Dry Process on Denim (Part-1)

Micro-Sanding:

                        A fabric finishing process where fabrics are sanded (real sandpaper) to make the surface soft without hair. It can be performed before or after dyeing. In this fabric treatment process, a series of cylindrical rolls in a horizontal arrangement, either wrapped with an abrasive paper or chemically coated with an abrasive, are used to create a soft, sueded hand. The denim is pulled over the face of the sand rollers creating a raised surface finishing. Some color reduction is experienced.

There are 3 ways for this technique:

•  Sandblasting
•  Machine sanding 
•  Hand sanding or hand brushing.

Used in various ways:

• Flat surfaces (tables, ironing boards)
•  On the dummy (inflatable dummies, sometimes standing, sometimes flat, sometimes 'seated‘) 
• Various templates can be used to create a 3D effect

Sand Blasting:

Jeanswear treatment that removes color from certain areas, either allover or placed, and gives the garment additional softness. Sand is actually shot towards the garment with a powerful spray gun. Recent technology has introduced "automatic" sandblasting, in which the jeans hang and rotate continuously.

• It is purely mechanical process, not using any chemicals. 
• It is a water free process therefore no drying required.Variety of distressed or abraded looks possible. 
• Any number of designs could be created by special techniques.  

It is a process applied on denim fabric garments to get heavy faddy effects on particular points. Sand blasting technique is based on blasting an abrasive material in granular, powdered or other form through a nozzle at very high speed and pressure onto specific areas of the garment surface to be treated to give the desired distressed/ abraded/used look.

 Procedure:

Picture: Sand-Blasting, Air Compressor with Nozzle

 

Picture: Hand-Sand, Sand Blasted Denim, Hand Sand Denim

• Individual garment to be processed is taken on a table. 
• Air compressor is started and pressure to be maintained between 3 – 4 kg/sq.cm. 
• Air compressor then stores air in the machine cylinder.Aluminum sand or silicon sand, Al₂(SiO₄)₃, is then taken in the chamber of the blasting machine. 
• Sand and compressed air are then sprayed over the garments at specific points at 10-20⁰ angle by hand spray pipe. 
• Sands pass into the machine by regulating system. 
• The machine comprises a blasting regulator and a hand regulator to control the amount of sand and compressed air respectively. 
• The angle of sand blowing is very important. Higher the blowing angle, higher the fading effect and higher the risk of fabric damage. 
• Fading is done on pre-marked areas. 
• Sandblasting is a hazardous technique and therefore, the area should be isolated from other working areas. 
• Handling of sandblasting gun is risky therefore, operators should use safety equipments like hand gloves, mask and gown.Production/hour/gun varies from 25 – 45 garments depending upon the degree of fading or extent of fading to be attained. 
• The faded garments are cleaned by shaking manually.After sandblasting, garments are washed and the technique is being followed may be normal, bleach or bio-stone.