Comparison between Progressive Bundle System and Unit Production System (UPS)

In readymade garment manufacturing plants various types of sewing systems are installed. A plant owner chooses these systems depending on the production volume, product categories, and cost effectiveness of high tech machines. Among those “Progressive Bundle System” (PBS) is mostly installed sewing system till date. In this production system bundles of cut pieces (bundle of 5, 10, 20 or 30 pieces) are moved manually to feed the line. Then inside the line an operator himself drag the bundle from side table and transfer the bundle to the next operator after completion of the work.


With the advancement of the technology mechanical material transportation systems are brought in the sewing plant. An overhead material transport system, known as UPS (Unit Production System) transports cut pieces hanged in hangers (one hanger for one piece) by automated mechanical transport system. It reduces manual transportation and it has many other benefits against the progressive bundle system. This article is not to recommend one to replace this well placed progressive bundle system. When to install a new technology is depend on various factors.

A comparison between these two production systems has been drawn in the following table on the basis of production KPIs (Key Performance Indicators) to show how an UPS system (overhead hanging and sensor controlled system) is most effective over PBS.
Parameters
Progressive Bundle System (PBS)
Unit Production System (UPS)
Transportation
-Manual transportation, many times helper are hired for this bundle transportation job.

-Operators stop their work to fetch bundles.

-Less effective in terms of production management. Resulted long response time.
-In this system an automated mechanical system carries pieces to each work stations.

-Easier pick up and dispose at each work station. Resulted quick response time
Through put time
-Compare to UPS, through put time longer in PBS. How much long will depend on the bundle size and no. of bundles kept in between two operators.
-Through put time in UPS is less compare to PBS. But it is not the minimum time as in this system there is WIP in between two operators.
Direct Labour content
- Direct labour content is high because usually operator does tying and untying of bundles, positioning components, pulling the bundle ticket and handling of work pieces.
-Direct labour content is less than PBS because an operator only sews the garment part rather than other tasks. In this system garment parts are held by the over head hanger, so less handling of garment components.
WIP level
-In PBS generally operators are asked to sew as much pieces as they can without considering back and front operators. This resulted piling up of work in the operations with higher work content.
-Less WIP in between operators. As workstation has limit of holding no. of hangers. Also after completion of operation hangers are transported to the next operation automatically.
Cutting work requirement
-As a result of High Work In Process (WIP) is required by sewing section, cutting sections are required to perform 60-70% more than actual production can handle.
-Lower WIP results in less cutting works. A balanced flow of material established in between cutting and sewing line.
Inventory Level
-Due high WIP and higher cutting, fabrics and trims need to stock in advance
-Less inventory for fabric and trims.
Excess labour requirement
- Usually in PBS needs more overtime works, repair work due to some unfinished operations.
-Plant with UPS system needs less overtime as planning is easy in this manufacturing system.

Reference: Various articles and websites.

Also read: Different types of production line layout (with Picture)


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