# Finding Optimum Design Parameters using Taguchi method?

#### DavidSt

##### Registered
Hi all,

I have a design with 6 factors (parameters) with levels varying from 8 to 4.
The goal is to find the combination of factors that gives the largest output value in the least number of experimental trials.

Most of the factors affect the output non-linearly, and many factors interact with one another non-linearly.

I have some prior distant experience with Taguchi methods, but not other DOE methods.
From what I recall, Taguchi methods work best to predict the optimal output value when the factors are linear and independent of one another (little to no interaction).

I was wondering whether people have had success implementing Taguchi methods for the design described above (i.e. multiple, multi-level, non-linear, interacting factors)? I would like to stick to Taguchi methods if possible if it will do the job.

To emphasize, although it would be nice to analyze the interaction between the factors, it is not of prime importance.
Also, accurately predicting the optimal output value is not of prime importance.
However, accurately predicting the factor levels that result in the optimal output value (or within 5% of the optimal for instance) in the least number of trials is of prime importance.

Thanks,
David

#### Miner

##### Forum Moderator
Staff member
Taguchi had many important contributions to the concept of robust design, but there are more efficient approaches to optimization than those he proposed. In your situation, I recommend a sequential experimentation approach.
1. If not much is known, start with 2^k screening designs with center points.
2. If a lot is known, use response surface designs to optimize
3. If starting with a 2^k screening design:
1. If there are significant main effects, but no interactions or curvature, explore the path of steepest ascent(descent)
2. If there is an interaction, move the next experiment's center point to the "best" corner of the current design
3. If there is a curvature effect, add axial points and analyze as a response surface design

Another approach to consider is EVOP (EVolutionary OPtimization).

#### DavidSt

##### Registered
Hi Miner,

Thanks for the response and sorry for the delay.

How much better would you suggest the sequential experimentation approach is compared to the Taguchi method for finding the optimal (or near optimal) factor values as described in my original post?

Using the Taguchi method, I could use a 32 trial design for the six factors of varying levels (8 to 4). When you say there are more efficient approaches, do you mean that the 32 trial Taguchi design would not likely yield parameter values that are in fact optimal due to the non-linear, interacting nature of the factors? (since if you are referring to the number of trials, 32 trials is quite efficient for my needs).

Assuming the former, could you recommend any good resources (webpages, books, ...) for a beginner to response surface design or 2^k screening designs? A resource that explains the concepts well, with straightforward examples, that would allow me to use the methods for my own design?

Thanks,
David

I Finding optimum transformation equation for two sets of data Using Minitab Software 15
Finding Independent License Holder (Medical devices) in Philippines Other Medical Device Regulations World-Wide 0
Stage 1 Finding. Request views and comments ISO 13485:2016 - Medical Device Quality Management Systems 3
External calibration - Finding in our 3rd party audit General Measurement Device and Calibration Topics 58
How to answer ISO9001:2015 audit finding of old revisions of documents being used? Document Control Systems, Procedures, Forms and Templates 8
Help with CAPA for an IATF finding regarding inspection documentation IATF 16949 - Automotive Quality Systems Standard 10
Auditor MDR (Presub audit) finding EU Medical Device Regulations 2
Using R package to implement Bayesian phase I/II dose-finding design for three outcomes ISO 13485:2016 - Medical Device Quality Management Systems 6
ISO 9001/IATF 16949 Audit Finding Question - Document Retention IATF 16949 - Automotive Quality Systems Standard 11
ISO 9001-2015 Internal audit finding Internal Auditing 14
Define timeline for Major and Miner Audit finding General Auditing Discussions 4
Closing a finding before closing meeting General Auditing Discussions 14
Audit Finding For Not Retaining Test Results ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 7
OHSAS 18001 external auditor finding personal interpretation? Occupational Health & Safety Management Standards 5
Received a Major finding during IATF Surveillance audit for loss of BIQS Level 3 (more than 6 SPPS in 6 months)...how should we address SYSTEMIC CA? IATF 16949 - Automotive Quality Systems Standard 11
Finding a flat or not modeling distribution: how to manage it? Capability, Accuracy and Stability - Processes, Machines, etc. 24
Looking for Tips on finding an IATF consultant Consultants and Consulting 6
Customer Audit Finding ISO13485:2016 7.6 ISO 13485:2016 - Medical Device Quality Management Systems 7
PED 2014/68/EU - Is this Traceability audit finding correct? Other ISO and International Standards and European Regulations 4
Design and Development Requirement - MDSAP Audit Finding Other Medical Device Regulations World-Wide 5
R Major nonformance finding was given during a closing meeting of a ISO9001 certification audit General Auditing Discussions 76
Audit finding - Components being transferred inter-plant Internal Auditing 3
Difficulty Finding A Notified Body for CE Marking - No Capacity Registrars and Notified Bodies 5
D AEA (Aerospace Experience Auditor) Challenges - Finding availability of AEA for witness AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 3
IATF 16949 7.1.5.3.2 FAQ #7 Audit Finding - External Calibration Laboratory IATF 16949 - Automotive Quality Systems Standard 7
Major Finding Elevation - Do I elevate this minor finding to a major one? AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 14
GM/VP softgrading internal audit finding - need feedback from an audit guru! General Auditing Discussions 11
Customer Requirements - AS9120B Audit Finding AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 24
IATF 16949 registration - Major Nonconformance Finding IATF 16949 - Automotive Quality Systems Standard 9
Hardness inspection Audit Finding Employee error Nonconformance and Corrective Action 6
How long should I have to correct an audit finding? VDA Standards - Germany's Automotive Standards 7
How to appeal a major audit finding ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 26
T Non-addressed Minor Finding elevated to Major Finding Internal Auditing 37
Definition Would a wrong definition constitute an Audit Finding? Definitions, Acronyms, Abbreviations and Interpretations Listed Alphabetically 3
Audit Finding Flowchart for Feedback General Auditing Discussions 6
Finding a Fixture Design Course to meet Customer Requirements General Measurement Device and Calibration Topics 3
Audit Finding - CAPA, Improvement Initiatives not filed in CAR System ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 5
O CFDA (China Food and Drugs Administration) Audit Finding Classifications China Medical Device Regulations 1
B Expired Materials (threadlocker) Audit Finding Classification? Internal Auditing 1
Is not training to ISO 9001 procedures a finding? General Auditing Discussions 16
Could I issue major finding for Inadequate Procedures Supplier Quality Assurance and other Supplier Issues 17
S Finding a substantial Equivalent Medical Device Other US Medical Device Regulations 4
H Cause analysis for an Audit Finding - Purchasing Procedure Content ISO 13485:2016 - Medical Device Quality Management Systems 9
Finding specific 510k guidance for Keratoprosthesis (MLP) Other US Medical Device Regulations 1
Is it a Finding if all Internal Auditors are from the Quality Department? Internal Auditing 18
A Writing an Internal Audit Report Finding for Employee Awareness of QMS Documents ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 11
S Audit finding for JPAL ISO 13485:2016 - Medical Device Quality Management Systems 1
R Can a external auditor raise a finding that is already identified in Internal Audit ? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 11
J Validating a stopped test due to never finding any defects Inspection, Prints (Drawings), Testing, Sampling and Related Topics 2
G Supplier Significant Environmental Aspects - Audit Finding ISO 14001:2015 Specific Discussions 21