The problems of “Flow” in a Process layout:
The flexibility of the small batch manufacture using a process layout is limited to the variety of the items produced. The flexibility is not with regard to time. In process layout, equipments performing similar operations are placed together in an area of the shop floor. Lathes may be in one area while the milling machines may be in another and the grinding machines in yet another work area. In manufacturing a component, it may need to go through all or some of these work areas, frequently more than once. Every time a machine may have to be set anew resulting in losses of time in terms of setup times and, more importantly, large wait times of the items waiting of their turn at the machine/work center due to the varying skewed workload at these work centers in their zigzag and varying and therefore unpredictable journey through the factory. This results in huge wait times for these semi-finished parts.
A delay on one operation may compound the delay in another operation required for the particular component on its route to completion. Since these components may be required for an assembly at the end, the assembling may be delayed for want of a particular component.
A machine in a process layout faces:
(1) Randomness or variability of the design of parts coming to it for production necessitating fresh setup each time and
(2) Randomness of the arrival of the parts at the machine due to randomness in the route each part traverses.
These two aspects of randomness compound each other increasing the randomness further. The sum and substances of all this is that the throughput times are long and uncertain, the customer bearing the brunt of all these deals. Some factories keep extra machines in the work centers or keep extra inventory of the finished goods, in order to take care of this problem. Thus, there may be much inventory sitting in the factory both the work-in-process kind and the finished goods kind, in addition to possibly excess machines sitting idly much of the time. Process layout caters to ‘intermittent flow’ type of production (another name for job shop production); and precisely the problem with this layout and production system is that of flow.
The Human Relations Problems in a Process Layout:
Since the persons with same/similar skills are deployed together in a work center resulting in different work centers having people with dissimilar skills, it may lead to:
(1) a lack of appreciation of the work of other work centers
(2) a lack of the need for cohesion within a work center
(3) diversion of focus from the final product and/or the company’s goal and
(4) an inflexible mechanistic organizational structure requiring a management intervention all too often to resolve conflict situations between work centers and between people belonging to the same work center.
The negative effect of such a lack of communication and of a lack of a sense of cohesion is acutely felt in the not-so-infrequent a situation when a particular high priority rush order has to be expedited through the various work centers. There is more often than not a resistance to the order cutting though the already set sequencing procedures and hierarchies. There is conflict between the work centers. The company’s goal is rarely in the picture and there is a need or frequent intervention by the management. This further divides the management from the (non-management) employees. Moreover the management gets preoccupied with fire fighting of this kind and would therefore be more inwardly focused than having an outward focus and understanding the customer and the external market in general. Thus, the company’s management ends up neglecting its main job. The functional layout (another name for process layout) ends up dysfunctional on these counts.
Of Course, just because we have mentioned the demerits of the process layout, it does not lose its merits viz., making large variety possible honing up skills of the workers as they repeatedly carry out he same operation, and giving them a better job satisfaction.
Problems in Line Layout or product Layout:
Line layout is great for flow, has excellent throughput times, eliminates the inter-departmental conflict because it is one joint line, however branched it may be and has almost nil work-in-process inventories but it is too big for making any quick changes in the product and in the process. It is inflexible on that count. One only wishes that it was small or short.