Quality - Management and Control , the 7 basic tools

Managing quality is crucial for businesses. Quality products help to maintain customer satisfaction and loyalty and reduce the risk and cost of replacing faulty goods. Quality improvement is a continuous process. The tools of Quality are used company – wide for advancement in total quality management. These are the basic techniques useful in solving problem concerning quality, cost, production volumes that arise in the workplace logically and effectively.

The basic 7 Tools of Quality are –

·       Histograms

·       Pareto charts

·       Cause and effect diagrams

·       Check sheets

·       Scatter diagrams

·       Flow charts

·      Controlcharts                                                                                                                                                                                                                                                                                                                            

HISTOGRAMS

Histograms are a graphical representation of data in a bar chart format used to observe the “shape” of the data. They can also be used to show the relationships of many different collections of data including any process that requires random samples to determine if the process is performing properly.

Some rules for developing histograms

·       The width of the histogram must be consistent.

·       The classes must be mutually exclusive and all inclusive.

·       The number of the classes is decided by 2^k >=n where n is the number of data values and k is the number of classes.

PARETO CHARTS

Pareto charts identify and prioritize problems that need to be solved. They can also be used for a variety of analyses. For example: identifying and prioritizing complaints from customers, store inventory and distribution of wealth among countries.

Some rules for developing pareto charts

·       Information must be selected based on types of defects that occur as a result of a process.

·       Data must be collected and categorized.

·       A histogram or frequency chart is constructed showing the number of occurrences.

CAUSE AND EFFECT OR THE FISHBONE OR THE ISHIKAWA DIAGRAM

These diagrams look like the skeleton of a fish, with the problem being the head and the causes being the head and the causes being the “ribs” and the sub-causes being the smaller “bones” stemming from the ribs. They are used as an abstract way to depict the causes and effects of the major problems in the process. For example – causes of delayed flight departures, broken/faulty products, late product delivery.

Steps in creating a fishbone diagram or cause and effect diagrams

·       State the problem directly in the head of the fish.

·       Draw the backbone and ribs.

·       Continue to fill out the diagram asking, “Why?” about each cause of the problem.

·       View the diagram and identify the core causes.

·       Set goals to address the core causes.

CHECK SHEETS

Check sheets are data gathering tools that can be used in forming histograms and pareto charts. These are a form used to record the frequency of occurrences of certain product or service characteristics related to quality. These can be either tabular or schematic. Examples of when check sheets may be helpful: tracking customer complaints at a restaurant, slow production times, faulty/defective products.

Steps in designing a check sheet

·       Identify common defects occurring in the process.

·       Draw a table.

·       The user places check marks on the sheet when a defect is encountered.

SCATTER DIAGRAMS

Scatter diagram is used to examine the relationships between variables. They are also used to investigate the possible relationship between two variables that both relate to the same “event”. A straight line of best fit (using the least square method) is often included. Examples of when scatter diagrams can be used to determine if there is a relationship: prevention costs and conformance , overtime hours versus days absent, determining if a particular defect is due to run size.

Steps in setting up a scatter plot

·       Determining the X (independent) and Y (dependent) variables.

·       Gather process data relating to the variables identified in step above.

·       Plot the data.

·       Observe the plotted data to see if there is a relationship between the variables.

FLOWCHARTS

A flowchart is a graphical representation of a process. The first step in many process improvement projects is to create a flowchart. An example of a process that could use a flowchart would be a restaurant. When a customer enters the restaurant, if there is a table available they are seated. If not, they can wait or sit at the bar and have a drink. When the table becomes available, the customer is seated. After eating, the patron pays for the food or can either leave or sit at the bar.

Symbols used in Flow Charts

·       Oval: Denotes the beginning or end of a program.

·       Flow line (arrow): Denotes the direction of logic flow in a program.

·       Parallelogram: Denotes either an input operation or an output operation.

·       Rectangle: Denotes a process to be carried out.

·       Diamond: Denotes a decision (or branch) to be made. The program should continue along one of two routes.

Steps in creating a flow chart

·       Develop a general process and then fill in the elements of the process.

·       Observe the people doing the process.

·       Determine which steps add value and which do not, to simplify work.

·       Determine whether the work actually needs to be done.

CONTROL CHARTS

A control chart is used to determine whether a process will produce a product or service with consistent measurable properties. A control chart has a nominal value or central line and an upper and lower control limit. Example of when to use control charts: quality inspection and checking for defects in products.

Steps in forming a control chart

·       Take a random sample from the process, measure the quality characteristics and calculate a variable or attribute measure.

·       If the statistic falls outside the control limits, then look for assignable causes.

·        Either eliminate or incorporate the cause. Reconstruct the control chart with the new data.

Maruti Suzuki Ciaz SHVS - The most fuel efficient premium sedan in India

SHVS stands for Smart Hybrid Vehicle by Suzuki.

The implementation of Suzuki’s SHVS system in the Maruti Suzuki Ciaz has made the car more fuel efficient than the earlier model. The Maruti Suzuki Ciaz SHVS is available only in the diesel engine model of the car. The new Ciaz diesel mild hybrid has an ARAI rated figure of 28.09 km/l.  This makes the Maruti Suzuki Ciaz diesel the most fuel efficient car in India.

Maruti Suzuki Ciaz is a mild hybrid system having a:

Regenerative braking

Suzuki’s new SHVS system works on the principle of regenerative braking. The regenerative braking system is an advanced braking system that is used along with the conventional braking system in hybrid vehicles. The conventional braking causes friction between brake pads and disc. It converts vehicle's kinetic energy into heat, which goes wasted. However, the regenerative system recovers some of the waste energy and puts it to use again. The system converts this waste energy into electricity. The electricity, saved charges the battery of the vehicle

. The system consists of an electric motor with dual function. It works as a motor, in one direction and also as a generator, in the opposite direction. While braking the motor runs in the opposite direction and becomes an electric generator. The Ciaz comes with a bigger lead acid battery in the SHVS model.

Integrated Starter Generator

Also referred as an ISG, Integrated Starter Generator allows the hybrid vehicle’s engine to instantly and quietly restart after the idle stop, when the engine shuts down to save fuel and emissions. Like an alternator, the ISG produces electric power when the vehicle is running, which is used to supply electric devices and/or to charge the battery. The ISG can help to decelerate the vehicle by generating electric power, which is called regenerative braking. The electric power generated charges the battery, reducing fuel consumption. If a clutch disconnects the ISG and the compressor from the engine during the idle stop, the ISG can drive the air-conditioning compressor via a belt. And since the ISG motor aids the Ciaz mild hybrid in acceleration with electricity, the engine does not have to rev as much when the car accelerates thereby saving fuel.

Idle Start/Stop

Maruti proves to be the best when it comes to squeezing out mileage from its cars and this technology takes it a step forward. The Maruti Ciaz mild hybrid also comes with idle start/stop technology that shuts off the engine when the car comes to a halt in order to save fuel in stop/start traffic conditions.  The high capacity battery supplies power to the ISG which is connected to the engine via belt (for smooth operation). The engine has a start-stop feature which automatically turns it off when you come to a stop, put the car in neutral and take your foot off the clutch. The engine restarts as soon as you press the clutch.

Power Assist

The Ciaz is fitted with high capacity batteries providing power to the ISG which in turn boosts the engine performance, taking load off the diesel motor at the time of acceleration. This results in better power delivery and less fuel consumption.

Gear Shift Indicator

Like all shift indicators this works the same way, informing the driver to shift at the optimum speed and revs to get better fuel economy.

TURBOCHARGER

Turbocharger is a mechanical device that is used to increase the power and efficiency of an engine by increasing the amount of air entering into the combustion chamber. More air into the combustion chamber means more amount of fuel will be fed into the cylinder and as a result one will get more power from the same engine if a turbocharger is installed in it. A turbocharger basically draws the air from the atmosphere and compresses it with the help of a compressor before it enters into the intake manifold at increased pressure. This results in more amount of air entering into the cylinders on each intake stroke. The compressor gets power from the kinetic energy of engine’s exhaust gases.

A turbocharger has three main components

1. A turbine (radial inflow turbine)
2. A compressor (centrifugal compressor)
3. The centre hub rotating assembly

How a turbocharger works

1.     Cool air enters the engine's air intake manifold and heads toward the compressor.

2.     The compressor fan helps to suck air in.

3.     The compressor squeezes and heats up the incoming air and blows it out again.

4.     Hot compressed air from the compressor passes through the heat exchanger, which cools it down.

5.     Cooled compressed air enters the cylinder's air intake manifold. The extra oxygen helps to burn fuel in the cylinder at a faster rate.

6.     Since the cylinder burns more fuel, it produces energy more quickly and can send more power to the wheels.

7.     Waste gas from the cylinder exits through the exhaust outlet.

8.     The hot exhaust gases blowing past the turbine fan make it rotate at high speed.

9.     The spinning turbine is mounted on the same shaft as the compressor. So, as the turbine spins, the compressor spins too.

10.  The exhaust gas leaves the car, wasting less energy than it would otherwise.

Turbochargers can be used with either petrol or diesel

 engines. An engine fitted with a turbocharger is much smaller and lighter than an engine producing the same power without a turbocharger, so a turbocharger car can give a better fuel economy.