Tannery work process steps one by one

Tannery flow chart
Raw material ►Raw trimming

Soaking
The first step of leather production restoration of water content up to 65% in salted, dry salted or dried skin and make it softer and flexible removal of dung , dirt and non wanted protein.
Liming
Opening up the skin structure to plump the collagen protein fibers bundle by mean of lime. Removal of hair and epidermis layer.

Mechanical process ►fleshing by mean of fleshing machine

flesh removed which consist of fat and nonwanted in next process

Deliming
After liming Deliming is the process to remove the chemically bonded lime. Non bonded lime is also removed through ammonium sulphite and other Deliming agents.
Bating
It effect a further opening up of the collagen fibers, depleting of the skin material, loosening of scud and scurf and splitting of the natural fat by the presence of lipases.
Degreasing
To remove a high content of natural fat, especially in sheep and lamb skins, some kind of goat skin, pig skin and many hides.
Pickling

The pelt is acidified to a pH<3.8>

Tanning

1. Chrome tanning 2. Vegetable tanning
Chrome tanning
A process which cross-linked with the collagen protein through different types of bond without modifying the natural fibers texture. This is carried out by means of chrome salts mostly chrome sulphite is used.
Wet blue
Chrome-tanned wet leather designated “wet blue”.
Vegetable/ synthetic tanning
The leather is tanned by means of natural tanning material which has the ability to bond with collagen protein like mimosa, quebracho, and chestnut.
Wet blue or vegetable crust storage
Damp storage
Upon completion of the tanning process the leather is intermediately stored on trestles or pallets for at least 24 hours.

Vegetable tanned leather are washed or preferably soaked upon completion of the tanning process in order to remove the considerable excess of unbound tanning agents, from the grain layer.

Production of natural or dyed crust

Direct dyeing ------indirect dyeing

Direct dyeing

It is carried out by shaving wetblue leather after saming setting and wieghing it to proceed for drum dying process. low cost less labour and mechanical work required. Quality of leather may varies from indirect process.

Indirect dying
1st making natural crust and than dying more time, labour and mechanical cost. The quality of leather is camparativly good to direct dying after dyeing leather is proceeded for dry most common method for drying is hang dry or air dry which is cheap.
finishing
This is last step of leather making finish leather mean leather is prepared for final use either for garment or footwear. Finish is done to give the leather desire attraction and look its shining effect and beauty.