Conventional natural rubber packaging normally cools and inspects the dried rubber, weighs and adjusts the charge, compresses it into the required bale form, checks weight and metal contamination, wraps or bags the bale, applies traceable identification and transfers the finished product to controlled storage. Conventional means that more handling or packaging actions are manual or mechanically assisted; it does not reduce product, weight, contamination or traceability requirements.
Before baling
Rubber condition after the dryer affects unloading, weighing, feeding, compression and packaging. The post-drying area should provide controlled cooling and a clean inspection route separated from raw materials, dirty water, maintenance work and waste handling.
Before the rubber enters the packaging line, confirm that required cooling is complete, there is no visible abnormality or obvious foreign matter, the batch and drying records remain traceable, and any suspect material has been isolated according to the plant procedure. External appearance does not replace required sampling and laboratory testing.
Weighing and weight adjustment
The dried rubber must be assembled into the target charge before baling. Where the available pieces do not equal the target weight, a rubber saw or other approved weight-adjustment method can prepare smaller pieces for combination with the main charge.
Weighing systems need calibration, routine checks, abnormal-reading controls and retained records. Target bale weight, tolerance and check-weighing frequency should be taken from the applicable standard, customer specification and trade requirement. Unrecorded manual exchange of material between bales breaks traceability and should not be used as an informal correction.
How the baler forms a bale
The prepared charge is placed in the baling chamber. A hydraulic system drives the platen to compress the rubber into the specified bale form, holds or controls pressure as required, returns the platen and releases the bale.
Bale formation depends on more than nominal hydraulic force. Rubber temperature and form, loading distribution, chamber geometry, hydraulic condition, press sequence, hold logic, discharge action and rubber recovery all influence the result. A baler should be selected for the required bale specification, continuous cycle, maintainability and its interface with upstream and downstream equipment.
Post-baling checks
Weight confirmation
The process may use full check weighing or a documented sampling plan. A bale outside the permitted range should enter a defined disposition route rather than continue without identification.
Metal detection
A metal detector can be integrated with the conveyor to detect metal contamination in the bale. Actual detection performance depends on the sensing method, bale size, product position, conveyor speed, surrounding interference and the validated test pieces.
The plant procedure should define challenge-test pieces, test frequency, alarm or rejection logic and the destination of affected bales. Function should be reconfirmed after start-up, product change, shift change or maintenance as required by the plant's verified procedure.
Internal and external checks
Where the quality plan requires an internal visual check, a defined sampling station can open or separate a bale for inspection. External checks can review form, surface condition and packaging readiness. These checks support but do not replace the applicable laboratory sampling and test plan.
Wrapping, bagging and marking
Depending on the product and customer requirement, a bale may use confirmed plastic film, a woven bag, a paper bag or another approved combination. Packaging selection should consider contamination control, storage and transport, customer unpacking and the way the rubber will be used downstream.
Marking may include product name and grade, net weight, production date, lot, producer and other information required by the applicable documents. Destination-market requirements and the agreed customer specification should be checked before the packaging equipment and label data are fixed.
Storage and traceability
Finished bales should be identified by lot and stored in defined areas so that released, pending and isolated product cannot be mixed. Storage controls should address water ingress, contamination, sunlight, heat sources, stacking and handling. Warehouse transactions must link each shipment to the production lot and its release result.
Typical equipment
A conventional packaging section may include cooling and unloading stations, scales, a weight-adjustment station and rubber saw, a single- or double-box baler, infeed and discharge conveyors, check weighing, metal detection, manual wrapping or bagging stations, marking equipment, pallets and handling equipment.
The exact order can change with the plant's inspection route, available space and customer requirement. The position of weighing, metal detection and inspection should be confirmed during process and layout engineering.
Frequently asked questions
Is a baler alone a complete packaging line?
No. A complete process also requires cooling, inspection, weighing and adjustment, conveying, contamination control, packaging, identification and finished-product handling.
Is there one universal bale weight and size?
No. Confirm the sales market, product standard, customer agreement, container or warehouse handling and downstream use before defining bale geometry and baler chamber size.
Can a conventional line be partially automated?
Yes. Weighing data, conveying, metal detection, traceability or selected heavy-handling stations can be automated. An upgrade must still match the existing dryer output, baler, building, safety zoning and operating procedure.
Technical reference: Introduction to Natural Rubber Primary Processing Technology, Chapter 4. Content prepared by the Sinyoung technical team.