Hauni Gd x2 Nano Size Folding Die For Hard Cigarette Packet Packing Machine

Pocket is a moulding part of cigarette packing machine that helps shape a cigarette packet.

Advantages Of Blackening

Blackening can be done in large batches (ideal for small parts).

It is far cheaper than similar corrosion protection systems, such as paint and electroplating.

There is no significant dimensional impact (the blacking process creates a layer about a micrometre thick).

Hot Blackening

Hot blackening involves dipping the part into various tanks. The work piece is usually "dipped" by automated part carriers for transportation between tanks. Oil is then applied to the heated part, which seals it by "sinking" into the applied porous layer. It is the oil that prevents the corrosion of the workpiece. These tanks contain, in order, alkaline cleaner, water, caustic soda at 140.5 °C (284.9 °F) (the blackening compound), and finally the sealant, which is usually oil. The caustic soda bonds chemically to the surface of the metal, creating a porous base layer on the part. 

Hot Black Oxide

Water must be periodically added to the bath, with proper controls to prevent a steam explosion.Hot baths of sodium hydroxide, nitrates, and nitrites at 141 °C (286 °F) are used to convert the surface of the material into magnetite (Fe3O4).