IPC-TM-650 EN 2022 试验方法.pdf - 第633页

Non-US power receptacles may be different from those illus- trated. 4.7 Calibration and Standardization The oscilloscope (vertical and horizontal amplifiers) shall bear a current calibra- tion sticker. The scope probe sh…

Scope

This

test method deals only with transients gener-

ated within the Unit Under Test (UUT) and not with transients

originating elsewhere (i.e., power line transients), which propa-

gate through the UUT.

This procedure measures transient voltage events appearing

at the hot tip of an electric hand soldering/desoldering tool,

which could be seen by the workpiece. The test electrode and

measuring equipment represent a workpiece having a high

impedance.

There are two times when transients testing should be done:

• Equipment qualification for purchase

• Incoming inspection of new or repaired equipment

A storage oscilloscope is used to observe and measure tran-

sient events. The test electrode is coupled to the vertical input

of the oscilloscope via a 10 MΩ probe. The UUT may be iso-

lated from ambient electronic noise by placing it in a screen

room or shielded enclosure and supplying filtered AC power.

Inside the shield, the hot tip of the UUT is touched to the test

electrode.

This test may be falsely influenced by radio frequency interfer-

ence and electromagnetic interference from lighting and

equipment found in the workplace and testing area. This will

normally be demonstrated by ambient transients of 1.5 V peak

being present. At a minimum, shielded test leads should be

utilized. To avoid these influences it may be necessary to per-

form the leakage and transient tests in a screen room. In lieu

of a screen room a separate test procedure, see Method

2.5.33.4, which makes a low cost shielded enclosure, which

should provide adequate shielding for the performance of

these test procedures.

Warning:

This

is a laboratory test procedure that may of

necessity expose terminals that carry line voltages. All stan-

dard laboratory safety procedures regarding the setup and

performance of tests with line voltage equipment must be

observed at all times.

Caution:

This

test is performed with soldering systems at

their normal operating temperature. Test personnel must take

adequate precautionary steps to protect themselves and oth-

ers from potential burns.

Applicable Documents

ANSI/J-STD-001

Requirements

for Soldered Electrical and

Electronic Assemblies

IPC-TM-650 Test

Methods Manual

2.5.33 Measurement of Electrical Overstress from Solder-

ing Hand Tools

2.5.33.4 Measurement of Electrical Overstress from Solder-

ing Hand Tools - Shielded Enclosure

Test Specimens

Test

specimens for this procedure are

detailed in Method 2.5.33.

Equipment/Apparatus

Apparatuses

utilized by the pro-

cedures that make up this test method are given in 4.1

through 4.5.2.

4.1

Test

electrode (see Section 3)

4.2

Storage

oscilloscope, 100 Mhz bandwidth or faster, 1

MΩ input vertical amplifier

4.3

Power

line filter, 20 ampere @ 115 VAC, 50 dB insertion

loss @ 5 Mhz/50Ω

4.4

Oscilloscope

probe - X10 Attenuation

4.5

Optional

4.5.1

Screen

camera, diskette, or hard copy waveform

printer

4.5.2

Screen

room or shielded enclosure capable of accom-

modating the entire UUT, cord, and handpiece. A filtered AC

power receptacle shall be available from within (see Method

2.5.33.4).

4.6

Preparation of Apparatus

Turn

on the oscilloscope

and allow it to warm up.

Connect the UUT to a shielded AC line filter assembly as

shown in Figure 1 and configure for typical operation.

Note: The

plugs are in power receptacles during measure-

ments. They are shown unplugged in Figure 1 for clarity.

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062

IPC-TM-650

TEST

METHODS MANUAL

Number

2.5.33.2

Subject

Measurement

of Electrical Overstress from

Soldering Hand Tools - Transient Measurements

Date

11/98

Revision

Originating Task Group

Manual Soldering Task Group (5-22c)

Material

in this Test Methods Manual was voluntarily established by Technical Committees of the IPC. This material is advisory only

and its use or adaptation is entirely voluntary. IPC disclaims all liability of any kind as to the use, application, or adaptation of this

material. Users are also wholly responsible for protecting themselves against all claims or liabilities for patent infringement.

Equipment referenced is for the convenience of the user and does not imply endorsement by the IPC.

age1of4

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Non-US

power receptacles may be different from those illus-

trated.

4.7

Calibration and Standardization

The

oscilloscope

(vertical and horizontal amplifiers) shall bear a current calibra-

tion sticker. The scope probe shall be adjusted/compensated

to display the square wave calibration signal generated by the

oscilloscope without undershoot or overshoot.

Procedure

5.1 Baseline Measurement

Turn

on the UUT and allow it

to warm up to a normal operating temperature. Touch the hot

tip to the tinned area of the test electrode. Apply solder to

form good electrical contact. Turn off the UUT. Adjust the

oscilloscope controls as required and record any ambient sig-

nals that are displayed by the oscilloscope. Attempt this for a

minimum of two minutes. Repeat this baseline test for a mini-

mum of three trials. If any ambient transients are greater than

1.5 V peak, measures must be taken to reduce the effects of

the ambient interference to below 1.5 V peak.

Place the UUT in a screen room or the shielded enclosure (see

Figure 2) if the test is to be conducted in a shielded enclosure.

If the shielded enclosure is utilized, arrange for support and/or

remote movement of the handpiece. Configure the UUT for

typical operation. In cases where function switches must be

operated, arrange for remote switch actuation, such as by

using a non-metallic rod through a small hole in the enclosure.

Position the tip of the handpiece for remote placement onto

the test electrode.

5.2

Test Measurement

Turn

on the UUT. Let the tip dwell

on the electrode while the UUT cycles power to maintain tem-

perature for a minimum of two minutes. Operate various other

functions of the UUT if present, such as the vacuum pump or

IPC-2.5.33.2-1

Figure

1 Apparatus for Transient Measurement

OSCILLOSCOPE

AC LINE

FIL

TER ASSEMBLY

1 MEGOHM

INPUT

RECEPTACLE

FOR UUT

UUT

10 MEGOHM

(X10) SCOPE

PROBE

TEST

ELECTRODE

STRAIN

RELIEF

LINE

FILTER

METAL BOX

BLK BLK

WHTWHT

GRN GRN

GRN

IPC-TM-650

Number

2.5.33.2

Subject

Measurement

of Electrical Overstress from Soldering Hand

Tools - Transient Measurements

Date

11/98

Revision

age2of4

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air

solenoid by actuating the UUT’s finger switch or foot

switch. Repeat these operations, fine-adjusting the oscillo-

scope for best display of any transient peaks for a minimum

of three measurable trials.

5.3

Calculation and Interpretation of Results

Record

the

peak amplitude (see Figure 3). All three measurement tri-

als must have peak voltages ≤ 2.0 volts.

The peak voltage shall be ≤ ± 2.0 volts.

6 Notes

tracking test results, record the measured values

on a copy of the form found in Method 2.5.33.

6.1

Oscilloscope Adjustments

good initial setup for the

oscilloscope was found to be as shown in Table 1.

It’s important to start from a position of low trigger sensitivity

and work toward high sensitivity. If one were to start with high

sensitivity, weak transients would trigger the oscilloscope

before the strong, more potentially damaging ones.

6.2

Discussion of Transients.

Transients

are generated

by voltage or current switching in the UUT. Switching typically

occurs in circuits that modulate heaters, drive LED displays,

IPC-2.5.33.2-2

Figure

2 Alternate Apparatus for Transient Measurement

AC POWER

BULKHEAD

LINE

FIL

TER

JUNCTION BOX

WITH RECEPTACLE

1 MEGAOHM

INPUT

OSCILLOSCOPE

SHIELDED ENCLOSURE

UNIT

UNDER TEST

TEST

ELECTRODE

GROUND

CLIP

ELECTRODE

BULKHEAD

10 MEGAOHM

(X10) SCOPE

PROBE

IPC-2.5.33.2-3

Figure

3 Transient Waveform Measurement

VPEAK

IPC-TM-650

Number

2.5.33.2

Subject

Measurement

of Electrical Overstress from Soldering Hand

Tools - Transient Measurements

Date

11/98

Revision

age3of4

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