Stream Production System (SPS), as an ergonomic concept of layout and working environment, is more than a simple production system. The system is developed by Roberto Inglesi, a consultant and an industry expert and the writer of this article.
The whole system is based on the concept of optimizing the working time of each worker by reducing the handling time, says Inglesi. It also makes the system systematic, synchronized and most importantly disciplined. He further talks about the benefits of automation and workstation reengineering for making shirt using different arrangements in stream system.
‘Stream’ production system (SPS), is often associated with production line configuration or the line layout. It is in fact, a combination of two different production systems that are “bundle” system for parts preparation and “unit production system” for assembly and which has more to do with movement of work.
A module which is an integral part of stream production system is composed of a certain number of groups which are totally independent and operating in the preparatory phase of the process where each individual group works on one component only. While making collars, cuffs, backs, sleeves and front is done only by bundle or beans system, in order to gain high efficiency the assembly of the garment is done by a unit production system which is either computerized or manual.
Since most garments are sewn in two-phase, parts preparation and assembly, the SPS can be easily adopted for any type of production process and in any type of garment.
In the SPS, the lines configuration is not standard, because of the variation in the building plan. Obviously, a factory with large and long premises of 45 metre will have straight line layout with parts and assembly following one after the other, whereas in a 25 metre floor length it will be more appropriate to have U-shaped one way line layout housing parts and assembly in opposite direction. No doubt the large straight line layout is more efficient and in particular the circulation of work will be more efficient.
The ‘SPS’ concept of group systems, has big advantage in areas such as style changeover without breaking production; run small or large orders efficiently, easily control the work in progress (WIP), facilitating the production management, reducing operator stress and consequently making the workforce more efficient.
In order to reduce the tagging work and minimizing errors in assembling the bundles, the progression of work is done with a bundle system that has sequential numbers sticking out on two sides of the box containing the part name and serial number.
Bundles move on the appropriate rail that are situated on both the left or the right side of the machine, the two ranges of machine can be setup at each side of rail especially for the balancing purpose when we are required to duplicate some operations.
The boxes for bundles in the production line can be of different dimension to fit the type of garment. The main objective of SPS is to reduce handling time and increase the needle down time (NDT) , therefore the workstations must be ergonomically setup in order to reduce material handling time and make the operator concentrate more on the operation itself than searching the right position of parts by turning it around several times, thus inevitably losing time. It is often seen that factories settle for the layout without considering the principle of ‘low gravity’ that generally defines the basic fundamental rule of production flow in any kind of industry. The operation sequence in many cases does not follow the bundle serial number, resulting in the creation of unbalanced line, leading to loss of productivity.
Using an appropriate beans system for part preparation not only improves the flow of work but it also makes the work environment more organized and easy to manage, with an immediate and positive impact on efficiency.
In order to evaluate how to derive the best efficiency from stream production system in a men’s shirt, the high number of operations demonstrate far better advantages and benefits. Since production is a sequence of operations with different process times but in a certain time and order, these processes form a link ring wherein, all those links must remain active because even if one link ring fails, the whole process stops.
Therefore, the two main factors that makes a difference in terms of performance are:
1. Operation Time Optimization, and
2. Movement of work across all operations (Work Flow),
In any production process, the operations involved can be executed by:
(a) One operator one operation (Static);
(b) One operator for a combination of 2/3 operations or more (Floater).
In both of the above cases, focus is on increasing NDT. With an ergonomic setup of workstation, one can reduce the handling time, but obviously a static operator will be able to perform best as he will be performing a sequence of similar movements all through the day. He will get accustomed to the motions throughout the day which will not only improve the speed but also reduce the stress. This mechanism is called auto reflex as it builds the efficiency automatically.
For balancing reasons, few operators as floaters, would be required. But it must be ensured that those operations are similar and not too far from each other in the layout. Generally one operator handling two different operations at same time are indicative of automation in the workplace where the loading time of machine is minimum and the sewing is driven automatically.
As a result, the stream production system is based on the concept of optimizing the working time of each worker by reducing the handling time which represents in many cases more than 75% of total processing time.
Many types of layouts are possible for line setup but the main concept that is defined by the SPS is based on the following criteria.
- Facilitate Production Management & Balancing – Assign the preparation of different parts of one garment to a specialized section. This will not only improve the individual efficiency but also definitely help the Production Manager in balancing the entire production process, increase the daily output and improve inventory control.
- Standardize – Make the workforce completely familiar with the operation assigned individually this way the auto reflex action will improve the individual’s efficiencies by as much as 300%.
- Flexibility – The researches on flexibility are generally focused towards producing different categories of garments on the same production lines. In other words the segregation of garment categories (part wise) into small and medium configured groups speeds up the process and respond fast to style change as well as to the repeats.
- Ergonomical Set-up – The ergonomic set-up reduces handling time, gives best working environment and reduces workers’ fatigue.
By reducing operator stress of chasing bundles and others unnecessary work, the SPS allow operator to concentrate more on the operation itself ultimately increasing and improving quality.
In production, waste is commonly related to time. In any manufacturing industry and especially in apparel manufacturing industry there are many processes which are just a waste of time which may go up to 75%.
The difference in the number of shirts produced per hour also depend on the machinery and equipment used, especially in parts preparation where the usage of special equipments like loading and unloading devices and special pre-folding machines reduce the handling time and definitely improve individual efficiency. Meanwhile, if the SPS is implemented on the normal and basic production lines the production systematically improves up to 30% from the actual. This has already been measured in several countries like India and Sri Lanka, where the production techniques and the operator skill too are almost the same.
Waste can have different causes at the origin. The importance is to identify and remove them as early as possible on the “Production Process Timeline” without affecting “Production Process Sequence”. Therefore, an accurate “Pre-production Analysis” is required in terms of products, means and machines.