IPC J-STD-003B.pdf - 第15页

3.5 Solder Bath Requirements 3.5.1 Solder Temperatures T in/lead solderability testing shall be done at a solder temperature of 23 5±5° C [473 ± 9 °F]. Lead-free solderability testing shall be done at a sol- der temperat…

The composition of the lead-free solder paste to be used in

Test S1 shall be Sn96.5Ag3.0Cu0.5 (SAC305) per J-STD-

005, mesh size of -325/+500, ﬂux type to be agreed upon

between user and vendor. The solder paste shall meet the

storage and shelf life requirements of the manufacturers’

speciﬁcation. Other lead-free solder pastes may be used

upon agreement between user and vendor

3.2.2 Flux The ﬂux for tin/lead solderability tests shall

be a standard activated rosin ﬂux #1 having a composition

of 25% ± 0.5% by weight of colophony and 0.15% ±

0.01% by weight diethylammonium hydrochloride (CAS

660-68-4), in 74.85% ± 0.5% by weight of isopropyl alco-

hol (see Table 3-1).

The ﬂux for lead-free solderability tests shall be standard

activated rosin ﬂux #2 having a composition of 25% ±

0.5% by weight of colophony and 0.39% ± 0.01% by

weight diethylammonium hydrochloride (CAS 660-68-4),

in 74.61% ± 0.5% by weight of isopropyl alcohol (see

Table 3-1).

3.2.2.1 Flux Maintenance Standard activated rosin

ﬂuxes #1 and #2 shall be covered when not in use and dis-

carded after eight hours or the ﬂux shall be maintained to

a speciﬁc gravity of 0.843 ± 0.005 at 25±2°C[77±3.6

°F] and discarded after one week of use.

3.2.3 Flux Removal Material used for cleaning printed

boards after solderability testing and prior to solderability

evaluations shall be capable of removing visible ﬂux resi-

dues.

3.3 Equipment The following criteria applies to all

methods and equipment (see APPENDIX C for a list of

equipment sources). Equipment that is speciﬁc to any of

the solderability test methods is described within the

method details.

3.3.1 Conditioning Equipment The conditioning equip-

ment shall be capable of maintaining the temperature and

humidity parameters speciﬁed in 3.4.2. The test specimens

shall be suspended so that no portion of the test specimen

is within 40 mm [1.57 in] of the test chamber walls. The

nonmetallic holders shall support the test specimens

between vertical to 45 ° angle during exposure. Care shall

be taken to not exceed the capacity of the conditioning

equipment. Excessive or improper loading will cause con-

densation of humidity on the surface of the test specimens.

3.3.2 Solder Pot/Bath A thermostatically controlled

static solder bath shall be used of adequate dimensions to

accommodate the test specimens. The solder bath shall

contain enough solder to maintain the temperature during

testing within the speciﬁed temperature limits (3.5.1) and

to prevent exceeding the contamination levels (3.5.2). The

wave solder pot temperature limits utilized for Test Method

D or Test Method D1 shall be deﬁned by agreement

between the user and vendor. Precautions should be taken

to avoid solder pot/bath damage due to metal erosion when

using Lead-free solder alloys.

3.3.3 Optical Inspection Equipment All test methods

requiring visual inspection shall be capable of 10X magni-

ﬁcation (see individual test methods), and may be equipped

with reticles, or equivalent, for measurement, when appli-

cable. An example of a reticle is shown in Figure 3-2.

Shadowless lighting shall be used for proper inspection.

3.3.4 Dipping Equipment Solder dipping devices shall

be mechanical/electromechanical and capable of control-

ling the immersion/emersion rates dwell time and immer-

sion depth as speciﬁed in 4.2 to 4.3.

3.3.5 Timing Equipment Timing equipment shall be

automated and accurate to the limits of the test method.

3.4 Preparation for Testing

3.4.1 Test Specimen Preparation and Conditioning for

Test

Care shall be exercised to prevent contamination

(by grease, perspiration, etc.) of the surface to be tested.

When agreed upon between user and vendor, the test speci-

men to be tested may undergo other types of pretreatments

such as degreasing, aqueous cleaning, copper and solder

brightening, or baking.

The prescribed pretreatments should reproduce actual pro-

cessing of the printed boards up to the time of assembly

soldering (see 6.3). If conditioning is performed, prebaking

is not recommended.

3.4.2 Durability Conditioning All test specimens identi-

ﬁed as requiring durability conditioning shall be subjected

to conditioning prior to solderability testing immediately

followed by a bake per 3.4.3. The durability test conditions

shall be 72 °C± 5 °C [162 °F ± 9 °F] and 85%± 3% Rela-

tive Humidity [RH]. The test specimens shall be exposed

for a test duration of eight hours ± 15 minutes.

3.4.3 Baking Immediately after conditioning and prior to

solderability testing, all boards shall be baked at 105 ± 5

°C [221 ± 9 °F] for 1 +1/-0 hours to remove surface mois-

ture and other volatiles. Test specimens shall be cooled to

room temperature prior to ﬂuxing and testing.

Table 3-1 Flux Composition

Constituent

Composition by

Weight Percent

Flux #1 Flux #2

Colophony 25 ± 0.5 25 ± 0.5

Diethylammonium hydrochloride 0.15 ± 0.01 0.39 ± 0.01

Isopropyl Alcohol (IPA) Balance Balance

Weight of Chlorine as % of solids 0.2 0.5

Note: APPENDIX C: Informative Annex contains a listing of industry test

ﬂux product sources.

IPC J-STD-003B March 2007

Provided by IHS under license with IPC

Not for Resale

No reproduction or networking permitted without license from IHS

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3.5 Solder Bath Requirements

3.5.1 Solder Temperatures

Tin/lead solderability testing

shall be done at a solder temperature of 235±5°C[473 ±

9 °F]. Lead-free solderability testing shall be done at a sol-

der temperature of 255±5°C[491 ± 9 °F].

3.5.2 Solder Contamination Control The solder in

solder baths used for solderability testing shall be chemi-

cally or spectrographically analyzed or replaced each 30

operating days. The levels of contamination and Sn content

must be within those shown in Table 3-2. The intervals

between analysis may be lengthened if the test results indi-

cate that the contamination limits are not being

approached. The composition of the lead-free solder,

including contamination levels, shall be maintained during

testing per Table 3-2 with the silver and copper element

levels adjusted for alloy requirements.

NOTE: An operating day consists of any eight-hour

period, or any portion thereof, during which the solder is

liqueﬁed and used.

If contamination exceeds the limits speciﬁed in Table 3-2,

then the solder shall be changed and the intervals between

analyses shall be shortened. A sampling plan shall be

developed, implemented, and documented, demonstrating

solder contamination process control.

20 15 10 5 0

IPC-003b-3-2

Figure 3-2 Example Reticle

Table 3-2 Maximum Limits of Solder Bath Contaminant

Contaminant

Maximum

Contaminant Weight

Percentage Limit

Sn Pb Alloys

a, b

Maximum

Contamination

Weight

Percentage Limit

Pb Free Alloys

a,c

Copper 0.300 0.800

Gold 0.200 0.200

Cadmium 0.005 0.005

Zinc 0.005 0.005

Aluminum 0.006 0.006

Antimony 0.500 0.500

Iron 0.020 0.020

Arsenic 0.030 0.030

Bismuth 0.250 0.250

Silver 0.100 4.000

Nickel 0.010 0.010

Lead N/A 0.100

Notes:

a. The tin content of the solder shall be maintained within ± 1% of the

nominal alloy being used. Tin content shall be tested at the same

frequency as testing for copper/gold contamination. The balance of the

bath shall be lead and/or the items listed above.

b. The total of copper, gold, cadmium, zinc, and aluminum contaminants

shall not exceed 0.4%. Not applicable to lead-free alloys.

c. These Maximum Contamination Weight Percentage Limits apply for

solderability testing using the SAC305 solder alloy. The use of other

lead-free solder alloys/maximum contamination weight percentage limits

may be used upon agreement between user and vendor.

March 2007 IPC J-STD-003B

Provided by IHS under license with IPC

Not for Resale

No reproduction or networking permitted without license from IHS

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4 TEST PROCEDURES

4.1 Test Procedure Limitations

The test procedures of

this speciﬁcation are applicable to most printed board con-

structions typical of the industry. It is recognized that thick

printed boards will not act the same as thin printed boards

due to their increased thermal mass, aspect ratio, number of

ground planes and weight of the solder column within the

hole. These factors greatly reduce the likelihood that all

holes will display completely wetted knees with top side

caps.

The test procedures of this speciﬁcation shall be followed.

If determined by an agreement between the user and ven-

dor that changes are necessary due to the physical charac-

teristics of a test specimen and not the solderability of the

test specimen surface, a new procedure shall be docu-

mented and used only for the applicable test specimen.

Changes in test procedures and ﬂux (see 3.2.2) shall take

into account the wetting time and ﬂux issues per 6.6 and

6.7.

4.1.1 Application of Flux The test specimens are to be

dipped in the ﬂux to the full depth to be soldered for 5-10

seconds. The ﬂux shall be maintained at the prescribed

composition deﬁned in 3.2.2. After withdrawal from the

ﬂux, the test specimen shall be allowed to drain vertically

for a maximum of 60 seconds. Excess ﬂux shall be

removed by blotting the surface to be tested with a piece of

absorbent, clean material. The solderability test shall then

be performed in not less than one minute, and not more

than ﬁve minutes, after blotting.

IPC J-STD-003B March 2007

Provided by IHS under license with IPC

Not for Resale

No reproduction or networking permitted without license from IHS

--`,,```,,,,````-`-`,,`,,`,`,,`---

//^:^^#^~^^"^~"^"^:$^~#:"#:$@:~^"$^:#*~^$^~:^#*^^:^^*\\