IPC-TM-650 EN 2022 试验方法.pdf - 第153页

1.0 Scope This method is designed for determining the treated weight of a specific area of prepreg. Treated weight is an alternative to Resin Content Percent as a means of deter- mining the usability and functionality of…

5.4.2

Calculate

the Resin Content (RC) of the material from

the treated weight (TW) and the basis weight (BW) of the fab-

ric for 41,290 mm

[64

The basis weight may be deter-

mined by any suitable method in Appendix A.

(

1−

)

x 100

where:

RC = Resin Content in %

BW = weight of the fabric as determined in accordance

with Appendix A

TW = treated weight from 5.3.4.

5.5

Report

5.5.1

Report

the Resin Content to the nearest .1%.

5.5.2

Report

the method used to determine the basis

weight of the reinforcement.

5.5.3

Report

any anomalies in the test or any variations from

the specified procedures or tolerances

6.0

Notes

6.1

The

solvent or volatile content of the prepreg (excluding

moisture) is considered part of the treated weight using this

method. If it is desired to exclude solvent content, the speci-

men should be vacuumed for an appropriate time and tem-

perature.

6.2

The

accuracy of this method for determination of resin

content is dependent primarily upon the accuracy of the basis

weight and the consistency of the reinforcement.

6.3.

The

effect of static charges may present a serious prob-

lem in weighing material which has been stored if the sample

is larger than the sample pan.

6.4

it is desired to check variation across the web the indi-

vidual specimens may be weighed separately or 4 specimens

may be cut down the web at each location to be tested.

6.5

Desiccator Conditions

The

Test Methods Task Group

determined that a great majority of test laboratories are unable

to consistently hold the Relative Humidity in a desiccator to

less than 20%. Based on data from participating company lab

management, the lowest practically feasible RH for use with

the affected IPC Test Methods is 30% maximum.

Appendix

Determination of Basis Weight of Reinforcement

All

the

following methods consider any finishes applied to the fabric

as part of the fabric. In most cases, the level of organic mate-

rial is negligible; however, special considerations have to be

made for material such as greige goods, which have substan-

tial amount of organic (5% or more), and for organic fabrics

which may have significant moisture content.

Methods shown are based on four specimens, with a total

area of 41,290 mm

[64.0

Method

Determine

the Basis Weight from the actual

length, width and weight of the roll.

BW = 806.4 WR

LxW

= Basis Wt in g

WR = Roll weight in lb.

L = Roll length in yds.

W = Roll width in in.

Method

Determine

the Basis Weight from median statisti-

cal or typical fabric weight in oz/yd

= 1.40 W

BW = Basis wt in g

W = Weight of 1 yd

oz.

Method

Determine

the Basis Weight from the actual fab-

ric weight at the beginning of the roll, using Method 2.1.6.1.

Method

Determine

the Basis Weight from the reported

weight supplied by the manufacturer.

BW = 1.40W

BW = Basis Wt in g

W = Weight of 1 yd

Method

Determine

the Basis Weight by consulting the unit

weight tables in the applicable documents; see 2.0.

IPC-TM-650

Number

2.3.16.1

Subject

Resin

Content of Prepreg, by Treated Weight

Date

12/94

Revision

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1.0

Scope

This

method is designed for determining the

treated weight of a specific area of prepreg. Treated weight is

an alternative to Resin Content Percent as a means of deter-

mining the usability and functionality of prepreg. This method

is applicable to both organic and inorganic reinforcements but

effective use of this technique requires knowledge of resin and

reinforcement specific gravity, as well as basis weight of the

reinforcement.

2.0

Applicable Documents

IPC-EG-140

Specification

for Finished Fabric Woven From

‘‘E’’ Glass for Printed Board

IPC-SG-141

Specification

for Finished Fabric Woven From

‘‘S’’ Glass

IPC-A-142

Specification

for Finished Fabric Woven From

Aramid for Printed Boards

IPC-QF-143

Specification

for Finished Fabric Woven From

Quartz (Pure Fused Silica) for Printed Boards

IPC-TM-650

Method

2.4.38, Prepreg Scaled Flow Testing

Method 2.3.16, Resin Content of Prepreg by Burn-off

3.0

Test Specimens

3.1 Size

The

prepreg specimen shall be two or more die

cut plies. Each ply shall be 140 ± 0.25 mm [5.5 ± 0.01 in] by

178 ± 0.25 mm [7.0 ± 0.01 in]. Use of the specimen for scaled

flow test (IPC-TM-650, Method 2.4.38) is recommended. See

2.4.38 for additional criteria.

Alternate specimen sizes such as 102 mm x 102 mm [4 in x

4 in] or 457 mm x 610 mm [18 in x 24 in] are acceptable by

agreement between supplier and user.

3.2

Quantity and Sampling

Unless

otherwise specified,

three specimens shall be taken from the lot at randomly

selected locations, whether taken from a roll or from precut

panels. Specimens shall be taken from the fabric roll (as sup-

plied by the manufacturer) no closer to the selvage (or cut

edge) than a distance equal to one-tenth of the width of the

roll.

4.0

Apparatus or Material

4.1

Analytical

balance capable of weighing to the nearest

0.001g.

4.2

Static

shield (a thin piece of metal, e.g., 7 oz copper foil

at least 25.4 mm [1.0 in] larger in length and width than the

prepreg specimen). This is not required if the balance pan is

larger than the specimen.

4.3

Sample

cutting press with die 140 ± 0.25 mm x 178 ±

0.25 mm [5.50 ± 0.01 in x 7.00 ± 0.01 in].

4.4

Kraft

paper or equivalent back up material for cutting

press.

4.5

Desiccator

capable of maintaining an atmosphere less

than 30% R.H. at 23°C [73°F].

5.0

Procedure

5.1 Specimen Preparation

5.1.1

Cut

the specimens to the specified size and configu-

ration, see 3.1.

5.1.2

Preconditioning

Unless

the prepreg is tested within

10 minutes of production, the specimen shall be desiccated

for a minimum of 4 hours. For referee testing, the specimens

shall be desiccated.

5.2

Test Conditions

The

test shall be performed at stan-

dard laboratory conditions. For materials which absorb mois-

ture rapidly, care should be taken to insure that moisture con-

tent is not significant by measurement immediately after

removal from desiccation.

5.3

Equipment Setup

Place

the static shield on the bal-

ance pan and zero the balance.

5.4 Measurement

5.4.1

Place

each specimen on the balance, ensuring that it

sits entirely on the static shield.

5.4.2 Determine

and record the treated weight of each speci-

men to the nearest 0.001g.

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062-6135

IPC-TM-650

TEST

METHODS MANUAL

Number

2.3.16.2

Subject

Treated

Weight of Prepreg

Date

12/94

Revision

Originating Task Group

MIL-P-13949 Test Methods Task Group (7-11b)

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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5.5

Report

5.5.1

Average

the individual specimen weight and report the

average per ply treated weight to the nearest 0.001g per 25.4

sq mm [1.0 sq in] .

6.0 Notes

6.1 The

volatile content of the prepreg (excluding moisture)

is considered part of the treated weight using this method. If

it is desired to exclude volatile content, the specimen should

be baked for an appropriate time and temperature.

6.2

The

effect of static charges may present a serious prob-

lem in weighing material if the specimen size is greater than

the sample pan.

6.3

it is desired to check variation across or along the

web, individual specimens should be taken from the location

in question.

6.4

it is desirable to check the weight uniformity of

the reinforcement, this can be done by burn-off similar to IPC-

TM-650, Method 2.3.16, if inorganic.

6.5

Calculations

Treated

weight can be used to specify

and/or predict prepreg thickness and resin content. Equations

to calculate thickness and resin content for woven fabric ‘‘E’’-

glass reinforced epoxy FR-4 prepreg are given below. The

calculations assume a resin specific gravity of 1.37 gr/cc and

an ‘‘E’’-Glass specific gravity of 2.59 gr/cc.

Woven ‘‘E’’-glass fabric nominal dry weights and tolerances

are assumed the values given in IPC-EG-140.

The

nominal

dry weights and tolerances for other reinforcements, such

as ‘‘S’’ glass, woven aramid, and quartz fabric, can be

found in IPC-SG-141, IPC-A-142, IPC-QF-143.

Appropriate

values

for the specific gravities of other resins and rein-

forcements and the basis weights of other reinforcements

are the responsibility of the vendor or can be negotiated

between vendor and user. Inorganic reinforcement basis

weight can be measured as given in 6.4.

6.5.1

Resin Content

The

resin content can be calculated

from the average per ply treated weight and the measured or

nominal unit glass fabric weight. Conversely, the treated

weight can be calculated from the resin content. Equations to

calculate both are shown below:

(

1 −

)

100

TW = BW

– (RC/100)

Where:

RC = resin content by weight

TW = treated weight (weight per area per ply)

BW = unit basis weight (weight per area per ply)

6.5.2

Prepreg Thickness

The

average prepreg thickness

can be calculated using the average per ply treated weight

and the measured or nominal unit glass fabric weight. Equa-

tions to calculate prepreg thickness for Scaled Flow test sized

specimens (38.5 square inches per ply) are given below:In

general:

1.585TW

–

1.585W

–d

)

For

‘‘E’’-glass reinforced FR-4 epoxy prepreg:

1.157 TW – 0.545 W

Where:

prepreg thickness (mils per ply)

TW = treated weight (weight per 38.5 sq in per ply)

unit glass fabric weight (weight per 38.5 sq in per

ply)

resin density (grams per cubic centimeter)

fabric fiber density (grams per cubic centimeter)

6.6

Desiccator Conditions

The

Test Methods Task Group

determined that a great majority of test laboratories are unable

to consistently hold the Relative Humidity in a desiccator to

less than 20%. Based on data from participating company lab

management, the lowest practically feasible RH for use with

the affected IPC Test Methods is 30% maximum.

IPC-TM-650

Number

2.3.16.2

Subject

Treated

Weight of Prepreg

Date

12/94

Revision

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