What Is FR4 Epoxy Laminate

October 01, 2024

Epoxy glass cloth laminate, it is to alkali-free glass fiber, by shearing, settling, bonding, baking and other processes made of non-woven fabrics known as glass fiber felt or non-woven fabric, China as early as the end of the 1960s began to trial production. Its structure is sparse, good permeability, isotropic, and glass cloth compared to the process is simple and inexpensive. To alkali short-cut glass fiber mat as reinforcing material, dipped in epoxy adhesive made of pre-impregnated material pressed into the epoxy glass mat laminated products, with excellent mechanical properties and processability, commonly used to manufacture support and used as a fixed piece for large-scale turbine generator windings end fixed. Overcome the metal fixing parts and easy to occur creepage phenomenon, thus greatly improving the reliability of large generator operation.

Epoxy fiberglass cloth laminate is made of alkali-free fiberglass cloth impregnated with epoxy resin and hot-pressed into a rigid board-like insulating material.IEC standard is subdivided into EPGC201, EPGC202, EPGC203, EPGC204, EPGC306, EPGC308 and other different levels; in the NEMA (U.S. National Electrical Manufacturing Association) standard is divided into G10, FR-4, G11, FR-5 and other levels. 4, G11, FR-5 and other levels.

Epoxy fiberglass cloth laminate has the following properties: good electrical properties under high humidity environment, good mechanical properties under medium temperature, flame retardant (FR series), voltage resistance, stable product quality and other characteristics. It can be processed into various parts by lathe machining, stamping, trimming, drilling, sandblasting, grinding, sawing and milling. Epoxy fiberglass cloth laminate is widely used in electric motors, electrical equipment, circuit breakers, switchgear, transformers, DC motors, AC contactors, explosion-proof electrical appliances, traveler wheels, low-voltage electrical insulating separators, etc., in the fields of electrical, electronics, automotive industry, medical care and so on.

HONY Plastic has various series of processing equipments, including machining centers, CNC grinding machines, CNC turning machines, CNC milling machines, bending machines, surface treatment stamping equipments, etc. HONY Plastic is able to provide insulating material parts processing services with stable and flexible processing capability to satisfy the needs of rapid prototyping, high-precision pricing and low-cost mass production.

FR-4 Epoxy Board Processing Flow

FR-4 epoxy glass cloth laminate product surface preparation and processing

1. After the copper surface has been patterned and etched to form the circuit, handling and contact with the PTFE surface should be minimized. The operator should wear clean gloves and place a compartmentalized film on each board for transfer to the next process.

2. The etched PTFE surface is rough enough for bonding. It is recommended that the PTFE surface be treated to provide adequate adhesion where sheets have been etched or where uncovered laminates will be bonded. The chemistry used in the pth preparation process can also be used for surface preparation. Plasma etching or sodium-containing chemistries such as FluroEtch® by Acton, TetraEtch® by Gore, and Bond-Prep® by APC are recommended. specific processing techniques are again available from the supplier.

3. The copper surface treatment should ensure bond strength. A brown copper monoxide circuit finish will enhance the surface shape for chemical bonding with TacBond adhesives. This process requires a cleaner to remove residues and processing oils. Next, fine copper etching is performed to create a uniform rough surface area. Brown oxide needle crystals stabilize the bonding layer during the lamination process. As with any chemical process, adequate cleaning after each step is necessary. Salt residues can inhibit bonding. The rinsing should be supervised and the pH value should be kept below 8.5. Dry the layers one by one and make sure that the surface is not contaminated with oils such as hand oils.

Stacking and Lamination

Recommended bonding (pressing or platen) temperature: 425°F (220°C)

1. 250ºF (100°C) bake the laminates to remove moisture. Store laminates in a tightly controlled environment and use within 24 hours.

2. A pressure field should be used between the tool plate and the individual electrolytic plates to allow for an even distribution of pressure in the control plate. Areas of high pressure present in the board and in the circuit board that will be filled will be absorbed by the field. The field also uniforms the temperature from the outside to the center. This creates a uniform thickness from control board to control board.

3. The board must consist of thin layers of TAC BOND provided by the supplier. Care must be taken to prevent contamination when cutting the thin layers and stacking. Depending on the circuit design and fill requirements, one to three bonding sheets are necessary. The area to be filled as well as the dielectric requirements are used to calculate the need for a 0.0015” (38 micron) sheet. Clean fine steel or aluminum mirror plates are recommended between laminates.

4. To assist in lamination, a 20 minute vacuum is applied prior to heating. A vacuum is maintained throughout the cycle. Evacuating the air will help ensure completion of the circuit encapsulation.

5. Temperature monitoring with proper cycling can be determined by placing thermocouples in the peripheral area of the center plate.

6. The board can be loaded onto a cold or preheated press platen for start-up. Thermal rise and cycling will be different if the pressure field is not used to compensate. Heat input into the package is not critical, but should be controlled as much as possible to minimize the gap between the peripheral and center areas. Typically, heat rates range from 12-20ºF/min (6-9°C/min) to 425ºF (220°C).

7. Once loaded into the press, the pressure can be applied immediately. Pressure will also vary with the size of the control panel. It should be controlled in the range of 100-200 psi (7-14 bar).

8. Maintain hot press heat at 425ºF (230°C) for at least 15 minutes. The temperature should not exceed 450ºF (235°C).

9. Minimize the time without pressure state during lamination (e.g., time transferring from the hot press to the cold press). Maintain pressure state pressure until it is below 200ºF (100°C).

Author:

Ms. Tina

E-mail:

sales@honyplastic.com

Phone/WhatsApp:

8618680371609