Photo chemical etching for automotive (also known as photochemical machining) is a cold subtractive manufacturing technology widely deployed in modern automobile manufacturing, including traditional fuelpowered vehicles and newenergy EVs. It combines photolithography imaging and selective metal chemical dissolution to fabricate intricate thingauge metal components without mechanical stamping impact, cutting force or laser thermal distortion. Distinct from stamping, laser cutting and woven mesh solutions, photochemically etched automotive components deliver burrfree edges, zero residual internal stress, high dimensional repeatability and digitaltooling flexibility. It meets strict automotivegrade requirements for functional reliability, vibration resistance and medium corrosion resistance, and serves numerous OEM and tierone automotive suppliers across the global automotive supply chain.

Modern automobiles contain large volumes of thin metal functional components operating under complex working conditions: engine oil and fuel filter meshes, precision sealing shims, sensor diaphragms, speaker grilles, newenergy battery connecting parts and fuelcell flowfield plates. These components demand stable flatness, precise microaperture arrays or complex irregular contours, while resisting engineoil corrosion, temperature fluctuation and continuous vibration shock. Photo chemical etching is optimised for metal sheet thickness ranging from 0.02 mm to 1.0 mm. Processcompatible materials cover 304 / 316L stainless steel, copper, aluminium, nickelbased alloys and titanium. Since design modifications only require updating digital phototool artwork instead of expensive hard stamping moulds, it greatly shortens prototype iteration cycles for automotive development projects.

1. Complete Photo Chemical Etching Workflow for AutomotiveGrade Parts

Step 1: DFM Review & Phototool Production

Process engineers perform DFM manufacturability assessment according to automotive CAD drawings. Critical parameters including aperture, web width, gasket groove feature, material thickness and panel nesting layout are comprehensively analysed. Pattern compensation is added to phototool files to offset isotropic lateral undercut generated in wet etching. Design features exceeding process capability limits are marked and fed back for drawing optimisation. Verified phototool film is manufactured for subsequent UV exposure. Proper DFM optimisation balances precision specification, component reliability and massproduction yield for automotivelevel products.

Step 2: Metal Sheet Surface PreTreatment

Raw metal sheets go through multistage pretreatment workflows. Alkaline degreasing removes rolling oil, fingerprints and surface particulate contaminants. Circulating rinsing is followed by mild microetching to generate uniform microroughness on metal surfaces, improving dryfilm photoresist bonding performance. Final deionisedwater rinsing and precise hotair drying are completed. Poor pretreatment will trigger photoresist peeling and etchant underseepage, leading to mass rejection of automotive components.

Step 3: Dryfilm Photoresist Lamination

Acidresistant dryfilm photoresist is hotroll laminated onto both sides of cleaned metal substrates. Lamination temperature, roller pressure and sheetfeeding speed are strictly controlled to eliminate air bubbles and surface wrinkles. Tiny air bubbles will cause local pattern damage, which is unacceptable for automotive functional parts. Laminated metal panels stay for thermal stabilisation before entering UV exposure station.

Step 4: Highprecision Doublesided UV Exposure

Compensated phototool films are precisely aligned on top and bottom surfaces of photoresistcovered sheets. Highintensity UV light cures photoresist on reserved metal regions to form corrosionresistant protective masks. Areas designated for etching keep uncured. Doublesided alignment exposure is mandatory for throughetched filter mesh and perforated components to guarantee symmetric upperandlower holewall geometry. Misalignment will produce irregular feature shapes and unstable realvehicle service performance.

Step 5: Developing & Preetch AOI Inspection

Panels pass through alkaline developer solution. Unexposed photoresist dissolves completely and clean etching windows are exposed, while cured protective masking remains firmly adhered. After sufficient circulating rinsing, Automatic Optical Inspection carries out fullsurface scanning to detect pinholes, incomplete development and pattern offset. Defective panels are eliminated before etching to reduce chemical consumption and rawmaterial waste.

Step 6: Selective Chemical Spray Etching

Clamped workpieces travel inside closedloop spray etching chamber. Materialmatched etchant is evenly sprayed onto exposed metal windows. Controlled chemical dissolution forms target microholes, outer contours or surface textures. Conveyor speed, etchant temperature, spray pressure and chemical concentration are monitored in realtime. Etching procedure stops immediately once target depth or full throughetch status is achieved, preventing overetchinginduced broken webs and dimensional outoftolerance.

Step 7: Photoresist Stripping & Multistage Circulating Rinsing

Hot alkaline stripping liquid removes all photoresist masking layers. Multicycle circulating rinsing thoroughly washes corrosive chemical residues trapped inside microstructures. Insufficient rinsing leaves residual etchant, which will trigger oxidation and corrosion failure after components are assembled inside vehicle fluid circuits.

Step 8: AutomotiveSpecific PostTreatment

Posttreatment schemes vary for different application scenarios. Standard workflow includes chemical cleaning, stressrelief treatment and precision vacuum drying. For engine compartment and underchassis components, passivation treatment enhances anticorrosion capability adapting to harsh working media. For precision filter elements, highpurity deionisedwater ultrasonic cleaning is implemented to eliminate surface microparticles. Decorative etched parts can support preprocessing for subsequent painting, filling colour or anodising treatments.

Step 9: Comprehensive Quality Inspection & Batch Traceability

Multidimensional quality verification is implemented for autograde components. Metrology instruments test critical dimension, sheet thickness and aperture tolerance. AOI fullarea scanning inspects cracks, broken webs and pattern distortion. Sampling verification includes flowresistance test, vibration test and mediumimmersion ageing test simulating realvehicle operating environment. All batchrelated process parameters and inspection records are fully archived to satisfy automotiveindustry traceability requirements. Qualified components are cut, sorted and packed for delivery.

2. Core Advantages of Photo Chemical Etching for Automotive

Burrfree & stressfree cold processing: No mechanical stamping or cutting force. Etched parts maintain excellent flatness, secondary deburring procedures are largely omitted, perfectly fitting thinwall automotive metal components.

Excellent batchtobatch repeatability: Digital phototool guarantees stable dimensional consistency among batches, suitable for largevolume serial production of automobile parts.

Lowcost fast iteration: No expensive hard stamping moulds. Design adjustments only modify phototool files, supporting rapid prototype verification and shortrun customised automotive projects.

High design flexibility: Realises dense microhole arrays, complex sealing gaskets, specialshape meshes and fine decorative patterns. Multiple metal material selections match diverse vehicle working conditions.

Balanced functional and decorative performance: Produce critical functional parts for engine, newenergy and electronic systems as well as delicate interior decorative components such as speaker grilles and metal inlays.

3. Process Limitations

Photo chemical etching belongs to isotropic subtractive manufacturing. Lateral undercut effect restricts the minimum aperture relative to sheet thickness. For thickgauge, largesize simple blanking parts, stamping delivers better economic benefits. Chemical etching manufacturing requires supporting professional wasteliquid treatment system.

4. Typical Automotive Application Cases

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

Conclusion

Photo chemical etching for automotive supplies a reliable precision manufacturing solution for thingauge metal components of fuel vehicles and newenergy automobiles. Strict fullchain process control from DFM evaluation to traceable quality inspection ensures burrfree edges, stable dimensional accuracy and mediumcorrosion resistance of finished autograde parts, widely recognised by automotive OEM and tierone suppliers worldwide.