Australian Plastic Fittings Packaging & Palletizing Line with Two-Stage Precision Weighing

Project Overview

An Australian customer engaged us to build a complete packaging and palletizing production line for plastic fittings. The line packs 100 plastic fittings into each PE film bag and is designed for a production rate of 20 bags per hour, after which the finished bags are automatically stacked onto pallets ready for storage and shipment.

Project Challenges

• Oversized material: Because the plastic fittings are relatively large, feeding the full batch into the weighing hopper in a single drop is not practical. Our engineers therefore adopted a two-stage discharge (dual-drop) weighing method, metering the material into the hopper in two separate discharges to achieve stable and reliable weighing results.
• Weighing accuracy: The core difficulty of this project is precise weight control. Due to the structure of the fittings, the parts sometimes tangle or interlock with one another, which can make the weight of each individual piece inconsistent and directly affect the final count accuracy of every bag.
• Stable robotic palletizing: Before palletizing, the product inside each bag must be levelled and settled (shaken flat) so that the palletizing robot can grip the bags smoothly and stack them evenly without misalignment.

Our Solution

To guarantee weighing accuracy, the line is equipped with two forms of refill (make-up) feeding that work together automatically:

Coarse feeding: When the hopper is still far from the target weight, a large volume of product is fed into the weighing hopper quickly. This stage maximizes efficiency and keeps the cycle time short.

Fine feeding: As the weight approaches the target value, the system automatically switches to fine feeding, adding the plastic fittings one by one into the weighing hopper until the exact target weight is reached.

This coarse-to-fine strategy effectively solves the accuracy problem caused by tangled or interlocked fittings: the coarse stage delivers speed, while the fine stage delivers precision, ensuring every PE film bag contains the correct quantity with minimal product giveaway.

After bagging, each bag passes through a flattening and settling unit that levels the product inside the bag before it enters the palletizing station. With the bag surface properly flattened, the palletizing robot can grip every bag reliably and build stable, neatly aligned pallets layer by layer.

Key Line Parameters

Customer Value

• Accurate every bag: the dual feeding strategy keeps weight deviation within a tight range even when fittings tangle together.
• High efficiency: coarse feeding preserves speed, so the line sustains the required output without sacrificing accuracy.
• Reliable stacking: flattened bags enable smooth robot gripping and stable pallet patterns, reducing downtime and product damage.
• Labor saving: from weighing to bagging to palletizing, the whole process runs automatically with minimal manual intervention.