Taguchi Testing

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21 Aug, 2024

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Taguchi Testing is a tool that aids in understanding the optimal operating window for manufacturing a product. It helps meet the expected standards and minimize the effects of external noise during the product's output process.

The Taguchi method is a statistical analysis tool that is applied in manufacturing and engineering to improve the quality of processes and products. The principles of Taguchi testing, which involve the efficient testing of multiple variables to determine optimal outcomes, are now used online for landing page optimization, sales letters, and PCC advertising.

What Is Taguchi Testing?

Taguchi testing is a technique for multivariate testing that thoughtfully minimizes the amount of testing needed.
It is akin to the comprehensive approach of full-factorial multivariate testing, where the goal is to discover the best mix of different elements in a campaign.
It is used to determine whether a product design can be mass-produced at an early stage of the New Product Introduction or NPI process.
The technique uses statistical analysis to compare several parameters at once and determine the best operating window for increased resilience and performance.

Taguchi Testing Explained

Taguchi testing is a method of multivariate testing that uses heuristics to reduce the number of tests required. It is similar to full-factorial multivariate, aiming to find the optimal combination of variants across key campaign components or elements. Taguchi optimization is a method used to balance rigorous statistical testing and compressed time schedules in product design.

It involves identifying parameters that will have a significant effect on system performance and narrowing them down for testing. The testing then detects the levels of each parameter to ensure robust performance. With the efficiencies of robust design experiments, it is possible to optimize a system design for reliable performance within a tight design schedule. It determines the optimal working window, and it also facilitates a shorter development process and a quicker launch of the product onto the market.

The method places a strong emphasis on the necessity of using an appropriate production process and product design to produce high-quality final goods. The analysis may be helpful, mainly when a manufacturing company transfers to a new supplier and takes the current mold tooling with it. The new supplier may produce items that fall outside the existing company's requirements because of different surroundings. They would only fully understand the design problem or identify the problem with a Taguchi analysis since the operating window can be too small.

Early analysis in product development is crucial as late-stage design changes can be costly and problematic. Taguchi testing should be used to determine whether a product design can be mass-produced at an early stage of the New Product Introduction (NPI) process. The outcomes might show whether the working window is too narrow and needs a lot of scraping or reworking or whether a redesign is required before moving on with more development.

Examples

Let us look into a few examples to understand the concept better.

Example #1

Suppose ABC Ltd, a car manufacturer, opts to use this method due to several reasons. Let us understand how they could use this in their manufacturing unit.

Firstly, this method offers reduced experimental size compared to traditional full-factorial experimentation. It means that ABC Ltd can achieve the desired level of performance with a smaller number of experiments, saving time and resources.

Secondly, this method focuses on robust design. It means that the designs derived from this method are more stable and less sensitive to variations in conditions. ABC Ltd can develop cars that perform consistently well across a range of real-world conditions, leading to improved customer satisfaction and reliability.

Lastly, this method utilizes signal-to-noise ratios as a unique set of performance metrics. These ratios allow ABC Ltd to evaluate the results of experiments accurately and objectively. By considering both the mean performance (signal) and the variability (noise), ABC Ltd can make informed decisions about the optimal parameter settings for their cars, ensuring better overall performance.

Example #2

Let us understand this method further through a research. The purpose of this research was twofold: to enhance the process yield rate for air cleaners in Toyota Corona vehicles and to identify the robust parameters for this process using the Taguchi method and experimental design. The study aimed to minimize nonconformities, reduce scrap costs, enhance the quality of injection of plastics, and decrease environmental pollution by reducing nonconformities and increasing the usage of recycled material. The researchers analyzed the injection mold using an L orthogonal table to investigate the relationship between injection conditions and nonconformities.

Through the application of the S/N ratio, ANOVA, and response surface methods, optimal conditions for parameter specifications and process standards were suggested. The findings have potential applicability to other products, and the research team aims to develop user-friendly software for implementing the Taguchi methodology in video instruction for both suppliers and users. Additionally, the researchers intend to apply the Taguchi method to other vehicle components and their respective processing methods.

Benefits

The advantages of conducting a Taguchi analysis in the early stages of product design and development, specifically during the New Product Introduction (NPI) process, are as follows:

Cost reduction in product development: By utilizing Taguchi analysis, businesses can avoid the lengthy and expensive trial-and-error testing phase. It saves both time and resources by identifying and focusing on the crucial factors that need to be tested.
Improved product quality at an early stage: Making changes to the product design becomes increasingly expensive as the development process progresses. By implementing Taguchi analysis early on, potential design flaws and quality issues can be identified and rectified, leading to improved product quality before significant investments are made.
Enhanced product performance: Taguchi analysis allows for the optimization of product parameters to achieve desired performance characteristics. Taguchi analysis can help determine the optimal parameter settings to achieve the desired standard or level of performance.
Reduced time to market: By minimizing the need for extensive development iterations, Taguchi analysis accelerates the product development process. It enables businesses to bring their products to market more quickly, gaining a competitive edge and capturing market opportunities sooner.

Better product dependability, happier customers, and lower manufacturing costs are all the results of this strategy. In summary, conducting Taguchi analysis early in the product design and development process offers several benefits. It includes cost reduction, improved product quality, better performance, and shorter time to market. These advantages contribute to overall efficiency and competitiveness in the marketplace.

Criticisms

Some points of criticism are given as follows:

These kinds of tests can take a lot of time to plan and administer.
This also requires a significant subject matter expertise.
Taguchi is still resource-intensive even though it potentially reduces the number of tests.
The Taguchi method is not theoretically sound and should be avoided in online testing due to its assumptions.

Frequently Asked Questions (FAQs)

1. Which software is used for Taguchi Testing?

The software utilized for Taguchi analysis may differ depending on organizational or individual preferences. Commonly employed software tools for Taguchi analysis include MiniTab.

2. What are the eight steps in Taguchi testing?

The Taguchi method comprises eight steps: problem identification, objective determination, factor and level selection, orthogonal array design, experimentation, data analysis, optimal parameter determination, and result verification.

3. What is signal in Taguchi testing?

Within the Taguchi method, the term "signal" pertains to the desired performance characteristic of a product or process. It represents the targeted output that necessitates optimization or maximization.

4. What is a Taguchi array?

A Taguchi array, also known as an orthogonal array, is a structured matrix used to represent a series of experiments in Taguchi testing. It facilitates efficient exploration of the parameter space by ensuring comprehensive testing of all factor and level combinations while minimizing the required number of experiments.