Refrigerator: Definition, Features, And Stakeholder Analysis

Describe the Causes of Power Supply Failure Problem 

Introduction to Refrigerators

The term refrigerator is referred with a common name, fridge and it is the electronic appliances that is used most commonly in a house. Refrigerator has thermally insulated compartment and a system to expel the heat towards outer part of the refrigerator, from the inner area, by using mechanical, chemical or electronic heat pump. The major and primary usage of the refrigerator is storage of food, by maintaining lower temperature, compared to the ambient room temperature. Lower temperature allows the temperature to store better, since the bacteria production rate becomes lower than at ambient temperature. Consequently, the spoilage rate of food is reduced to a greater extent. The inner part of the refrigerator is maintained with the temperature, which is just a few degrees of temperature greater than the freezing point temperature of water. And perishable food storage needs optimum temperature that ranges from 3⁰ to 5⁰ C of temperature. Refrigerator is also referred as an icebox, which was used widely in America.

Several new features are added for the refrigerators through the development of the new technology. The new features are

1. Easier accessability of water through the dispenser, within the door
2. Chilled ice
3. Automatic defrosting

Refrigerators are available throughout the world with various capacities, smaller one with minimum of 4L to biggest of maximum of 600L capacities. The smallest refrigerator can store total 6 cans of beer. Most of these refrigerators and freezers are designed and manufactured to have free standing and also designed to fit as one module in the kitchen.

The direct purpose of the freezers or refrigerators for the customers is for purchases of the drinks and food so that save money can be saved and consumed during the leisure times. Applications involve in both the commercial and domestic purposes. The purpose of domestic refrigerators is the storage of the domestically processed items of food and packaged food. Commercial refrigerators are designed and developed basically like beverage cooler with glass door. The design is with the re-load condition and with larger and better systems for cooling. These refrigerators are developed to be compatible with the system to fulfil the frequent door opening and larger drinks throughput support features.

Refrigerator manufacturing is done worldwide by several companies, such as Samsung, Whirlpool, LG, Haier and others. Samsung is founded on 1^st March, 1938, by the founder, Lee Byung-chul and manufactures consumer electronics. The company has the revenue of more than US$305 billion. Samsung electronics is one of the important divisions of Samsung. The division, Samsung Electronics is founded in 13^th January, in 1969, in South Korea, serving worldwide. The sales networks and assembly plants are spread in total 80 countries providing the employment to more than 308,745 employees. By revenue, Samsung electronics stands as the largest consumer electronics maker, information technology company and chipmaker. It’s market share is more than US$372.0 billion.

Features of Refrigerators

The list of stakeholders, including both external and internal of the Samsung refrigerators is shown as the following. As Samsung has several kinds of stakeholders, since it is an international company, only most influential and major stakeholders are considered for stakeholder analysis.

MOST INFLUENTIAL STAKEHOLDER	RESPECTED EXPECTATIONS
Internal Stakeholders
CEO and Chairman	§ Continuously increasing return on the investment, by implementation of higher valued strategies § Good analysis conducted on the expectations and needs of the customer, for better refrigerators analysis § Achieving the best research and development in the refrigerator industry, by guiding and proposing the entire R & D team § Continuous improvement of reputation for the brand with improved market share
Engineering Department	§ Implementing sophisticated and advanced technology in the industry with improved R & D § Improved influence on innovation for automotive aftermarket parts § Enhanced and improved design compared to the contemporary products in the market
Samsung Refrigerator Employees	§ Employment security § Stable environments for working § Better refrigerator quality § Improving consumer demand and customer satisfaction for refrigerator
Shareholders	§ Improving share value § Improved ROI (Return on Investment) § Advanced innovation on the refrigerator adopted technologies
External Stakeholders
Customer	§ Robust refrigerator § Warranty with longer period § More reliable refrigerator § Longer refrigerator life § Least number of complaints § Best post sales and technical support § Increased value for spent money § Cheaper price compared to the competitors § Improved aftermarket product’s functional support
Distributors and Retailers	§ Robust refrigerating product § Pricing to be predictable and fair § Delivery to be on-time and prompt § More reliable product § Minimum number of complaints § More and more features § Refrigerator with stronger parts and body
Suppliers	§ Profits to keep on increasing § More and more number of orders for wider refrigerator range § Regular orders and reliable and increased business § Improved raw material demand, improving business potential § While new refrigerator product development, expectation of innovative cooperation
Competitors	§ Share market to decline § Inferior refrigerator quality § Decreased features § Share value to decline in share market § Minimal competitive advantage with stalled and ineffective innovation
Environmental Experts and Lovers	§ Reduced and minimal environmental impact § Improved 3R – Reduce, Reuse and Recycle § Usage of recyclable material for production § Reduced resources still maintaining increased efficiency
Regulators in Government	§ Carbon emission and environmental regulations adherence § Applicable consumer legislation adherence § Prescribe warranty period adherence

Customer needs can be captured through several existing methods, for tabulating the Voice of Customer (VoC) methodology, through categorization of the needs and requirements after the collection. customer requirements are gathered and categorized through different methods of data acquisition.

Among those methods, the most important and quite oftenly used methods for capturing customer needs are the following (Akpolate 2004, Cooper & Dreher 2010).

1. Customer Advisory Boards
2. Customer Complaints
3. Customer Interviews
4. Customer visits
5. Ethnographic Methodologies
6. Focus Groups
7. Survey Questionnaires

The customer questionnaire method helps to capture the customer needs through a large number of diversified customers and it is cost effective method. This process can be conducted through various media, such as mail, internet, etc. One directional contact form is used to collect the customer needs through customer survey questionnaire, as it needs only seeking the answers in a written format of questionnaire, by engaging and communicating with the customers. But, great emphasis is needed, such as open ended question, being direct to the customers, etc. to ensure good quality of questions to obtain reasonable accuracy for the answers. Ratings from 1 to 5 is used for indication of the disagreeable or agreeable levels and satisfaction and dissatisfaction levels, to ensure better accuracy, based on the outcomes or results intended to obtain, to which the customers are expected to respond.

Customer needs categorization of the needs can be done optimally with the survey questionnaire, on the basis of the customers responses and this method is same as the method of the customer interview. This method helps to obtain quantifiable data, which is further used for anlaysis and it is based on the answers and quality that is inherent by the customers, participating.

About 5 to 8 customer individuals are formed as one focus group for a specific product, to obtain qualitative data. The customers can be either current or past customers (Kitzinger 1995, Alkapolat 2004). The method of focus groups is a bit varied from the method of the customer interview, in terms of encouragement of the groups towards the customer needs discussion done by themselves, instead of formal process of answering the questions, as done in the interviews. Focus group discussion is initiated by posing an open ended question, posed by leader of the group and the discussion is continued and moved ahead with the participants, as they are encouraged to express the views of them, regarding the services and products and there is no formal structure of the discussion, as in interviews. The method is unlike formal interview one-on-one interaction and reading the questionnaire and writing the responses, but like direct interaction, so data after the discussion is more qualified and accurate (Kitzinger, 1995). It provides the results obtained from broader and wider range of customers participating in the discussion.  

Refrigerators and Their Capacities

Customer interviews help to extract insights of the customer and this method is proved to be succinct and cost effective. The results obtained after the interview are assessed on the basis of different factors, like kind of customers, like new, past, present or customers who are most trusted, etc., the ways of discussion in the interview, such as through face to face, internet or telephone, the size of the customers, like one-to-one or group interviews (Griffin & Hauser 1993 & Akpolat 2004).

Though the interview structure is based on various parameters, as discussed above, the basic framework selected for conducting interviews is same relatively. Interviewer prepares specific and related questions, before the interview to ensure obtaining desired information, for customer needs exploration. Then the questions are further structured. The data obtained is further categorized and analyzed as for customer attributes qualification, like spoken, subconscious and basic needs of customers (Yang, 208). These attributes become the basis for analysis and identification of the specific product’s potential functional requirements.

The data obtained from the customer interviews can be quantifiable, considering right size of sample data at the appropriate circumstances, such as appropriate structure and question style, though this method is qualitative data analysis. But, it is quite possible as the result and quality are dependent on the style of questioning, like at the end either solution or problem is obtained, instead of focus on the specific need or requirement, wrong information can also be resulted.

The methodology of ethnographic research is a most and comprehensive methods to research and obtain the customer needs (Cooper & Dreher, 2010). The method involves diferent ways of conducting the interviews contextually and observations are performed systematically and simultaneously, by establishing the communication with the customers, in the environment right in their place. The process is implemented while the customer makes use of the service or product and the interaction is recorded through the video (Goffin et al, 2012). There is no need for the interview questionnaire or survey predefined. But posing the right and relative questions is done contextually, while the product is being used by the customer. So, compared to the customer interviews and survey questionnaire, this methodology is less formal, as there are no standard or predefined questions are involved. While the interaction is going on, interaction with the customer on the site helps the companies to determine and understand, whether the responses from the customer are incorrect or correct, in terms of revealing the customer needs. Such informal process of interaction also helps to understand and analyze both the indirect and direct customer needs.

Applications of Refrigerators

In terms of acquiring the needs of the customers, indirectly, customer visits stands as one of the effective methods. This methodology is similar to the survey questionnaire and customer interviews for acquiring the customer needs. Here, the customer is accompanied by the employee, irrespective of the customer visiting the organization premises or not and the other way around also. Prior to the visit of the customer by the employee, the organization prepares and get ready with the conversational guide and notices the insights of the customers subconsciously. In such method, while analyzing the customer responses, qualitative data can be obtained, from the customer (McQuarrei, 2008). However, this method involves longer process and consumes considerably much more time and the visits to the customers are based on the structure of the organization and vary according to the need to acquire a fair quantity of data that may or may not be feasible or worth. In this context a significant factor for obtaining qualitative and accurate data is the selection of the customer choke selected for the visit. The final results depend on the style of posing the queries to the customer and their respective responses and so are highly subjective.  

In this context, selection of Samsung refrigerator for quality planning and analysis is done on the basis of the selected method is the survey questionnaire. This method is performed in a process of five sequential steps and repeated in an iterative way.

Defining the survey objectives and goals

After conducting the survey, the following are determined as the goals and objectives.

1. To obtain the customer needs information to Samsung
2. To obtain evidences for customer dissatisfaction and the associated areas of improvement
3. To obtain the research and design department’s insights to predict the future customer requirements and towards product innovation by adopting breakthrough technologies

Develop the survey plan

This method of survey questionnaire is chosen to conduct through the medium, internet. The questionnaire is placed in a web link within the home page of Samsung website. The survey is not timed for completion and size of the sample is 300 customers and the customer get ample time to answer the queries in relaxed manner. Identification of the participating customers can be done only through the model number specification of the refrigerator they bought and used and remain anonymous. Hence, participation needs the model number specification for ensuring that only customers of Samsung have participated, so that better accuracy can be ensured for the results.

Design and test requirements

Refrigerator’s selected attributes’ significance is scored through designing a questionnaire, on a 1 to 5 scale, where 5 score represents the most significance and 1 as the least significance.

Refrigerator Manufacturers

So, the following scoring and relevant significance is followed during the survey questionnaire.

Figure: Survey Questionnaire

S.No.	SELECTED ATTRIBUTE	SCORE (1-5)
1	Compressor longer life
2	Control panel to be more user friendly
3	Cooling speed enough or in less time
4	Easier spare parts availability
5	Efficient in space management
6	Efficient in terms of energy
7	Features to be easier to use
8	Fresh and Hygiene stored food
9	Fresh food for longer time
10	Look and style of refrigerator
11	Maintenance to be easier
12	Minimal impact on environment
13	Minimal or no complaints
14	Minimum consumption of power
15	Minimum or no noise
16	More refrigerator capacity
17	Odourless interior
18	Optimal operation
19	Overall performance
20	Refrigerator to be reliable for cooling
21	Right value for money
22	Robust and strong parts of the refrigerator
23	Technical support to be more reliable and friendly
24	Uniform and even temperature inside the refrigerator
25	Warranty for longer period

Table: List of selected significant attributes for Refrigerator

The scale is taken with a smaller number, 1 to 5 as it can be easier for the participating customer to respond to the queries.

Prior to actual deployment of the survey questionnaire, a trial run is performed initially, so that the validity of the response can be well ensured and helps in question style calibration accordingly.

Once the responses are collected from 300 respondents or participants, each attribute’s score is summed up to calculate cumulative and overall score and they further be categorized into musts, wants and desirables three categories, on the basis of criteria as shown in the table following.

CATEGORY	CUMULATIVE SCORE
Desirables	<600
Wants	600 - 1050
Musts	>1050

Table: Three categories of attributes

Conducting the survey

Then survey questionnaire is deployed in the homepage of the Samsung website and survey is conducted with the selected questionnaire style and proposed scale.

Analysis of the Results

The refrigerator’s attributes are recorded, after receiving the responses from the customers as the following.

S.NO.	SELECTED ATTRIBUTES	CUMULATIVE SCORE	AVERAGE SCORE
1	Compressor longer life	1420	4.72
2	Control panel to be more user friendly	1256	4.18
3	Cooling speed enough or in less time	1124	3.74
4	Easier spare parts availability	963	3.21
5	Efficiency in space management	968	3.22
6	Efficient in terms of energy	846	2.82
7	Features to be easier to use	1444	4.81
8	Fresh and Hygiene stored food	966	3.22
9	Fresh food for longer time	1356	4.52
10	Look and style of refrigerator	569	1.89
11	Maintenance to be easier	893	2.97
12	Minimal impact on environment	456	1.52
13	Minimal or no complaints	596	1.98
14	Minimal or no noise	356	1.18
15	Minimum consumption of power	752	2.5
16	More refrigerator capacity	1092	3.64
17	Odourless interior	854	2.84
18	Optimal operation	421	1.4
19	Overall performance	985	3.28
20	Refrigerator to be reliable for cooling	1225	4.08
21	Right value for money	1036	3.45
22	Robust and strong parts of the refrigerator	1452	4.84
23	Technical support, reliable and friendly	1026	3.42
24	Uniform and even temperature inside the refrigerator	1358	4.52
25	Warranty for longer period	1112	3.7

Table: Recorded responses for each attribute

The responses received have to be categorised now categorized using the Voice of the Customer Chart, on the basis of category criteria specified in the survey design phase and also on the basis of the results received from the questionnaire. The chart is drawn as the following.

Quality Function Deployment method is used to correlate the ten specific requirements from the requirements of the customers, listed above. The rating score from each of the response is to be collected and gathered from the calculated average score from the survey questionnaire completed so far.

Each of the obtained value from the questionnaire has to be multiplied by 2 so that score is calculated for the scale of 1 to 10, replacing scale of 1 to 5. Such upscaling helps in obtaining increased degree of accuracy and consistency. Then a value system of 1-3-9 is used to specify and detail the relationship in between the customer needs and quantifiable design requirements. Here, 1 indicates the weakest, 3 as medium and 9 as stronger relationship.

Absolute score is then multiplied with importance or significance factor, against each relevant attribute to the design requirements, after calculating and assigning the relationship. Then absolute value is obtained by accumulating or summing up these values.

Once the calculations are completed, the QFD resultant is shown as the following.

	CUSTOMER REQUIREMENTS	SCORE RATING	DESIGN REQUIREMENTS
			Capacity	Warranty	Eco-friendliness	Smart Diagnosis	Hygiene Fresh	Door Cooling	User friendly Control Panel	Smart invertor Compressor	Humidity controller	Deodorizer
NEEDS	Refrigerator to be reliable for cooling	8.16			3	9	9	9	6	6	3	6
	Fresh food for longer time	9.04					9	9		9	9	9
	Robust and strong parts of the refrigerator	9.68		9	6
	Features to be easier to use	9.62				9	9	9	9		9	6
	Cooling speed enough or in less time	7.48				6	9	9		9	9	9
	Control panel to be more user friendly	8.36							9
	Uniform and even temperature inside the refrigerator	9.04			6		9	9	3	9	3	3
	Compressor longer life	9.44		9		3	3	3		9
	Warranty for longer time	7.4		9				9	9	9
	More refrigerator capacity	7.28	9
WANTS	Minimum consumption of power	5			9			3	3		3	3
	Easier parts availability	6.42							3	9
	Efficient in terms of energy	5.64		3	9	6	6	6	3	9	9	9
	Technical support to be reliable and friendly	6.84		9		9
	Fresh and hygiene stored food	6.44				9	9	9	3	9	9	9
	Maintenance to be easier	5.94		9		9	9	9	9	9	9	9
	Efficient in space management	6.44	9
	Overall Performance	6.56				9	9	9	9	9	9	9
	Odourless Interior	5.68				6	9	3	3	3	6	9
	Right value for money	6.9	6	9	6	3	9	3	6	6	3	3
DESIRABLES	Minimal or no complaints	3.96		9		6			6	9	3	3
	Minimal impact on environment	3.04			9	3				9	3	3
	Look and style of refrigerator	3.78	3						9
	Optimal operation	2.8		9	3	9	9	9	9	9	9	9
	Minimal or no noise	2.36	9	6	3		6		9			9
	TARGETTING VALUE		650 L	10 Years	5 Star Rating	Smart Diagnosis System	Hygiene Fresh System	Door Cooling System	User-friendly control panel	Smarter invertor compressor	Humidity controller system	Deodorizer
	ABSOLUTE SCORE		36	81	54	96	114	108	108	132	96	108

Stakeholder Analysis for Samsung Refrigerators

 After calculations of the absolute score for the design requirements, against the customer requirement attributes, five design requirements with higher scores are finally selected and they are the following.

1. Smart Invertor Compressor
2. Hygiene fresh system
3. Door Cooling System
4. User-friendly control panel
5. Deodorizer 

Failure Mode and Effective Analysis is then conducted for the top 5 scored design requirements, as the following table. 

PART / FEATURE	POSSIBLE FAILURE	EFFECT ON REFRIGERATOR	CAUSE OF FAILURE	RISK BEFORE ACTION TAKEN			RISK CONTROLLING ACTION	RISK AFTER THE ACTION
				P	S	R		P	S	R
Smart invertor compressor	Breakup	Inefficient operation and fatal accidents	Gas in compressor	2	3	11	Fill adequate amount of gas	1	3	3
Hygiene fresh system	No special hygiene function	Inefficient hygiene	Defective Microcontroller	2	4	12	Replacing the microcontroller	1	4	4
Door cooling system	No special or uniform cooling system	No uniform cooling system	Defective Microcontroller	2	3	8	Replacing the microcontroller	1	3	3
User-friendly control panel	Buttons or board non-functional	Ineffective interaction between user and machine	Defective User interface board	2	4	6	Replacing the user interface board	1	2	2
Deodorizer	System non-functional	Ineffective control of development of bacteria	Defective deodorizer system	3	3	4	Replacing the deodorizer system	1	3	3

Table: Measures of risk and control

Risk for each of the design requirements and the following technical consequences can be measured as the following table. 

LEVEL	DESIGNATION	TECHNICAL
1	Marginal	Refrigerating system remains operational – A little correction required
2	Minor	Refrigerating system remains operational – minor correction required
3	Moderate	Refrigerating system operation interrupted – Minor rectification required
4	Significant	Refrigerating system remains operational – Major correction required
5	Major	Refrigerating system stopped – Impossible rectification

Table: Measures of consequences

Probability of the risk level of each of the proposed requirement can be detailed as the following table.

LEVEL	DESCRIPTOR	PROBABILITY	DESCRIPTION
1	Unlikely	Lesser than 0.01	Event occurs rarely
2	Possible	0.02 to 0.05	Event occurs fewer times
3	Likely	0.05 to 0.49	Event probably occurs at sometime
4	Probable	0.49 to 0.99	Event occurring at some time
5	Higher probability	Greater than 0.99	Most possible occurrences of the event

Table: Measurement of likelihood

GR-M772HLHM Refrigerator is made by LG needs the following major components.

1. Freezer
2. Compressor

For effective selection of supplier, 10 different criteria of selection is considered, as the compressor is the key and refrigerator’s vital part.

1. Service history
2. Reputation
3. Reliable customer service
4. Reliability of product
5. Range of products
6. Quality of product
7. Quality assurance procedure
8. Price
9. Location and distance
10. Lead time

Compressor stands as a vital and key product for the refrigerator, as it is highly technical product and the supplier system selection for this component stands a vital factor for efficient refrigerator.

Evaluation of the supplier can be done with three steps, as the following.

1. The key factors defined and specified before for weighing the evaluation criteria for supplier. Weightage is conducted on a scale of 1 to 10, where 10 indicates as most import and 1 indicates least important.
2. Based on the supplier’s capability for meeting of the requirements, suppliers are to be scored on a scale of 1 to 10, again 10 indicating most important and 1 as least important. Ratings are given based on the perceptions on the supplier.
3. Finally, weighted score gets and score of weightage are multiplied with each of the score. Selection of supplier should be on the basis of the total score.

The selection process above has to get implemented with the format as tabulated below and the outcome correspondingly.

		SHORT-LISTED SUPPLIER
SELECTED CRITERIA	WEIGHING	SUPPLIER 1		SUPPLIER 2		SUPPLIER 3
		Score	Weighted score	Score	Weighted score	Score	Weighted score
Lead Time	8	6	48	7	56	8	64
Location & Distance	7	7	49	6	42	7	49
Price of the product	7	6	42	7	49	9	63
Quality assurance procedure	8	8	64	8	64	9	72
Quality of Product	9	9	81	8	72	9	81
Range of Product	6	9	54	9	54	7	48
Reliability of the product	9	7	63	9	81	8	72
Reliable customer service	8	9	72	6	48	7	56
Reputation	8	8	64	9	72	7	56
Service History	8	8	64	7	56	8	64
TOTAL		77	601	76	534	79	625

The Short-listed supplier evaluation is done, for the supply of compressor, on the basis of ratings, assigned to the same. From the report, 625 is taken as the highest score and hence the selected supplier is Supplier 3.

For the refrigerator production, the following overall 10 processes are considered to address as the following.

1. Design

The refrigerator product design is done, taking the factors, such as market trends, ground breaking technology and the current customer needs. This process contains the final drawings.

2. Process of Supplier Selection

The supplier selection process is done for the products, manufactured and produced external to the organization.

3. Process of Goods Inspection

Goods inspection is done to ensure that the Inspection and Test Plans (ITP) completeness for verification of the supplying products.

4. Process of Component Internal Manufacturing

The process involves in the design drawings dispatch to respective departments and is performed for the internal manufacturing, with the relative guidelines for the process of manufacturing and actual manufacturing process.

It includes, as the following.

• Dispatch of the drawings to the casting and NC milling departments
• Housing casting, having any of the allowances of machining
• Machining of 3 axis NC related to the bore surfaces and internal mating
• Hard anodising
• Dimensional checks for checking critical dimensions
• Overall quality final inspection

5. Final Process of Assembling

The final assembly process includes consolidation of the internally manufacturing and supplied components and assembling them systematically, altogether to shape final refrigerator.

6. Process of Packaging

The packaging process has refrigerators collection, collecting and packing against the related quality documentation process, along with the packaging of the auxiliary components associated for appropriate installation.

7. Process of Distribution

Distribution process consists of packaged products loading into traceable batches over the delivery trucks and moving forward with the process of distribution to the retailers and distributors.

8. Process of Invoicing

Customer Needs Acquisition

Invoicing process involves collection of funds and accounting related activites.

9. Process of Quality Assurance

Quality assurance process consists of checking of periodic confirmation to all internal quality assurance measures consisting of different processes Non-Conformance Reports, ITPs, forms, process forms, traceability reports, etc., of material. The process ensures the credibility of assurance of manufacture of refrigerator against the standard quality measures and specifications.

10. Process of Advertising Campaign

The process is implemented to plan the strategies of marketing and advertising towards the Samsung refrigerator exposure, for improved profits from increased sales.

SPC charts tools help the companies in pinpointing and visualising the statistics anomalies, in specific process performances. The charts take the specific processes’ effectiveness measure and support to visualize the patterns of process performance. Hence, the company is enabled to identify the performance and analysis of process with the relative variation.

Features of the SPC charts are as the following.

1. Upper Control Limit – Indicates the acceptable range upper limit in process variation
2. Lower Control Limit – Indicates the acceptable range lower limit in process variation
3. Centre Line – Indicates the process characteristics’ mean value

Categorization of the SPC charts is done on the basis of the sets of attribute and variable data. Attribute data represents the characteristics of quality that are represented non-numerically.

1. P-Chart – Supports plotting the proportion or fraction of defective items from a specific size of sample and registration of number of defective items stands proportional to the size of the sample
2. Np-Chart – Supports plotting the quantity of defective items from a constant size of sample and LCL, UCL and centreline values are constant and helps to indicate the counting of defective items, instead of proportion
3. C-Chart – Helps in plotting the defects after detecting, from a constant size of sample and centreline stands as defects’ average and counts number of total defects, instead of items that are defective

SPC charts used for better variations of process procedure, in-depth analysis are shown by the following.

• X bar Chart & R bar Chart

These two charts, when combined can provide better analysis, though they have varied purposes. The purpose of the X bar chart is to plot the average of measurements with centreline and helps depicting measurements’ averages’ average, in sub-groups. The purpose of the R bar chart is to plot the range of measurements in sub-groups. The averages of the ranges show its centreline.

• X-Chart

The chart is used to measure the 1 sample size data, once and helps analysis of the patterns of forming, with the values of measurement for a time’s single unit and comparing them with patterns that are controlled processes. 

A variable sample size gives defectives from scrutinizing of refrigerators. It considers 20% of total machines, from one batch and the analysis is done by the P-Charts.

Consider the total number of registers produced in three weeks of time. Then the following are the important and specified parameters. 

p = items proportional to defective ones

   = x / n

x = total items that are defective and

n = size of sample

P bar is calculated as, centreline  = ∑p / k

k = total number of days 

	DAY	x	n	p	P bar	UCL	LCL
WEEK 1	1	16	91	0.175824	0.141	0.25058	0.03162
	2	15	96	0.15625	0.141	0.268417	0.044083
	3	16	90	0.177778	0.141	0.29868	0.056876
	4	18	94	0.191489	0.141	0.31324	0.069738
	5	14	94	0.148936	0.141	0.2591	0.038772
WEEK 2	6	16	95	0.168421	0.141	0.28361	0.053232
	7	15	93	0.16129	0.141	0.275707	0.046874
	8	15	90	0.166667	0.141	0.284518	0.048816
	9	17	92	0.184783	0.141	0.306176	0.063389
	10	14	91	0.153846	0.141	0.267313	0.040379
WEEK 3	11	13	92	0.141304	0.141	0.250254	0.032355
	12	16	96	0.166667	0.141	0.280776	0.052558
	13	16	95	0.168421	0.141	0.28361	0.053232
	14	13	93	0.139785	0.141	0.247658	0.031912
	15	12	93	0.129032	0.141	0.233319	0.024745
WEEK 4	16	13	91	0.142857	0.141	0.252904	0.03281
	17	13	94	0.138298	0.141	0.245116	0.03148
	18	12	92	0.130435	0.141	0.23577	0.025099
	19	12	93	0.129032	0.141	0.233319	0.024745
	20	16	95	0.168421	0.141	0.28361	0.053232
			∑p	2.999

The P-Chart

Refrigerator manufacturing process is determined to be in control, technically, on the basis of the p chart results.

When refrigerator, a sophisticated and huge technical machine is manufactured, the associated problems are certain. The problems can any or more than one of the following.

1. Short or open circuits
2. Problems with power supply
3. Problems resulting from mis-alignment problems
4. Possible Leakages
5. Parts and components breakage
6. Issues of pressure of compressor gas
7. Insufficient or incomplete assembling
8. Human errors
9. Errors related to operation
10. Components missing

Customer Survey Questionnaire

The above problems can be encountered and solved with the various techniques of problem solving as the following.

1. Why-why diagram
2. Process flow chart
3. Pareto diagram
4. Gantt Chart
5. Check sheet
6. Cause and effect diagram
7. Brainstorming

Now consider one of the specified problems above, called’power supply failure’ and then the following techniques are applied to solve the problems and find the respective solutions.

1. Why-why diagram
2. Pareto diagram
3. Check sheet
4. Brainstorming

Let us implement these problem solving techniques now.

The power supply failure problem is brought before the experts group and recording of the responses must be done, so that the possible causes can be found. The responses can be of the following.

Problem: Power Supply Failure

The following are the possible causes for the problem.

1. Cables get disconnected
2. Disconnected cables
3. Human error
4. Power supply to be defective
5. Problems with assembling
6. Problems with connection
7. Unchecked supply of power

The potential causes possibility can be analysed with the check sheet. The method is implemented only after why-why and brainstorm problem.

ROOT CAUSE POSSIBLE	POSSIBLE OCCURRENCES	ABSOLUTE PERCENTAGE	ACCUMULATIVE PERCENTAGE
Cables get Disconnected	25	25	25
Human Error	10	10	35
Power Supply to be Defective	15	15	50
Problem with Assembling	10	10	60
Problems with Connection	20	20	80
Unchecked Power supply	20	20	100
TOTAL	100

Post implementation of the four problem solving techniques proposed, exploration of the power supply problem’s final root causes is done. Then the necessary measures, actions and corrections are developed and implemented in the production process.

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