[squale]

Okay let me try to explain best I can.. I attached a picture to help in my explanation.

I have a tube of hand lotion, plastic tube. The tube is open ended, meaning it's NOT sealed yet.

I can measure the O.D. of the tube before it's sealed no problem. So say the OD of the tube at the top where the open end is measures 25mm... well then all the way at the bottom of the tube right before the tube cap it will still measure 25mm in OD.

The problem comes into play when the tube is crimped and sealed.. As soon as you crimp and seal the tube it will change the OD measurements of the tube from top to bottom.. lets call this the 'profile' of the tube. I need to know what the profile of the tube is going to look like when it's sealed.

I use a loft feature in solidworks to make the tube. I figure there must be some sort of a math equation to figure this profile out. Something like.. Given the tube O.D. and the length of the tube... when the tube gets sealed, you need to know what the seal width will be and then how the profile of the tube is going to change along it's full length. Any math guru's here?

[JerryFlyGuy]

How accurate does it need to be? I'd think using the circumference on the tube before it's crimped should match the circ of it after it's crimped [w/in a tolerance anyway]..

Fwiw

JFG

[clembrant]

Draw an ellipse, then use an equation making the perimeter a constant. As you flatten the vertical your horizontal should widen.

[clembrant]

here are some pics

[oeffner]

the measurement should remain the same. all you did is change the shape of the material. Only the shape has changed. To change the dimensions you would have to add or subtract material. A string wrapped around the tube will still fit any place on the tube only the shape formed by the string would change
of course this is just my opinion and I was wrong once !