Customized 4L Bleach Filling, Capping, Labeling and Shrink Packaging Line

Large-volume bleach packaging requires more than placing several standard machines on the same conveyor. The liquid may be highly alkaline and corrosive, while the large plastic containers require stable conveying, accurate filling, reliable cap tightening and consistent label placement.

ZONESUN developed a customized packaging solution for a household cleaning product manufacturer. Designed for approximately 4 L plastic bottles, the complete line integrates bottle feeding, corrosive liquid filling, cap feeding, servo capping, double-sided labeling and shrink bundling.

The equipment configuration and production-line layout were developed around the customer's product characteristics, bottle samples, cap structure, label dimensions, target output and available installation space.

1. Project Overview

The customer needed an automatic production line for filling a high-alkaline bleach product into large handled plastic bottles. After filling, each bottle had to be capped, labeled on two sides and grouped for shrink packaging.

The main packaging requirements included:

Item	Project Requirement
Product	High-alkaline bleach
Filling volume	Approximately 4 L
Container	Large handled plastic bottle
Closure	Plastic screw cap
Label	Two self-adhesive labels
Labeling position	Opposite sides of the bottle
Target output	Up to approximately 30 bottles/min
Secondary packaging	Multiple shrink bundle formats
Production mode	Continuous automatic operation

2. What Challenges Did the Customer Face?

Corrosive Liquid Compatibility

Bleach is different from ordinary beverages, oils or cosmetic liquids. Its alkaline and corrosive characteristics may affect unsuitable pumps, valves, pipes, seals and filling nozzles.

For this reason, the filling system could not be selected according to filling volume alone. The wetted components had to be evaluated according to the customer's actual liquid composition.

Before production, ZONESUN requests the product composition or Safety Data Sheet so that suitable liquid-contact materials can be confirmed.

Stable Conveying of Large Bottles

Approximately 4 L bottles are wider and heavier than common beverage and cosmetic containers. Bottles with handles or irregular side profiles may also be difficult to guide and position consistently.

The conveyor width, bottle guides and transfer positions were therefore designed around the supplied bottle samples. This helps reduce bottle shaking, jamming and misalignment as the containers move between the different machines.

Continuous Cap Feeding and Tightening

The production line needed to automatically feed and tighten relatively large plastic screw caps.

Both the cap feeding mechanism and the capping section had to match the cap diameter, cap height, thread structure and bottle neck. Consistent tightening was especially important because insufficient torque may cause leakage, while excessive torque may damage the cap or bottle neck.

Double-Sided Label Positioning

The handled bottle required two separate self-adhesive labels to be applied to opposite sides.

Because the container is not a simple round bottle, stable guiding and positioning are necessary before label application. The labeling heads, bottle guides and dispensing positions were configured according to the actual bottle and label samples.

Secondary Packaging for Heavy Bottles

The filled bottles also had to be arranged into different bundle formats for transportation.

Because each bottle contains approximately 4 L of liquid, the completed bundles are relatively heavy. The grouping, film wrapping, shrink tunnel and discharge conveyor therefore had to be configured for stable movement of the finished packs.

3. What Machines Are Included in the Line?

Automatic Bottle Feeding System

At the beginning of the line, an automatic bottle feeding and unscrambling system organizes empty plastic bottles and transfers them onto the main conveyor.

Bottle detection helps coordinate the feeding system with downstream production. When bottles accumulate, the system can temporarily stop feeding; when more bottles are required, operation resumes.

This reduces manual bottle placement and supports continuous production.

Customized Chain Conveyor

A widened chain conveyor connects the individual processing stations.

Its width, guide-rail spacing, transfer height and operating direction are selected according to the customer's bottle dimensions and workshop arrangement. Adjustable guides help stabilize the large containers while allowing the production line to be adapted if compatible bottle formats are introduced later.

12-Head Corrosive Liquid Filling Machine

The core of the line is a 12-head gravity filling machine configured for the customer's high-alkaline bleach product.

Multiple filling heads process several bottles simultaneously, helping the line reach the required production output. The filling-head height and bottle positioning structure are adjusted according to the container.

Depending on the product's chemical composition, foaming behavior and fluidity, the filling speed and nozzle operation can be adjusted during sample testing.

The final configuration of tanks, pipes, valves, seals and other wetted parts must be confirmed according to the actual product rather than assumed from its general application.

Automatic Cap Feeding System

After filling, screw caps are automatically sorted and supplied to the capping section.

The cap feeding track and discharge mechanism are made according to the customer's cap sample. This helps maintain the correct cap orientation and ensures that caps are delivered continuously to the bottle necks.

If the cap design changes, the corresponding feeding components may also need to be adjusted or replaced.

Servo Four-Wheel Capping Machine

Once the caps have been placed, bottles enter a servo-controlled four-wheel capping machine.

The capping wheels tighten each screw cap while the bottle holding structure keeps the container stable. Capping speed, pressure and tightening performance can be adjusted according to the cap material, thread design and required torque.

Compared with relying entirely on manual tightening, the automatic system improves consistency and supports continuous operation.

Double-Sided Labeling Machine

The next station applies two self-adhesive labels to opposite sides of each bottle.

The labeling system is customized according to:

The bottle guides and label dispensing units work together to improve label placement consistency on the large handled containers.

Sleeve Shrink Bundling System

After labeling, finished bottles enter the secondary packaging section.

The bottles are grouped according to the required pack format and wrapped with shrink film. The bundle then passes through a shrink tunnel, where controlled heat causes the film to contract around the containers.

This process creates a compact multipack that is more convenient for storage, handling and transportation.

Because the finished bundles are heavy, their final format, conveyor load and discharge method should be confirmed before production.

4. Complete Packaging Process

The complete workflow is as follows:

This integrated process reduces manual transfer between separate machines and creates a more consistent production flow from empty bottle feeding to secondary packaging.

5. How Was the Production Line Customized?

This project required more than connecting standard machines. The individual systems had to be coordinated according to the product, container and production environment.

The main customizations included:

The final machine configuration is confirmed only after reviewing the actual product and packaging samples.

6. Production-Line Layout Planning

ZONESUN also prepared a preliminary layout based on the customer's available production area.

The layout considered the position of the bottle feeding system, main conveyor, filling machine, capping section, labeling machine and shrink packaging equipment. Sufficient space also had to be reserved for operators, maintenance and material movement.

Before finalizing a line layout, customers should provide:

7. What Samples Are Required Before Production?

To customize and test a similar bleach packaging line, the customer should provide representative samples and technical information.

These normally include:

If the actual liquid cannot be shipped, the customer should provide its viscosity, density, foaming behavior, corrosiveness and other relevant properties. ZONESUN can then discuss a suitable substitute material for preliminary testing.

8. Testing Before Delivery

Before shipment, the machines can be tested using the confirmed packaging samples.

The main inspection points include:

Actual production speed and filling performance depend on the product, container, cap, label, shrink format and final machine configuration.

9. Suitable Applications

Although this production line was developed around a bleach packaging requirement, a similar configuration may be adapted for other compatible household or industrial liquids, including:

The same machine cannot automatically be assumed suitable for every chemical product. Material compatibility, safety requirements and filling characteristics must be evaluated separately for each application.