GB/T 4721-1992 General rules for copper-clad laminates for printed circuits
Some standard content:
National Standard of the People's Republic of China
General rules for copper-clad laminated sheets for printed circuits
GB/T 4721-92
Replaces GB4721--84
This standard adopts the international standard IEC249 "Metal foil substrate for printed circuits" (1985-1988 edition). 1 Subject content and scope of application
This standard specifies the common requirements for copper-clad laminated sheets, such as terms, models and naming, copper foil requirements, appearance, dimensions, test methods, mechanical processing, inspection rules, marking, packaging, transportation and storage. This standard applies to copper-clad laminated sheets for printed circuits (hereinafter referred to as foil-clad sheets). 2 Reference standards
Abbreviations of plastics and resins
GB 1844
GB2036 Terminology and definitions for printed circuits GB2828 Sampling procedures and sampling tables for batch inspection by counting (applicable to inspection of continuous batches) Sampling procedures and sampling tables for periodic inspection by counting (applicable to inspection of stability of production process) GB2829
GB/T4722 Test methods for copper-clad laminates for printed circuits GB4723 Copper-clad phenolic paper laminates for printed circuits GB4724 Copper-clad epoxy paper laminates for printed circuits GB4725 Copper-clad epoxy glass cloth laminates for printed circuits GB5230
Electrolytic copper foil
3 Terminology
3.1 Copper-clad face
The copper-clad surface of the foil-clad board.
3.2 Bonding surface
The surface of the foil board after the copper foil is etched away.
3.3 Laminated surface
The surface of the single-sided foil board without copper foil. 3.4 Cold punching
The punching process of the foil-clad board at a board temperature between 20℃ and 60℃. 3.5 Hot punching
The punching process of the box-clad board at a board temperature exceeding 60℃. 4 Model and naming
4.1 The first letter C (copper) of the product model indicates copper foil. Approved by the State Bureau of Technical Supervision on July 8, 1992 and implemented on April 1, 1993
GB/T 4721-92
4.2 The second and third letters indicate the resin used for the base material. PF stands for phenolic resin
EP stands for epoxy
UP stands for unsaturated polyester
SI stands for silicone
TF stands for polytetrafluoroethylene
PI stands for polyimide
BT stands for bismaleimide triazine
4.3 The fourth and fifth letters indicate the reinforcing material used for the base material. CP stands for cellulose fiber paper
GC stands for alkali-free glass fiber cloth
GM stands for alkali-free glass fiber felt
AC stands for aromatic polyamide fiber cloth
AM stands for aromatic polyamide fiber felt
The inner core of the base material of the foil-clad board is made of cellulose paper as the reinforcing material, and alkali-free glass cloth is attached to both surfaces. "G" can be added after "CP" to indicate it. 4.4 At the end of the letter, a short dash is used to connect two digits to indicate the product number of the same type but different performance. Copper foil phenolic paper laminates are numbered 01~20; copper foil epoxy paper laminates are numbered 21~30; copper foil epoxy glass cloth laminates are numbered 31~40; copper foil epoxy synthetic fiber cloth or felt laminates are numbered 41~50; copper foil polyester glass fiber cloth or felt laminates are numbered 51~60; high temperature resistant copper foil laminates are numbered 61~70; high frequency copper foil laminates are numbered 71~80. 4.5 The letter F is added after the product number, indicating that the foil laminate is flame retardant. 4.6 According to the principle of model formulation, read out in order, add "laminate" at the end to be the name of the product, the product number is listed before the product name, and the product number can be used as the abbreviation of the product model. For example: CPFCP-03 product is named No. 03 copper foil phenolic paper laminate, referred to as "No. 3 board". 5 Copper Foil Requirements
The technical requirements of electrolytic copper foil used for foil-clad laminates shall comply with the provisions of GB5230. 6 Appearance
6.1 General Surface Appearance
6.1.1 The rear end surface of the foil-clad laminate shall be neat after cutting, and there shall be no delamination and cracks. 6.1.2 The copper foil surface shall not have bubbles, wrinkles, pinholes, deep scratches, pitting and glue spots that affect its use. Any discoloration or dirt shall be easily wiped off with a hydrochloric acid solution with a density of 1.02g/cm\ or a suitable organic solvent. 6.1.3 The laminated surface shall not have defects such as bubbles, indentations, scratches, lack of glue and foreign impurities that affect its use. 6.2 High-quality Surface Appearance
In addition to meeting the requirements of Article 6.1, the copper foil surface shall also meet the following requirements. 6.2.1 The copper foil surface shall have no scratches with a depth greater than 0.010mm, and no scratches with a depth greater than 1/5 of the nominal thickness of the copper foil. The total length of scratches with a depth greater than 0.005mm but not greater than 0.010mm shall not exceed 1m/m21 on the total area of the test board. Note: 1) This requirement applies to the surface of 35μm and 70μm copper foils. The allowable scratches on the surface of 18um copper foil are still under consideration. 6.2.2 The total area of all pinholes shall not exceed 0.012mm2 on an area of 0.5m2. 322
GB/T 4721-92
Any foil-clad board shall not have more defects of the types listed in Table 1. Table 1 Types, sizes and allowable numbers of defects
Size (length if no specification)
Inclusions
Wrinkles and bubbles
Not larger than
3.0 or width 1.0
4.0 or height 0.1
3.0 or width 1.0
4.0 or height 0.1
Any size
Note: 1) The total number of indentations of these two sizes is 13. 2) The total number of indentations of these two sizes is 3. Permissible number of defects
On a board with an area of about 1m23
Any number
Any number
Any number
On any area of 300mm×300mm
Any number
Any number
Any number
3) For boards of 1m or more, the values in the 4th column apply to any area of 1m, while the values in the 5th column apply to any area of 300mm×300mm of the same board. For boards less than 1m, the values in the 5th column apply to any area of 300mm×300mm. 6.3 After etching away the copper foil, the substrate (bonding surface) is not allowed to have pitting, holes, lack of glue, white spots, looseness and foreign impurities (including cured resin particles) that affect use. The color is uniform and consistent, and a small amount of irregular color changes are allowed. 7 Size
The recommended nominal area of the foil-clad board should comply with the provisions of Table 2. 7. 1
Recommended nominal area and deviation of foil clad laminate
Recommended nominal area (l×b)
1000×1000
1 200×1 000
Note: Foil clad laminates with non-recommended nominal areas can be manufactured by negotiation between the supplier and the supplier. Deviation
7.2 The nominal thickness and single-point deviation of the foil clad laminate shall comply with the provisions of Table 3. However, the difference in thickness between any two points on the same sheet shall not exceed the absolute value of the single-point deviation.
Nominal thickness
GB/T4721-—92
Table 3 Nominal thickness and single point deviation of foil-clad boards
Under consideration
Glass cloth base 1
Note: ①Thickness and deviation are not applicable within 25mm from the edge of the board. No matter how large the board surface is, at least 90% of the area is within the deviation, and individual points are allowed to be no more than 125% of the allowable deviation.
②Non-nominal thickness can be manufactured by negotiation between the supply and demand parties, and its deviation shall be implemented according to the grade with the larger nominal thickness value. ③The nominal thickness and single point deviation of thin foil-clad boards for multi-layer printed circuit boards shall be specified separately. 1) Single point deviation of CEPCP(G)-23F type using glass cloth base. 7.3 Verticality
Verticality of foil-clad laminates shall be tested in accordance with Chapter 24 of GB/T4722, and its value shall comply with the provisions of Table 4. Table 4 Verticality
Dimensions
1000×1000
1200X1000
8 Test methods
Verticality
Performance test methods of foil-clad laminates shall comply with GB/T4722, and shall be specified in the product standards when otherwise required. 9 Machinability
Foil-clad laminates shall be able to withstand mechanical processing such as shearing, punching, drilling, sawing, and milling. The mechanical processing methods and evaluation standards of foil-clad laminates may be negotiated by both parties or recommended by the manufacturer.
10 Inspection rules
10.1 Identification inspection
GB/T 4721—92
When the product is finalized for production, the raw material process is changed, or the production is resumed after one year of suspension and the product is certified, the normal production products shall be subject to identification inspection.
10.1.1 Sampling plan
10:1.1.1 The sample is randomly selected from each model and specification of the product applied for identification in normal production, and the sample size is one sheet (each side of the double-sided foil plate is selected separately).
10.1.1.2 The number of samples required for the identification test shall be cut from the sample unit in accordance with the provisions of Table 2 in Chapter 3 of GB/T4722. 10.1.2 Inspection items
The inspection items shall be in accordance with the provisions of the product standards.
10.1.3 Judgment rules
If one item is unqualified, it shall be judged as unqualified for identification. 10.2 Quality consistency inspection
10.2.1 Inspection batch
An inspection batch includes all the foil-clad laminates that are inspected at one time and are produced with the same (same batch or equivalent) materials, using the same process and under basically the same conditions.
10.2.2 Group A inspection
Group A inspection is carried out according to the items specified in Table 5. Table 5 Group A inspection
Inspection items
Verticality
Warp
10.2.2.1 Sampling plan
Requirements, clauses
(GB 4723~4725)
Methods Chapters, clauses
(Chapters in GB4722)
Group A inspection is batch inspection, and counting sampling is carried out according to the special inspection level S-2 in GB2828. The acceptable quality level (AQL) is 2.5. The sampling plan and the number of acceptable judgments are shown in Table 6. Table 6 Sampling plan for Group A
Inspection items
Dimensions, verticality, warpage
10.2.2.2 Rejected batch
Batch range
26~150
151~1200
1201~3500
Sample size (sheets)
Normal inspection
Strict inspection
Number of qualified judgments
If an inspection batch is rejected, the supplier can screen it and re-provide the inspection batch for re-inspection. The re-inspection should adopt strict inspection. The re-inspection batch should be separated from the normal batch and clearly marked as a re-inspection batch. 10.2.3 Inspection of Group B
The inspection items of Group B shall be carried out in accordance with the provisions of Table 7. The samples of Group B shall be randomly selected from the batches that have passed the inspection of Group A. 325
Inspection Items
Peel Strength after Thermal Shock
Blistering Test for Thermal Shock
10.2.3.1 Sampling Plan
GB/T 4721—92
Table 7 Group B Inspection
Requirements Chapters and Articles
(GB 4723~4725)
4.2.5 Table 7-2
4.2.5 Table 7-3
Methods Chapters and Articles
(Chapters in GBA722)
One sample is randomly selected from each batch of products, and each side of the double-sided foil-clad board needs to be selected separately. The qualified judgment number is 0.10.2.3.2 Handling of Sample Units and Qualified Batches Sample units and batches that have passed the Group B inspection can be delivered according to the contract or order. 10.2.3.3 Handling of rejected batches
If an inspection batch fails, the supplier shall take measures and resubmit the inspection batch for re-inspection. The re-inspected batch shall be subject to stricter inspection. Three samples shall be taken for re-inspection. If the re-inspected batch still fails, the batch shall be deemed unqualified. 10.2.4 Group C inspection
Group C inspection is a periodic inspection, and the inspection items shall be carried out in accordance with the provisions of Table 8. Group C inspection samples are randomly selected from the batches that have passed the inspections of Groups A and B.
Table 8 Group C Test
Test Items
Surface resistance and volume resistivity
After wet heat treatment in a humid chamber or recovery
At high temperature
Surface corrosion
Edge corrosion
After wet heat treatment and recoveryDielectric constant and dielectric loss factorPull-off strength
Peel strengthbzxZ.net
At high temperature
After exposure to solvent vapor
After simulated electroplating
After heat
Punching
Weldability
Bending strength
Flammability
Water absorption
White spot test
Note: 1) Only GB4725 applies.
10.2.4.1 Sampling plan
RequirementsChapter and clause
(GB 4723~~4725)
4.1 Table 2-2, 3
4.1 Table 2-6
4.1 Table 2-7
4.1 Table 2-4.5
4.2.5 Table 7-1
4.2.5 Table 7-2
4.2.5 Table 7-5
4.2.5 Table 7-4
4.3. 2 Table 8-1
4.3.2 Table 8-2
4.3.2 Table 8-3
4.3.2 Table 8-41)
Method Chapter, Article
(Chapter in GB4722)
(Month)
Group C inspection is based on GB2829, with a sampling plan of 50 unqualified quality level (RQI) and 1 discrimination level. If three samples are taken each cycle (one sample is taken from each side of the double-sided foil-clad board), the qualified judgment number is 0. 10.2.4.2 Unqualified
If the sample unit drawn according to the sampling plan fails to pass the Group C inspection, the batch of products is considered unqualified. 10.2.4.3 Handling of rejected batches
If an inspection batch fails and is rejected, the supplier may correct or screen out the defective boards and resubmit them for re-inspection. The re-inspection batch shall be sampled twice as many as the normal batch, and the re-inspection batch shall be clearly separated and marked from the normal batch. If the defect cannot be screened out, the supplier must make process corrections and take samples from the corrected batch. If the same defect is found in the batch inspection, it indicates the supplier's responsibility and should be negotiated with the purchaser to resolve it. The purchaser should be notified of the batch that has been delivered.
11 Marking, packaging, transportation, and storage
11.1 It is recommended to print the manufacturer's identification mark on the reinforcement material on the surface of the base material of the foil clad board. The color of the mark should be red for flame retardant box clad boards; other colors different from red for non-flame retardant foil clad boards. The maximum distance between adjacent repeated marks shall not exceed 75mm. The vertical direction of the mark symbol is consistent with the longitudinal direction of the reinforcement material of the base material. The longitudinal direction should be indicated by an arrow on the double-sided foil clad board. 11.2 The packaging of the clad board must ensure that the product quality is not affected. 11.3 The foil-clad boards are packaged in the same direction, and the package should be accompanied by a product certificate indicating the manufacturer's name, product name, model and specification, nominal thickness of the copper foil, batch number, manufacturing date and production license number. Note: 1) When the nominal thickness of the copper foil of the double-sided clad box board is different, it is expressed as ×××/×××. 11.4 The outer surface of the package should be marked with the manufacturer's name, product model and name, product specification, batch number, manufacturing date, gross weight, net weight and words or symbols such as "Caution to prevent moisture", "Rainproof", and "Handle with care". 11.5 During transportation and storage, foil-clad boards should be protected from rain, high temperature, mechanical damage and direct sunlight. 11.6 Foil-clad boards should be placed flat off the ground and stored in a dry, corrosive gas-free room with a temperature not exceeding 35°C and a relative humidity not exceeding 76%. 11.7 The storage period of foil clad laminates is one year from the date of leaving the factory. If the period is exceeded, they can still be used if they are inspected according to technical requirements. 327
GB/T 4721-92
Appendix A
Copper clad laminate model correspondence table
(reference)
The correspondence between some models of copper clad laminates is shown in Table A1. This table is for reference only and is not a technical basis. Table A1 Correspondence table of some models of copper-clad laminates Name
Copper-clad phenolic paper laminate
Copper-clad phenolic paper laminate
Copper-clad phenolic paper laminate
Copper-clad phenolic paper laminate
Copper-clad phenolic paper laminate
Copper-clad phenolic paper laminate
Copper-clad phenolic paper laminate
Copper-clad phenolic paper laminate
Copper-clad phenolic paper laminate
Copper-clad phenolic paper laminate
Copper-clad phenolic paper laminate
Copper-clad phenolic paper laminate
Copper-clad box epoxy paper laminate
Copper-clad epoxy paper laminate?
Copper clad epoxy glass cloth laminate
Copper clad epoxy glass cloth laminate
Copper clad epoxy glass felt laminate 2)
CPECP-01
CPFCP-02
CPFCP-03
CPFCP-04
CPFCP-05F
CPFCP-06F
CPFCP-07F
CPFCP-08F
CPFCP-09F
CPFCP-10F
CEPCP-22F
CEPCP(G)-23F
CEPGC-31|| tt||CEPGC-32F
IEC-249-2-1
IEC-249-2-2
IFC-249-2-6-FHI
IEC-249-2-7-FV
IEC-249-2-14-FV
IEC-249-2-3-FV
IEC-249-2-9-FV()
IEC-249-2-4
IEC-249-2-5-FV
IEC-249-2-10-FVO
Note: ①NEMA is the standard of the National Electrical Manufacturers Association of the United States, and MIL is the US military specification. ②（）is the customary model, but not the official NEMA model. 1) The flammability of this model is the horizontal method, while the corresponding GB.NEMA model is the vertical method. 2) Glass cloth is pasted on both surfaces.
Additional notes:
This standard is proposed by the Ministry of Machinery and Electronics Industry of the People's Republic of China. This standard is under the jurisdiction of the Guangzhou Electric Science Research Institute of the Ministry of Machinery and Electronics Industry. This standard was drafted by the Guangzhou Electric Science Research Institute of the Ministry of Machinery and Electronics Industry and Factory 704. The main drafters of this standard revision are Lin Zhenru and Zhu Hongjiao. 328
(XXXP-FR)
(XXP-FR)
(XXPC-FR)
XPC-FR
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