Today we discuss about Total productive maintenance(TPM) as a waste elimination tool.
TPM defined as TPM (Total Productive Maintenance) is a maintenance philosophy designed to integrate equipment maintenance into the manufacturing process.
The goal of any TPM program is to eliminate losses tied to equipment maintenance or, in other words, keep equipment producing only good product, as fast as possible with no unplanned downtime. The unique feature of TPM is Autonomous Maintenance.
Autonomous Maintenance defined as Machine adjustments made by their operators who are deemed to have unique knowledge about the machines. It is a principal component of total productivity maintenance (TPM).
In TPM mainly focus 16 losses and eliminate from the process.16 losses’ are:
A Seven major losses that impede overall equipment efficiency
1 Failure losses (Breakdown)
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
2 Set up and adjustment losses
Stoppage losses that accompany set-up changeovers
3 Cutting blade change losses
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.
4 Start-up losses
When starting production, the losses that arise until equipment start-up, running-in and production processing conditions stabilize.
5 Minor stoppage and idling losses
Losses that occur when the equipment temporarily stops or idles due to sensor actuation or jamming of the work. The equipment will operate normally through simple measures (removal of the work and resetting).
6 Speed losses
Losses due to actual operating speed falling below the designed speed of the equipment.
7 Defect & rework loss
Losses due to defects & reworking.
Losses that impede equipment loading time
8 Shutdown (SD) losses
Losses that arise from planned equipment stoppages at the production planning level in order to perform periodic inspection and statutory inspection.
Five Major losses that impede workers efficiency
9 Management losses
Waiting losses that are caused by management, such as waiting for materials, waiting for a dolly, waiting for tools, waiting for instructions etc.
10 Motion losses
Man-hour losses arising from differences in skills involved in etc.
11 Line organization losses
Idle time losses when waiting for multiple processes or multiple platforms.
12 Distribution losses
Distribution man-hour losses due to transport of materials, products (processed products) and dollies.
13 Measurement and adjustment losses
Work losses from frequent measurement and adjustment in order to prevent the occurrence and outflow of quality defects.
Three major losses that impede efficient use of production subsidiary resources
14 Energy losses
Losses due to ineffective utilization of input energy (electric, gas, fuel oil, etc) in processing.
15 Die, jig and tool losses
Financial losses (expenses incurred in production, regarding renitriding, etc.) which occur with production or repairs of dies, jigs and tolls due to aging beyond services life or breakage.
16 Yield losses
Material losses due to differences in the weight of the input materials and the weight of the quality products.
We have discussed many lean tools in our lean tools series. This post by our guest consultant is about the lean tools in apparel industry. Read On…
“Eight Lean Tools” defined as waste elimination tools. With lean manufacturing we mainly focus on waste. Waste defined as “Anything that adds Cost to the product without adding Value”.
Total productive Maintenance:
“The Combination of Best features between Productive & Predictive Maintenance by innovative Management strategies With total employee Involvement.”
“Through sort, set, shine, standardize and sustain create better workplace organization”.
“The use of controls that enable an individual to immediately recognize the standard and any deviation from it”.
Standardized Work Process:
“It is the current agreed upon best method to complete the work in a process.”
“Team-based improvement activity that significantly reduces setup and changeover time.”
“A signal, usually a card, used to signal the movement or production of materials.”
“The prevention of making errors, which would result in defects and lost time.”
“Using the systematic problem solving tool to sort out problem.”
“Through balance workload among work station creates Continues flow.”
We will discuss each of these tools in detail in the future posts.
Six sigma is the strategy concerned with reducing the amount of variation concerned with completing a process on a repeated basis, so that the overall product can function at a level that is acceptable to the customer. It is also the practice of constant improvement by identifying defects that can be brought under control in order to improve the functionality of the end product. While it may seem like six sigma is a highly technical skill, in reality it is used in many different sectors. It is not uncommon to see six sigma practices implemented into marketing, sales, and customer support organizations as well.
Initially created and implemented by Motorola, most companies have implemented some sort of version of a six sigma program in most of their departments. There are some companies that even require all personnel to be trained in six sigma implementations and policies. It uses statistical methods integrated with quality and lean processes to measure the possible and recognized improvement in the process. If implemented properly, entire teams and sub organizational structures (i.e. black belts, green belts, etc) are implemented to guide personnel in the proper conduct of the six sigma process and bringing the culture to the workplace successfully.
The idea behind six sigma is revealed in the name of the process… through identification of sources of variation and cost, teams are formed to find what the sources are, and then the variation is measured and plotted. It is then analyzed to see if there are other, uncontrollable aspects of the data that may be effecting the way that the parameter is measured.
All of these are taken into consideration, and then the corrective action that is supposed to bring the process to within six sigma of the target value is implemented, or in other words, the process is improved. Over time, the process is conducted with the corrective action in place, and the parameter, once again, is measured.
This measurement is plotted, just as it was prior to the corrective action implementation, and the corrective action is analyzed for its effectiveness. The team then discusses what actions can be implemented to ensure the quality improvements are maintained and the progress is not lost by a lack of control over the corrective action.
The beauty of six sigma is that it can be used in any application, in any business, at any time. As stated before, there are plenty of documented case studies that show how six sigma can be effectively used inside of everything from sales and marketing to very complex manufacturing procedures. With the proper training and teams in place, the sky is the limit with regards to the amount of improvement an organization can realize by implementing the six sigma infrastructure.
As can be seen in Figure (1), there are five basic steps to completing a six sigma project. The first is “Define”, in which the parameter in that will be the focus of the project is identified. Additionally, the impact to the bottom line of the business is discussed and the potential savings is measured. It is at this point in which the company will decide whether or not to pursue further action in the improvement of the parameter, and whether the time and funding spent toward the improvement will pay off in the end.
Next, the parameter is measured in the “Measure” phase. Statistic relevance is taken into consideration as well as other sources of variation such as gage error. It is determined how well the actual parameter can be brought under control by measuring it with respect to the sigma value of a normally distributed curve.
Take, for example, a process that has 1000 opportunities for a defect. Of these opportunities, 2 defects emerge. This obviously means the process has .002 DPO, or defects per opportunity. From that, we can figure out what our DPMO, or defects per million opportunities. To do this, we simply multiply the DPO x 1 million. Our process has a level of 2,000 DPMO. This means that for every million pieces of this product we produce, 2,000 of them will be defective.
From the DPMO and our DPMO/σ table, we find that our σ value is 4.37. By looking at Figure (2), you can interpret this to mean that you will have a 99.73% chance of having between 1,987 (-3σ) and 2,014 (+3 σ) defects for every 1,000,000 parts produced.
Once this is completed, the team comes together and analyzes the data in the “Analyze” phase. If the previous two phases were correctly conducted, it will show where the greatest room for improvement exists, and the corrective actions are identified with the estimated improvement calculated.
Improvement is measured after the corrective action is implemented in the “Improve” phase. This phase is almost identical to the “Measure” phase, but more strong influence is placed on the corrective action’s impact on the final parameter variations.
Finally, the last stage is “Control”, in which the corrective action is either modified or changed such that a long term realization of improvement is shown. Many times the corrective action is temporary in nature and must be modified to be able to sustain the improvement.
While anyone can be taught to brainstorm and start six sigma projects, it should be noted that without a focused and well trained team, there is a very large possibility for failure inside of the six sigma project. It is recommended that a dedicated team be placed in charge of every project and assist the champion in making the project run smoothly.
Six sigma has been proven to set companies apart from each other with its effectiveness. It is practiced in almost every major corporation and almost always results in a better, leaner, and more proficient company.
Avoiding this is a very important job of all people who work in a company, primarily a lean expert, or someone who works on the quality team. There are many ways in which the quality team can approach the problem, and the 5 why technique is one of them. It is designed to help get to the real root cause of a problem, so the cause can be addressed through a short term or long term corrective action. The corrective action, then, can be tracked for its effectiveness.
The 5 why system is one in which the simple question “why?” is asked at 5 different levels of a problem to get to the bottom of the situation. It was first used in the early 1970’s by the Toyota Company, who is often credited with being the pioneer of modern quality.
If used correctly, it can provide a way to help identify the true root cause of the problem by using a feedback system. An added benefit is that it can be used both on an individual basis as well as a part of a group attack. It can, and should, also be integrated into the Kaizen, lean, and Six Sigma methods.
It can also be used in conjunction with other tools, such as root cause analysis software and fishbone diagrams to help aid in the discovery of the true root cause and identifying the cause and effect associated with it. While some other root cause analysis tools are complex and require experts to run them, even a two year old knows how to ask the question “why”, so the much more simplified approach is easy to adopt to the level of each individual worker.
Of course, it may seem like the five why method is too good to be true: a simple, effective way to approach complex technical issues that anyone can apply? This is the exact argument that most “five why” critics have used against the system: it is not as effective as thought.
The biggest argument is that, while it is purported to get to the foundation of the problem, in reality, most people stop at the surface level symptomatic issues that appear to be plaguing them on a daily basis. By asking the question “why?”, most will simply come up with another symptom instead of working their way back to the root cause. They will then fix the additional symptom, proclaiming to have found and corrected the root cause, when in fact the problem they were trying to solve never actually is fixed.
Another pitfall that the critics of this system claim detracts from its effectiveness is the tendency for personnel to stop at their level of knowledge or comfort, instead of digging deeper and thoroughly investigating the limits of their technical knowledge. It is too easy for the “five why” method to reward and promote the “quick fix” answer of simply satisfying the question “why”, instead of more thoroughly finding a technical answer.
Lastly, while simplicity is one of the merits of the system, it is also purported to be one of the downfalls. Because anybody can conduct the five why method, they actually do, and do not seek professional assistance in determining whether the “why” they submit is a true, actual “why” and not a surface level quick fix.
Of course, there can be more than one “why” to every reason, as demonstrated by Figure (1). The seal could leak because of improper installation of the seal, or possibly an inadequate seal design. Each one of those has their own “why” branches, which address the more subsurface issue causing the “why” before it.
As stated earlier, anyone can use this method. However, care and consideration should be taken to at least fully train the personnel who will be in charge of leading the five why inquisition, as it is very easy to scratch the surface of the challenge and never actually dig to the subsurface root causes.
The 5 why technique is a great tool when used in conjunction with other tools as an aide in finding the root cause of a problem. Like any other tool, it should be wielded by someone who understands how to thoroughly investigate problems and conduct a solid root cause analysis.