Korea Ever-Power IBM blow mould cavity polishing follows a five-step diamond compound sequence from initial surface restoration to final mirror finish. The blow mould cavity is removed from the ZQ machine, disassembled, and inspected for wear marks, corrosion pits or parting line edge damage before polishing. Step 1 — 600 grit paper: removes surface wear and oxidation from the previous production run; creates a uniform scratch pattern for subsequent diamond steps. Step 2 — 15 um diamond compound on felt bob: removes 600 grit scratches; produces Ra 0.30-0.40 um surface. Step 3 — 6 um diamond compound: produces Ra 0.15-0.20 um surface. Step 4 — 3 um diamond compound: produces Ra 0.05-0.10 um surface (adequate for PP RCP and HDPE IBM Korean cosmetic standard). Step 5 — 1 um diamond compound and felt buff: produces Ra 0.025 um mirror finish (required for ABS IBM and Korean luxury cosmetic PP IBM at department store quality standard). Total polishing time: Ra 0.025 um mirror finish requires 8-12 hours of skilled toolroom time per cavity for a standard Korean cosmetic IBM blow mould cavity (50-80 mm diameter, 80-120 mm height). A 10-cavity ZQ40 blow mould re-polish therefore requires 80-120 hours of toolroom time — Korea Ever-Power schedules blow mould re-polish during planned ZQ machine maintenance periods to minimise Korean customer production programme disruption.

IBM blow mould parting line flash is a thin polymer fin produced at the blow mould parting line when the two blow mould halves do not close with sufficient force or dimensional accuracy to prevent polymer penetration at the mould contact surface. Although IBM is marketed as a zero-flash process (the preform is already substantially formed before blow inflation, producing no primary base trim flash), secondary parting line flash can occur at the blow mould body parting line under three conditions. Blow mould parting line wear: the blow mould parting line mating surfaces (the flat faces of the two blow mould halves that contact each other when closed) wear progressively from the repeated impact and pressure of mould closure at each cycle. P20 parting line surfaces show measurable wear at 5-8M cycles (0.01-0.03 mm surface recession per face); H13 surfaces wear more slowly (5-8M cycles to the same recession level). When parting line recession exceeds 0.05 mm per face (0.10 mm total gap), the blow pressure (4-8 bar) forces polymer into the parting line gap, producing flash. Correction: re-machine the parting line contact surfaces flat by removing 0.1-0.15 mm per face, then recheck mould closure force. Mould closure force inadequacy: if the ZQ machine blow mould clamping force is insufficient for the blow pressure at the projected container area, the mould gap opens under blow pressure. Korea Ever-Power verifies blow mould clamping force specification against container projected area and blow pressure at mould design stage. Mould contamination: polymer debris or contamination on the parting line contact surfaces prevents full mould closure. Standard operating procedure: inspect and clean blow mould parting line surfaces every 200,000 cycles as part of Korea Ever-Power ZQ machine preventive maintenance schedule.

Yes — the IBM blow mould cavity steel affects container surface quality through three mechanisms beyond cavity polish level. Thermal conductivity: P20 (thermal conductivity ~29 W/mK), H13 (~24 W/mK) and S136 (~20 W/mK) have different thermal conductivities. Higher-conductivity P20 removes heat from the container surface faster during blow mould contact — which is advantageous for HDPE and PP household IBM (faster cooling = shorter cycle time) but can produce a slightly duller surface on cosmetic PP IBM (too rapid surface quenching prevents full gloss transfer from cavity). S136’s lower thermal conductivity at the blow mould surface allows the PP melt to stay in contact with the cavity longer before quenching, improving cosmetic PP IBM surface gloss transfer. This is one reason Korea Ever-Power sometimes specifies S136 blow mould cavities (not just neck inserts) for Korean luxury PP RCP IBM at mould temperature 55-70°C, even when the container is PP rather than ABS. Surface micro-texture retention: harder steels (S136 Rc 50-54, H13 Rc 44-48) retain the polished surface micro-texture longer than P20 (Rc 28-34) under repeated polymer melt contact. At 1M cycles on P20 cavity, micro-scale surface roughening becomes measurable (Ra increases from 0.025 um to 0.05-0.08 um); the same degradation on H13 or S136 occurs at 4-6M cycles. For Korean luxury cosmetic IBM where gloss measurements are taken at Korean brand incoming QA and the brand expects consistent 85-95 GU across all containers throughout the programme, harder cavity steel provides more cycles of consistent gloss before re-polish is required. Corrosion pitting: as noted for pharmaceutical IBM, P20 pitting from humidity degrades surface micro-texture independently of polish wear — another reason S136 is specified for Korean pharmaceutical and Korean high-humidity production environment IBM applications.

Korea Ever-Power makes three specific IBM tooling modifications for bioplastic (PHA and PLA) IBM production programmes versus standard HDPE/PP IBM tooling. S136 stainless for all wetted mould components: PHA IBM produces trace crotonate (from PHA thermal degradation) and PLA IBM produces trace lactic acid vapour (from PLA hydrolytic degradation) that will slowly corrode P20 and H13 steel injection cavity and core rod surfaces at the microscopic pitting level over extended production programmes. Korea Ever-Power specifies S136 stainless injection cavities, S136 neck inserts and S136 core rods for all bioplastic IBM tooling to provide corrosion resistance against these bioplastic degradation product vapours. Hot runner for high-value bioplastic: PHA and PLA resin costs (3-5x HDPE) make cold runner waste (15-30% of shot weight) commercially significant for bioplastic IBM programmes above 2M units/year. Korea Ever-Power offers hot runner injection mould systems for bioplastic IBM to eliminate runner waste and reduce resin cost per container by 15-25%. Reduced thermal mass tooling: PHA’s narrow 25°C processing window requires that the IBM injection mould thermal mass be minimised to allow rapid barrel temperature response — Korea Ever-Power designs bioplastic IBM injection cavities with optimised cooling channel layout and reduced inter-cavity steel mass to achieve rapid temperature equilibration and response. This modified thermal design also improves PLA IBM cycle time by achieving faster preform solidification at the reduced PLA mould temperature (30-50°C versus PP cosmetic IBM mould at 55-70°C), partially compensating for PLA’s longer cooling time from PLA lower thermal conductivity versus HDPE and PP.