A buyer sends a 3D file of a Bluetooth earbud case and expects a quote: “ABS, two cavities, 5,000 shots.” The mould shop that quotes on those three lines alone will deliver a shell that warps 0.3 mm on the lid seam, shorts the antenna window with conductive paint, leaks at IPX5 because the TPE gasket seat is 0.05 mm off, and cracks the hinge after 40,000 open-close cycles. A Bluetooth headset shell is not a soap dish—it carries a PCB, a mic duct, an antenna keeper, a charging-pin boss, a TPE seal groove, and a snap-fit that must survive 300,000 cycles, all inside a 0.6–1.2 mm wall. The injection programme has to settle five constraints before the first electrode is cut: material shrink direction, runner drool vs gate vestige, slider/seal tolerance, antenna window vs post-paint, and cavity balance across a 300k–1M shot life. The Bluetooth headset — Bluetooth Headset Plastic Injection Mould Shell Enclosure ABS PC PA PA6 6 GF POM PP PET PVC HDPE Hot Cold Runner Single Multi Cavity 300000 1000000 Shots UG PROE CAD CNC Milling Grinding Precision Electronic Enclosure OEM ODM Manufacturer Guangdong Shenzhen Szplastic-injection Power Bank Medical Device Shell​ is the object those constraints act on: a Guangdong-built precision mould (CNC + milling + grinding, UG/PROE/CAD, hot or cold runner, single or multi cavity, 300,000–1,000,000 shot rated) that comes out of a 9-step workflow starting with a deposit and ending with after-sales return visit. But why does PA6/6+GF shrink 0.3% anisotropically while ABS shrinks 0.5% isotropically and that difference decides gate location, how does a hot-runner tip for POM avoid drool that a cold runner would never show, and what makes a Guangdong/Shengzhen shop running the deposit→sample→mass→balance model a mould partner rather than a CNC broker relabeling a Dongguan blank? Below is the full breakdown for TWS brands, audio OEMs, medical-device enclosure buyers, and power-bank houses evaluating a shell programme whose real spec is “five constraints closed before T1,” not “ABS, two cavities, 5k shots.”

Why a headset shell is five mould constraints, not one plastic box

The Bluetooth headset — Bluetooth Headset Plastic Injection Mould Shell Enclosure ABS PC PA PA6 6 GF POM PP PET PVC HDPE Hot Cold Runner Single Multi Cavity 300000 1000000 Shots UG PROE CAD CNC Milling Grinding Precision Electronic Enclosure OEM ODM Manufacturer Guangdong Shenzhen Szplastic-injection Power Bank Medical Device Shell​ is anchored in five reconciled facts—shrink/warp direction, runner chemistry, seal-slider tolerance, antenna-window vs paint, and cavity-life balance:
  • Shrink Direction Decides Gate Location: ABS 0.5% Isotropic, PA6/6+GF 0.3% Anisotropic.​ ABS and PC/ABS shrink ~0.5% uniformly, so a fan gate at the case spine centers the sink. PA6/6+GF shrinks 0.3% along flow and 0.1% across fiber—meaning a center gate on a PA6/6+GF earbud shell bows the antenna wall 0.15 mm because the glass fibers pull the melt forward and relax sideways. The mould design has to shift to a three-point submarine gate or a hot-tip at the hinge boss to neutralize fiber orientation. A quote that says “PA6/6+GF, same gate as ABS” ships a warped shell; the szplastic page lists PA6/6+GF explicitly because the shop expects to re-run the fill simulation, not copy the ABS gate.
  • Hot Runner For POM/PC Avoids Drool; Cold Runner For PA Avoids Thermal Crack.​ POM (acetal) degrades above 240℃ and strings at the nozzle; a Mold-Master or Yudo hot-tip with a closed valve gate cuts the string but needs a 0.5 mm land and a 220–230℃ melt. PC likes a hot runner too (avoid cold-sprue stress cracking) but the tip must be 250–260℃ with a 12 mm insulated manifold. PA6/6+GF conversely welds to a hot-tip steel face and forms a brown degradation ring after 50k shots—so PA runs better on a cold runner with a pinpoint gate and a manual degate. The szplastic spec line “Hot/Cold Runner” is not a menu option, it is a material-dependent decision: POM/PC→hot, PA→cold, ABS/PP→either.
  • IPX5 Seal Needs A 0.02 mm Slider, Not A 0.1 mm Boss.​ A TWS case rated IPX5 holds a TPE gasket in a groove; the groove width tolerance is ±0.02 mm or the gasket rolls. That tolerance comes from a cam-slider in the mould (not a hand-finished boss), and the slider wears 0.005 mm per 100k shots—so a 1,000,000-shot mould needs a hardened insert (H13, 52 HRC) on the slider face or the IPX5 fails at shot 600k. The szplastic “Mould life 300000-1000000 shots” line is the reason the quote must name the slider steel, not just the cavity steel (P20/718H for the cavity, H13 for the slider).
  • Antenna Window Vs Conductive Paint: Mould The Keeper, Don’t Mask It.​ A 2.4 GHz BLE antenna sits on the inner wall behind a thin (0.6 mm) PC window. If the post-process is conductive (EMI) paint or metallized UV, the painter will overspray the window unless the mould moulds a 0.3 mm step keeper that the mask jig locates on. Moulding the keeper (not milling it after) keeps the window concentric to the antenna trace within 0.05 mm. The szplastic page lists “Surface treatment: As customer’s request” precisely because the mould has to anticipate the painter—spray, vacuum metallize, or laser etch—before the first cavity is cut.
  • Multi-Cavity Balance At 300k Shots Is A Flow-Length Problem, Not A Machine Problem.​ A 4-cavity TWS-shell mould on a 120T machine looks balanced on the first 500 shots; at 80k shots cavity 3 weighs 0.4% less because its runner branch is 12 mm longer and the POM crystallizes faster. The fix is not a bigger machine, it is a naturally-balanced runner (H-melt with equal thermal length) plus a hot-manifold with individual zone PID. The szplastic “Single or Multi Cavity” line implies the shop will simulate fill balance at 50% / 90% / 100% cavity before T1—because a 4-cavity that drifts 0.4% is a scrap program at 300k shots, not a tuning issue.
  • Guangdong Shop 9-Step Deposit Model Is The MOQ Gate.​ The szplastic workflow is contract → down payment → preliminary R&D communication → scheme confirmation → design and sampling → sample confirmation → mass production → final payment before shipment → inspection and shipment → shipment confirmation → after-sales follow-up. That sequence is why the effective MOQ is not “1 mould” but “deposit clears the R&D-talk slot.” A brand with one SKU and a 5k-unit forecast still pays the deposit, gets UG/PROE DFM, T1 in 4–7 weeks, sample confirm, then 5k units. The deposit model separates serious audio OEMs from tire-kickers who want a “free DFM”—and the 300k–1M shot life is quoted only after the scheme is confirmed, not on the inquiry form.

szplastic-injection / Guangdong supply context

From the node (products/bluetooth-headset/) + site header (Power Bank, Bluetooth, Medical Device Shells) :
  • Maker:​ szplastic-injection (Shenzhen/Greater Guangdong precision plastic injection mould maker), contact Mr. Shan +86 13823654746
  • Origin:​ Guangdong, China (Mainland)
  • Shaping mode:​ Plastic Injection Mould
  • Materials:​ Plastic, PA, PA6/6+GF, ABS, POM, PC, PP, PET, PVC, HDPE (any color)
  • Machines:​ CNC, Milling, Grinding
  • Runner:​ Hot / Cold Runner
  • Mould life:​ 300,000 – 1,000,000 shots
  • Cavity:​ Single or Multi Cavity
  • Design SW:​ UG, PROE, CAD
  • Surface:​ As customer’s request (polish, texture MT, paint, metallize, laser etch)
  • Workflow:​ 9-step contract→deposit→R&D talk→scheme→design+sampling→sample confirm→mass→balance→inspect/ship→after-sales
  • Scope:​ Bluetooth headset, power bank shell, medical device shell, precision electronic enclosures
  • URL:​ https://szplastic-injection.com/products/bluetooth-headset/

Key characteristics and application scope

  • Product Name:​ Bluetooth headset
  • Alternate Terms:​ szplastic-injection TWS earbud shell injection mould ABS PC PA6/6+GF 300k-1M shots hot cold runner, Guangdong Bluetooth headset enclosure OEM ODM precision electronic shell, Shenzhen power bank medical shell same line bluetooth headset mould, szplastic-injection.com earbud case plastic injection programme
  • Process class:​ Precision plastic injection moulding of consumer-audio enclosures (not vacuum forming, not CNC milled prototype, not die casting)
  • Core Applications:
    • TWS earbuds (case + bud shell)​ — 0.6–1.2 mm wall, antenna window, mic duct, TPE gasket groove, hinge boss
    • Over-ear / on-ear headphone cups​ — PC/ABS two-shot, foam-ring seat, slider arm cavity
    • Power bank enclosure​ — ABS/PC, UL94 HB/V0, silk-screen panel, button boss (same line as headset)
    • Medical device shell​ — POM/PC, ISO 10993-touchable, polished cavity, traceable steel cert (same shop scope)
    • Companion logic:​ Same PO pulls power-bank shell + headset shell + medical knob so one DFM review covers three enclosures.

Application logic by buyer type

  • TWS Brand (EU, 20k units/yr):​ ABS/PC blend case + PA6/6+GF bud shell, 4-cavity cold-runner for PA / hot-tip for PC case, 0.02 mm slider seal, antenna keeper moulded, UG DFM, T1 5 weeks, 20k units after sample confirm.
  • Audio OEM (US, 80k units/yr):​ Over-ear cup in PC/ABS two-shot, 2-cavity hot runner Mold-Master, 718H cavity + H13 slider, 500k shot life, metallized face via keeper step.
  • Medical Device Maker (Germany, 15k/yr):​ POM housing, cold runner pinpoint, polished cavity Ra 0.2, steel cert S136, ISO 9001/ISO 13485 referenced, 300k shot guarantee.
  • Power Bank House (SE Asia, 120k/yr):​ ABS V0 case, 8-cavity hot runner, 1M shot life, silk-screen panel boss moulded not milled, shares deposit slot with headset SKU.

Procurement and spec checklist

When specifying Bluetooth headset — Bluetooth Headset Plastic Injection Mould Shell Enclosure ABS PC PA PA6 6 GF POM PP PET PVC HDPE Hot Cold Runner Single Multi Cavity 300000 1000000 Shots UG PROE CAD CNC Milling Grinding Precision Electronic Enclosure OEM ODM Manufacturer Guangdong Shenzhen Szplastic-injection Power Bank Medical Device Shell:
✅ Material​ — name exact resin (ABS H2938 vs PC 2805 vs PA6/6+GF 30%); shrink rate per datum sheet.
✅ Wall​ — 0.6–1.2 mm nominal; reinforce hinge boss to 1.5 mm. / ✅ Runner​ — POM/PC→hot (Mold-Master/Yudo, valve gate); PA→cold (pinpoint); ABS/PP→either.
✅ Cavity​ — single for <10k/yr, 2–4 for 20–80k, 8 for >100k; demand naturally-balanced H-runner simulation.
✅ Slider/seal​ — IPX5 needs cam slider ±0.02 mm, H13 52HRC insert, wear budget 0.005 mm/100k shots.
✅ Antenna window​ — mould 0.3 mm keeper step; specify post-process (conductive paint / metallize / laser).
✅ Mould steel​ — cavity P20/718H (300k) or S136 (1M+ medical); slider H13; base LKM/HASCO/DME.
✅ Life​ — 300,000 min, 1,000,000 max; T1 4–7 weeks, fine-tune 2 weeks.
✅ Workflow​ — deposit clears R&D-talk slot; sample confirm gate before mass; balance before shipment.
✅ Docs​ — UG/PROE/STEP source accepted, steel cert, mold-flow report, CMM first-article.

Conclusion: The headset shell is five constraints closed before T1, not ABS in two cavities

The Bluetooth headset — Bluetooth Headset Plastic Injection Mould Shell Enclosure ABS PC PA PA6 6 GF POM PP PET PVC HDPE Hot Cold Runner Single Multi Cavity 300000 1000000 Shots UG PROE CAD CNC Milling Grinding Precision Electronic Enclosure OEM ODM Manufacturer Guangdong Shenzhen Szplastic-injection Power Bank Medical Device Shell​ does not start with “ABS, two cavities, 5k shots”—it starts with shrink direction (ABS 0.5% isotropic vs PA6/6+GF 0.3% anisotropic deciding gate location), runner chemistry (hot-tip for POM/PC, cold pinpoint for PA), seal tolerance (0.02 mm cam slider, H13 insert, 0.005 mm/100k wear), antenna keeper moulded not masked, and cavity balance simulated to 100% fill before T1. Built on a Guangdong/Shengzhen CNC+milling+grinding hall running UG/PROE/CAD, hot/cold runner, 300k–1M shot rated steel, and a 9-step deposit→sample→mass→after-sales workflow, the programme treats the headset shell as a precision electronic enclosure alongside power-bank and medical-device shells on the same PO. Paired with a power-bank V0 case and a POM medical knob in one DFM review, it becomes the audio+enclosure anchor in a mould program whose metric is “five constraints closed before T1,” not “cheapest ABS box.”

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