Productivity improvement through Total Productive Maintenance (TPM): Part II of III

Productivity improvement through Total Productive Maintenance (TPM): Part II of III

Goals of TPM®

TPM has the goal of improving productivity and reducing cost.TPM will improve yield, capacity, flexibility, quality and contribute to the safety of the work environment.

Why TPM®?

Fundamental concept of the plant efficiency

16 Losses


Availability Losses (5)

1) Break Down Loss(failure losses).

Losses due to failures. Types of failures include sporadic function stopping failures and function-reduction

failures in which the function of the equipment drops below normal levels like replacement of parts or repair, cases requiring 5 minutes or more for repair.

Target is zero failures.

To attain zero failure ,it is necessary to correct the misconception

about breakdown maintenance that failures are unavoidable.

2) Planned Maintenance Time Loss (shut down losses)

Times when equipment is shutdown for maintenance. However shutdown-related work greatly affects the operating time rate of equipment .shutdown related work must be regarded as a loss and reduction of shutdown work time must be sought.

3) Setup Loss

e.g. Change of Dies, machining fixtures etc.

Setup and adjustments losses refers to time losses from the end of the production of a previous items through product-change adjustment to the point where the production of the new items ic=s completely satisfactory. SMED must. Adjustments how to reduce, eliminate? One shot adjustment or trail or error till 3-4 components are tried.

4) Tool Change Loss/cutting blade losses

e.g. Change of Drill, tap, reamer, cutter etc.

Stoppage losses caused by changing the cutting blade due to breakage or caused by changing the cutting blade when the service life of the grinding stone ,cutter or bite has been reached.

What is your tool change losses ? 5 or > 10%.

Normally a fix number or time is set but if the tool breaks before that –it leads to change ,adjustment and a new sort over all again .

5) Start Up Loss

e.g.. Furnace , Paint Shop Oven etc.

Start up losses are defined as time losses from :

  1. Start –up after periodic repair.
  2. Start- up after suspension (long time stoppage).
  3. Start up after holidays,
  4. Start up after lunch breaks.

When starting production, the losses that arise until equipment starts up, running  in and production processing conditions stabilize.

Does your machines have ‘Monday Disease’.

Losses of Performance (2)

6) Minor Stoppage Loss

i.e. Frequent stoppages for short time from seconds to less then 5 minutes for recovery.

e.g. Component stuck to die while stamping etc.

Losses that occurs when the equipment temporarily stops or idles due to sensor actuation or jamming of the work, chute clogging. The equipment will operate normally through simples measures (removal of the work and resetting).

The definition of these losses is as follows

1. Losses that are accompanied by temporary functional stoppage.
2. Losses allowing functional recovery through simples measures (removal of abnormal work pieces and resetting.)
3. Losses that do not require parts exchange or repair.

To reduce minor stoppages ,it is important to adequately analyse the phenomena Involved and thoroughly eliminate minor defects. The target number of minor defects is zero.

7) Reduced Speed Loss

e.g. 50 parts produced against standard of 53 parts as a cycle time increased to 9 min. from 8.5 due to less speed/feed.

These are losses that occur because the equipment speed is slow. They can be defined as follows;

Losses due to a diff between the design speed (or standard speed for the item concerned ) and the actual speed.

Losses caused when the design speed is lower then present technological standards or the desirable condition.

If the design speed is 60 seconds and actual cycle time is 65 seconds then the loss is 5 seconds.

The target is to reduce the difference between design speed and actual speed to zero


Loss due to Quality (1)

8) Defects & Rework

i.e. any reworked or rejected product shows direct time loss due to poor Quality.

Sporadic defects are easily fixed , so they are rarely left uncorrected .chronic defects ,in contrast , are often left as they are, because their causes are difficult to perceive and measures to correct them are seldom effective

To realize zero defects, it is necessary to radically review defective phenomena.


Losses Impeding Human Efficiency (5)

09) Management Losses

e.g. Raw Material/Person not available esp. poor planning.

Waiting losses that are caused by management, such as waiting for material, waiting for a dolly, waiting for tools, waiting for instructions, waiting for repairs of breakdowns, etc.

10) Operating Motion Loss (OML)

e.g. Excess motions like walking, bending, stretching etc.

These include motion losses due to violation of motion economy ,losses that occur as a result of skill differences, and walking losses attributable to an inefficient layout.

11) Adjustment & Measurement Loss

e.g. Frequent tool adjustment after few components.

Work losses from frequent measurement and adjustment in order to prevent the occurrence and outflow of quality defects.

12) Line Organization Loss (LOL)

e.g. 75 % Manpower utilization due to poor line balancing.

These are waiting time losses involving multi-process and multi stand operators and line-balance losses in conveyor work.

13) Logistics Loss/distribution losses/losses resulting from failure to automate.

e.g. Operator Travels/waits for want of material on stage.

Distribution man hour losses due to transport of materials, products(processed products) and dollies.

These are also personnel losses resulting from non replacement with automated systems, although such replacement could be done. They include for instance cases in which automated loading and unloading leading to manpower reduction is not implemented, although it could be done.

Losses of Costs (3) –Three major losses that can impede effective use of production resources.

14) Yield Loss

e.g. Excess material stock/weight, Excessive splashes etc..Material losses due to differences in the weght of the input materials and the weight of the quality products.

Increasing casting wall thickness to avoid blow holes leading to more machining time and loss of material.


15) Energy Loss

e.g. Losses due to heat radiation, leakage of fuel, air, oil ,losses due to ineffective utilization of input energy (electric ,gas, fuel oil, steam, air and water etc) in processing.etc.

Because of electricity ,fuel, utility costs represents a high percentage of the total cost, all companies are striving to reduce them.

16) Die/Tool loss

e.g. loss of tool due to regrinding, Poor life of molds etc, Repairs of Dies/Tools, FOS consumables.

These are monetary losses resulting from the mfg and repair of dies, jigs and tools necessary for the production of products.

Mfg new moulds, replacement at the end of service life, breakdown, repair is expensive.

To reduce mfg costs it is absolutely necessary to extend MTBF of mould repair, to prevent product breakage and to extend the service life of replacement parts.all companies are striving to reduce them.

Keep watching this space to read Part III & Part III of this subject.

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