1.INTRODUCTIONMany assembly lines in industry contain a combination of automated and manual workstations. These cases of partially automated production lines occur for two main reasons:Automation is introduced gradually on an existing manual line. Suppose that demand for the product made on a manually operated line increases, and it is desired to increase production and reduce labour costs by automating some or all of the stations. the simpler operations are automated first, and the transition toward a fully automated line is accomplished over a long period of time, Meanwhile, the line operates as a partially automated system.
Certain manual operations are too difficult or too costly to automate. Therefore, when the sequence of workstations is planned for the line, certain stations are designed to be automated, whereas the others are designed as manual stations.Examples of operations that might be too difficult to automate are assembly procedures or processing steps involving alignment, adjustment, or fine-tuning of the work unit. These operations often require special human skills and/or senses to carry out.
Many inspection procedures also fall into this category. Defects in a product or part that can be easily perceived by a human inspector are sometimes extremely difficult to identify by an automated inspection device. Another problem is that the automated inspection device can only check for the defects for which it was designed, whereas a human inspector is capable of sensing a variety of unanticipated imperfections and problems The following assumptions are made to analyse the performance of a partially automated production line:Workstations perform either processing or assembly operations;processing and assembly times at automated stations are constant, though not necessarily equal at all stations;synchronous transfer of parts;no internal buffer storage;the upper-bound approach is applicable; andstation breakdowns occur only at automated stations. Breakdowns do not occur at manual stations because the human workers are flexible enough, we assume, to adapt to the kinds of disruptions and malfunctions that would interrupt the operation of an automated workstation.For example, if a human operator were to retrieve a defective part from the parts bin at the station, the part would immediately be discarded and replaced by another without much lost time and is based on the assumption that of human adaptability.1.1 DEFINITION OF SEMI AUTOMATIONSemi-Automation ” Making a particular function/part of a process easier and faster, but still involves human interaction. In semi-automated processes, part of the task is automated, while the end part of the task involves human operation center424815000Fig.1.1 Semi automated machine 2.NEED OF PARTIAL AUTOMATIONIn semiautomated assembly system engage the operator to load/unload parts and to perform checks at every station to allow an automated conveyor to continue down the assembly line.Manual assembly systems don’t lend themselves to large increase in production or a significant decrease in rejected material.The right degree of automation depends up on budgetary needs over the life of the machine. As well as their manufacturing goals for the product.Partial automation systems are useful for companies that need to improve their manufacturing processes but are not able to completely remove the operator assistance. Some assembly systems are too difficult to automate reliably.Partial automated systems are needed when the volumes don’t justify a fully automatic system.Many companies go for this option to realise the significant process improvements while retaining the adoptability of human operator.Semi-automated systems are high density storage systems that allow you to store multiple pallets in a deep lane configuration. The system also gives you the flexibility of retrieving pallets from any lane with multiple SKU (stock keeping unit) locations without driving into the system.A semi-automated system is a great option for companies looking to improve their manufacturing process but are not able to completely remove their operator assistance. These systems should be considered if your company involves some aspects of assembly that are too difficult to be performed reliably by a fully automated system.Pallets are loaded and unloaded into the system from the first or Home position at either end with a cart. The cart is controlled by a hand-held radio transmitter which allows the carts to perform multiple functions to suit your storage needs. The cart is designed to transport pallets being stored into the system, and retrieve the pallets as needed for shipment. This allows storage systems to be much deeper than other high-density systems 3.ROLE OF PARTIAL AUTOMATION3.1 PARTIALLY AUTOMATED STRAPPING The loading of the carton in a packing is done by the human operator. And the powered rollers are used to move the carton towards the strapping machine to strap the carton. Fig.3.1 Loading of carton  The carton is further strapped width wise at equal distances and moved on to on to a platform from which the human operator can carry the unloaded cartonFig.3.2 Equally spaced strapping After completing the strapping operation, the carton is moves forward to the conveyor. then the cartoon will be received by the operator.Fig.3.3 Receiving the carton by operator The role of human operator in strapping operation is shown in the above figures 3.1 and 3.3.4.ADVANTAGES OF PARTIAL AUTOMATIONLabour productivity is greatly improved: A process that is not automated at all can be very time-consuming. The jump from no automation to semi-automation brings huge benefits, and the jump to full automation often brings limited benefits.Human operators still need to use their brains: They still pull the trigger. It means they understand the steps to follow, and they can think of better ways of organizing their work.Processes are much more flexible: Since each task (rather than the whole process) is automated, the general workflow of a process can be reorganized easily.Continuous improvement is possible: Once you buy a big machine, you are stuck with it. Continuous improvement is impossible. The key is to keep control over the sequence of the tasks and the way they are performed. It is possible with low-complexity semi-automation.5.DISADVANTAGES OF PARTIAL AUTOMATIONIn partial automation human intervention is still needed.As compare to full automation partial automation is not suitable for higher production rates.To implement partial automation to the manual assembly line there is some investment is required.Compare to manual process it is costly.6.APPLICATIONSThe partial automation is employed in packaging operations.It is widely implemented in manual assembly line to improve the operator’s safety.In recent times it is implemented to cars also.It is also used in inspection operations.7.CONCLUSIONSPartial automation ensures the human operator to monitor and exercise supervisory control on the process.It provides an opportunity for human to take decisions to optimize the process. Human operator can take decisions for process control considering various alternatives based on the actual process conditions.7.REFERENCES Mikell P. Groover, Automation, Production Systems and CIM, PHI Pvt, Ltd., 1998