WHAT IS WHEEL BLOW MOLDING

Did You Know?

Wheel (rotary) blow molding is a form of extrusion blow molding in which multiple blow molds are mounted around a rotating wheel. A continuous parison (or parisons) is extruded; revolving molds capture and blow the parison as they pass the head, enabling very high‑output production of bottles and other hollow articles. Typical systems can also run multilayer co‑extrusion.

At-A-Glance Facts:

Also called: rotary wheel blow molding; rotary continuous extrusion
Typical where: high‑volume HDPE bottles (e.g., laundry detergents, motor oil, single‑serve juices, dairy), where low cost per bottle is critical
Machine scale: wheels commonly carry ~6–30 molds, with continuous parison capture at the head; some designs are vertical or horizontal, and may be continuous‑motion or indexing
Characteristic tradeoffs: high throughput/efficiency and tight weight consistency (captured parison at both ends), but changeovers are more involved and machines are often dedicated to a narrow bottle size/format once built

Typical Defects (rooted in setup or tooling)

Flash/deflash issues if pinch‑off geometry/edge wear is not maintained

Wall‑thickness variation from suboptimal parison profile or die‑gap timing

Neck/finish variation (note: calibrated finishes are generally not produced on wheels)

Quality & Inspection (common checks)

Bottle weight (tight control is a key wheel attribute), wall‑thickness mapping, leak testing, dimensional checks (neck/finish, handle geometry where applicable), and visual for flash and seams. (General EBM practices; wheel platforms emphasize weight consistency via captured parison.)

Surface Engineering Options

Siloed by what you’re seeing on the tool (symptoms) so you can choose the right surface solution.

Start with the question: did the metal fail, or is it failing?

In rotary wheel blow molding, symptoms like sticking on wheel/pocket surfaces, scuffing or wear on sealing faces, heat-related finish issues, and contamination marks are the bridge between performance issues and root cause.

Metal failures we target

Sliding wear / scuffing on wheel surfaces
Galling on high-contact sealing faces
Edge wear on pockets & tooling features
Corrosion / pitting (materials & resin chemistry dependent)

Performance failures we target

Sticking / adhesion / material pickup
Cycle inconsistency driven by surface behavior
Short maintenance intervals / frequent cleanups
Heat-related quality issues (hot spots, haze, finish defects)

Important: “Armoloy-available treatments” are what we provide. “Other industry options” are common alternatives that may be supplied by other providers.

What you’re seeing (symptoms)	Likely failure mode	Armoloy-available treatments	Other industry options (not offered by Armoloy)	Benefit focus
Sticking or material pickup on wheel surfaces, pockets, or contact zones; inconsistent release	Friction + adhesion (material pickup) driven by surface roughness and chemistry	Electroless Nickel + PTFE (EN-PTFE) (where specified) Reduces friction and adhesion that drive sticking and cleanup frequency. High-Phos Electroless Nickel (ENP) (where specified) Uniform barrier coverage where corrosion resistance and thickness control matter.	DLC (PVD/PACVD) Low-friction thin films supplied by external providers to reduce adhesion.	Performance failures Sticking, cycle stability
Scuffing or sliding wear on wheel surfaces, sealing lands, or high contact zones	Adhesive + sliding wear; often tied to repetitive contact and motion	Thin Dense Chrome (TDC) Thin, uniform hard surface to help mitigate wear while preserving critical dimensions. Surface engineering consult We’ll validate hardness, friction behavior, and dimensional build for your specific contact interface.	CrN (PVD) Hard, thin films used by external coating providers for anti-wear and anti-galling benefits.	Metal + performance Wear mitigation / longer tool life
Edge wear on pockets, sealing features, or tooling edges affecting part quality or consistency	Abrasive wear and geometry loss on sharp/high-contact edges	Thin Dense Chrome (TDC) Hard, thin protection to help retain critical geometry where tolerance and fit matter.	Hard PVD films (e.g., CrN variants) Common when an external provider is selected for edge protection.	Metal failures Wear mitigation / geometry retention
Corrosion marks, staining, or haze after cleaning/washdown; contamination-prone surfaces	Corrosion initiation + roughness/buildup sites; chemistry & moisture accelerate attack	Electropolish + passivation (where applicable) Surface smoothing and corrosion-resistance restoration to reduce buildup sites and improve cleanliness.	ASTM A967 passivation (industry standard process) Often specified for stainless corrosion performance improvements (performed by qualified providers).	Metal + performance Corrosion control & cleanliness
Heat-related finish defects, hot spots, haze, or thermal inconsistency affecting molded parts	Thermal management limitation (heat extraction and stability); not purely a surface failure	Surface engineering consult We help confirm where surface treatment helps, where it should be avoided, and how to protect critical areas without compromising heat transfer.	High-conductivity copper alloys (e.g., MoldMAX® / AMPCOLOY®) Material/insert solutions to improve heat extraction in hot zones.	Performance failures Quality stability / thermal control

How to use this section: Tell us the symptom, where it shows up (wheel surfaces, pockets, sealing faces), the resin/additives, and your dimensional constraints. We’ll validate the best Armoloy-available treatment—or point you to a proven industry alternative when that’s the better engineering call.

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Rotary Wheel Blow Molding

WHAT IS WHEEL BLOW MOLDING

How It Works (typical sequence)

Typical Defects (rooted in setup or tooling)

Quality & Inspection (common checks)

Surface Engineering Options

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