×
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!
  • 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

Jobs

Trying to use vibration to insert tubing- need guidance

Trying to use vibration to insert tubing- need guidance

Trying to use vibration to insert tubing- need guidance

(OP)
I am sliding a small metal cylinder into plastic tubing (nylon) and keep getting high frictional forces (ie it jams or damages the plastic)- I can't use lubrication - so I thought about vibration to keep it dynamic- any thoughts or guidance?

RE: Trying to use vibration to insert tubing- need guidance

Thoughts -

Do you have a length to diamter issue?
Do you have the ability to use either of the following to aid in assembly - heat to expand the nylon or expand the nylon with air pressure during assembly.

good luck

RE: Trying to use vibration to insert tubing- need guidance

The tubing has considerable damping for vibration energy. If I were to try vibration, I would probably excite the tube at its ring frequency. This would be the first vibration mode where the diameter expands and contracts. There are formulas available to calculate this frequency. A small diameter thin wall tube will have a very high frequency and the actual displacement will be low. I doubt that bending vibration modes would help, but that is another possiblility.

For temperature method try cooling metal tube and warming plactic tubing and then work very fast before temperatures equalize.

Walt

RE: Trying to use vibration to insert tubing- need guidance

Try cooling the cylinder using the spray that plumbers use to freeze central heating pipes (Arctic spray? - from a Hardware store)

RE: Trying to use vibration to insert tubing- need guidance

(OP)
Thanks for the vibration insight.  Is there an on-line reference for the ring frequency calculation?
To answer the length:diameter ratio question, it's 60:1, so there is a lot of friction condition and potential for damage / failure to complete the insertion.
I do have a cooling option available (I use electronics cleaner duster spray from a can), it's just not a long term, operator friendly option.  I also have compressed air-vortex chillers available, but they get noisy.

RE: Trying to use vibration to insert tubing- need guidance

It works if you keep it "dynamic" ?
Spin the cylinder during insertion?

I can expand and pop the handgrips right off my motorcycles with compressed air. How much would the nylon have to expand to make clearance?

RE: Trying to use vibration to insert tubing- need guidance

Not gonna work.  Too much damping in the plastic, and you'll kill the vibration in the section of interest as you slide the cylinder in.  Think pressure and temperature like these guys are saying

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