INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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!

*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.

Jobs

Machinable non-conductive structural material recommendations

Machinable non-conductive structural material recommendations

Machinable non-conductive structural material recommendations

(OP)
Looking for a material to use for a structural component of dimensions roughly 5x5x5"

Hard brittle plastics are out do to bending loads. Wood too fibrous, plus it may get wet.

- Must be machinable
- Rigid
- Electrically non-conductive
- The more isotropic the better
- Can support tapped threads

Right now considering G10 FR4 fiberglass. Link
Though the directional properties due to the sheet layup are not ideal. Though it is machinable and can be had in thick blocks

RE: Machinable non-conductive structural material recommendations

(OP)
That's really interesting thanks for the link. Cool material. I'll look into it. It has a lot of the properties I'm looking for, but a bit concerned about the hardness and fracture toughness as this part will be dynamically loaded.

RE: Machinable non-conductive structural material recommendations

A bit short in info, so a very large number of possibilities exist.

You've posted here so a short glass fiber bulk or sheet molding compound springs to mind (may be called 'long' fibres but they're not continuous). The SMCs tend to be quite layered but won't be as layered as GR10 FR4. Injection moldable materials are also available. Matrixes of more pricey higher peformance plastic such as PEEK or PPS are available or engineering thermoplastics like Nylon may be good enough, and good performance from thermosets like epoxy or vinyl ester can be had.

Quantum Composites (http://www.quantumcomposites.com/) might well have something suitable. You could also try TenCate, but I find their website quite confusing (they've eaten a lot of the older companies such as CCS). Victrex advertise a lot of short glass reinforced grades of PEEK (http://www.victrex.com/en/datasheets/datasheets.ph...). There are a million glass reinforced Nylons (at random via Google http://catalog.ides.com/datasheet.aspx?culture=en&...).

The Macor courtesy of CoryPad is certainly interesting but it is rather frangible (fracture toughness under 5 MPa√m or ksi√in). If 'hard brittle plastics' are out then Macor won't be any better. Is this part subject to shock loads?

It depends quite a bit on what your requirements really are: is weight important or cost? What sort of quantity? And so on. Your requirements as listed seem a bit confusing: a 5"x5"x5" cube and bending might be a problem? Also I'd seek to quantify your 'rigidity' (some sort of strength or stiffness in psi/MPa) and 'electrically non-conductive' (dielectric strength in V/length or resistivity in ohm-m) properties. Also you'd like it isotropic and yet are considering a G10 FR4 laminate. If you can't quantify the degree of isotropicity then perhaps say why it needs to be 'The more isotropic the better'.

If you refine your needs a bit (the strength needed and temperature extremes are probably the most important) I'm sure you'll get good advice from our associates in the Polymer engineering forum (http://www.eng-tips.com/threadminder.cfm?pid=334). Also, I take it that you've no constraints on manufacturing method? Or do you want to make whatever it is in-house?

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!


Resources


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