Build a Self-Reliant Bottled Water Line with Cap & PET Preform Injection Molding

Due to the high transportation costs and unstable external supply chains in remote locations, we recommended a one-stop plant integration approach. The client sourced all key components from Huarong, including injection molding machines, molds, and downstream processing equipment to create a fully integrated production base.

Two types of injection molding machines were deployed:

• General-Purpose Injection Molding Machine: Paired with cap molds for high-speed bottle cap manufacturing.
• PET Preform Injection Molding Machine: Paired with hot runner preform molds for transparent PET preform production.

 

Cap molding demands high-speed clamping and stable injection pressure to avoid defects such as flash or short shots. The HR220N offers:

• Stable injection pressure for consistent part quality
• Support for high-cavity cap molds to boost productivity

Related product: General Injection Molding Machines – HRN Series

Further reading: Injection Molding for Plastic Bottle Caps: Manufacturing Processes & Applications

Other successful cap case: The Science Behind Plastic Caps: How are Plastic Bottle Caps Made

 

PET preform molding requires specialized equipment due to the material's sensitivity to moisture and heat. HR420PET is engineered for such demands, with:

• PET-optimized screw design: Reduces shear heat to preserve resin properties
• Excellent clarity and wall thickness consistency: Achieved through stable injection velocity and pressure curves
• High-cavity support with hot runner and valve gate systems: Enables high-volume production

Related product: PET Preform Injection Molding Machine－PET Series

Other successful cap case: PET Preform Manufacturing: A Customer Success Story with Huarong

 

 

PET’s sensitivity to moisture means that even slight water retention can cause part defects. We provided a full auxiliary solution, including:

• Dehumidifying Dryer & Loader Combo: Removes moisture and ensures consistent feed
• Vacuum Auto Loader: Ensures continuous material feeding and reduces downtime
• Mold Dehumidifier with Air Return Collector: Keeps mold surfaces dry and prolongs mold lifespan
• Chiller Unit: Accelerates cooling and ensures stable cycle time

Further reading: PET Preform Molding Solution: A Detailed Guide to PET Preform Manufacturing

 

 

After caps are injection molded with perfect form, they must undergo additional processing to meet tamper-evident safety requirements. Specifically, each cap needs slitting and folding operations to create the locking ring (tamper-evident band).

Huarong assisted the client in implementing a cap slitting and folding system to ensure:

• Precise and uniform slitting lines — enabling smooth, easy opening for end users.
• Strong and secure folding — reinforcing the ring structure so that it remains durable and compliant with safety standards.

The integrated system includes:

• Slitting Device
• Folding Mechanism

 

 

 

For first-time users of cap and PET preform molding, mastering both machine operation and process know-how is a critical journey. Huarong supports full capability transfer through:

• On-site installation and mold testing (cap and PET molds)
• Injection parameter setup and stabilization
• Operator training (machine logic, troubleshooting, maintenance)
• Process knowledge, including PET drying, cooling, and injection pressure tuning
• SOPs for mold cleaning, mold changes, and hot runner care

Thanks to this complete onboarding system, the client quickly moved from zero knowledge to full control — even with limited manpower in a remote factory.

Related article: Injection Molding Machine Maintenance PDF and Checklist

 

 

During our visit to the client's injection molding business, we found a spacious, bright, and well-organized workspace. Every operator followed a structured flow, backed by Huarong's full technical support — from machine installation and mold setup to the mold change process and post-processing system integration. Every step, from molding to finishing, met quality expectations.

 

By implementing Huarong’s one-stop solution — machine → mold → post-processing → auxiliary systems — the client achieved:

 

 

A PET preform machine is specifically designed to handle PET resin, which is highly sensitive to heat and moisture. It features a PET-optimized screw design, precise temperature control, and compatibility with high-cavity hot runner molds. In contrast, general-purpose machines are used for a wide range of plastic materials and are ideal for items like bottle caps or general packaging components.

Not recommended. Cap production and PET preform production have very different technical requirements — particularly in screw design, material drying, cycle time, and mold temperature. For best efficiency and part quality, it is strongly advised to use dedicated machines for each.

Cap slitting and folding create the tamper-evident band — a ring that separates when the bottle is opened for the first time. This post-molding process ensures product safety, regulatory compliance, and consumer trust. Without it, caps may not meet industry packaging standards.

Huarong provides on-site support for machine installation, mold testing, setting injection parameters, and conducting trial runs. We also offer systematic training for operators — covering machine logic, troubleshooting, mold maintenance, hot runner care, and PET material handling. Our goal is to help customers reach independent production as fast as possible.

Key equipment includes:

• Dehumidifying dryer to eliminate moisture from PET resin
• Vacuum loader for consistent material feeding
• Mold dehumidifier to prevent condensation on mold surfaces
• Chiller to ensure precise temperature control and short cycle time
  These ensure high clarity, dimensional accuracy, and reduced defect rates in preforms.

 

 

At Huarong Group, we’re more than an injection molding machine manufacturer — we’re your strategic partner in building independent production capacity, improving quality, and ensuring long-term sustainability.

Our belief is simple:
“Industry Alliance Creates Value. Innovation Delivers High Quality.”

We remain committed to providing optimized injection molding solutions for every industry.

• Group Name: Huarong Group
• Brand: Huarong, Yuhdak, Nanrong
• Service Offerings: Injection Molding Machine, Vertical Injection Molding Machine, Injection Molding Automation
• Tel: +886-6-7956777
• Address: No.21-6, Zhongzhou, Chin An Vil., Xigang Dist., Tainan City 72351, Taiwan
• Official Website: https://www.huarong.com.tw/