FR-4 Board Manufacturing Technology

  In the field of composite materials, an increasing number of companies are using FR-4 epoxy insulation boards to replace old materials. Among the widely used copper-clad boards in the electronics industry, FR-4 material has maintained its dominant position.

  It possesses excellent flame retardancy, insulation properties, and complies with global certifications for halogen-free environmental safety. In a sluggish global market, factories are streamlining costs, and FR-4 material offers a very competitive price. These conditions have stimulated a growing demand for FR-4 material in the market.

  Here, we share two of the most common FR-4 material manufacturing technologies.

  FR-4 Resin Solution Technology

  The formulation of resin solution in the epoxy resin copper-clad board industry has remained largely similar for many years.

Preparation method:

  1. Mix and prepare a solvent mixture by stirring dimethylformamide and ethylene glycol monomethyl ether.

  2. Add dicyandiamide and stir until dissolved.

  3. Add epoxy resin and mix thoroughly.
  4. Dissolve methyl imidazole in an appropriate amount of dimethylformamide, then add it to the above materials and continue stirring.
  5. After aging for 8 hours, take samples for testing relevant technical requirements.

  Resin Solution Technical Requirements:
  1. Solid content: 65% to 70%.
  2. Gel time (171°C): 200 to 250 seconds.

  Bonding Sheet Manufacturing Technology

  Manufacturing process:

  After unwinding the fiberglass cloth, it passes through guide rollers and enters the glue trough. After impregnation, it passes through an extrusion roller to control the resin content, then enters the oven. During the oven process, solvents and other volatiles are removed while the resin is semi-cured. After exiting the oven, it is cut according to size requirements and neatly stacked on a storage rack. Adjust the gap of the extrusion roller to control the resin content. Adjust the temperature, air volume, and speed of each temperature zone in the oven to control the gel time and volatile content.

  Testing method:

  During the bonding sheet manufacturing process, in order to ensure quality, it is necessary to regularly test the resin content and other technical requirements. The testing method is as follows:

  1. At least 25mm from the edge of the bonding sheet, cut 3 samples in the left, middle, and right directions. The sample size is 100mm × 100mm, with diagonal lines parallel to the warp and weft.

  2. Weigh each sample (W1), accurately to 0.001g.
  3. Place the samples in a muffle furnace at 524-593°C and burn for 15 minutes or until all carbides are removed.
  4. Transfer the samples to a dryer and cool to room temperature.
  5. Weigh each sample again (W2), accurately to 0.001g.
  6. Calculate: Resin content = [(W1 - W2) / W1] × 100%.

  Cost-effectiveness, environmental friendliness, and sustainable recycling are the future direction of materials. The FR-4 manufacturing technology is also evolving with market demand. As a professional factory specializing in the production and research of FR-4 materials, we have always been attentive to industry development trends. Our engineers actively participate in the future material revolution. Contact us to get free samples of FR-4 boards and learn more about the latest developments in FR-4 materials.