A Visual Control System for the Workplace - Assignment Example

(2) (a) (i) Why is 5S frequently referred to as "visual control" Visual control and 5S are the foundation of Lean Manufacturing System. Visual control uses visual and other sensory devices to guide everyday decisions such as "When to cross the street". Conceptually, visual control is not the same as 5S but the two ideas are closely linked and often used together. (ii) What are the 4 power levels of 5S devices Give an example of each power level. The 4 power levels of 5S devices are: Power Levels Examples 1 Passive Addresses 2 Assertive Alarms 3 Aggressive Shelf Width 4 Absolute Sensors (b) What are the five elements of the "5S system" Briefly describe each element, and describe what each of them can achieve. Five Elements of the 5S system: 1st Element: SORT It involves discarding all items that are not needed for current production or clerical operations. This is also known as "red-tagging". Examples of such items would be outdated machinery, defective parts and inventory, broken tools and so on. The main goal of sorting is organization and it helps in reducing the following problems: Overcrowded workplace Stored items that physically block communication amongst employees Wasted time Costly/unnecessary inventory Stagnant process flow 2nd Element: SET IN ORDER It involves arranging needed items in such a way that they are easy to use and label them so that it can be easily found and put away. Implementing set in order prevents waste of motion, searching, human energy, excess inventory, defective products and unsafe conditions. 3rd Element: SHINE This involves regular cleaning up to ensure that the workplace is brought back to proper order at the end of each day. This helps in creating a workplace where people enjoy working. Problems avoided by implementing shine are as follows: Poor morale/work efficiency due to filthy work environments Overlooked defects in dark, messy factories Injuries Insufficient machine check up maintenance 4th Element: STANDARDIZE It is the method used to maintain the first three S. Duties of sorting, setting in order and shining are ingrained into regular work routine. Standardize activities prevent: Return of old, undesirable conditions Piling of unnecessary items Disarray of tool storage sites 5th Element: SUSTAIN This allows an organization to sustain its 5S program by ensuring that 5S becomes part of the company culture. (c) Why is 5S usually one of the first improvement activities a company undertakes on the journey towards "World Class" 5S is the key to world class performance because it is all about creating a more effective workplace that is well organized, free of clutter, and organized so that it provides the following benefits: Improved quality with zero defects Decreased cost through reduced waste Improved delivery through less production delays and downtime Increased morale because of cleaner, healthier workplace Increased safety (3) (a) What, exactly, is meant by the term Single Minute Exchange of Dies (SMED) Single Minute Exchange of Dies (SMED) is the approach to reduce output and quality losses due to changeovers. The phrase "single minute" means that all changeovers and startups should take less than ten minutes. (b) Another popular name for SMED is QCO. What is meant by the term "QCO" Quick Changeover (QCO) eliminates or reduces non-value added activities in the setup and teardown processes of manufacturing, allowing companies to quickly and efficiently change from one product to another. (c) Describe a 4 step procedure that could help a process or company achieve QCO (1) In Preliminary Stage, internal and external setup is not differentiated. Internal setup can be performed only when machine is shut down and includes activities like fixing an attachment to machinery. External setup can be done while the machine is still running. It includes activities such as preparation and transfer of dies. (2) In Stage 1, internal and external setup is differentiated using techniques such as preparation of checklist, performance of function checks and improvement of transport of parts and tools. (3) In Stage 2, internal setup is converted to external setup. In order to find ways to convert, the true functions/purposes of each operation is looked into. The operating conditions are prepared in advance, essential functions are standardized and intermediate parts are used to ease in transition. (4) In Stage 3, all aspects of setup operations are streamlined. This is done by implementing parallel operations, using functional clamps, eliminating adjustments, and mechanization. (d) Give five examples (include simple diagrams) of some typical tooling arrangements used in the 4th step. (1) C-shaped washer method of clamping (2) U-slot method of clamping (3) Spring stops (4) Magnets, vacuum suction (5) Interlocking methods (Fitting and joining two parts together without use of a fastener) (4) (a) (i) List Ohno's classic 7 wastes and give an example of each of them. Ohno's 7 wastes are: Wastes Example 1 Transport Double handling 2 Inventory Excessive safety stock 3 Motion Walking between spaced work centers 4 Waiting Operators slower than line 5 Over Production Delivery too early 6 Over Processing Variation from the standard 7 Defects Rework (ii) Which of these is considered to be the most important and why Give two potential causes of this particular waste. Out of the 7 wastes, Over Production is the most important one because it is also the most serious waste of all. It was considered most serious waste by Ohno because it was the root of so many problems. Over production hinders smooth flow of goods and leads directly to excessive lead time, storage time and storage cost. Defects may not be detected early and also false pressures on work rate generated increase the risk of defects. Also overproduction leads to excessive work in queue/ work in process inventories, separating process and blocking communication. The potential causes of over production are: MRP push rather than Kanban pull Large batch sizes People generally like to look busy Poor way of utilizing people (b) (i) What is meant by the term "Pre-Control" Pre-control is a technique that helps operators control the process so that production of defective parts is avoided. (ii) Name 3 of the 4 key benefits claimed for the Pre-Control system Key benefits of pre-control system are: (1) Simplicity (2) Economy (3) Speed (iii) Describe the mechanics of running Pre-Control on a production process. In pre-control, a chart (as shown below) is prepared with the span between the specifications limits divided into colored bands. Individual items are taken from the process, measured and plotted on the charts. The initial process adjustment, and subsequent patterns are based on the pattern of points: Initial Adjustment (Qualification): 5 parts in a row are in the green OK to run 1 part in the yellow restart the count two consecutive parts in the yellow one part in the red adjust the process and restart the count Operation: take 2 consecutive parts from the process first part checked is green continue operation first part checked yellow check the second part second part green continue operation second part yellow or either part red stop and adjust the process (5)(a) What does each "S" in the 5S system stand for Give a brief summary of the meaning of each "S" The "S" in 5S stands for Sort, Set in order, Shine, Standardize and Sustain. 1st Element: SORT It involves discarding all items that are not needed for current production or clerical operations. This is also known as "red-tagging". Examples of such items would be outdated machinery, defective parts and inventory, broken tools and so on. The main goal of sorting is organization and it helps in reducing the following problems: Overcrowded workplace Stored items that physically block communication amongst employees Wasted time Costly/unnecessary inventory Stagnant process flow 2nd Element: SET IN ORDER It involves arranging needed items in such a way that they are easy to use and label them so that it can be easily found and put away. Implementing set in order prevents waste of motion, searching, human energy, excess inventory, defective products and unsafe conditions. 3rd Element: SHINE This involves regular cleaning up to ensure that the workplace is brought back to proper order at the end of each day. This helps in creating a workplace where people enjoy working. Problems avoided by implementing shine are as follows: Poor morale/work efficiency due to filthy work environments Overlooked defects in dark, messy factories Injuries Insufficient machine check up maintenance 4th Element: STANDARDIZE It is the method used to maintain the first three S. Duties of sorting, setting in order and shining are ingrained into regular work routine. Standardize activities prevent: Return of old, undesirable conditions Piling of unnecessary items Disarray of tool storage sites 5th Element: SUSTAIN This allows an organization to sustain its 5S program by ensuring that 5S becomes part of the company culture. (b) 5S is often referred to as "visual control." Explain why this is so. Visual control and 5S are the foundation of Lean Manufacturing System. Visual control uses visual and other sensory devices to guide everyday decisions such as "When to cross the street". Conceptually, visual control is not the same as 5S but the two ideas are closely linked and often used together. (c) There is a "hidden agenda" behind most companies' 5S implementations. What is this "hidden agenda" Hence explain why 5S is usually one of the first improvement activities a company undertakes. 5S is the key to world class performance because it is all about creating a more effective workplace that is well organized, free of clutter, and organized so that it provides the following benefits: Improved quality with zero defects Decreased cost through reduced waste Improved delivery through less production delays and downtime Increased morale because of cleaner, healthier workplace Increased safety (6) (a) What is meant by the term Quick Change Over (QCO) Quick Changeover (QCO) eliminates or reduces non-value added activities in the setup and teardown processes of manufacturing, allowing companies to quickly and efficiently change from one product to another. (b) Another popular name for QCO is Single Minute Exchange of Dies (SMED). Where did this term originate, and precisely what is meant by it The origin of SMED (Single-Minute Exchange of Die) dates back to 1950 when Shigeo Shingo of the JMA was asked to perform an efficiency improvement survey at Toyo Kogyo's Mazda plant in Hiroshima. During Shingo's study, he witnessed a die change on an 800-ton press. He observed several workers removing the old die and then searching around the press for something. Shingo asked one of the workers was what going on and he replied that "one of the mounting bolts for the new die was missing". The worker continued searching and after more than hour returned with what appeared to be the missing bolt. It ended up that the worker had borrowed the bolt from another die and that this problem had previously caused them problems when performing changeovers. From his analysis, Shingo found that the 800-ton press was utilized in the main operation for less than 3% of an entire day. He decided that a more organized system needed to be creating during changeover. The operation of organizing and preparing the bolts could be done while the machine was still running, an external operation. In addition to solving the bolt problem, the entire changeover procedure was improved by shifting as many aspects of the setup externally. This activity resulted in a 50% improvement in efficiency and reduction in the bottleneck. Seven years later Shingo made an advance in his SMED concept. Single Minute Exchange of Dies (SMED) is the approach to reduce output and quality losses due to changeovers. The phrase "single minute" means that all changeovers and startups should take less than ten minutes. (c) What is the normal 4 step procedure to help a process or company achieve QCO (1) In Preliminary Stage, internal and external setup is not differentiated. Internal setup can be performed only when machine is shut down and includes activities like fixing an attachment to machinery. External setup can be done while the machine is still running. It includes activities such as preparation and transfer of dies. (2) In Stage 1, internal and external setup is differentiated using techniques such as preparation of checklist, performance of function checks and improvement of transport of parts and tools. (3) In Stage 2, internal setup is converted to external setup. In order to find ways to convert, the true functions/purposes of each operation is looked into. The operating conditions are prepared in advance, essential functions are standardized and intermediate parts are used to ease in transition. (4) In Stage 3, all aspects of setup operations are streamlined. This is done by implementing parallel operations, using functional clamps, eliminating adjustments, and mechanization. (d) Give five examples (include simple diagrams) of some typical tooling arrangements used in the 4th step. (1) C-shaped washer method of clamping (2) U-slot method of clamping (3) Spring stops (4) Magnets, vacuum suction (5) Interlocking methods (Fitting and joining two parts together without use of a fastener) (7) (a) (i) List THREE definitions of Waste. (1) Waste is opposite to value. (2) Waste refers to products or services which require rectification or don't meet the customer's needs. (3) Production of items that no one wants is a waste. (ii) Define Value Added Activity. Any activity that changes the nature, shape or characteristics of the product, in line with customer requirements, is a value added activity. Examples are welding, assembly, polishing and so on. (iii) Give TWO examples of Non-Value Added Process Production Activity. Inspection Transportation (b) (i) List the 7 wastes 1) Transport 2) Inventory 3) Motion 4) Waiting 5) Over Production 6) Over Processing 7) Defects (ii) Describe the Waste of Excess Inventory and the problems it causes, giving TWO examples of this particular Waste. Excess inventory is a waste because: (1) It adds to the costs (2) Extra storage space is required (3) Extra resource to manage it is required (4) It hides shortages and defects (5) It increases risk of damage and deterioration Excess inventory waste is caused by: (1) Production schedule not level (2) Inaccurate forecasting of inventory requirement (3) Excessive downtime or setup (4) Push instead of pull (5) Large batching (6) Unreliable suppliers Excess inventory is a waste because it causes the following problems: (1) It increases leadtime (2) It ties up money that could be used to improve processes (3) It prevents rapid identification of problems (4) It separates process steps and reduces communication (5) Its true cost is much higher than the money tied up in it (6) Inventory hides problems by covering them up Examples of excess inventory: (1) So much inventory at workplace that double handling is needed (2) Excessive safety stock (iii) Give THREE examples of the Waste of Waiting. (1) Operators waiting (2) Operators slower than line (3) Late deliveries (c) Describe a method of Analyzing, Categorizing and Eliminating Waste in a Production Line. 5W Method: When analyzing background of a problem, the question "why" is being asked FIVE times. Has the problem arisen because of: machine, worker, material, measurement or method 5W method very quickly leads to discovery of the main reason and to a solution of the problem. Poke Yoke Method: It is an error-preventing strategy. The basic idea of this method is to design a process in such a way that it is impossible for errors to occur; and if they do occur, they are eliminated quickly. Error preventing devices in a process are designed in such a way that errors cannot be made. Devices can operate by detection and by using audible or light warnings. Andon: Andon is a semaphore above the production line. It shows the production process line status. Colors of the semaphore lights are the same as traffic lights used on streets. If a worker detects a small anomaly on the production process line, he lights the YELLOW LIGHT on the semaphore and thus asks for help. If the worker detects a larger anomaly, he lights the RED LIGHT and thus stops the production process on this particular line. GREEN LIGHT on the semaphore indicates that the production process on the line flows normally, without difficulties. And on allows the workers to assume responsibility for execution of production processes of the line. (d) What do you think would be the most successful tools for a Process Improvement team to use in a "full power" 5S implementation In other words, which tools for Sustain do you think would be the most successful and in what circumstances The following tools may be effectively used for Process Improvement: (1) Kaizen (2) Total Productive Maintenance (TPM) (3) Total Quality Management (TQM) (4) Just in time (JIT) (8) (a) What is meant by the acronym "PVR" and why is it an important Process Improvement Tool "PVR" stands for Process Variability Reduction. PVR is an approach to reduce variation in our production and transactional processes in a way that dramatically reduces the variation in our transactional outputs. PVR is an important Process Improvement Tool because it increases process stability, consistency and quality. b) What does DMAIC stand for DMAIC is an approach to reduce process variation through Six Sigma. It stands for: Define the problem or issue Measure the outcome Analyze what is driving or causing the problem Improve the process by acting on the information and confirming the outcome Control the new process to maintain the gain c) What is meant by the terms "Key Measures" and "Process Measures" Key Measures is metrics describing quality of the process output, as viewed by the customer. It tells us where we are versus where we should be. Key measures describe the process output. Process Measures is metrics describing the inputs, steps and/or components of the process. It helps us determine how to get where we should be. Process measures describe the process inputs and potential sources of variation. d) Name and describe 2 measures that can be used to describe each of the following: i) The position of a process: A. Average/Mean: Mathematically, Average or Mean = Sum of all data points / Number of data points Mean reflects all data values. But it is influenced by extreme values only. B. Median: It represents the center number after the data has been sorted in either ascending or descending order. Median is more robust than Mean is to outliers or extreme values. ii) The spread of a process: A. Range: It represents the distance between the maximum data value and the minimum data value. It uses only two data points. It is influenced greatly by extreme values. B. Variability Ratio: It is the ratio between the First and the Third quartiles of data. It is a number between 0 and 1. It indicates the amount of variation in the process. The lower the number, the more variation and the higher the number, the less variation. It is robust to an extreme value. e) Describe and give an example of Pareto Analysis. Pareto Analysis is a statistical technique in decision making that is used for the selection of a limited number of tasks that produce significant overall effect. It uses the Pareto Principle (also known as the 80/20 rule) the idea that by doing 20% of the work you can generate 80% of the benefit of doing the whole job. Or in terms of quality improvement, a large majority of problems (80%) are produced by a few key causes (20%). This is also known as the vital few and the trivial many. A Pareto Chart shows the relative magnitude of a problem. It helps focus on the causes that will have the greatest impact if solved. It can also provide multiple perspectives of magnitude of the problem. Pareto Chart Procedure - Make a list of categories or problems to compare. - Select a standard unit of measurement or metric. - Gather the data on a Check Sheet or other form. - Draw bars representing the magnitude of the unit of measurement for each category, and display in order of magnitude. - Review and act on the information! An example of a Pareto Chart is as follows: Plate Defects by Frequency Plate Defects by Cost: Another example showing relative frequency of causes for errors on websites: f) Why is a Pilot scheme often used prior to the full implementation of a problem solution What different types of Pilot Scheme can be used A Pilot scheme is used prior to the full implementation of a problem solution because of the following purposes it serves: (a) Merges the planning stages and implementation stages of project development (b) Serves as a way to educate management and build support for project. (c) Verifies costs and benefits (d) Allows evaluation of hardware, software, database design, procedures and alternatives. Types of Pilot schemes: (a) Demonstration: Allows management to see system in production (b) Prototype: Full-scale model of future system. FMEA Q6) a) Explain why there is a need for FMEA to be used by companies. Failure Mode and Effect Analysis (FMEA) provides the companies with a tool that can assist in providing reliable, safe, and customer pleasing products and processes. It can be used to: Develop product or process requirements that minimize the likelihood of those failures. Evaluate the requirements obtained from the customer or other participants in the design process to ensure that those requirements do not introduce potential failures. Identify design characteristics that contribute to failures and design them out of the system or at least minimize the resulting effects. Develop methods and procedures to develop and test the product/process to ensure that the failures have been successfully eliminated. Track and manage potential risks in the design. Tracking the risks contributes to the development of corporate memory and the success of future products as well. Ensure that any failures that could occur will not injure or seriously impact the customer of the product/process. (b) Worksheet Potential Failure Mode Potential Effects of Failure Potential Causes of Failure Current Controls Existing Conditions OCC. SEV. DET. RPN Hook comes off wall Coat falls on to the floor (a)Wear and Tear 9 8 2 144 (b)Excess Load 5 6 8 240 Recommended Actions and Status Responsible Area Revised Controls Resulting Conditions OCC. SEV. DET. RPN Use more durable screws 4 4 2 32 Warning mentioned in a conspicuous place & manner 2 4 2 16 (c) Risk Priority Number (RPN) is the product of Severity, Occurrence and Detection. This gives a measure of how much risk the customer is exposed to for each potential failure mode listed in the Design or Process. Severity is a ranking for potential injury, occurrence shows how often the failure mode occurs and detection is the ranking as to detection of the failure when it occurs. Risk Priority Pattern (RPP) is the product of Severity and Occurrence. RPP is important because it tells how many times one can expect the problem to happen and how bad it is. Every time a problem occurs someone has to fix it or pay for it. If the detection number is very low that means that the problem should not get to the customer but it does not mean that the problem is not happening. The scale for RPP only goes up to 100. In the above worksheet, it can be seen that RPN in case (a) is 144 which is lower than that of case (b) which is 240. However, RPP is 72 (9x8) in case of (a) which is higher than that of case (b) being 30 (5x6). Therefore it becomes necessary to use RPP in addition to RPN to decide how the resources should be allocated to fix a problem or change a design/process. Read More