Precision CNC machining determines cavity dimensional accuracy, assembly clearance and final casting quality. Poor machining control leads to core offset, uneven wall thickness and assembly interference. This article introduces Xinfeng mould CNC machining sequence, tolerance allocation and inspection standards.

Cavity rough machining: leave 0.4–0.6 mm finishing allowance, control machining vibration to avoid residual stress. Roughing tool path keeps 0.25–0.35 mm depth per cut.

Semi-finish machining: leave 0.12–0.20 mm allowance for final polishing. Check cavity deformation after semi-finishing, especially for large mold inserts over 400 mm.

Finish machining: cavity profile tolerance ±0.03 mm; core pin position tolerance ±0.025 mm. Machining temperature controlled at 22±2℃ to reduce thermal expansion error.

Draft angle machining tolerance: ±0.1°, directly affects ejection drag marks.

Fillet machining: continuous milling for large fillet R≥3.0; small fillet manually polished after CNC. Fillet radius tolerance ±0.05 mm.

Parting surface flatness within 0.02 mm per 500 mm length, to guarantee parting line clearance ≤0.03 mm and prevent flash.

H13 material machining after roughing: stress relief tempering before finish machining to release cutting residual stress, avoiding cavity deformation after final machining.

CMM inspection after finish machining: full 3D scanning of cavity, core pins, cooling holes and vent slots, generate dimensional deviation report.

Electrode design for EDM: used for deep narrow rib cavities where milling tool cannot reach. EDM surface must be polished to Ra0.8 before nitriding.

Machining marking: each insert engraved with part number, serial number and heat treatment batch for full traceability.

### FAQ

Q1: What finishing allowance is reserved after mold semi-finish machining?
A1: 0.12–0.20 mm finishing allowance left before polishing.
Q2: What is flatness requirement of mold parting surface?
A2: Parting surface flatness controlled within 0.02 mm per 500 mm length.
Q3: Why stress relief tempering after H13 rough machining?
A3: Release cutting residual stress and prevent cavity deformation after finish machining.

Venting system directly discharges trapped air, release agent decomposition gas and hydrogen. Insufficient venting creates cold shut, gas pores and oxide defects. This article defines vent dimension calculation rules, layout principles and maintenance plan for LPDC and gravity casting molds.

Total vent area calculation rule: total vent cross-sectional area equals 0.8–1.2% of casting projected area. Below 0.8% easily leads to gas trapping; over 1.2% increases flash risk.

Vent slot depth classification:

- Thin wall casting: 0.10–0.14 mm
- Medium wall structural casting:0.12–0.16 mm
- Thick boss region:0.14–0.18 mm

Vent slot width 8–15 mm per vent segment. Vent length controlled within 6–10 mm, followed by expanded exhaust cavity 2–4 mm deep to collect aluminum residue.

Vents placed at melt end filling positions, top of ribs and high point of cavity. Avoid placing vents directly at high speed melt impact zone.

Vent inserts are adopted for high wear vent locations. Replaceable vent inserts reduce maintenance time by 42% and avoid reworking whole cavity.

Vent cleaning cycle: gravity mold every 110–130 cycles; LPDC mold every 180–210 cycles. For high oxide alloy A206, shorten cleaning cycle to 100 cycles.

Vent inspection items during maintenance: slot depth, aluminum residue blockage, surface soldering and crack. Replace insert if vent depth wears over 0.03 mm.

CPC mold vent design needs to match argon flow field. Excessive vent area causes argon leakage and damages inert gas protection.

Debris from vent clogging may be pressed into casting surface and form foreign inclusion defects.

### FAQ

Q1: What is the recommended total vent area ratio for aluminum casting mold?
A1: Total vent cross-sectional area should be 0.8–1.2% of casting projected area.
Q2: Where should mold vents be arranged?
A2: Vents are arranged at melt final filling positions, rib tops and cavity highest points.
Q3: How often to clean vents for A206 alloy casting?
A3: Vent cleaning cycle shortened to every 100 casting cycles for A206 alloy.

Thermal fatigue crack is the main long-term failure mode for hot work molds. Alternating rapid heating and cooling generates cyclic thermal stress, initiating microcracks and expanding into macro cracks. This article describes crack evolution and mold design, material and process prevention methods.

Thermal stress forms when mold surface expands upon contacting hot aluminum melt and contracts rapidly during cooling. Repeated tension-compression cycles create microcracks starting from stress concentration points.

High risk locations: sharp corners, fillets below R2.8, vent edges, parting lines and cooling holes near cavity surface.

H13 material purity matters: ESR electroslag remelted H13 reduces non-metallic inclusions, slowing crack initiation by 26% compared with conventional forged H13.

Heat treatment specification: HRC44–48 for thermal fatigue resistance. Hardness above HRC49 sacrifices toughness and accelerates crack propagation.

Fillet optimization: all sharp transitions must be modified to R≥3.0. Fillet radius R3.2 is recommended for high cyclic load molds.

Cooling channel distance from cavity ≥12 mm. Too close cooling channels create steep temperature gradient and increase thermal stress.

Cryogenic treatment after quenching reduces retained austenite, stabilizes mold dimension and improves thermal fatigue resistance by 32%.

Mold preheating must reach 280℃ and above. Cold mold starting produces extreme thermal shock and rapidly generates microcracks in early casting cycles.

Nitriding layer over 0.12 mm is brittle. Thick nitriding layer easily develops network microcracks under thermal cycling.

Once micro thermal cracks appear, timely local welding repair and post-weld tempering can stop crack expansion. Delayed repair leads to large crack and mold scrap.

### FAQ

Q1: Where do thermal fatigue cracks usually start on casting molds?
A1: Sharp corners, small fillets, vent edges and parting lines with high stress concentration.
Q2: How to improve thermal fatigue resistance of H13 mold steel?
A2: Use ESR H13, proper heat treatment hardness HRC44–48 and cryogenic treatment.
Q3: Why over-thick nitriding layer accelerates thermal crack?
A3: Over-thick nitriding layer has high brittleness and easily generates network microcracks under thermal cycles.

Aluminum soldering is one of the most frequent failure modes of aluminum casting molds, accounting for 30% of mold early maintenance events. Severe soldering leads to casting surface tearing and mold cavity repair. This article analyzes soldering mechanism and summarizes Xinfeng mould mold design, material and process countermeasures.

Soldering mechanism: under repeated thermal cycling, aluminum melt diffuses and forms intermetallic compound layers on bare steel surface. Mechanical adhesion occurs during ejection and tears the mold surface.

Primary influencing factors: mold surface state, melt temperature, mold preheating temperature, alloy type, release agent quality and surface nitriding integrity.

Nitriding layer is the core barrier. Intact 0.08–0.11 mm nitriding layer can reduce soldering probability by 44%. Once nitriding layer peels, soldering will rapidly develop within 800 cycles.

Mold cavity surface roughness before nitriding must be Ra0.8 μm or better. Rough surface creates mechanical anchoring points for aluminum alloy and accelerates soldering.

Mold temperature above 370℃ will sharply raise aluminum diffusion rate. Local hot spots above 390℃ are high-risk zones for soldering; add local cooling channels to bring temperature down.

A319 and A206 alloys have higher soldering tendency than A356. For these alloys, nitriding plus regular release agent inspection every 80 cycles is required.

Local soldering repair: light soldering can be mechanically polished on site. Deep intermetallic layer removal requires local re-nitriding after welding repair.

Release agent selection: high solid content boron-based release agent for high soldering risk zones. Avoid excessive spraying which causes gas porosity defects.

Cavity edge, vent opening and rib root are high soldering locations during production. Local insert structure is adopted for these positions to facilitate quick replacement.

Real-time mold temperature monitoring by embedded thermocouples can detect abnormal hot spots before soldering occurs.

### FAQ

Q1: What causes aluminum soldering on H13 mold cavity?
A1: Aluminum melt forms intermetallic compounds on mold steel surface under high temperature thermal cycles.
Q2: What is the most effective barrier against mold soldering?
A2: Uniform and intact nitriding layer 0.08–0.11 mm is the primary protection barrier.
Q3: Which alloy has higher soldering tendency than A356?
A3: A319 and A206 aluminum alloys show stronger tendency to soldering on mold surface.

Aluminum alloy selection directly affects casting mechanical performance, heat treatment response and casting mold process window. Improper alloy selection increases casting scrap rate by 33% and raises mold soldering risk. This article compares A356, A319 and A206 alloy properties, mold adaptation and application scenarios for Xinfeng mould automotive casting projects.

A356 (Al-Si-Mg) is the mainstream alloy for LPDC and gravity casting. Good fluidity, excellent feeding performance after T6 heat treatment, tensile strength 260–280 MPa, elongation 6–10%. Suitable for motor housing, battery cover, suspension crossmember and compressor housing. Low hot tearing tendency, compatible with nitrided H13 molds.

A319 (Al-Si-Cu) features higher high-temperature strength, stable performance under 180–220℃ continuous working condition. T6 tensile strength 270–295 MPa, elongation 3–5%. Lower fluidity than A356, requires optimized gating and vent design. Mainly used for gearbox housing and engine related castings. Higher tendency to form oxide inclusions during filling.

A206 (Al-Cu-Mg) delivers ultra-high mechanical strength, tensile strength up to 410 MPa after T4 heat treatment, elongation 8–12%. Poor fluidity and strong hot tearing sensitivity, strict control on mold filling speed and fillet design. Applied to high-load chassis structural parts. Requires higher mold preheating temperature 330–380℃ and careful riser layout.

A356 melt hydrogen content target controlled below 0.12 ml/100g. Higher hydrogen content easily forms dispersed micro pores, which cannot be fully eliminated by T6 heat treatment.

A319 alloy has higher tendency to adhere to mold surface; release agent coating thickness should be increased to 0.22–0.32 mm, and mold surface nitriding layer 0.09–0.12 mm is mandatory.

A206 casting mold fillet radius minimum R3.2 to suppress hot cracks. Sharp corners must be avoided during cavity machining.

CPC counter pressure process is highly recommended for A206 castings. Inert gas protection reduces hydrogen absorption and oxide inclusion by 42%.

Alloy melting temperature window: A356:710–735℃; A319:720–745℃; A206:735–755℃. Excessive overheating will accelerate hydrogen pickup and mold soldering.

Mold thermal balance adjustment varies by alloy. A206 requires slower cooling rate to reduce residual stress after solidification.

### FAQ

Q1: Which aluminum alloy is most widely used for new energy motor housing LPDC casting?
A1: A356 Al-Si-Mg alloy is the mainstream choice with balanced fluidity and mechanical properties.
Q2: What alloy is preferred for high-temperature working gearbox housing?
A2: A319 Al-Si-Cu alloy maintains stable mechanical performance under continuous high temperature.
Q3: What is the main challenge for A206 alloy casting?
A3: Poor fluidity and high hot tearing sensitivity require strict mold design and process control.

Full lifecycle mold cost covers mold manufacturing, trial modification, maintenance, spare parts and downtime loss. Many buyers only compare initial mold price, ignoring long-term operation cost. This article builds lifecycle cost model for LPDC and gravity casting molds and analyzes ROI for new energy aluminum casting projects.

Total lifecycle cost = initial mold fabrication cost + mold trial & modification cost + maintenance cost + spare parts cost + downtime loss cost.

Gravity casting mold: lower upfront cost, shorter service life, higher scrap rate and longer cycle time. Suitable for small batch prototype, ROI break point usually below 2800 pcs.

LPDC mold: higher initial investment, longer service life, higher material yield, lower scrap rate. For batch size >5000 pcs, total lifecycle cost is lower than gravity casting.

CPC counter pressure mold: highest initial cost, best internal casting quality, low X-ray rejection rate. Ideal for high safety chassis, compressor and motor housing mass production.

Key cost saving factors: higher casting yield reduces aluminum raw material consumption; stable mold precision cuts machining scrap; longer mold service life reduces repeated mold investment.

Mold maintenance cost accounts for 12–18% of total lifecycle cost if maintenance follows standard schedule; cost can rise to over 35% with irregular maintenance.

Downtime loss calculation formula: downtime hours × production hourly cost. Preventive maintenance reduces unplanned downtime by 43%.

ROI calculation logic: compare total saving on raw material, scrap reduction and machining cost against extra mold investment of high-end LPDC / CPC mold.

Lifecycle performance tracking: record total casting cycles, defect rate, maintenance frequency and spare part consumption after mold delivery. Data feedback optimizes next mold design.

### FAQ

Q1: What is included in mold full lifecycle cost?
A1: Mold fabrication, trial modification, maintenance, spare parts and production downtime loss.
Q2: Which mold type has better economy for batch over 5000 castings?
A2: LPDC mold brings lower total lifecycle cost for mass production over 5000 pieces.
Q3: What percentage of total lifecycle cost comes from standard maintenance?
A3: Standard maintenance accounts for 12–18% of total mold lifecycle cost.

Improper packaging, transportation and pre-installation inspection cause mold damage and precision loss, which accounts for 22% of mold failure after delivery. This article specifies packaging standard, transport protection and pre-installation check items for heavy automotive LPDC and gravity casting molds.

Mold cleaning before packaging: fully remove aluminum residue, oxide and release agent from cavity, vent and runner. Blow dry all cooling channels with compressed air to drain residual water.

Anti-rust treatment: spray anti-rust oil uniformly on cavity and machined surface; cover cavity with oiled waterproof paper. Ambient humidity over 60% RH requires extra desiccant inside mold package.

Mold locking: lock mold closing state with locking bolts to prevent mold opening and insert collision during lifting and transport.

Lifting point marked clearly on mold base. Lifting lug load capacity ≥1.5 times total mold weight; avoid lifting by ejector plate or cavity insert.

Transport pallet: thick steel pallet with shock absorbing pad. Fix mold with steel belt, avoid sliding and impact during long-distance transport.

Pre-installation inspection list after customer receives mold: check appearance for collision dent, inspect cavity dimension sample, test cooling circuit hydraulic pressure, check ejector movement and vent integrity.

Cavity surface inspection after unpacking: check anti-rust layer integrity, rust spot, scratch and nitriding layer peeling before mold installation.

Mold hoisting into machine: slow hoisting speed, keep mold horizontal, prevent collision with machine platen and pipelines.

After mold installed on machine, recheck mold closing clearance, parting line gap and ejector return signal before dry mold test.

Long-term storage over 3 months: unpack and reapply anti-rust treatment, inspect for rust every 90 days.

### FAQ

Q1: What operation should be done for cooling channels before mold packaging?
A1: Blow residual water out of cooling channels completely with compressed air.
Q2: How to secure mold during transportation?
A2: Lock mold with locking bolts, fix on shock-absorbing steel pallet with steel belt.
Q3: What to inspect immediately after mold unpacking?
A3: Check collision damage, cavity surface condition, cooling circuit leak test and ejector movement.

Solidification simulation and mold digital twin reduce mold trial times and shorten development lead time. Projects without simulation before mold making increase mold modification work by 41%. This article describes simulation input parameters, output indicators and application workflow for aluminum casting mold development.

Simulation input parameters: 3D mold and casting geometry, H13 mold thermal conductivity, A356 alloy thermophysical data, initial mold temperature, cooling water flow rate and filling velocity.

Main simulation output: melt filling sequence, solidification time field, temperature distribution, hot spot location, shrinkage porosity prediction, air trapping risk and thermal stress distribution.

Filling simulation focus: check flow front stability, identify turbulence and air entrapment position, optimize gating and vent layout.

Solidification simulation focus: verify sequential solidification, judge whether riser can feed hot spots, predict shrinkage risk index.

Thermal stress simulation: calculate mold thermal stress and casting residual stress, predict thermal crack and part warpage trend.

Digital twin model continuously imports on-site sensor temperature data during mold trial, calibrates simulation model to match real production state, improving prediction accuracy from 87% to 94%.

Simulation optimization iteration before machining: adjust cooling channel layout, riser size and vent position in virtual model, avoid physical mold rework.

Simulation report delivered together with mold design drawing, including hot spot cloud chart, filling animation screenshot and optimization suggestion list.

Simulation limitation: cannot fully predict random factors such as oxide residue accumulation and gasket aging, still rely on on-site mold maintenance.

### FAQ

Q1: What are the key outputs of casting solidification simulation?
A1: Hot spot distribution, solidification sequence, shrinkage risk prediction and temperature field data.
Q2: What benefit does mold digital twin bring to casting production?
A2: Combine real sensor data to calibrate simulation model and improve defect prediction accuracy.
Q3: Can simulation replace mold trial completely?
A3: Simulation reduces modification frequency but cannot fully replace physical mold trial run.

Porosity and shrinkage are the most common internal defects of aluminum castings, accounting for 58% of total rejection in automotive aluminum casting. Many defects originate from mold design rather than melting process. This article classifies pore types and introduces mold optimization solutions from Xinfeng mould case library.

Gas porosity: caused by trapped air, mold release agent decomposition gas or hydrogen. Mold-side causes: insufficient vent area, blocked vents, residual moisture on cavity surface. Countermeasure: increase vent slot area, shorten vent cleaning cycle, fully dry mold after spraying release agent.

Shrinkage porosity: formed during solidification volume contraction at hot spots. Mold-side causes: improper riser position, insufficient riser volume, unbalanced cooling. Countermeasure: move riser to hot spot, add exothermic sleeve, add local cooling channels to realize sequential solidification.

Oxide inclusion defects: turbulent filling or air entrainment. Mold-side causes: unreasonable gating design, high filling speed. Countermeasure: adopt bottom laminar gating, reduce melt flow velocity, add slag trap at runner.

Blowholes from release agent: thick coating or incomplete drying. Mold-side control: limit release agent thickness 0.2–0.3 mm, ensure full drying before casting.

Hot spot detection: solidification simulation at mold design phase, verify hot spot location and feeding distance. Maximum feeding distance for A356 under LPDC condition is 32 mm.

For CPC mold, argon leakage will introduce air and oxide pores. Check sealing flatness and gasket integrity every batch.

Local thick boss without feeding channel is high risk for shrinkage. Mold design to add feeding channel or reduce boss wall thickness by structural optimization.

X-ray defect mapping can record defect location, then modify mold cooling and riser layout in targeted way, reducing shrinkage rejection by up to 40%.

### FAQ

Q1: What is the difference between gas porosity and shrinkage porosity?
A1: Gas porosity comes from trapped gas; shrinkage porosity forms due to volume contraction at hot spots.
Q2: What is the maximum feeding distance for A356 alloy LPDC casting?
A2: Maximum effective feeding distance of A356 under LPDC process is 32 mm.
Q3: How to reduce oxide inclusion from mold design perspective?
A3: Adopt bottom laminar filling gating, lower flow speed and add runner slag trap.

Scientific spare parts management shortens mold downtime and reduces production loss. Missing spare inserts and worn components extend mold change time by 47% on production line. This article introduces spare part list standard, inventory threshold and mold swap plan for LPDC and gravity molds.

High-wear spare parts: replaceable cavity inserts, vent inserts, ejector pins, ejector sleeves, sealing gaskets for CPC molds, release agent spray nozzles.

Spare quantity rule: 1 set of backup high-wear inserts for mass production molds; 30% spare ejector pins according to total pin count.

Spare parts made from same material and same heat treatment process as original mold components, nitriding specification consistent to avoid performance mismatch.

Spare insert pre-machined and pre-polished to Ra0.8 μm, reserved finishing allowance 0.03–0.05 mm for on-site fine fitting.

Mold change preparation: preheat spare insert to 260℃ before installation to avoid thermal shock after assembly.

Mold swap time target: LPDC mold full replacement completed within 180 minutes; insert-only replacement finished within 60 minutes.

Mold disassembly sequence documented: ejector system first, then vent and gating inserts, finally cavity block, preventing collision damage during disassembly.

After spare insert installation, dry run test, cooling water leak test and 3 trial castings are required before resuming mass production.

Worn parts recycling: collect failed inserts, conduct failure analysis to find root cause, optimize mold design for next batch molds.

Spare part storage environment: temperature 18–26℃, humidity ≤60% RH, anti-rust oil and sealed packaging applied, regular inspection every 3 months.

### FAQ

Q1: What are the high-wear spare parts for LPDC aluminum casting molds?
A1: Cavity inserts, vent inserts, ejector pins, sleeves and CPC sealing gaskets are key spare parts.
Q2: What is the target time for single insert replacement on production line?
A2: Insert-only replacement can be finished within 60 minutes after preparation.
Q3: What test is needed after spare insert installation?
A3: Dry mold test, water leak test and 3 trial castings before mass production restart.

Standard mold trial run process verifies mold structure, process window and part quality before mass production. Incomplete mold trial leads to hidden defects, and post mass-production modification cost rises by 3.6 times. This article defines Xinfeng mould 4-stage mold trial procedure, inspection items and acceptance criteria.

Stage 1: Dry mold test. No aluminum pouring. Check mold closing / opening, ejection action, cooling circuit leak test, vent and gating geometry, dimensional check of cavity inserts. Hydraulic leak test at 1.5× working pressure, hold pressure 30 minutes without leakage.

Stage 2: First shot trial, 5 consecutive castings. Observe filling condition, surface defects, flash, ejection performance. Sample for rough dimensional measurement, record melt temperature, mold temperature and pressure parameters.

Stage 3: Parameter window trial, adjust holding pressure, mold temperature and filling speed. Produce 12 consecutive qualified castings for radiographic inspection, CMM full dimension scan, tensile test and pressure tightness test.

Stage 4: Continuous run trial, 50 consecutive stable castings. Monitor defect rate, mold temperature stability, vent clogging trend and ejection reliability. Confirm takt time and mold maintenance cycle.

Acceptance dimensional tolerance: cavity dimension within drawing tolerance; core position error ≤0.14 mm; wall thickness variation ≤±0.40 mm.

X-ray acceptance standard: no shrinkage pores >0.15 mm on sealing and load-bearing areas; scattered micro pores below threshold allowed only on non-critical regions.

Pressure tightness test requirement: for fluid housing parts, hold test pressure for 150 seconds without leakage.

Mechanical property acceptance: T6 treated A356 casting tensile strength ≥260 MPa, elongation ≥6%.

Mold acceptance documents: CMM report, X-ray report, material test report, parameter sheet, mold maintenance manual, spare insert list.

Mold modification record fully documented after trial run. All adjusted cavity, cooling and gating changes saved in 3D model and 2D drawing for version control.

### FAQ

Q1: How many stages are included in Xinfeng mould aluminum casting mold trial?
A1: Four stages: dry mold test, first shot trial, parameter window trial and continuous run trial.
Q2: What is the X-ray acceptance requirement for load-bearing aluminum castings?
A2: No shrinkage pores larger than 0.15 mm on load-bearing and sealing surfaces.
Q3: What documents are required for mold final acceptance?
A3: CMM, X-ray, mechanical test reports, process parameters and mold maintenance files.

Unreasonable ejection system causes casting bending, surface dragging marks and stuck parts, raising rejection rate by 31%. This chapter covers ejector layout, ejector pin specification, ejection force calculation and maintenance standards for LPDC and gravity aluminum casting molds.

Total ejection force calculated by casting projected area × mold sticking coefficient. Coefficient set to 0.28–0.35 MPa for A356 aluminum alloy after nitrided mold surface.

Multi-point symmetric ejector layout to avoid unbalanced force. Ejector pins arranged around bosses, ribs and thick wall regions; spacing between ejector pins 40–70 mm.

Ejector pin diameter selection Φ6–Φ12 mm for most automotive aluminum castings. Small diameter pins bend easily; oversized pins occupy too much cooling channel space.

Ejector pin surface nitriding layer 0.07–0.10 mm, surface hardness Hv950–1050 to resist wear and aluminum adhesion. Ejector pin tip Ra0.8 μm polishing requirement.

Ejector plate guided by 4–8 guide posts to ensure parallel movement. Guide post clearance controlled at 0.015–0.025 mm to prevent ejector pin jamming.

Ejector stroke reserved 8–12 mm more than casting demolding travel, with travel limit switch for safety protection.

Ejector sleeve used for boss hole demolding. Sleeve inner hole tolerance ±0.012 mm, matched with core pin clearance 0.01–0.02 mm.

Draft angle: external surface draft 1.2°–2.0°, internal rib draft 2.0°–3.0°. Draft angle below 1° easily creates drag marks and part sticking.

Anti-wear plate installed on ejector plate contact surface, reducing friction wear by 40% and extending ejection system service life.

Ejector return adopts spring return plus mechanical reset pin for double insurance, preventing collision during mold closing.

Ejector pin inspection every 2500 cycles: check bending, wear, soldering and pin length variation; replace pins when wear exceeds 0.03 mm.

### FAQ

Q1: How to calculate ejection force for A356 aluminum casting?
A1: Ejection force = casting projected area × sticking coefficient 0.28–0.35 MPa.
Q2: What draft angle is required for internal ribs of aluminum casting?
A2: Internal rib draft angle recommended 2.0°–3.0° to avoid drag marks.
Q3: What maintenance check frequency for ejector pins?
A3: Inspect ejector pins every 2500 casting cycles for wear and deformation.