Home  About us  Products  Contact us  News articles / Videos  Finishing news  Links  Blog  Site map

Abrasive media     Buffing / Polishing machines     Dry Ice Blast cleaning machines     Electro chemical Deburring machines   

Honing machines     Sand Blasting machines     Sand blasting nozzles     Shot Blasting machines      Super Finishing machines    

Thermal Deburring machines    Ultra Sonic cleaning machines     Vibratory Finishing machines     Spare parts      Used Finishing Machines   

 

Thermal Spray Technology

Thermal spraying is a very well established & a high cost effective, extremely versatile technology that is used commercially to produce a wide variety of coatings, not only for adding superior properties but also for the performance qualities in a given engineering surface on which metallic or non metallic ( ceramics, carbide, plastics ), and mixture of these materials with unique physical properties are deposited in atomised molten or semi molten condition with the help of compressed air or gas on substrate to form a dense, adherent coating. The coating material may be in the form of wire, powder and powder filled cord to meet a range of physical criteria. The varieties of products and coatings that can be enhanced by thermal spray are virtually limitless. The major advantage of Thermal Spray process is that there is no damage / distortion to components and coating is almost instant.

     
  Flame Spray Guns / Systems :-  
  Coating material in the form of single wire, cord or powder is melted in an Oxy-fuel gas flame and molten material is atomised by compressed air and accelerates towards specially prepared substrate to form dense strongly adherent coating.  
     
  This Flame Spray process carried out correctly is called a "cold process" (relative to the substrate material being coated) as the substrate temperature can be kept low during processing avoiding damage, metallurgical changes and distortion to the substrate material.  
     
  Combustion Wire Spray Systems :-  
  The metal wire is fed concentrically into the flame, melted and atomized by the compressed air, and the molten droplets are propelled towards a prepared surface where they solidify and bond to the substrate to form a coating. . By controlling the rate of feed of the wire through the flame, we can control the melt and atomization of metals with various melting points.  
   
     
  Combustion Powder spray system :-  
  The combustion powder process is similar to the combustion wire process, except that it has the advantage of using powder materials as the coating feedstock, which allows for a much wider range of coating material options. In addition, the use of powder allows for a greater degree of freedom for spray gun manipulation. The flame spray process is only limited by materials with higher melting temperatures than the flame can provide or if the material decomposes on heating.  
   
     
  ARC Spray Systems :-  
Electric Arc Spraying :-
In the Arc Spray Process pair of electrically conductive wires are melted by means of an electric arc.The molten material is atomised by compressed air and propelled towards the substrate surface. The impacting molten particles on the substrate rapidly solidify to form a coating.
 

Electric arc spray coatings are normally denser and stronger than their equivalent combustion spray coatings. Low running costs, high spray rates and efficiency make it a good tool for spraying large areas and high production rates. Electric arc spray systems are offered that feed wire by either an air or electrical motor. Electric arc spraying has the advantage of not requiring the use of oxygen and/or a combustible gas.

     
  PLASMA Spray :-  
 

A plasma is an electrically conductive gas containing charged particles. When atoms of a gas are excited to high energy levels, the atoms loose hold of some of their electrons and become ionised producing a plasma containing electrically charged particles - ions and electrons.

 

A high frequency arc is ignited between an anode (nozzle) and a cathode (electrode). Process gases (generally mixtures of Argon, Nitrogen, Hydrogen and Helium) flowing between them is ionized to become a plume of hot plasma gas that exceed the temperature of 6,600 oC to 16,600 oC (12,000 oF to 30,000 oF). When the coating substrate to produce a strongly adherent coating. The work piece remains cool because the plasma is localised at the gun.

 

Plasma Spray is perhaps the most flexible of all of the thermal spray processes as it can develop sufficient energy to melt any material, the number of coating materials that can be used in the plasma spray process is almost unlimited.

 
     
  Velocity Jet ( HVOF ) :-  
 

The HVOF (High Velocity Oxygen Fuel) Thermal Spray Process is basically the same as the combustion powder spray process (LVOF) except that this process has been developed to produce extremely high spray velocity. There are a number of HVOF guns which use different methods to achieve high velocity spraying. One method is basically a high pressure water cooled HVOF combustion chamber and long nozzle. Fuel (kerosene, acetylene, propylene and hydrogen) and oxygen are fed into the chamber, combustion produces a hot high pressure flame which is forced down a nozzle increasing its velocity. Powder may be fed axially into the HVOF combustion chamber under high pressure or fed through the side of Laval type nozzle where the pressure is lower. Another method uses a simpler system of a high pressure combustion nozzle and air cap. Fuel gas (propane, propylene or hydrogen) and oxygen are supplied at high pressure, combustion occurs outside the nozzle but within an air cap supplied with compressed air. The compressed air pinches and accelerates the flame and acts as a coolant for the HVOF gun. Powder is fed at high pressure axially from the centre of the nozzle.

 
     
 

mktg. reps. for Guns / Systems / Spares :-

 
 

VOHRAS  INTERNATIONAL

 
 

F-19/10, Krishna nagar, Delhi-110051, Mobile: 9212004471

 
 

 metalfinishing@yahoo.co.in      www.finishingmachines.com

 
 

Guru Nanak Enterprises, Vohras International,  Shot blasting machines, Sand blasting machines, Vibratory finishing machines,

 Thermal deburring machines, Thermal spraying technology Electro chemical deburring machines,  Dry ice blast cleaning, Sand blasting nozzles,

  Hanger model shot blasting machines, Paver shot blasting, Tumblast shot blasting machines, Table model Shot blasting machines, Spare parts,

 Continuous conveyor model Shot Blasting, Plastic media, Stainless steel media, Ceramic media, Mass finishing compounds, Used Finishing Machines,

 important enquiries, Denim sand blasting, Finishing news

Home  About us  Products  Contact us  News articles / Videos  Finishing news  Links  Blog  Site map

hosted by  APYL Softwares - Jodohost