Automotive industry photo etching, also known as photochemical machining, is a subtractive cold chemical manufacturing technology widely adopted across traditional fuel vehicles and newenergy electric vehicles. By combining photolithography and selective metal chemical dissolution, it fabricates complex thingauge metal components without mechanical stamping, cutting or laser thermal impact. Compared with stamping, laser cutting and woven mesh processes, photoetched automotive parts feature burrfree edges, zero residual internal stress, high dimensional repeatability and flexible digital tooling. It satisfies both functional component requirements and decorative aesthetic demands, and has become an important manufacturing solution for many automotive OEM and tierone suppliers.

Modern automobiles contain numerous thin metal parts working in complex environments: engine oil and fuel filtration elements, sealing gaskets, sensor diaphragms, speaker grilles, newenergy battery and fuelcell components. These parts require stable flatness, precise microapertures or intricate contours, while resisting oil corrosion, temperature cycling and vibration shock. Photo etching performs well for thin metal sheets typically ranging from 0.02 mm to 1.0 mm. Processsuitable materials include 304 / 316L stainless steel, aluminum, copper, nickel alloys and titanium. Design modification relies on digital phototool files, no expensive hard stamping moulds are required, greatly shortening prototype iteration cycles for automotive projects.

1. Core Photo Etching Workflow for Automotive Components

Step 1: DFM Review & Digital Phototool Generation

Process engineers conduct DFM manufacturability assessment based on automotive drawings. Key parameters such as aperture, web width, gasket groove, material thickness and panel nesting layout are analysed. According to isotropic undercut rules of wet etching, pattern compensation is added into phototool artwork. Features beyond process limits are fed back for drawing optimisation. After confirmation, phototool film is output for UV exposure. Good DFM balances precision requirement, part reliability and massproduction yield for automotivegrade parts.

Step 2: Metal Sheet Surface PreTreatment

Raw metal sheets go through alkaline degreasing, circulating rinsing and mild microetching. Rolling oil, fingerprints and surface particles are fully removed to form uniform microroughness, improving dryfilm photoresist adhesion. Final deionisedwater rinsing and hotair drying are completed. Poor pretreatment will trigger resist peeling and etchant underseepage, causing mass defective automotive components.

Step 3: Dryfilm Photoresist Lamination

Acidresistant dryfilm is hotroll laminated onto both sides of cleaned metal substrate. Lamination temperature, roller pressure and feeding speed are strictly controlled to eliminate bubbles and wrinkles. Bubbles will lead to local pattern loss, which is unacceptable for auto functional parts. Laminated panels undergo thermal stabilisation before exposure station.

Step 4: Doublesided Precision UV Exposure

Phototool films are aligned on top and bottom surfaces of photoresistcovered sheets. Highintensity UV light cures photoresist on reserved functional regions to form corrosionresistant protective masks. Areas to be etched remain uncured. Doublesided alignment exposure is critical for throughhole filter sheets and mesh parts, ensuring symmetric holewall geometry. Misalignment will result in irregular feature shapes and unstable component performance.

Step 5: Developing & Preetch AOI Inspection

Panels pass through alkaline developer solution. Unexposed photoresist dissolves completely to open etching windows, while cured masking stays firmly attached. After full rinsing, AOI fullsurface scanning detects pinholes, incomplete development and pattern offset. Defective panels are eliminated before etching to reduce chemical and rawmaterial waste.

Step 6: Selective Chemical Spray Etching

Clamped panels enter closedloop spray etching chamber. Materialmatched etchant is evenly sprayed onto exposed metal areas. Selective chemical dissolution forms target microholes, contours or surface textures. Conveyor speed, liquid temperature, spray pressure and chemical concentration are monitored in realtime. Etching stops immediately once target depth or full throughetch is achieved to avoid overetchingcaused broken webs or dimensional overtolerance.

Step 7: Photoresist Stripping & Multistage Rinsing

Hot alkaline stripping solution removes all photoresist masking layers. Multicycle circulating rinsing thoroughly washes residual etchant trapped inside microstructures. Insufficient rinsing leaves chemical residues, leading to corrosion risk when parts work inside vehicle fluid circuits.

Step 8: AutomotiveGrade PostTreatment

Posttreatment varies by application. Standard workflow includes chemical cleaning, stress relief and precision drying. For engine and undervehicle components, passivation treatment improves corrosion resistance. For medicalgrade equivalent automotive filter parts, highpurity deionisedwater ultrasonic cleaning is applied. Decorative parts can support surface pretreatment for subsequent painting, anodising or colour filling.

Step 9: Comprehensive Quality Inspection & Batch Traceability

Multidimensional quality inspection is carried out for automotivelevel parts. Metrology instruments verify critical dimension, thickness and aperture tolerance. AOI fullscan checks for cracks, broken webs and pattern distortion. Sampling tests cover flow resistance, vibration resistance and medium immersion ageing simulating realvehicle working conditions. All process parameters and inspection records are archived to satisfy automotive industry traceability requirements. Qualified parts are cut, sorted and packed for delivery.

2. Key Advantages of Automotive Industry Photo Etching

Burrfree & stressfree: Pure chemical cold processing, no mechanical impact. Components maintain excellent flatness, free of burrs that require secondary deburring, ideal for thinwall auto parts.

High dimensional repeatability: Digital phototool guarantees consistent part quality across batches, suitable for largevolume automotive serial production.

No hardtooling cost: Design adjustments only modify phototool files. Fast iterations support prototype verification and shortrun customised automotive projects.

Excellent design flexibility: Supports dense microhole arrays, complex gaskets, specialshape meshes and fine decorative patterns. Multiple metal material options match diverse vehicle working conditions.

Balanced functional and decorative performance: Produce both engine filter functional components and interior speaker grilles, logo inlays with delicate aesthetic effects.

3. Process Limitations

Photo etching belongs to isotropic subtractive manufacturing. Lateral undercut restricts the minimum aperture relative to sheet thickness. For thick, largesize simple blanking parts, stamping may deliver better economic performance. Chemical etching production requires complete wasteliquid treatment system.

4. Typical Automotive Application Fields

 Engine & fuel system: oil filter elements, fuel injection filter screens, sealing shims and gaskets  Newenergy vehicles: battery connection components, fuelcell flowfield plates, hydraulic system microfilter sheets  Automotive electronics & sensors: sensor diaphragms, electromagnetic shielding sheets, encoder components  Interior & acoustic system: car speaker grilles, decorative metal inlays, backlight perforated panels  Chassis and hydraulic control: precision thin shims, microvalve filter components

Conclusion

Automotive industry photo etching provides a reliable manufacturing solution for highprecision thinwall metal components in modern automobiles. Strictly controlled fullchain process from DFM evaluation to traceable quality inspection delivers stable, burrfree auto parts, covering fuel vehicles and fastgrowing newenergy vehicle market demands.