IPC-TM-650 EN 2022 试验方法.pdf - 第89页

1.0 Scope A method for determining whether or not the powder in a solder paste complies with the relevant powder type. The ASTM B-214 standard screen powder size distribu- tion method has been found to be acceptable. 2.0…

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Figure
3 Microhm Meter Calibration Curves
IPC-TM-650
Number
2.2.13.1
Subject
Thickness,
Plating in Holes Microhm Method
Date
1/83
Revision
A
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1.0
Scope
A
method for determining whether or not the
powder in a solder paste complies with the relevant powder
type. The ASTM B-214 standard screen powder size distribu-
tion method has been found to be acceptable.
2.0
Applicable Documents
ASTM E11
BS.410
DIN 4188
ISO 565
ISO 3310
3.0 Test Specimen
Approximately
150 grams of solder paste
4.0
Equipment/Apparatus
Vibratory
test sieving machine
Test sieves to BS.410, ASTM E11, DIN 4188, or ISO 565 and
ISO 3310 with mesh openings of 150, 75, 45, 38, 25 and 20
micrometers
Sieve bottom receiver and lid
Balance (scale) with an accuracy of 0.01 g
Beaker 400–600 ml
Watch glass
Solvent
Acetone
Spatula
5.0
Procedure
5.1 Preparation
5.1.1
Wait,
if necessary, until the solder paste is at room
temperature.
5.2
Test
5.2.1
Homogenize
the paste by stirring with the spatula.
5.2.2
Weigh
paste containing approximately 110 g of solder
alloy into the carefully cleaned beaker.
5.2.3
Add
approximately 50 ml solvent.
5.2.4
Stir
the mixture with the spatula so that the flux in the
paste can dissolve in the solvent.
5.2.5
Cover
the beaker with the watch glass.
5.2.6
Let
the beaker with the watch glass stand until the
solder powder settles.
5.2.7
Decant,
carefully, as much as possible of the fluid
without losing any of the solder powder.
5.2.8 Repeat
the extraction procedure five times, using 50
ml solvent for each extraction.
5.2.9
Add
approximately 50 ml acetone to the washed sol-
der powder and stir with the spatula to assist in drying.
5.2.10
Let
the solder powder settle.
5.2.11
Decant,
carefully, as much as possible of the
acetone.
5.2.12
Repeat
the acetone wash 2 additional times.
5.2.13
Allow
the powder to dry at ambient temperature until
the weight is constant.
5.2.14
Weigh
test sieves, with mesh opening sizes appro-
priate for the type of powder being tested, and the sieve bot-
tom receiver. Typical sieves required are shown in Table 1.
T
able 1 Screen Opening
T
ype 1 150 75 20
Type 2 75 45 20
Type 3 45 25 20
Type 4 38 20
The
Institute for Interconnecting and Packaging Electronic Circuits
2215 Sanders Road • Northbrook, IL 60062
IPC-TM-650
TEST
METHODS MANUAL
Number
2.2.14
Subject
Solder
Powder Particle Size Distribution—Screen
Method for Types 1-4
Date
1/95
Revision
Originating Task Group
Solder Paste Task Group (5-24b)
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.
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5.2.15
Place
the sieves on the receiver with the sieve with
the smallest opening on the receiver and processing sequen-
tially upward to the largest opening screen.
5.2.16
Weigh
the powder and put this in the top sieve.
5.2.17 Place the lid on the sieve combination and transfer
this to the sieving machine.
5.2.18
Run
the machine for approximately 40 minutes.
5.2.19
Reweigh
the sieves and the receiver.
5.2.20
Subtract
the original weights of the sieves and the
receiver to obtain the weights of powder with sizes greater
than, within, and less than the nominal size range from Table
2A and 2B.
5.3
Evaluation
Express
the masses of the powder above,
within, and below the nominal size range as percentages of
the mass of the original sample. Enter data in Table 3.
T
able 2A % of Sample by Weight—Nominal Sizes
Less
Than 1%
Larger Than
80% Minimum
Between
10% Maximum
Less Than
Type 1 150 Microns 150–75 Microns 20 Microns
Type 2 75 Microns 75–45 Microns 20 Microns
Type 3 45 Microns 45–25 Microns 20 Microns
Table 2B % of Sample by Weight—Nominal Sizes
Less
Than 1%
Larger Than
90% Minimum
Between
10% Maximum
Less Than
Type 4 38 Microns 38−20 Microns 20 Microns
Table 3
T
ype 1 +150µm
+75
µm
+20
µm
–20
µm
T
ype 2 + 75 µm
+45
µm
+20
µm
–20
µm
T
ype 3 + 45 µm
+25
µm
+20
µm
–20
µm
T
ype 4 + 38 µm
+20
µm
–20
µm
IPC-TM-650
Number
2.2.14
Subject
Solder
Powder Particle Size Distribution—Screen Method for
Types 1-4
Date
1/95
Revision
P
age2of2
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