Garments Dyeing Machines Various types of garments dyeing

Garments Dyeing Machines Various types of garments dyeing machines have been developed and all those garments dyeing machines can be classified into following two groups. • Pedal dyeing machine • Rotary dyeing machine Pedal dyeing machine: • Pedal type garments dyeing machine is the first and oldest type of garments dyeing machine still used in the European countries. • Pedal garments dyeing machines are two types that is overhead pedal type and side pedal type. • It is generally used for the woolen knit wear type garments dyeing. • Dyeing cost is higher in pedal type dyeing machine due to manual operation, higher labor load, manual loading-unloading, chemical feeding etc. reasons. • This type of machine is not used in Bangladesh.

Continued…. Rotary dyeing machine: • Rotary garments dyeing machine is the modified version of pedal type garments dyeing machine. • Rotary garments dyeing machines are of two types: (i) Normal atmospheric pressure type (Less than 100 degrees) and (ii)High temperature type (more than 100 degrees dyeing temperature). The HT type dyeing machine is microprocessor controlled machine.

Continued…… Atmospheric Pressure Rotary Garments Dyeing Machine: • This type of machine is widely used in Bangladesh. • It is made of stainless steel. • In the machine, there are two stainless steel cylinders one inside the other. • The outer cylinder is solid and has two sliding doors like microbus at the upper middle half position of the cylinder. • The cylinder is fixed on the machine frame and the machine frame is tightly fixed on the floor with heavy foundation to avoid jerking during operation of the machine. • There also two chemical dosing doors on the sliding doors to facilitate chemical addition during machine running.

Continued…. • The inner stainless steel cylinder is perforated having two stainless steel side shafts. The side shafts are fixed with the machine frame through ball bearing. • Two machine pulley is fixed on the two side of the side shafts. With the help of two big high power motor & motor pulley, the machine pulley is rotated. • As a result the inner perforated cylinder can rotate freely in side the outer cylinder. • The perforated inner cylinder has two spring loaded doors. The doors of the inner cylinder and outer cylinder is aligned to the same position by the use of a inching motion switch, to load and unload garments to be dyed. • The inner cylinder can be rotated at 5 to 35 rpm through control panel of the machine. • The rotation of the inner cylinder is automatically controlled for clock-wise and anti-clockwise direction by reversal driving unit which is simple electronic circuit. • The dual direction movement of the inner cylinder is used to avoid roping affect of the garments during dyeing.

Continued…… • There are three to four inches gap between the inner and outer cylinder. A solid steam pipe is situated between the gap. • Dyeing temperature is controlled by a dial & indicator situated in the panel board of the machine. • Garments movement during garments dyeing is performed by the three triangular shape bars inside the inner cylinder. • From the overhead water tank a water pipe is connected to the bottom side of the outer cylinder. • The machine automatically stops rotation with alarm sound to attract the attention of the operator for the next operation. • The capacity of the dyeing machine is 60 kg to 500 kg. The same machine can be used for pretreatments before dyeing.

Continued…… High Temperature Rotary Garments Dyeing Machine: • • • High temperature rotary garments dyeing machine is the modified and latest version of the atmospheric pressure type rotary garments dyeing machine. It is controlled by microprocessor which is not presently used in Bangladesh but using in the developed countries. Garments dyeing can be carried-out up to 140 degrees in it. Very big central door facilitates materials loading and unloading mechanically. Light machine structure facilitates high speed machine running with safe balance. Simple A/C drive and A/C converter facilitate 5 to 35 rpm of main cylinder. Additional two chemical tanks may be attached for auto dozing of dyes and chemicals in the machine. Separate liquor circulating pump, heater and filter facilitates additional liquor circulation, heating, and liquor filtration and hence better quality of dyeing. The machine is available only built in form hence less risk of installation and running problem. It is a fully programmable automatic garments dyeing machine. In this machine up to 200 dyeing program can be saved & reused easily

Basic Theory of Garments Dyeing • Depending on the wet fastness requirements of garments, the garments is dyed with direct dyes and reactive dyes. If reactive dyes are used in dyeing, the following advantages may be achieved. – – – suitable for short and automatic dyeing process Good level dyeing is achieved Dye migration and diffusion is better. Color-fastness is acceptable Total color range is available Two types of reactive dye is available in the market, namely • HOT brand dyes • COLD brand dyes Hot brand reactive dyes are commonly used for cotton garments dyeing.

Basic principle of garments dyeing with hot brand reactive dyes • • • Cotton garments may be dyed with hot brand reactive dyes as per following line diagram of basic dyeing principle. At first load hot water and add salt, lubricant, sequestering agent and maintain liquor ph at 7. Then load garments and start machine. Raise the temperature of the dye bath to 80°c with in 30 mins. After 5 mins at 80°c, add dye within 15 mins time. Continue dyeing for 30 mins. Add alkali to the dye liquor slowly within 15 mins. Continue dyeing process for 30 -60 mins. Reduce liquor temperature to 70°c and then drop the liquor. Washed thoroughly at 40°c to 45°c for 5 mins to remove the unfixed. Then drop the liquor, again wash with normal water for 5 mins to clean. Then softener may be applied on the garments to improve the softness properties.