Name: Automotive PCB (HDI R-FPCB)
Brand: PCB Printed Circuit Board and PCBA manufacturing
Rating: 5 (1 reviews)

Description
Data Sheet

1. Industry Development & Application Trend of R-FPCB

The application of HDI-structured R-FPCB in automotive PCBs has driven its technological upgrading. With the advancement of PCB technology, R-FPCB has been widely applied, and its global supply is expected to grow substantially. Its excellent durability and flexibility make it ideal for automotive electronics, gradually expanding market share at the cost of rigid PCBs.

R-FPCB’s light weight, thin thickness and compact structure make it suitable for portable and automotive electronics, the main drivers of its output growth. Industry insiders predict it may outperform other PCBs in the next few years.

R-FPCB has a high manufacturing threshold but strong resistance to harsh environments, favored by automotive electronics manufacturers. Integrating rigid PCB durability and flexible PCB adaptability, it has become a strategic focus for PCB enterprises to seize market opportunities.

Miniaturization, weight reduction, error-free wiring, flexible assembly and 3D assembly are inevitable demands for electronic products. Light, thin and flexible interconnection technologies like R-FPCB are increasingly valued in automotive electronics.

With expanded applications, R-FPCB has evolved from single-sided to double-sided, multilayer and rigid-flex boards. Fine line width/pitch and surface mounting impose strict requirements on production, including substrate treatment, inter-layer alignment, dimensional stability, decontamination, micro-hole metallization reliability and surface coating.

HDI R-FPCB

2. Overview of HDI R-FPCB

HDI R-FPCB integrates HDI technology with rigid-flex structure, enhancing circuit density and miniaturization, which aligns with the high integration trend of automotive and portable electronics.

3. R-FPCB Design & Production Fundamentals

3.1 Definition & Classification

R-FPCB is a composite board with one or more rigid and flexible areas, classified into reinforced flexible boards and rigid-flex multilayer boards to meet different application needs.

3.2 Pre-Production Preparation

Adequate preparation, including professional material knowledge, is critical for R-FPCB production. Material selection directly determines process difficulty, product performance and reliability.

4. R-FPCB Material Selection (Maxipcb's Professional Practice)

Maxipcb selects high-performance materials based on industry experience and application scenarios to ensure R-FPCB stability and reliability.

4.1 Flexible Substrate Selection

Maxipcb adopts DuPont’s AP adhesive-free PI flexible substrates, which have excellent flexibility, electrical properties and heat resistance but high hygroscopicity and poor alkali resistance. Adhesive-free substrates are chosen because common adhesives (acrylic, polyester, modified epoxy) have inherent defects, while Maxipcb prioritizes DuPont AP over Japanese epoxy series for better performance.

4.2 Rigid Substrate Selection

After testing epoxy boards (poor adhesion) and FR-4/G200 (warpage due to resin incompatibility), Maxipcb selected PI resin rigid materials, laminated with P95 substrates/prepregs. This matching resin system avoids post-thermal-shock warpage, meeting automotive electronics requirements.

4.3 Adhesive Selection (Rigid-Flex Junction)

Maxipcb uses No-flow prepregs for rigid-flex lamination to prevent glue overflow and transition area damage. For RoHS, high Tg and impedance requirements, raw material characteristics (thickness, dielectric constant, Tg, environmental protection) are strictly verified.

5. R-FPCB Manufacturing Process & Key Control Points

R-FPCB differs from ordinary PCBs in design and manufacturing. Maxipcb controls each key process with professional teams and advanced equipment to ensure product consistency.

5.1 Inner Layer Single-Sheet Pattern Transfer

Electrolytic cleaning is preferred for flexible single sheets (avoids deformation from mechanical wiping), ensuring surface cleanliness and roughness for 0.1mm~0.15mm line width/spacing. Acid etching requires controlled rate and anti-curling measures (auxiliary guide plates, closed ventilation).

5.2 Flexible Material Multi-Layer Positioning

To address PI substrate dimensional instability, Maxipcb designs alignment patterns, uses OPE-drilled positioning holes (eliminates wet processing errors) and X-ray drilling (improves precision), meeting 0.1mm~0.15mm inter-layer registration requirements.

5.3 R-FPCB Lamination

Key controls: reduce strong alkali process temperature/time for PI; horizontally bake flexible sheets to avoid deformation; use silicone rubber gaskets for good lamination; ensure glass cloth direction consistency, rigid board thickness (0.8~1.0mm) and flexible window processing precision.

5.4 R-FPCB Drilling

Sharp drill bits are used and timely replaced; drilling speed/feed are optimized (avoids overheating or drill breakage); high-speed machines and aluminum/epoxy backing plates are adopted to ensure hole quality and avoid burrs.

Model : Automotive PCB (HDI R-FPCB)

Material : FR-4+PI

Layer : 1+2+1

Color : Green/White

Finished Thickness : 1.2mm

Copper Thickness : 0.035mm(1OZ)

Surface Treatment : ENIG 2U"

Minimum line width / distance : 0.1/0.1mm

Application : Automotive electronics rigid-flex pcb prototype

Automotive PCB (HDI R-FPCB)

Description

Data Sheet