Quality Engineering Assessment For Waffy Chocolate Flavour Product - Case Study

Describe about the case study is performed on the Waffy biscuit products?

As the average customer has been educated and become more conscious about the quality of the products bought by them, the concern of the quality standards to be followed by the companies of the products has also been increasing. The quality standards can be investigated and analysed through quality engineering techniques.

Waffy Chocolate is the product selected for the quality engineering report. Waffy Chocolate is one of the flavours of the waffies produced and sold by Dukes, India. Dukes makes the Waffy products, in addition to many other products, like chocolates, confectionaries, newbies. The product is marketed and sold also, as gift packs that are best suitable for the birthday parties and other kinds of parties for the children as well as the adults and teenagers. The company offers the Waffy, Chocolate with various offers and the offer that is presently available, at the time of the consideration of the product for the quality engineering case study is the buy 1 get 1 offer. The offer allows the customer to get one Waffy free of cost, when one Waffy is bought. And at the same time, if the customer chooses to buy only one or only one Waffy is left in the rack of the shop, it would be sold for half of the cost. The company uses the selling strategy of buy 1 get 1 to attract more customers to buy the Waffies.

Dukes, India has a tag line, ‘Energy Unlimited’ and wishes to become a consistent source of sweet Delight. The company is taken to the greater heights, by channelizing its boundless energy to make the products that are universally accepted, satisfying and appealing and the product to under the universal banner of quality food. The company was started before two decades, on the name of Ravi Foods Pvt. Ltd, and created its niche in food segment called processed foods. The diversified foods have the customers within the mother country and also outside the mother country. The company successfully runs with 12 plants installed and working in India.

The product, Waffy with chocolate flavour is nicely packed with fancy and elegant looking pack. The size is also bigger and it attracts the customer for more valued food content present in the pack. Since the product is offered with special offer, like buy 1 get 1, the customer becomes a little sceptic about the quality as well as the quantity of the product. However, as a standard company, following all the norms of the quality related to the product, it is important that whatever is specified on the pack must be justified. This quality engineering report on Waffy with chocolate flavour assess the quality factors, majorly on the weight of the overall product as well as the individual pieces of the product that in combination should be equal to the weight of the overall net weight of the product.

Company

To conduct the quality assessment of the Waffy wafers, produced and marketed by Dukes, the weight of the overall wafer and each of the wafer in the packet are measured to check whether the sum of the all the wafers in the packet is equal to the net weight of the overall packet.

The measurement system analysis helps to assess the overall measurement system adequacy for specific application. When the process outputs are considered, there are two kinds of variation sources called,

Measurement system variation, which is considerably large, when it is compared to the other one, however this system many not provide the complete and useful information needed

Part to part variation

Before the data is collected from the processes, the measurement system analysis is to be performed for confirming that the measurement made by the measurement system is consistent, accurate and can determine the discrimination among all the parts, chosen in the measurement.

The measurement systems analysis is  performed to find the answers for the following questions.

Will the measurement system be discriminate between various parts, adequately?

Can the measurement system be stable for over a period of time?

Can the measurement system be accurate for the entire range of the parts?

Two Waffy wafers are taken and the total weight of the packet is measured. The total weight is compared with the net weight printed on the packet of Wafers. Then the packet is opened and each of the wafer is measured accurately. Before the wafer is measured, the digital display is to be adjusted to zero, initially and the plate or base of the weighing machine has to be levelled horizontally.

Now, the first Waffy packet is given to the operator 1 and the second packet is given to the operator 2. Initially, the operator 1 measures the overall weight and the individual wafer weight of the first packet and notes down all the readings shown in the weighing machine. Similarly, the candidate 2 weight the overall Waffy packet 2, both for the overall weight of the packet as well as the individual wafer of the packet and notes down all the readings shown in the weighing machine.

In the phase 2, the Waffy packets are to be exchanged between the operator 1 and operator 2. After exchanging the wafer packets, again the same procedure has to be followed. The operator 1 weighs the weight of the Waffy packet 2 and the operator 2 weighs the Waffy packet 1 and again each of the findings of the readings must be noted on the paper, as before.

Quality Concern

The results of weights of each of the wafer from each of the packet are taken and considered as inputs to calculate R&R percentage. The calculation should reveal the variation of the weight of the product, between the actual weight and the weight printed on the Waffy packet. If there is any variation, the extent of variation has to be calculated. The variation has to be analysed by drawing X and Y bars. The chart should show the variation between the weight after the manufacturing process and weight after the product is bought and consumed.

The aim of the quality engineering assessment for the Waffy chocolate flavour is to assess the quality standards followed by the company, in providing the accurate weight and so quantity, which is again one of the quality factors, which are set expectations to the customers.

The objective of quality engineering assessment of the Waffy chocolate flavour product is to investigate the standards of quality of manufacturing process, in terms of producing and packing the wafers up to the weight determined by the company and investigates the variation if any. The final analysis is done on the basis of the results obtained from the Gage R&R analysis and the control chart.

The manufacturing process of the Waffy, chocolate flavoured waffies is simple and the process is very conventional. The manufacturing process is done in various stages. Dukes processes the manufacturing process of the Waffy biscuits in all its 12 plants installed in India.

In the first stage all the ingredients are taken. The major ingredients needed for the Waffy biscuits are strtch, flour, sugr, soda, salt, flavours, preservatives, vanaspati, colors,e tc. During this stage, all the ingredients are procured and collected for the making of the waffy biscuits.

These ingredients are taken in large amounts. As the first part or phase of the manufacturing process, the flour is taken and it is mixed with the starch, salt, soda and others with the water. After mixing the ingredients, a mixer and paste are formed.

The paste is then taken into moulds. These moulds are pre-heated to some degrees of temperature already. The moulds are shaped in such a way that the wafers are produced in a particular shape after the process of baking.

Then the cream is prepared. For the preparation of the cream, sugar, essence, colours, sugar and flavours are required. The cream is prepared in the planetary mixer.

Quality Assessment

After the wafers and the cream are prepared, the following stage is to spread the cream that is prepared on the wafers. After the cream is pread on the wafer, the wafer is then sandwitched with another wafer.

After the entire product is made, the sheets of the large wafer is cut to the required sizes.

As th final stage, the wafers that are cut would be packed in the pre-determined size of the packets for the wafers.

Gage R&R is one of the measurement system analysis techniques that makes use of the ANOVA or Analysis of Variance for Repeatability and Reproducibility. The technique can be applied not only for the gauges or gages, but also for various kinds of test methods, measuring instruments and other measuring systems.

The Gage R&R measures the variability amount that is induced right in the measurements, by the very measurement system. It compares the total variability found in determining the measurement system viability. According to the practicalities of the measured systems, there are many factors that affect the measurement system, as the following.

Measuring instruments

Test methods

Operators

Specifications

Specimens or parts.

The measurement or precision has importantly The two important aspects that are determined through Gage R&R are,

Repeatability – that measures the variation resulted by a single operator or by a single instrument to measure the same product, measured under the same conditions.

Reproducibility – that is the measure of the same product that replicate the specimen, and this variation induced is measured when multiple operators or multiple laboratories or multiple instruments measure

The study of Gage R&R is used to compare the variation of the measurement system to the total process tolerance or variation.

When a crossed Gage R&R is used for the study, it can answer many questions, as follows.

Whether the measurement system variability is small, when compared to the variability of the manufacturing process?

Whether the measurement system variability is small, when compared with the limits of the process specification?

How much the variability from the measurement system would be caused from the differences among the operators?

Whether the measurement system would be able to discriminate among the parts?

The measurement done for the Waffy biscuits has the following elements considered.

Reproducibility for appraiser variation

Repeatability for instrument variation

Actual variation part as part to part variation

The Gage R&R analysis evaluates the appraisers and instrument contribution in the process of measurement. The analysis helps to resolve the data collected in terms of part to part variation and the corresponding measurement process of it.

Measurement Systems Analysis

Product

Figure 1: The Waffy product from Dukes

The packet consists of two slots covered with plastic wrapper. And the two slots are again packed with a small box, made of hard paper. So, the Waffies are covered in three layers, a plastic wrapper, paper wrapper and the final wrapper outside.

Figure:  Neutral Indication

Figure: Total weight of the Waffy

Figure: Weight of One Slot

Figure: Weight of One Waffy

The total weight of the Waffy = 92.498 g

The net weight of the Waffies are given over the pack = 75 g

the weight of the slot 1 = 40.784 g

the weight of the slot 2 = 40.390 g

and there are total 12 Waffies present in the total two slots.

So, the operator 1 has taken the slot 1 with 6 Waffies and slot 2 with 6 Waffies in it for measurement and

The operator 2 has taken the slot 1 and slot 2 with each 6 Waffies in them for the measurement initially.

Operator 1 – Slot 1 & 2 Measurement

	Operator 1
Sample	Slot 1	Slot 2	Range
1	6.403	6.209	0.194
2	6.543	6.547	-0.004
3	6.094	6.409	-0.315
4	6.83	6.509	0.321
5	6.723	6.237	0.486
6	6.129	6.465	-0.336

Table 1: Slot 1 & 2 measurement by operator 1

Operator 2 – Slot 1 & 2 Measurement

	Operator 2
Sample	Slot 1	Slot 2	Range
1	6.098	6.192	0.094
2	6.945	6.654	0.291
3	6.439	6.488	0.049
4	6.435	6.439	0.004
5	6.456	6.498	0.042
6	6.851	6.122	0.729

Table 2: Slot 1 & 2 measurement by operator 2

The data collected for the weight of each of the Waffy present in both the slots and the equations for the Gage R&R are calculated with the help of the spreadsheet.

R = Average range measured by Operator 1 and Operator 2

= 0.003 g

X a = Average Waffy measured by Operator 1

= 6.451 g

X b = Average Waffy measured by Operator 2

= 6.468 g

X diff = Xa – Xb

= -0.0164 g

For net specified measurement is 75 g

And there are 12 Waffies in the packet.

So, the average weight of the Waffy = 75 / 12 = 6.25

and when the tolerance considered is 3%, then the

Upper Specification Limit = 6.25 * 0.03 + 6.25

= 6.25 + 0.1875 = 6.4375

Lower Specification Limit = 6.25 - 6.25 * 0.03

= 6.0625

n = no. of samples taken

= 12

t = no. of trials

= 2

Repeatability = R * 4.56

= 0.129 * 4.56

= 0.0163

Repeat Percentage (%) = [Repeat / (USL – LSL) ] * 100

= 4.357

Where, k = 3.65

= 0.060

Reproducibility percentage (%) = [ Reproducibility / (USL – LSL) ] * 100

Assessment Procedure

= 15.954

R&R percentage (%) =

= 16.538
The quality standard of the product of any company can be analysed through R&R results and the standards are analysed as the following.

If R&R% < 10%, the quality standard is good the product is world-class product

If R&R% < 30%, the quality standard is acceptable and the product needs improvement, wherever possible

If R&R% > 30%, the quality standard is poor and it is not acceptable

The same calculations performed as shown in the spreadsheet.

	Operator 1			Operator 2
Sample	Slot 1	Slot 2	Range	Slot 1	Slot 2	Range
1	6.989	6.929	0.06	6.098	6.192	0.094
2	6.198	6.547	-0.349	6.945	6.654	0.291
3	6.094	6.409	-0.315	6.439	6.488	0.049
4	6.121	6.509	-0.388	6.435	6.439	0.004
5	6.723	6.434	0.289	6.456	6.498	0.042
6	6.002	6.465	-0.463	6.851	6.122	0.729
mean	6.3545	6.548833333	-0.194333333	6.537333333	6.398833333	0.2015
		R=	0.003583333
		Xa=	6.451666667
		Xb=	6.468083333
		Xdiff=	-0.016416667
		USL=	6.4375
		LSL	6.0625
		n=	12
		t=	2
		Repeat % =	4.357333333
		Reproducibility =	0.060
		Reprod. % =	15.954
		R&R % =	16.538

Table 3: Gage R&R

So, the final Gage R&R percentage is 16.538, which is more than 10% and less than 30%. So, the quality standards of the product acceptable, but needs improvement wherever possible.

Analysis of variance or ANOVA procedure is used by Minitab for calculating the variance components. And it uses the components for estimation of the variation of the percentage occurred from the measuring system. The variation of the percentage can be obtained from the Gage R&R table.

The table used for the ANOVA table is a two-way ANOVA table. The table includes the part, operator-by part interaction and also the operator.

The R-chart is used for evaluation of the repeatability that is resulted in a process. Each of the point specified and pointed in the R-chart is the representation of the measurements made by the operators. In case any of the point falls far away from the control limit, the measurement is considered as that the operator finds it difficulty to measure the same piece or Waffy again, especially, as a contestant manner. Such operator measurement issues can be corrected after identification, while the measurement is being done.

Each of the point shown in the Xbar chart represents the variation of the part to part, according to the data given in the data set as results. It is easy to identify that most of the weights measured by the operators, fluctuate from the reference point called the control limits. The control limit in this case is also called as the blind zone of the respective equipment used. As a result of that, the measuring instrument could not differentiate various parts that are measured. In such cases, the measuring instrument, here in this case, the weighing machine to be effective, the pointed values are better to be out from the control limit or the blind zone to the possible extent. The identical patterns are also to be observed in this analysis, from the graph of the operator. It is because, it can represent the overall mean of the measured values from the data set given or entered.

Aim

Figure 2: R chart and X bar

The chart shown for the component variation clues us regarding the variation in measurement when the same item is weighed at another instance. So, the measured value of the Waffy, when measured by the operator 1 does vary to the weight measured by the operator 2. The chart also clues us the overall components that would in turn result and contribute in the variation of the measurement data set. The more the difference between one to another part, the contribution is more to the overall variation, when compared to the other components, like repeatability, reproducibility or gage R&R.  

The process capability analysis is one of the statistical analysis methods that have the objective of comparing the outputs obtained from the in-control processes against the limits specified by using capability indices. The comparison can be obtained from the ratio of the spread that is found in between the specifications of the processes to the process’s actual spread values.

Conclusion

The case study is performed on the Waffy biscuit products, manufactured and produced by Dukes company in India. The quality analysis of the Wafffy biscuit product is done on the basis of Gage R&R. The product is Waffy and the company is Dukes. The quality concern that is considered for the case study is discussed followed by a quality assessment. A brief details about the measurement system analysis is done. Later the assessment procedure through which the assessment is conducted is discussed in various phases. Later the aim and objective of the case study is reported, which is to perform Gage R&R for the selected products. The manufacturing product of the Wafffy biscuits by the company is detailed of how the Waffies are made in various stages.

A detailed Gage R&R analysis is discussed followed by the calculations performed based on the data collected through measurement of the weights of the Waffies. The analysis is further extended by using the software, Minitab, in which the R chart and X bar and component analysis is done and finally all the analysis reports are presented.

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