EMI (Electromagnetic Interference) and RFI (Radio Frequency Interference) shielding parts are thin metal components used to isolate electronic circuits. They prevent internal radio-frequency signals from leaking outward and protect sensitive circuits from external electromagnetic noise. Photochemical etching produces flat blanks for a full range of shielding structures: shielding cans, shielding frames, shielding gaskets, spring fingers, contact shunts, vented shielding covers. Typical materials include nickel silver, copper alloy, beryllium copper, SUS304 / SUS316 stainless steel, with thickness ranging from 0.03 mm to 0.4 mm. Half-etch bend lines and array ventilation holes can be integrated in one etching operation.

Step-by-Step EMI/RFI Shielding Etching Workflow

1. DFM Design Review Engineers evaluate unfolded part geometry, half-etch bend creases, contact finger profiles, vent holes and locating cutouts. Undercut compensation is added to CAD drawings to offset isotropic wet etching. Half-etch depth is precisely defined to guarantee reliable bending and spring performance for shielding fingers.

2. Metal Surface Pre-treatment Thin metal substrates go through degreasing and ultrasonic cleaning. Removal of oil, fingerprints and oxide layers ensures uniform dry film lamination and avoids pattern defects or poor adhesion.

3. Dual-sided Dry Film Lamination Photosensitive dry film is laminated on both sides of the metal sheet under controlled heat and pressure.

4. UV Exposure & Development UV light transfers the full shielding component pattern onto the photoresist. Unprotected resist covering areas to be removed is washed away by developer, exposing bare metal for etching. This step forms outlines, ventilation micro holes and controlled blind half-etch lines.

5. Dual-sided Controlled Spray Etching (Core Step) Two etching modes are implemented on the same panel:

· Through etching: Fully penetrates the metal sheet for outer contours, cutouts and ventilation holes.

· Blind / half etching: Partial-depth etching to create thin bend lines and flexible spring fingers without cutting through the base material. Etchant concentration, temperature, spray pressure and conveyor speed are tightly regulated to stabilize etching depth and dimensional tolerance.

1. Resist Stripping & Multi-stage Rinsing The cured photoresist mask is stripped off. Multiple rinsing cycles eliminate residual etchant to prevent surface corrosion of shielding alloys.

2. Quality Inspection Inspect overall dimensions, half-etch depth, hole size, flatness, edge quality and spring finger profile. Check that bend lines fold cleanly without cracking.

3. Optional Post-treatment Plating finishes such as nickel, tin or silver can be applied to boost conductivity, solderability and corrosion resistance. The flat etched blanks are then sent for secondary bending or forming to create 3D shielding housings and spring contact fingers.

Core Advantages of Etched EMI/RFI Shielding Parts

1. Precision half-etched bend lines and spring fingers Controlled blind etching forms consistent creases and flexible contact fingers. Bending is predictable with low risk of cracking. Complex multi-cavity shielding frames and segmented spring contacts can be produced in one panel.

2. Burr-free smooth edges and micro vent arrays Metal is removed at molecular level, leaving clean edges with no micro-tears or burrs. No secondary deburring required. Integrated vent holes maintain airflow while preserving shielding effectiveness.

3. Stress-free flat blanks Non-contact chemical etching introduces no residual stress or work hardening. Thin shielding sheets remain flat, avoiding warpage before assembly. Elastic performance of beryllium copper spring fingers stays stable.

4. High pattern flexibility Combine outlines, irregular cutouts, dense vent holes and bend lines in a single process. Multiple different shielding designs can be nested on one metal panel to improve material utilization.

5. No hard tooling cost, fast prototyping Only digital photomask artwork is required. Design revisions only update CAD files, which is ideal for electronic R&D, prototype validation and low-to-medium volume custom shielding projects.

6. Wide material compatibility for shielding Works with high-conductivity shielding alloys including nickel silver, copper, beryllium copper and stainless steel. Parts support plating to optimize surface conductivity for RF applications.

Typical Applications

· Consumer electronics: Smartphones, TWS earbuds, smartwatches, Bluetooth and Wi-Fi modules

· Automotive electronics: Radar, ADAS modules, ECU, high-speed camera circuit boards

· Industrial electronics: Sensors, power inverters, communication controllers

· Medical electronics: Portable diagnostic instruments, high-frequency medical sensors

· Aerospace & defence: RF modules, radar assemblies, high-speed communication circuits

· Semiconductor test fixtures and high-frequency PCB assemblies

Design Considerations

Wet chemical etching is isotropic, lateral undercut must be compensated during CAD design. Half-etch depth is normally 30%~70% of substrate thickness. Deep drawn complex 3D shielding enclosures are better suited for stamping. Etching produces 2D flat blanks; secondary bending or forming is required for 3D shielding cans and spring contact structures. Shielding performance depends heavily on material choice and surface plating.