Stamping process consist of using a tooling engraved with a design (logo) and to strike it ( using a press ) against a raw material ( mostly iron or brass ) and thus recreating the engraved logo on the tooling onto the material with an embossed / debossed effect.
Most common stamping is a 2D process with up ( relief, embossed ) area and down (recess, debossed ) with each of those relief surface and recess bottom being flat, like a staircase.
3D stamping process is made with a different tooling that has been engraved in 3D, using more advanced computerized and numerical CNC engraving process ( the same used to make injection tooling for instance ).
The difference will be both relief surface and recess bottom are no longer flat but convex/oblong
Design engraved down on the tooling will be embossed ( relief ) on the material
Design engraved up on the tooling will be debossed ( recess ) on the material
Stamping recessed area is usually around 0.2 to 0.3 mm depth suitable for both soft & hard enamel process.
Without further process, leaving recess area without color enamel, is called blind stamping.
Stamping can be made by many different type of press most common are vertical press 50t and 80t.
For more special items, like large item, convex shape or high precision stamping we use hydraulic press, 250t and 500t.
Blind stamping is expensive and very slow but very qualitative
