Heat sealing 热合

Edges are welded with heat rather than sewn.

Back end 后道 Required by 103 of the 247 products we catalogue.

What actually happens

A heat seal closes completely where a sewn seam has needle holes, which matters for fine powders and for moisture barrier.

What to specify

Say what is going in the bag — powder fineness decides whether a sewn seam is acceptable at all.

How it goes wrong, and what catches it

The failure mode. Weak or intermittent seals that pass visually and open in transit.

The control. Seal integrity tested on sampled bags rather than assessed by eye.

We publish which of our plants runs this process — see the capability matrix. We do not publish which plant runs a given order.