You can see this in the fogging of some clear plastics on the outside surface.
Binding sheet metal to hard plastioc.
This is done through the application of force on a workpiece.
Your tapping should start at one end of the evolving bend.
You must use two hands to do this with even pressure or your material will twist slightly as you bend it unless you are working with a very thin narrow strip.
Do this until it bends toward the form block and achieves your desired angle gradually and evenly.
Holding the sheet material evenly with both hands both in protective gloves push the sheet up gently bending it against the line of the jig as shown in the photo above.
Commonly used equipment include box and pan brakes brake presses and other specialized machine presses typical products that are made like this are boxes such as electrical enclosures and rectangular ductwork.
The force must exceed the material s yield strength to achieve a plastic deformation.
To prevent damage or unsightly dents it s best to use a rubber plastic or rawhide mallet to gently tap the metal.
Bend the metal with your mallet.
Also known as press braking flanging die bending folding and edging this method is used to deform a material to an angular shape.
When a bend is made in sheet metal or plastic the outside of the material structure expands while the inside compresses.