×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

#### Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

# Factorial design

## Factorial design

(OP)
I hope I will explain my problem clearly. I want to do pilot plant tests to first screen the significant factors out of five factors, then carry out a response surface DOE to optimise the plant settings based on a few of the significant factors.

My problem is that it is not possible to set any of the factors to their exact values according to the matrix, e.g. pressure 100.0 bar, temperature 80.0 oC. There will be a slight variation in all of these values. For some of the factors the variation can not simply be ignored, not too much, but it is significant. Is there a way of taking this into account?

I hope someone will be able to assist.

Thanks

### RE: Factorial design

There is a slightly complex theoretical answer, in which you examine noise in your experiment, or there is a rather easier if less efficient answer, which is to measure the sensitivity of your responses to small changes in each factor and then use those to 'correct' your main DOE results.

Personally I'd be inclined to make sure that your levels are set say at least 5 times the natural variability in the factor apart, and use the nominal level in your analysis.

Cheers

Greg Locock

New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

### RE: Factorial design

(OP)
Thanks Greg. This really helps. Thanks again.

### RE: Factorial design

(OP)
Thanks Greg. This really helps. Thanks again.

#### Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

#### Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Close Box

# Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!