Autonomous maintenance

All three cycles of the TPM improvement plan (see Figure 4.1) involve the principle of autonomous maintenance, or operator asset care. In the Japanese TPM approach, there are seven steps of autonomous maintenance (see Figure 4.7). These are given below together with the necessary linkages to the three-cycle, nine-step TPM improvement plan.

Step 1 Initial cleaning

This starts with the 5 Ss mentioned in Chapter 1. The cleaning of machines and production plant gives operators an insight, which they never had before, into the condition of their machines. They can therefore use their eyes, ears, nose, mouth and hands to help their maintenance colleagues as an 'early warning system'. By working together as a team they can ensure effective asset care and release maintenance people for tasks requiring a higher level of training and skill. The full implications of the cleaning regime cannot be over-emphasized because ultimately it leads to the reform of the whole production process. To understand this clearly it pays us to look again at the Japanese 5 Ss and the 'localized' CAN DO approach, and the way in which their application leads to fundamental changes in the workplace.

The Japanese 5 Ss emphasize the concept of keeping things in the workplace under control.

Seiri (organization)

This is the practice of dividing needed and unneeded items at the job site and quickly removing the unneeded ones. It also means integrating material flow with the best known operational methods.

To better understand the meaning of unneeded items, these can be divided into three different categories:

• Defective products

• Not useful items

• Not urgent objects, right now

There are six recommended categories in seiri with their own targets for improvement:

• Stock, inventory

• Containers, pallets

• Conveyors, trucks, forklifts

Seiton (orderliness)

This means orderly storage, putting things in the right place. Those things can then easily be found, taken out and used again when they are needed. It doesn't simply mean lining things up neatly; it means there is a place for everything, and everything should be in its place! The locations of equipment, tooling and materials are clearly defined, displayed and maintained.

Seiso (cleaning)

This refers to cleaning the workplace regularly, to make work easier and to maintain a safe workplace.

Seiketsu (cleanliness)

This means being aware of the need for maintaining a clean workplace, not just through cleaning programmes but through ensuring that spillage of liquids and dropping of materials, packaging, etc. is avoided.

Shitsuke (discipline)

This means to formalize and practise the above items continuously each day as you work, to have the discipline to always work to these principles.

In WCS International we have developed an eleven-step plant-wide clear and clean exercise for our clients as a start point to put the philosophy of 5S or CAN DO into practice. This is often implemented shortly after initial TPM pilot equipment projects have been launched, in order to get everyone involved at an early stage. It is not used as a forerunner of TPM, as is the usual case with the Japanese approach. The Japanese seem quite prepared to spend six to twelve months cleaning up a plant. In the Western world we do not quite have the same level of patience, and we need to experience early live equipment examples called pilots in order to illustrate, prove and believe in the TPM process.

The initial plant clear and clean process is described as follows:

Clear out

1 Zone the plant into clear geographical areas with clear management responsibility. (See the plant plan for your shift's responsibility area.)

2 Carry out a first-cut physical run for items that can be immediately thrown away today because it is obvious they are not needed.

3 Carry out a second red-tag/red-label/red-sticker run, which needs to be more structured and thoughtful.

4 It is obvious that if you are to get rid of a great many items, you will need a great many waste disposal containers (say six strategically placed skips). Some items will be wanted but are in the wrong place: 'There must be a place for everything, and everything must be in its right place.'

5 For things to be in the right place'we need to paint clear gangways and clear markings on the floor for anything mobile (i.e. sillages, raw material, work in progress, etc.). Correct racking, shadow boards, labelling and other visual storage aids will form an important part of this stage.

6 Keep the workplace organization under a permanent microscope.

Clean up

7 Do the obvious sweeping and vacuuming of the work area.

8 Inspect and clean every square centimetre of the equipment. Remember: every square centimetre.

9 Identify the points of accelerated deterioration. Where are the leakages and spillages occurring, and why? Ask 'why?' five times.

10 Get to the root causes of dust, dirt and scattering and eliminate those reasons. We will achieve a dust-free plant if - and only if - we achieve this step. All the previous nine steps are useless unless step 10 is achieved.

11 Revisit steps 1 to 10 and continuously improve.

Step 2 Countermeasures at the source of the problems

Cleaning, checking, oiling, tightening and alignment of equipment on a daily basis enable operators to detect abnormalities as soon as they appear. From then on, operators learn to detect problems and to understand the principles and procedures of equipment improvement. To set this in perspective, we can list some examples of situations where the operators have not been trained to be equipment-conscious:

• dirty or neglected equipment

• disconnected hoses

• missing nuts and bolts, producing visible instability

• steam leaks and air leaks

• air filter drains in need of cleaning

• jammed valves

• hydraulic fluid and lubricating oil leaks

• measuring instruments too dirty to read

• abnormal noises in pumps and compressors

These are glaring examples of a failure to maintain the most basic equipment conditions, but we are deluding ourselves if we believe such situations never arise - they do! Even brand new equipment, if neglected, will rapidly deteriorate (i.e. after just a few days) and its performance and output will drop as a consequence.

Use of visual management techniques

When the equipment has been cleaned and the weaknesses have been found and corrected, the next phase of the TPM process is to draw attention to the

Objective

Objective

Figure 4.6 Improvements right way of doing things by clear visual aids. This is error-proofing: to make it easy to do things right and difficult to do things wrong (Figure 4.6). Some examples of visual marking to encourage ease of inspection, discipline, order

• Where sight glasses are used, make sure that they are clean and that the high and low points are boldly marked and colour coded so that they

• Mark gauges green for 'go' and red for 'no go'.

• Use small windmills to indicate extraction fans and motors working.

• Indicate the correct level on oil bottles as a maximum and a minimum. An elastic band on the bottle will show the level at the previous check,

• Use line indicators on bolts and nuts to show position relative to their

• Provide inspection windows for critical moving parts.

• Colour tag clearly those valves which are open and those which are

• Highlight critical areas which must be kept scrupulously clean.

• Identify covers which are removable by colour coding them.

• When there is an agreed inspection routine, number in sequence those

• Prepare quality colour photographs of equipment standards and ensure

• Make up shadow boards for tools and spares so that the correct location

• Indicate the correct operation of machines by instructions and labels which are visible on the machine, kept clean and accessible.

• Display charts and graphs adjacent to the equipment to show standards

Having completed the first two steps towards autonomous maintenance, operators will have learned to detect problems and to understand the principles and procedures of equipment improvement. They can now take the next

Step 3 Cleaning and lubrication standards

Much will have been learned from the initial cleaning, orderliness and discipline procedures, and it will now be possible to set standards for the ongoing care of plant and machines. This will lead logically towards the next step.

Helped by other members of the team, operators can be guided towards the point where they can carry out general inspection themselves. They will then have reached the stage where they know the function and structure of the equipment and have acquired the self-confidence to make a much more significant contribution towards the goal of more reliable machines and better

Step 5 Autonomous inspection

As the term implies, operators can now carry out self-directed inspection

Step 6 Organization and tidiness

Initial cleaning and the application of the 5S/CAN DO philosophy will by now have worked through and started to have major effects. In parallel with this, operators will have reached the stage where they can take responsibility for performing autonomous inspection - always within the limits of their skills, experience and training and always backed, where necessary, by their maintenance colleagues. They will have developed an understanding of the relationship between equipment accuracy and product quality. This leads to

Step 7 Full autonomous maintenance

At this stage, operators will be equipped to maintain their own equipment. This will include cleaning, checking, lubricating, attending to fixtures and precision checking on a daily basis. They are now equipped to apply their newly developed skills and knowledge to the vital task of continuous

The key point of emphasis in developing these asset care routines is empowerment. The operators' and maintainers' own ideas are encouraged and adopted on the basis that 'If it is my idea and it is embodied in the way in which we operate and look after our equipment, then I will stick with it!' On the other hand, 'If it is imposed from above, then I might tick a few check boxes, but I won't actually do anything!' The progress from cleaning to full autonomous maintenance is illustrated in Figure 4.7.

The condition cycle of the TPM improvement plan (Figure 3.19) moves

Full autonomous maintenance

Knows the relationship between equipment accuracy and product quality

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