninsulated Wire AWG

Minimum Turns

of

Minimum Turns

of

I

30

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7

I

28

6 26

7

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24

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5

I

22

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5

I

20

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4

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Sufficient

for intimate

contact

of 3 corners

of the

wrapost

*Required for Modified solderless wrapped connections only

Table 17-4 Wire Size (in inches)

Wi re Uninsulated

AWG Wire

0.D

0.0420 +.O02 0.201 +0.0006/-0.0002 24

Insulation

0.D

0.0265 +0.0015 0.159

+

0.0004/-0.002 26

I

28

I

0.0126

+

0.0004/-0.0001

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0.230 +0.0015

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30

I

0.010

+

0.003/-0.0001

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0.0195 +0.001

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17.2.4 Guidelines for Mounted Component Configura-

tion

Except as noted in Section 17.3, the devices and

materials described in this Section have been designed for

throughhole mounting, and are used for electrical as well as

mechanical purposes. Reliable assemblies are the result of

proper design for the use of these devices. Design consid-

erations include proper hole diameters to permit solder

flowthrough (in plated-through-holes), adequate land sizes

to permit filleting between the land and the component, and

suitable finishes on the printed board and the component.

All areas to be soldered should be tin or tin-lead plated and

reflowed. Areas to be wire-wrapped or probed (as in test

points) are usually gold plated.

17.3 Surface Mounting

With the exception of wires,

these devices are not suitable for surface mounting. Wires

4-24

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Licensed by Information Handling Services

COPYRIGHT Association Connecting Electronics Industries

Licensed by Information Handling Services