IMPLEMENTING CELL MANUFACTURING IN ALCAST PVT. LTD.
Lean manufacturing is essential approach these days in almost every manufacturing industry. It mainly focuses on Reducing waste, minimizing non- value adding activities and increasing the production output by reducing cycle time for each item. Lean manufacturing is a methodology which consists of some scientific techniques to increase product quality and accuracy. Cell manufacturing is also one of lean manufacturing technique which focuses on reducing operation time, eliminating material handling and processing time by arranging the machines in suitable sequence as similar operation required on the component. Cell manufacturing is all about having a complete manufacturing plant inside a manufacturing industry where all the raw material comes in and finished product is released at the end. The basics of cell manufacturing starts with arranging similar parts of same group and then aligning all the machines in order of operation. Some of methodologies used in cellular manufacturing are takt time and takt base line balancing. This case study is focused on ammunition components for defense industry. The study was carried on all process activities based upon takt time and all the units were analyzed for reduction of non-value adding activities such as material handling, bottlenecking and waiting time. The better cell design plays vital role in overcoming all the manufacturing drawbacks and increases the product output quality with minimum of the waste.
Lean manufacturing is widely used in all the leading automotive and supplier industries to increase the overall efficiency. As a result of automotive growth many other industries like aerospace, tire industries are looking forward to adapt lean principles. Cell manufacturing is a grouping philosophy which is an application of lean manufacturing in which similar parts are grouped in same families and machines are aligned according to operation on the parts. This saves lot of material handling time, processing time and improve product quality. The cell manufacturing technique is applicable in almost any kind of small and big industry but the problem is that when it comes to calculation of takt time of complete manufacturing process through intercellular and intracellular movements, there is quite a bit time waste in locating machine and supply parts from one machine to another machine which is randomly positioned or it is positioned more than 5 meters of distance away from worker. In this case study the solution is provided by implementing new layout of cell arrangement based upon methodologies of lean principles or in other words a cellular layout which follows lean manufacturing.
Cellular layout for Lean manufacturing:
The case study is carried out on ISO-certified defense manufacturing unit, ALCAST Pvt. Ltd. It is a supplier of missile components and sub-assemblies. Some of important supplies are fuse DA5A, fuse 161, components for illuminating bombs, strike mechanism assembly, smoke missiles etc. From all the components, the DA5A fuse is selected to elaborate the concept of lean manufacturing. It works upon rotational speed to compress the spring and is used to initiate ignition of any small to large quantity of explosive. It consists of following sub-assemblies as mentioned below in table:
After adapting to the cellular manufacturing, the work schedule has been based on just in time production system and all the components were made as per daily schedule which led to no more than 1-day storage of inventories. The result is that the total value added activities have been increased by eliminating the Machine downtime or ideal waiting time. Each machine is working in cell of operations which will prevent the time wastage in Processing. Also, by implication of cell layout the operator has to no longer walk on the shop floor to collect the material from the inventory and then place on the station to process it from downstream to upstream, so this will prevent major time loss in handling the material and increase the total output to achieve the manufacturing target of 12000 pieces/month right on time.
At Future state, the modified data is collected to check improvement by adapting cellular layout:
Total processing time including loading and unloading = 1697s
Total material handling time = 137s
Total slack time = 240s
Total excess time = 377s per part
Total time required to manufacture one part of lower body = 2074s = 34min 56s
Conclusion: In this case study the cellular manufacturing methodology is used to improve the present layout of the machines and their operation. In past condition there is only one operation happening at one machines and then all the parts are going to stay at the inventory before the next operator starts working on them. This led to increase in slack time and also the processing time of operation on components. The setup of machines is arranged and number of stations were reduced by combining similar operation because of which all the components started flowing in sequence and there is just in time production unlike keeping components in inventory. The upgradation helped to improve the value added activities by reducing machine ideal time, slack time and other nonvalue adding activities. The material handling time is very important in CM and it can affect the performance on major scale. So, material handling time is reduced by using singular flow in line and reducing the worker movement. CM provides the solution to this problem by using conveyer or chain flow which moves the component continuously from one operator to another restricting their movement to single spot. There is always scope for improvement by Lean principles. Further by using this technique we can run the line at full efficiency by balancing the work load on each machine. This will give the maximum output from the cellular manufacturing.
If I was the project lead I would have done more deep study for the operation applied on lower body of DA5A fuse because as we know Lean is continuous improvement methodology and I still see that we can combine machine operation number 12 and 22, this will help to do reaming and final reaming to remove dust on the same machine. Also operation number 6 which is making small flat hole and 13 which is simple drilling to make small flat hole larger can be performed together on the drill machine number 3, this will help us to eliminate two machine operators. The manual operation number 20 and 23 to remove burr can be united altogether by skipping this operation at 20 and both these burr can be removed by operator at operation 23. This will help us to reduce the total number of operations on lower body to 21 which were earlier used to be 25.
Material Handling time Before/ After
Drill 8 + Drill 16
26s / 1s
Drill 3 + Drill 9
2s / 1s
Manual burr removal
Also, my approach to project will based upon proper organization of machines in workplace by using the kaizen principle like 5S. It deals with keeping our work place clean and organized. It is basic key tool to maintain safer environment and sustain the continuous improvement by maintaining product quality.
· My rule of thumb will be to first sort all the machining operations like drilling, reaming, grinding or other manual operations in a cell according to processing time by keeping in mind the line balancing Technique so that each of machine is working at equal pace and also it will help to minimize the stations by performing all similar operations at single station and then pass it to upstream for next operation.
· Then I will set all the machines on the shop floor space in 5 meters of radius which will restrict the worker movement and material handling time.
· I will also make a check list for regular maintenance and cleaning of each machine so that there will less chances of breakdown of machine which will prevent our non-value adding loses.
· After that I will create a standardized check sheet to keep all the processes working at same good pace and also maintain the safe work environment.
· Finally based upon 5S principle the most important part is to sustain the improvement, I will create a team to maintain all the records and regular checks after proper duration of time and analyze the process by timeline method or by using graphs.