Substrate Cleaning/Pretreatment Facilities

To obtain high quality coatings, high quality substrates that are prepared and cleaned well are the most essential requirements. Presence of dust or grease can adversely affect the uniformity of coatings and their adhesion to the substrates. Defects once introduced during the coating stage are seldom removed by post treatment techniques like curing or annealing. In view of this, the Centre for Sol-Gel Coatings has procured state-of-the-art cleaning equipment suitable for a variety of substrates. EPG, based on prior experience, had made recommendations for upgraded versions of some of the equipment, making this facility at ARCI better than the one at EPG's location at Saarbrucken, Germany.

The cleaning facilities established at the Centre are the following:

Flat glass cleaner

A flat glass cleaner is available for cleaning of glass substrates of varying dimensions. The equipment has a working width of 1300 mm. Typically, the substrate size can vary from 1000 mm long and 1000 mm wide to 300 m long and 250 mm wide. The thickness can be between 1-8 mm and the conveyor speed can be varied from 2-5 m/min. The machine uses demineralized water for cleaning.

Pre-treatment System

Sword Brush Cleaner

This is for cleaning glass, metal or plastic substrates by removal of the fine layer of dust that forms on substrates. The machine can handle substrates with maximum dimensions 1500 mm in length and 1500 mm in width. Minimum dimensions that can be handled are 250 mm x 250 mm and thickness can vary between 2 mm and 50 mm. The conveyor speed can be from 2-7 m/min.

Flat spray unit

Plasma Pre-treatment System

A fully programmable plasma pretreatment unit has been set up for activation of the substrate surfaces. The manipulation of substrate position and substrate handling is made possible by a 6-axis robot. Depending on the nature of the substrate and coating, this technique can be used to improve the adhesion properties of the coating on the substrate. The plasma temperature is approximately 300oC and the substrates can be glasses, metals or plastics. Samples can range from 100-300 mm in length and 100-300 mm in width, depending on the nature and mass of the substrate. Working distance can be varied between 6 and 20 mm.

Ultrasonic Cleaners

Ultrasonic cleaners of capacities 110 and 210 litres have been installed for removal of grease and accumulated dust on the surface of the substrates. Maximum weight of the substrates for the two units are 20 and 40 kg, respectively.