Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*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.

Students Click Here


Thickness measurement QA for large surface areas (1500x1500)

Thickness measurement QA for large surface areas (1500x1500)

Thickness measurement QA for large surface areas (1500x1500)

Hi All,

I'm looking for a way to check the thickness of large pieces of honeycomb (1500mmx1500mm)

Until now we've been measuring the thickness at various points along the edges and averaging out, however this is not very accurate as it doesn't take any measure of the points within the edges.

Our process is very thickness sensitive and there seems to be a considerable amount of variation coming from our suppliers.

Ideally I would like a method to ensure the majority of the honeycomb piece is NOT LESS than X mm, with a precision of at least 0.05mm

Are there any standard methods of making this kind of dimensional check?

Thanks for your help!

RE: Thickness measurement QA for large surface areas (1500x1500)

What are you using now, a spring-loaded dial indicator with large anvils? All you need is a reasonably stiff and flat table top (a granite table would be idea but not necessary) to support the core while measuring. Mount the dial indicator over the center of the table on a beam that allows the core to move freely under the indicator. There are electronic indicators if you need to collect data electronically.

RE: Thickness measurement QA for large surface areas (1500x1500)

IRstuff: the variation we're getting depends on suppliers, it ranges from +/-0.2mm to +/-0.05mm every 200mm along the edge periphery. I'm looking to get a clearer picture of the average thickness of the entire honeycomb sheet by getting a grid of measurements of maximum 200mm x 200mm apart across the whole area (so about 60 measurements per 1500x1500 sheet)

Compositepro: We have been taking measurements along the edges with vernier calipers until now.
I imagine it would be difficult to measure over the non-continuous surface of the honeycomb using spring loaded indicators, have you had success in doing so? I should think the indicator tip would fall into each individual honeycomb cell and then catch on the cell sidewalls as it passes over the sheet.


RE: Thickness measurement QA for large surface areas (1500x1500)


Get a flat point for your indicator like this. Link

John H. Dunten, CD
Certified Drafter

RE: Thickness measurement QA for large surface areas (1500x1500)

DraftingMan/Compositepro: I've just understood the "spring loaded indicator with large anvils" is in fact what draftingman has proposed.. That certainly sounds like a good solution to try out - I had never seen one of those before.
I might attempt the beam setup with a "large anvil" LVDT, if can find one with the required accuracy, so that I can capture the data for QA.

Thanks All for your input!


RE: Thickness measurement QA for large surface areas (1500x1500)


My first thought was basically the same as Compositepro's suggestion. However, depending on the stiffness and flatness of the honeycomb, you may have a gap between it and the table at the measurement location. To avoid including the gap in your local thickness measurement, you could mount another indicator tip-up through a hole in the table and then sum the readings. Display units capable of addition and subtraction are available for electronic gages.


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.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


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:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close