Difference between Extruded and expanded foam!
Difference between Extruded and expanded foam!
(OP)
Hi
I am trying to understand what do these two terms mean? They both have closed cell polymer structures?
What kind of foam is used in making the of firm packing foams?
Please correct me if any information is incorrect. Appreciate your help in advance.
Thanks,
V.
I am trying to understand what do these two terms mean? They both have closed cell polymer structures?
What kind of foam is used in making the of firm packing foams?
Please correct me if any information is incorrect. Appreciate your help in advance.
Thanks,
V.





RE: Difference between Extruded and expanded foam!
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: Difference between Extruded and expanded foam!
This is as used in packing foam materials, not aircraft structural foams.
Extruded foam ( we are talking Styrofoam here) is a foaming material extruded through a die , it is homogenous. Expanded foam is often called bead board, It is made by steam heating Styrofoam pellets in a die box until they expand and adhere to each other it is not as strong as extruded foam.
Sometimes so called firm expanded foam is a rapid two part polyurethane foam injected into a plastic bag in a box with components to be shipped in the box but separated from the foam by the plastic bag, the foam expands and surrounds the components protecting them from shipping damage.
On aircraft foams, Some PVC foams are expanded foams, where a foaming material is expanded and cured in a box, then sawn into sheets and sections for later use. There are other foams, but if I describe them all I will have several pages here without answering your question.
B.E.
You are judged not by what you know, but by what you can do.
RE: Difference between Extruded and expanded foam!
RE: Difference between Extruded and expanded foam!
Yes, if it is a polystyrene extruded foam, go by the weight of the foam in Lbs per cubic foot, the heavier the foam the firmer it is.
Also do not forget the Polyurethane two part packaging systems I mentioned.
One of the newer items on the market is an extruded starch based foam that is bio degradable, it too can be bought in different densities.
Here is a link http://www.starchtech.com/biodegradable-packing-pe...
So if you are packing something to ship, you have to determine what foam you, and the customer want. Be aware that starch based foams do not do well in High humidity.
If you are using this for an aircraft part, then the Blue Dow extruded foam, is most commonly specified for hot wire cutting.
B.E.
You are judged not by what you know, but by what you can do.
RE: Difference between Extruded and expanded foam!
http://www.ecovativedesign.com/mushroom-materials/
RE: Difference between Extruded and expanded foam!
http://greatstuff.dow.com/pdfs/factsheet.pdf
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: Difference between Extruded and expanded foam!
RE: Difference between Extruded and expanded foam!
Thanks for the info. I assumed they were similar because their textures are fairly similar.
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers