Giving a new lease of life to components

“I would sum up our activities into three words : Component Restoration Solutions.”
Mr. Himansu Doshi, Director, Plasma Spray Processors

“We believe in building relations and providing flexible and practical solutions to our customers,” says
Mr. Dhimant Doshi, Director, Plasma Spray Processors

You know CHANDRAYAN, the satellite launched by ISRO. Critical components going into this spacecraft, which have to withstand high temperatures and pressures, have been plasma coated by our company – says a proud Dhimant Doshi, Director, of M/s Plasma Spray Processors. “This is just an example of our participation and our catalytic contribution to nation building,” states Dhimant Doshi.

Plasma Spray Processors an ISO 9001:2008 certified (PSP for short) headquartered in Mumbai is a brainchild of the duo, Mr. Himansu Doshi and Mr. Dhimant Doshi, both veteran maintenance engineers with a mechanical background. The venture was started in 1984 with a view to giving a new lease of life to components and machinery parts which are otherwise discarded once they are worn out or corroded. Dhimant claims that PSP are the pioneers in using Plasma for surface coating and the first to introduce HP/HVOF (High Pressure/High Velocity Oxy Fuel) in the year 1992 for repair and maintenance in India.

Full-fledged Coating Facility
PSP has a full-fledged facility at Taloja, 50 km from Mumbai, for offering thermal spray process related services for coating and refurbishment of components retarded by wear, corrosion, erosion, abrasion and for high service temperatures. The company has a team of dedicated experts to handle complex coating jobs using Plasma Spray, Twin Arc Spray, Combustion Flame Spray and High Velocity Oxygen Fuel Spray popularly known as HVOF and Plasma Transferred Arc (PTA). In Plasma Transferred Arc, the coating material is fed into and heat source created by ionization of a gas in an electric arc between electrodes.

PSP’s well equipped coating plant for refurbishment of components

The substrate and coating material is locally melted and spread. In Plasma Spraying, in contrast to other thermal spray techniques, uses a flame or arc where the temperature at the root is between 10000 and 12000 deg. C and the material in powder form is fed through the flame to form a mechanical bond on the substrate. In Twin Arc Spraying, two spraying wires of the same material are melted in an arc and are sprayed.

In Powder Flame Spraying, the spraying consumables in powder form are melted in an acetylene-oxygen flame & are accelerated on to the prepared surface by means of expanding combustion. Finally, in the HVOF spraying process, continuous gas combustion with high pressure takes place in the combustion chamber. In the central axis, spraying consumables in powder form are fed.

Each process has its own advantages and economics. PSP is well poised to advise the clients on the right selection of the most appropriate process for a specific application depending on the hardness, surface finish and service temperature. “Sometimes the customer also gives specifications based on which we do the coating. The high end customers are quite discerning,” points out Mr. Dhimant.

Wide Ranging Services
PSP is an ISO-9001-2008 company. Its services spectrum includes:

• Metal spraying services, carbides, ceramics as protection against corrosion, wear, abrasion, heat, for various environments like acids and alkalis
• Refurbishing damaged machine parts
• New parts coating at defined positions to achieve the required properties like ceramic coating, carbide coating as super hard surface.
• Steel coating for sliding fits, rolling bearing blocks, etc.
• Bronze alloys for bearing casings, bushings, etc.
• Super- hard molybdenum layers for paper industry, hydraulic piston rods, etc.
• Ceramic materials on pump shafts protection sleeves, yarn paths, plungers, etc.
• Ceramic coatings on metals (ferrous, non-ferrous)
• Aluminium oxide, titanium oxide, zirconium oxide for electrical insulation, heat insulation and wear protection.

The in-house facilities include Equipment for plasma spraying, wire flame spraying, arc spraying, HVOF and liquid gas as well as combustion flame spraying. The supporting equipment available are 8-axes robot, Blasting Machine and Room, Lathes & Grinding Machines, Turn tables, finishing machines, and the latest testing and measuring equipment and also small in-house Lab for testing of coatings.

“There are exceptional cases where the customers want us to do the coating in-situ. In that case we take the requisite machines to the customer’s end and do it,” reveals Dhimant.

Samples of some assorted jobs done by PSP

Ever-expanding Clientele
PSP has an impressive list of satisfied customers. Prominent among them are ISRO, NTPC, GTRE, Jindal Steel, Kirloskar Brothers, Deepak Fertilizers and Siemens. The company serves industry segments as diverse as Chemical, Fertilizer, Steel, Paper, Printing, Power, Oil fields, Automotive, Glass, Textile, Pump and Compressor, Shipping, & Cement and so on.

The latest at PSP is the bi-metallic coating for extruder screws & injection moulding screw. The company has collaboration with Extreme Coatings, USA for this new technology. This process, according to Doshi’s, has a lot of potential and is a boon for extrusion machines manufacturers and users.

PSP has ambitious growth plans. “Our company is growing at the rate of 20% every year,” states Dhimant, beaming. “But the point to be noted is our ability to provide flexible and practical solutions to our customers with the ideology of building not just business, but relations.” The company which has celebrated its 30 years of service to industry underlines that it has built up its reputation by using cutting-edge technologies and doing the toughest jobs which others seldom dare take up! We strongly believe that customer satisfaction is our satisfaction and promote the credo ‘Do It Right The First Time.’

– P.K. Balasubramanian.