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Low-cost automation - An insight

Competitiveness, primarily with high productivity and quality at low cost, is a major manufacturing need, which can be fulfilled by low-cost automation

The current financial crisis faced all over the world has posed tremendous challenges on the manufacturing organisations. Even at low volumes, and large variety, they have to be competitive with minimum investment. Low-cost automation can play an important role in this situation

H uge corporations with tremendous financial strength, technical leadership and multinational market can achieve quality even in severe competition. But organisations in developing countries with constraints on all the above, i.e. finance, technical leadership and limited market and very low labour productivity have to achieve productivity and quality through strategies workable under such conditions. There are many methods available to increase competitiveness.

Prof N Ramakrishnan Mechanical Engineering DepartmentIIT-Mumbairamkrish@me.iitb.ac.in
Figure 1: Methodology for LCHA
Figure 2: LCHA Development cycle
Figure 3: Mechanical system
LCHA is a very effective, competitive and cost effective tool for the manufacturing industries
Figure 4: Hydraulic system
Figure 5: Pneumatic system
Figure 6: Electric system

One of the very practical, safe, economical, rewarding methods is the application of low-cost automation (LCA) pursued in Japan with a lot of enthusiasm from around 1960s. In India also LCA has been found to be useful for small enterprises employing a few people to huge manufacturing organisations employing thousands of people. Big organisations like L&T, Siemens, Mahindra & Mahindra, Bajaj Auto, etc, made a separate cell involved in in-house development of LCA. However, these devices were useful only to replace the muscular effort of the labour.Developments in microelectronics started during 1970s and have added considerable power to LCA. Electronic sensing, data acquisition, data processing and sophisticated controllers have given an excellent combination of hi-technology at low cost. This adds considerable intelligence into the automation system. The author coined the terminology ‘Low cost Hi-tech automation’ (LCHA) in 1994 to highlight the significance of the combination.

Low-cost automation

LCA is a technology that creates some degree of automation around the existing equipment, tools, methods, people, etc, using mostly standard components available in the market with low investment so that the payback period is short (a few weeks to less than a year).

Low-cost high-tech automation

Low-cost automation coupled with sensors, microcontrollers and data storage/processing facility with considerable capability enhancement is LCHA.

Listing advantages

The following advantages have made LCHA very popular.

Financial constraint does not hinder LCHA. Capital equipment is very expensive and has long payback period. On the other hand, it is built around existing resources. Hence the investments required are lower and payback period is short. Going in a progressive way, the same money can be used again and again when the payback period is shorterLabour productivity can be increased. This will reduce the percentage of labour cost in the total costSmaller batch size also becomes viable for LCHA. Expensive automation will need sufficiently large batch size to be cost-effectiveRising raw materials cost necessitates better utilisation of the material, less W.I.P. and less rejection. LCHA can help in these as below:In-house development: since the people involved in the activity are encouraged to participate in the development, the people develop skill to maintain, and even repair them. This reduces the break-down cost and timeRisk is less: One goes step-by-step approach. Hence the risk due to heavy investment or selection of wrong technology, etc, is minimised

Of limitations

However, LCHA has also some limitations.

Development takes time: When you buy a ready-made automatic machine, time involved in developing, troubleshooting, modification, etc, is avoided. LCHA, being custom built and generally in-house, takes more timeLearning time: Technology like CNC needs very little time for changing from one drawing to another, since the skill is inbuilt into the programme. LCHA uses manual participation and hence will take some time to learn whenever change is incorporated.

It is needless to add that the advantages far outweigh the limitations. In Japan and what are called Asian Tigers, this has been widely used because this is the most attractive proposition for small entrepreneurs.

Fields of application

It is very interesting to state that any manufacturing activity is a potential candidate for LCHA. To clarify this point further:

All activities related to discrete manufacturing: Irrespective of the product, all activities like loadings feeding, clamping, machinery welding, forming, gauging, assembly, packing, etcProcess industries: Chemicals, oils, powders, pharmaceuticals, etcMining: very useful for mining operationsManufacture of explosives: volatile products like LPG, etc

The advantage of pneumatics, which is widely used in LCHA (namely the fact that air is a very medium against fire), makes LCHA very attractive for the following:

Printing & Packing: LCHA widely usedAgriculture: tilling, sawing, pluckingStock breeding: Controlled mixing and distribution of food, collecting milk, eggs, cleaning the cages, etc, can be done with LCHAFood processing: this is a newly developing area with considerable growth potential

It is obvious from above that any area of productive activity has potential for application of LCHA.

Methodology for LCHA

Figure 1 shows the methodology used for LCHA, which is simple and self- explanatory.

What is important to note here is that stages 1 and 2 are very crucial for stage 3. Since many alternatives are possible, an in-depth study of the existing system and ability to visualise the modifications to make automation easier can make the implementation much easier. The third stage, conceptual development brings out the ingenuity of the designer of LCHA system in coming out with an elegant solution. During these three stages, good interaction between the people working in the areas chosen for LCHA and the designer of the LCHA system is essential. With more than twenty-five years in these areas, I can confidently say that the success or failure of LCHA, during implementation, is highly influenced by the thoroughness of preparation during these three stages. The experience of the LCHA expert in conceptualising a viable solution using appropriate technologies, considering the economic viability and easiness of maintenance right at this state is the most important requirement for successful implementation. The well-known techniques in industrial engineering, like work sampling, pre-determined motion and time studies (PMTS), developing a better method (DBM) coupled with the principles of ‘design for automation’, and the comparative evaluation of available techniques for LCHA will be very useful in implementation.

System synthesis & development

Figure 2 shows how the designer should proceed in a systematic manner for developing LCHA systems. A variety of systems (mechanical, hydraulic, pneumatic, electrical and electronics) are available. Since each system has its own advantages and limitations, one can build up a simple LCHA device using one of them based on technical evaluation. However, in most of the practical applications, hybrid systems are used where the advantages of different devices are made use for minimising the effect of the disadvantages.

Mechatronics

Mechatronics is a synergetic integration of precision mechanical control system with microelectronics, computers and information technology. When LCA is upgraded with mechatronics it becomes LCHA. This enhances the system capability many times with little additional investment. The advantages of adding mechatronics in LCHA are:

Using low-cost highly reliable sensors critical parameters of the system can be continuously monitoredUsing microcontrollers very sophisticated control programs can be incorporatedUsing parallel subunits reliability can be enhancedUsing communication ports and information technology different subunits can communicate with each other and enhance the advantages of integrationSystems can be made capable to communicate with other systems to improve system performanceSystem can generate data regularity and store the result so that performance history is easily available

LCHA and India

India has a tremendous advantage over the developed countries. To begin with:

LCHA is custom-built. Design and development cost cannot be recovered by large volume production. Compared to the developed nations, the cost of engineering personnel is significantly lower than developed countries. Hence, in India we can make it much cheaper than many other nationsCustom-built automation with LCHA can take care of the production volume consideration. This can avoid under automation or over automationMicro electronics and sensors add reliability, quality and appropriate intelligence to the machine. Hence the cost to benefit ratio will be very high.

It can be reasonably stated that a sophisticated automatic system can be developed within 25 to 35 per cent of the cost incurred in developed nations. There is no doubt that India will be a major power in global manufacturing. LCHA is a very effective, competitive and cost-effective tool for the manufacturing industries irrespective of what product they make and the production volume.

Review of technologies

A look at the review of the technologies:

Mechanical systems

Mechanical systems are very beneficial for appropriate conditions. Figure 3 shows a fully mechanical system, operated by cams. These mechanical systems have the limitation of being useful for mass production of identical components.

Hydraulic systems

They use pressurised oil for operation. Hydraulic pumps, valves, actuators and auxiliary elements like accumulators, intensifiers, etc, are used to develop hydraulic systems. Figure 4 shows an example of hydraulic system.The major advantage of hydraulic systems is their high power density. This makes them very compact in heavy load applications controlling speed force torque, etc.

Pneumatic systems

When the loads are low and speeds are high, in generally light industries, pneumatics is an attractive solution. Most of the medium and big industries provide compressed air as a service in their plants. A large variety of components (valves, cylinders, motors, etc) are available in the market. High speed manufacturing operations (filling, packing, printing, small sub unit assemblies, etc) use pneumatic units very extensively. Figure 5 shows an example of a pneumatic circuit.

Electric systems

The electric drives and control technology has seen tremendous growth in the last few decades. Variable speed AC motors, AC or DC servo motors, stepper motors, linear motors, etc, are available today in different sizes, power levels and capabilities.

Earlier, the concept was to use minimum number of motors and mechanical systems (gearboxes, mechanisms, indexing devices, chain drives, belts, etc) for multiple components. The current trend is to use a large number of motors for operating individual elements and minimising mechanical subsystems. This will add to flexibility, compactness, weight reduction, more reliability and less maintenance. Figure 6 shows an electric system.

Hybrid Systems

If we combine the individual advantages of the above mentioned types of systems in an appropriate way, we can get a hybrid system which will be the best custom-built solution to a set of specific requirements.

In conclusion

When the manufacturing industry in India was excited about the economic boom and the expansion of almost all manufacturing units to meet the increasing demand, it appeared that we are ready to be a global manufacturing hub.

The worldwide recession, slump in demand for products and the precarious condition of the automobile industry have created a sense of confusion, gloom and uncertainty. The author feels understanding and application of LCHA will be one of the strategies that may help us. This recession period can be a good time to get into it.

The author wishes to acknowledge the assistance provided by his graduate student, Abraham Palaty for the preparation of this article.

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