The Advantages of NAS 630 Steel Plate in PCB Lamination Process

The Advantages of NAS 630 Steel Plate in PCB Lamination Process

1. Introduction

In the Printed Circuit Board (PCB) manufacturing process, lamination is a crucial step that involves bonding multiple layers of substrates, copper foils, and prepregs together under high temperature and pressure. The quality of the lamination directly affects the performance and reliability of the final PCB product. NAS 630 steel plate, a precipitation - hardening stainless steel, has emerged as an excellent choice for components in the lamination process, such as lamination templates and press pads. This paper will elaborate on the advantages of NAS 630 steel plate in the PCB lamination process.

2. High Dimensional Stability and Flatness for Precision Lamination

2.1 Significance of Dimensional Stability and Flatness in PCB Lamination

Precise control of layer - to - layer alignment (layer registration error ≤ 50μm) and thickness uniformity (thickness deviation ≤ 10%) is essential in PCB lamination. Any deviation can lead to electrical performance issues, such as short - circuits or impedance mismatches.

2.2 Advantages of NAS 630 in this Aspect

NAS 630 steel plate, after precipitation - hardening heat treatment, exhibits an extremely low coefficient of thermal expansion, approximately 10.8×10⁻⁶/℃. During the lamination process, which typically involves temperatures ranging from 170℃ to 200℃, the thermal deformation of NAS 630 is minimal compared to common carbon steels or aluminum alloys.

Moreover, through precision machining techniques like grinding and polishing, NAS 630 can achieve a high surface flatness, usually ≤ 0.02mm/m. This ensures that the pressure applied during lamination is evenly distributed across the entire PCB stack. When the pressure is uniform, each layer of the PCB stack is bonded uniformly, avoiding problems such as "false lamination" (insufficient inter - layer adhesion) or "over - lamination" (excessive thickness deviation) caused by uneven pressure.

3. High Strength and Anti - Deformation Ability under High - Pressure Environment

3.1 High - Pressure Conditions in PCB Lamination

The lamination process of PCB requires high pressure, typically ranging from 1.5MPa to 4.0MPa (about 15 - 40kgf/cm²), and the steel plates need to withstand cyclic loading. A single lamination cycle may last for 2 - 4 hours, and the plates may be used for 10 - 20 cycles per day.

3.2 Strength - Related Advantages of NAS 630

After precipitation - hardening treatment, NAS 630 has an impressive tensile strength of 1100 - 1300MPa, which is much higher than that of common carbon steels (400 - 600MPa), and its yield strength reaches 950 - 1100MPa. This high strength enables NAS 630 steel plates to maintain their rigidity under high - pressure conditions in the lamination process without permanent deformation.

For example, the high strength of NAS 630 effectively prevents the "edge effect" (insufficient pressure at the edges of the stack) or "central depression" (excessive pressure in the center) caused by the deformation of the steel plate. As a result, the inter - layer adhesion of multi - layer PCBs is consistent, ensuring the quality and reliability of the final product.

4. High Temperature Resistance and Thermal Fatigue Resistance for Long - Term Use

4.1 Thermal Cycling in PCB Lamination

The lamination process of PCB involves a "heating - holding - cooling" cycle. The temperature of the steel plate rises from room temperature to 200℃ and then drops back. During this process, the steel plate is repeatedly subjected to thermal stress, which may cause thermal fatigue, leading to cracks or surface oxidation.

4.2 High - Temperature - Related Advantages of NAS 630

NAS 630 has excellent high - temperature resistance. When used at temperatures below 200℃ for a long time, its mechanical properties hardly degrade. In addition, it has strong resistance to thermal fatigue. After repeated thermal cycling, it is not easy to generate micro - cracks.

Compared with common carbon steels (which are prone to oxidation and rusting) or 45 - steel (whose strength decreases significantly at high temperatures), the service life of NAS 630 can be extended by 3 - 5 times. This not only reduces the cost of frequent replacement of tooling but also ensures the stability of the production process.

5. Excellent Corrosion Resistance to Avoid PCB Contamination

5.1 Corrosive Environment in PCB Lamination

During the lamination process, the prepreg (PP) releases a small amount of resin volatiles (such as epoxy monomers). In addition, solvents like alcohol and acetone are often used to clean the steel plates. Under such conditions, common steel materials are easily corroded, and rust may contaminate the PCB surface, resulting in problems such as pad oxidation or insulation failure.

5.2 Corrosion - Resistance Advantages of NAS 630

NAS 630 contains 17% chromium (Cr) and 4% nickel (Ni), which can form a dense oxide film on its surface. This oxide film endows NAS 630 with good corrosion resistance to organic solvents, resin volatiles, and humid environments. Even after long - term use, there is no rust, effectively preventing contaminants from transferring to the PCB stack. This is particularly important for high - reliability PCBs used in fields such as automotive electronics and aerospace, where product quality and reliability requirements are extremely high.

6. Good Surface Machinability to Meet Lamination Process Requirements

6.1 Surface State Requirements in PCB Lamination

In PCB lamination, the surface state of the steel plate is strictly required. On one hand, it is necessary to avoid adhesion of the resin from the prepreg (to prevent "sticking to the plate"), and on the other hand, it is necessary to ensure close contact with the stack (to reduce air bubbles).

6.2 Surface - Machinability Advantages of NAS 630

NAS 630 can achieve a surface roughness of Ra0.1 - 0.8μm through precision grinding, and the specific value can be adjusted according to the type of prepreg (PP). For example, for ordinary FR - 4 substrates, a surface roughness of Ra0.4 - 0.8μm is suitable, which can reduce resin adhesion; for high - frequency PCBs (such as PTFE substrates), a surface roughness of Ra≤0.2μm is required to avoid scratching the soft substrate.

In addition, after aging treatment, the surface hardness of NAS 630 reaches HRC40 - 45, which has strong wear resistance. Even after long - term use, the change in surface roughness is small, ensuring a stable lamination effect.

7. Conclusion

In summary, NAS 630 steel plate offers a series of advantages in the PCB lamination process, including high dimensional stability, high strength, excellent high - temperature and corrosion resistance, as well as good surface machinability. These advantages make NAS 630 an ideal material for key components in the lamination process. It effectively addresses key issues such as uneven pressure, dimensional deviation, contamination risks, and tooling wear in the lamination process, especially for high - layer - count PCBs (such as those with 12 or more layers), thick copper - clad boards (≥3oz), or high - precision PCBs (such as IC substrates). By using NAS 630 steel plate, PCB manufacturers can improve the quality and production efficiency of PCB lamination, and enhance their competitiveness in the market.