How is 3M dual lock made?

[fpjeepy]

It's that stuff that is like super strong velcro. I use it all the time, the fastest way to fasten some things. But I got to thinking today. How do they make it? It's millions of tiny mushrooms, but mushrooms don't pull out of a mold so if they aren't injection-molded how are they made?

[yachi]

My guess is they push a hot plate onto the straight filaments to just deform the tops, the pull it away.

[fpjeepy]

I like that, but they look so perfectly spherical on the tops

[HPstache]

It's that stuff that is like super strong velcro. I use it all the time, the fastest way to fasten some things. But I got to thinking today. How do they make it? It's millions of tiny mushrooms, but mushrooms don't pull out of a mold so if they aren't injection-molded how are they made?

Hmmmm interesting question...  Mechanical engineer here who works in manufacturing.  You can make injection molded parts that would not appear at first glance to be able to be ejected from a mold using slides that are internal to the mold which close of cavities during the molding process but then slide out of the way during ejection... but I don't think that's what is happening here, that would be insanely complex for a product like this.  My initial guess would be that it's molded as spikes that are longer than the finished part and then run through a secondary process that heats the end of the spike to form a bulb.  They look really consistent though, so if they are doing it this way they must have a really controlled heating and cooling process to form bulbs that are exactly the same.  Would be curious as to what others think.

[HPstache]

I like that, but they look so perfectly spherical on the tops

Now that I see this closeup picture, I will revise my guess (due to the flat bottoms of the bulbs) that they are molded as strips with spikes and then the strips are loaded into a machine that pushes the feature-less spikes into a heated roller that has concave pockets so that you get the rounded tops and flat-ish bottoms.

[fpjeepy]

I'll buy it. Thanks

[MayDay]

Former 3M Engineer here.

I'm not telling!

Haha I actually don't know how they make that product but it follows the 3M strategy: make it by the mile, sell it by the inch.