Manufacture and processing
The pilot plant comprises 17 drums of three different sizes that have been manufactured locally. They can process between two and fifteen skins. After dyeing and fatliquoring the skins are set, and the gloving leathers hang-dried for between 24 and 36 hours according to substance. This is mainly a suspension drying method supported as necessary by heat cells. This operates in four drying sheds each of 20,000 skin capacity. This arrangement consists of parallel rows of drying rails fitted with pins from which the skins are suspended. The skins are manually loaded and unloaded from floor level, but there is a second layer of drying rails, and these are serviced from an operating platform mounted on a track that can be moved along the whole floor area. The skins are then softened using a combination of seven milling drums of local manufacture, and hand staking on a bank of eight hand staking machines all fitted with dust extraction. Skins for shoe upper leathers are vacuum-dried, then vibration staked, and buffed.
After grading, the wet blue skins are trimmed before blue setting and shaving. About 20% of the workforce is women.
The finishing department comprises two Gemata roller coating and five spraying machines. All are fitted with electric radiant elements for finish drying. In addition to printing and feed-through roller presses, the department is equipped with glazing machines and milling drums.
Stainless steel processors are used for soaking, unhairing and pickling processes. These are of various sizes and have been manufactured in Indonesia. Four stainless steel hide processors made in Indonesia are used for an 18-hour soak and hair dissolving process for raw sheep and goat skins. Three of these vessels have a working capacity of 500 skins, the fourth a capacity of 700 skins. When there is an excessiv
e number of skins available for soaking—say following festivals—the plant capacity can be increased by suspension soaking in static pits. In this event the skins are individually suspended from bamboo frames.
Fleshing carried out using three floor-mounted fleshing machine and this followed by deliming and pickling in an 18 hour process in three more hide processors of similar size.
All of the skins are inspected in the pickled state. The interior of this department is lined with panels made from split bamboo as this helps to reduce the temperature in the building
Two types of tannages are carried out on site. One is chrome tannage, the other wet white, and this takes place in eight elevated tanning drums. These are slow-revolving, four being 2.5m diameter x 3 m across and manufactured by Vallero, the remainder are of smaller size being manufactured locally. The drums are serviced from an elevated feed platform running along the back of the drums. The chemicals are raised to this level from the chemical store by lift. At the rear of these tanning drums there is a series of concrete tanks—one for each drum—where salt is dissolved to make up the salinity of the tanning bath and to prevent swelling of the pickled skins.
The tanning department comprises eight tanning drums. Four of these have been manufactured locally.
Skins purchased in the pickled condition are wet back, dropped from the drums into containers, stacked into bundles and spun in a centrifuge for dewatering. These are then inspected, trimmed and graded. Wet blue manufactured on site, and skins purchased in the wet blue condition, are also trimmed and graded according to substance, size and four quality grades.
Both the dyeing and tanning drums are serviced from elevated platforms running along the rear of the drums.
As each skin is shaved it is checked for substance to ensure conformity, and this is followed by dry wheeling on a batch of buffing wheels to remove residual fibres and clean the flesh side. Each batch is then weighted and dyed.