ISBMネック仕上げエンジニアリング：
韓国のボトルガイド

P20 プレ硬化鋼（硬度30～36HRC）— 韓国PCO飲料規格

P20 is the standard Korean ISBM neck insert steel for PCO 1881 and PCO 1810 beverage applications. At ±0.10mm PCO OD tolerance, P20’s hardness provides adequate dimensional stability for typical Korean beverage production volumes (8–15M shots/year per cavity). P20 does not provide sufficient corrosion resistance for Korean PETG processing — PETG’s slightly acidic melt (pH equivalent from glycol modifier hydrolysis) causes P20 to develop surface oxidation at the thread profile crests after 3–4M shots, increasing thread surface roughness and beginning to affect neck OD dimensional consistency. Acceptable for PET beverage; replace with 2316 for PETG cosmetic applications.

2316マルテンサイト系ステンレス鋼（硬度32～36HRC）—韓国のKビューティーおよび医薬品業界標準

2316ステンレス鋼は、32～36 HRCの硬度（±0.04mm GPI公差での寸法安定性に十分）と316Lと同等の耐食性（PETG溶融物、研磨洗浄剤、韓国の夏の湿気に耐性）を兼ね備えています。韓国のKビューティーPETG化粧品、韓国の医薬品、韓国の手指消毒剤のネックインサートは、標準で2316ステンレス鋼が指定されています。±0.04mm GPI外径での耐用年数：寸法が公差を超える前に、キャビティあたり12～20Mショット。これは、韓国のKビューティーPETGネックインサートの交換の標準間隔です。2316韓国化粧品ネックインサートには、Ra ≤ 0.05μmのダイヤモンドラッピングが標準で、Kビューティーボトルの寸法再現精度と目視によるねじ表面品質の両方を向上させます。

H13熱間加工用工具鋼（硬度48～52HRC）—韓国CRC製薬

H13は、韓国製ISBMネックインサートの中で最高の硬度（48～52 HRC）を誇り、製造期間全体にわたって±0.03mmのCRC寸法安定性が求められる用途に適しています。韓国の製薬業界におけるCRC製造量（年間400万～600万ショット）において、H13 CRCネックインサートは1,000万～1,500万ショットにわたって±0.03mm以内の寸法精度を維持します。これは、同じ外径公差の2316ステンレス鋼の3倍の耐用年数です。H13 CRCインサートのコストは2316ステンレス鋼よりも約35%高くなりますが、製造中に±0.03mmを超える寸法ずれが発生した場合に必要となるCRC性能試験の再認定頻度が低くなるため、そのコストは正当化されます。

Q1 — 韓国のISBMネックODは、韓国の夏季生産における生産シフトに伴い増加するのはなぜですか？

Korean ISBM neck OD progressive increase over the production shift in Korean summer (July–August, ambient 32–38°C) has one primary cause: thermal expansion of the neck insert assembly as it heats from ambient to steady-state operating temperature during the production shift. The neck insert assembly — steel neck inserts mounted in the injection station cavity — heats progressively from 20°C at Korean morning startup to 65–80°C at steady-state production temperature (the thermal contribution from the PET melt at 280°C conducted into the neck zone). The thermal expansion of the P20 or 2316 stainless steel neck insert over this 45–60°C temperature rise is approximately 0.008–0.012mm OD increase per degree Celsius — at 50°C rise, the insert bore expands by 0.4–0.6mm. This bore expansion translates directly to a 0.4–0.6mm increase in neck OD from Korean morning startup to steady-state production temperature. Korean ISBM producers who perform their shift OD measurement at morning startup and use this measurement for the full production lot may be validating bottles against a cold-insert baseline that does not represent the warm steady-state production. Korean neck finish QC best practice: measure neck OD at 30 minutes after production start (when the neck insert has reached approximately 70% of its steady-state temperature), at 2 hours (near steady-state), and again at 6 hours — the progressive OD increase from these three measurements confirms the thermal expansion behaviour and the steady-state OD that the Korean brand’s closure supplier has calibrated their closure dimensions against.

Q2 — プロセス設定が同じであるにもかかわらず、韓国製ISBMキャビティのネック外径値が異なるのはなぜですか？

Cavity-to-cavity neck OD variation in Korean ISBM multi-cavity production has three primary causes. First — neck insert dimensional variation from manufacture: even when neck inserts are ordered from the same Korean mould maker for a 4-cavity or 6-cavity tool, individual inserts may have bore dimensions that vary by ±0.03–0.06mm from the nominal dimension due to machining tolerance stack-up in the insert manufacturing process. Korean ISBM producers should measure all neck inserts with an air gauge before mould assembly to confirm all inserts are within ±0.02mm of each other — inserts outside this batch consistency target should be reworked before assembly. Second — differential thermal expansion from uneven cooling circuit flow: cavities with higher cooling water flow (lower coolant temperature, shorter circuit path) run cooler, and their neck inserts maintain slightly smaller OD than cavities with restricted flow (higher coolant temperature). A cooling circuit flow balance check (measuring coolant temperature at inlet and outlet of each cavity’s cooling circuit) often reveals ΔT variations of 5–12°C between cavities in Korean multi-cavity production — requiring flow rate balancing with adjustable flow restrictors to equalise cavity temperatures. Third — differential injection fill rate: in multi-cavity hot runner systems, cavities at different distances from the manifold central feed can fill at slightly different rates, creating different packing pressures and different final neck OD dimensions. Korean ISBM hot runner balancing — either geometric (equal runner length) or thermal (independent heated zone per cavity) — is required to achieve consistent cavity-to-cavity neck OD for Korean K-Beauty and pharmaceutical applications.

Q3 — 韓国のISBM製造業者は、韓国ブランドの資格が再取得されることなく、ネックインサートの交換をどのように管理すべきでしょうか？

Korean ISBM neck insert replacement — necessary when insert dimensional drift exceeds the application tolerance from production wear — must be managed without triggering a full Korean brand re-qualification event (which typically requires 4–8 weeks and 30–50 first-article samples). Korean ISBM producers can minimise re-qualification scope by demonstrating that the replacement insert produces neck OD within the original first-article specification range. Protocol: (1) Before replacing, measure the worn insert bore at 8 positions (4 quadrants × 2 heights) and document the wear map — this establishes the dimensional baseline for the wear life record; (2) After inserting the new insert, run 10 qualification shots and measure neck OD at 4 quadrants on each of 5 consecutive bottles per cavity; (3) Confirm the new insert OD is within ±0.01mm of the original first-article mean OD; (4) Submit the dimensional comparison data to the Korean brand quality team as a “component change notification” (부품 변경 통보) rather than a full first-article resubmission — Korean brands who have accepted a pre-agreed component change protocol from their ISBM suppliers allow insert replacement without full re-qualification if dimensional data confirms equivalence. Korean ISBM producers who have not pre-agreed a component change protocol with their Korean K-Beauty or pharmaceutical brand customers are required to submit a full first-article package on every insert replacement — a qualification burden that motivates pre-agreement negotiation during initial supplier qualification.

Q4 — 韓国製ISBMのネック仕上げ仕様は、韓国製静止水ポンプ（PCO 1881）から韓国製トナーポンプ（GPI 24/410）に切り替える際に、どのような変更が必要ですか？

韓国製ISBMマシンをPCO 1881スティルウォーターからGPI 24/410 K-Beautyトナーポンプ生産に切り替えるには、金型本体の完全な変更に加えて、ネックゾーンのハードウェアを3つ変更する必要があります。1つ目はネックインサートの交換です。PCO 1881ネックインサート（27.43mmボア、2条ねじ）をGPI 24/410インサート（24.08mmボア、3条ねじ）に交換する必要があります。これは精密なインサート交換であり、微調整ではありません。GPI 24/410インサートは、ボア径、ねじ形状、および取り付け方法においてPCO 1881インサートとは全く異なります。2つ目はネックインサートの鋼材のアップグレードです。PCO 1881生産がP20鋼インサートで実行されていた場合、GPI 24/410 K-Beautyトナーインサートは2316ステンレス鋼でなければなりません（PETGの耐腐食性と±0.04mm外径精度のため）。 P20 インサートは、韓国の PETG 生産実行期間にわたって ±0.04mm を維持できません。金型交換時にアップグレードすることで、K-Beauty トナーの生産開始後に 2 回目の交換を回避できます。3 番目 - ネック冷却調整: 小型の GPI 24/410 ネックインサートは、PCO 1881 インサートよりも熱容量が小さいため、起動後すぐに定常動作温度に達し、同等の冷却水流量では、PCO 1881 よりもわずかに高い温度で動作します。韓国の ISBM オペレーターは、PCO 1881 から GPI 24/410 に切り替える際に、ネックの定常温度を維持し、切り替え後の PETG 生産の最初の 30 分で小型の GPI インサートを過冷却することによるネックゾーンのショートショットを回避するために、ネック冷却水流量を 10–15% 減らす必要があります。

Q5 — 韓国ブランドの受入検査では、ネック仕上げの外径公差はどのように検証されますか？

Korean brand incoming neck finish inspection uses three methods depending on the application tier. Method 1 — Attribute gauge (go/no-go ring gauge): the most common Korean beverage brand incoming inspection method. A calibrated go ring gauge at nominal OD + tolerance (e.g., PCO 1881 + 0.10mm go) and no-go ring gauge at nominal OD − tolerance (PCO 1881 − 0.10mm no-go) are applied to each sampled bottle — pass if the go gauge slides over the neck threads smoothly, fail if the no-go gauge engages. This method is fast (5 seconds per bottle) and requires no measurement skills, making it practical for Korean filling line incoming inspection at 100 units per delivery lot sample. Method 2 — Variable measurement with digital calliper or air gauge: used by Korean K-Beauty, pharmaceutical, and premium beverage brand quality departments for supplier qualification audits and periodic incoming verification. Records actual OD values at 4 quadrants; enables statistical process capability calculation (Cpk) for supplier assessment. Method 3 — Functional closure engagement test: 20 consecutive bottles are fitted with the production closure and torqued to the Korean brand’s specified application torque (typically 15–20 N·cm for 28mm closures) — all 20 closures must achieve full thread engagement without cross-threading, and all 20 must unseal at a torque within the brand’s specified removal torque range. This functional test is the most commercial test method — it directly validates that the neck finish performs correctly in the Korean brand’s filling and consumer use context, regardless of whether the actual OD measurement is at the tolerance limit or the nominal centre.

Q6 — 韓国の炭酸飲料製造において、韓国のPCO 1881と韓国のMCA 29/25ネックの違いは何ですか？

MCA 29/25 is an alternative Korean CSD neck finish introduced by some Korean beverage equipment manufacturers as a higher-flow alternative to PCO 1881 for Korean 1.5–2.0L CSD bottle formats. PCO 1881 at 27.43mm OD is the dominant Korean CSD neck standard for 250ml–1L formats; MCA 29/25 at 29mm OD with a 25mm inner bore provides approximately 35% larger flow area for faster filling at Korean high-speed CSD filling lines operating above 40,000 bottles per hour. The engineering differences relevant to Korean ISBM neck design: MCA 29/25 has a larger OD (29.0mm versus PCO 1881’s 27.43mm) — requiring a correspondingly larger neck insert bore and a slightly heavier neck weight (+0.4–0.6g per bottle); the MCA 29/25 thread pitch is the same as PCO 1881 (2-start), but the thread depth is slightly greater to accommodate the larger diameter engagement. Korean ISBM producers who supply Korean CSD bottlers who have upgraded their filling lines to MCA 29/25 closures for their 1.5L Korean cola line may receive Korean brand requests to transition their ISBM bottle from PCO 1881 to MCA 29/25 — a neck insert change (not a full mould body change) that requires new inserts and a neck OD re-qualification against the Korean brand’s MCA 29/25 closure supplier’s dimensional specification.