Plasma Spray
Conventional plasma spray, commonly referred to as atmospheric plasma spray (APS), is the most versatile method for applying thermal spray coatings. With the ability to control the many facets of the plasma spray process, you can not only spray a wide range of materials, from metallics to ceramics, but also onto virtually any material. With minimal coating distortion, the plasma torch can apply coatings to both small and large parts nearly continuously. The high degree of melting and particle velocity yields higher deposit densities and bond strengths than both flame and electric arc, making plasma coatings perfect for protection and refinishing applications.
Following you'll find Equipment, Parts & Information for the Thermach Plasma Spray Thermal Spray Coating System.
The term “thermal spray” is used to describe a group of coating processes that are used to apply metallic or non-metallic coatings. These processes can be broken up into four major categories: plasma, electric-arc, flame, and cold spray. While differing in methodology, all methods heat the coating material (in powder, wire, or rod form) to a molten or plasticized state and propel those droplets towards a prepared substrate to form a coating.
Thermal spray coatings are economical and versatile and are used to provide functional surfaces to protect or improve prepared substrates or components. With abilities to spray virtually any material that melts without decomposing, thermal spray offers vast possibilities when it comes to what it can coat.
Coating Characteristics:
Rapidly solidified, metastable structures
Lamellar structures
Some inclusions
Low residual stress
High bond strengths
Minimal base-material interactions
Minimum thickness 0.003” (ROT)
Rough as-sprayed surfaces, 50-400min
Advantages:
Thick Coatings
High Deposit Rates
Relatively low capital investment
Wide selection of materials
Simplified waste disposal
Used worldwide for:
Additive manufacturing
Anti-skid
Biocompatibility
Corrosion
Decorative
Electromagnetic
Electrical/electronics
Materials processing
Mold making
Restoration
Sealing
Thermal Barrier
Wear
Etc.
Industries Served:
Aerospace
Agriculture
Automotive
Electronic
Food Processing
Infrastructure
Materials Processing
Medical/surgical
Paper Making
Petrochemical
Printing
Recreation
Repair and Restoration
Tooling
Etc.
Thermach offers several product systems for your thermal spray operation: Plasma, Electric Arc System (Twin Wire Arc), HVOF (High Velocity Oxygen Fuel), Powder Delivery and Custom Systems made specifically for your application.
In the Plasma Spray process, an electric arc is created between an anode and cathode through which a process gas passes.
The high energy electric discharge energizes the process gas into a super-heated ionized gas, creating a state of matter known as plasma. Metal or ceramic powders are injected into the plasma stream which heats and propels the powder onto a substrate.
The most commonly used primary gases are Argon and Nitrogen. The addition of secondary gases, such as Helium, Nitrogen or Hydrogen can significantly increase the heat and therefore the velocity of the plasma stream.
Several factors affect the Plasma Spray operation, including cathode/anode design, current, gas mixture and gas flow. Controlling these factors allow Plasma Spray systems to create temperatures in excess of the melting point of any known substance.
Plasma spray coatings are applied using a high temperature process that involves injecting powdered coating material into a plasma flame. The material is rapidly heated and then accelerated toward the substrate. Once it reaches the surface it begins to cool, forming a hard coating on the substrate. The high temperatures involved in plasma coating allow the use of ceramics and other materials that have a high melting point.
Plasma spray coating is a highly versatile process that is in a variety of industries & applications:
Aerospace
Medical
Marine
Electronics
Automotive
Mechanical Engineering
Petrochemical
The temperatures in the heating region of the plasma plume can range from about 11,000-36,000°F (6,000-20,000°C), which is more than the melting range of most substances. Being able to vary parameters between this range, gives the user the ability to spray an array of materials onto nearly any substrate. The high degree of melting and particle velocity leads to high densities and bond strengths, which make it great for spraying aluminum, chrome, and Zirconium oxides.
Some of the benefits of utilizing Plasma Spray are:
Coatings are dense, with good adhesion
Has the ability to spray a wide range of materials
Can spray ceramics efficiently
Can virtually run continuously, minus maintenance
Has lower oxide content and porosity than flame and electric arc
Minimal substrate distortion on both small and large components
Sprayed substrates can be made from a variety of materials, such as plastics, metals, and ceramics
Build-up can be from a few micrometers thick to a few millimeters
Thermach thermal spray equipment is a smart, reliable choice for coatings, in the factory and in the field.
Here are the applications where Plasma Spray is most commonly utilized:
Corrosion Protection
Wear Resistance
Heat and Oxidation Resistance
Inert chemical resistance
Thermal Barriers
Electrical Resistivity and conductivity
Anti-galling
Part Restoration
Aerospace
Automotive
Biomedical
Chemical
Electronics
Marine
Industrial
Plasma Control Systems
The Plasma Control System from Thermach is designed for user-friendly and safe operation. It is the industry leading choice for consistent plasma coatings.
To automate your thermal spray operation, see the NEW AT-3200 Mass Flow Control Console here.
Thermach continues to provide the thermal spray industry with innovative, safe and authoritative designs. Your Thermach service team offers end-to-end set-up, product support, and custom equipment and part design.
You can count on Thermach for exceptional technology and production methods.
Thermach is a specialist. We manufacture equipment and parts for the thermal spray industry. That means we are your coating partner, not your competitor.
The AT-3010 Plasma Spray System was designed for ease-of-use, safe operation and consistent plasma coatings.
At the center of the system is the AT-3010 Console. CE-certified, this system features touchscreen technology, automatic start-up and shutdown sequences, an hour meter tied to an automated preventative maintenance system, and a series of built-in process alarms and warnings.
The AT-3010 features a built-in user-operated Safety Purge System that exceeds industry standards. This purge system allows a user to power up the console into a safe condition. All of the components of the system are designed so that all electrical signals and power entering and leaving the AT-3010 console during purging are deactivated to ensure that a dangerous condition prior to purging does not exist.
Using AT-1200 Powder Feeders, the AT-3010 console commands the feeders and offers closed-loop RPM feed rate control.
System Components
The Power Supply’s amperage is closed-loop controlled by the console, which monitors the voltage at the power supply and plasma torch.
Requirements:
Electrical: 230 / 460 / 575VAC, 3 Phase, 60Hz (50Hz Optional) 180 / 90 / 72 Amps
Isolation Box: Unit is powered by the AT-3000 Console
Optional: 100kW Power Supply; see Power Supply Manual
Overall dimensions: 23" wide x 38" deep x 30" high (58.4cm wide x 96.5cm deep x 76.2cm high)
Crated weight: 600 lbs. (273kg)
To add this product to your quote request click here.
The Arc Starter is a solid-state high-frequency ignition unit powered by the console and requires no adjustments to operate.
Unit is powered by the AT-3000 Console. 115VAC, 1 Phase, 50/60Hz 1A
Overall dimensions: 22" wide x 25" deep x 15" high (58.9cm wide x 63.5cm deep x 38.1cm high)
Crated weight: 120 lbs. (55kg)
To add this product to your quote request click here.
The AT-3000 series of consoles are NEMA 12 rated and purged to NFPA “Z” standards.
The controllers can either sequence the ignition process manually or automatically, giving the user flexibility in production or research. A touch screen interface provides operators ease of use and status signals of the process.
Gas flows are set by critical orifices, which offer repeatable results. The console commands the powder feeders and offers closed-loop feed rate control.
Requirements:
Electrical: 110VAC, 1 Phase, 50/60Hz 15A
Purge Air: 65 PSI, 10 SCFM Minimum
Argon: 250 PSI Supply Maximum
Helium: 250 PSI Supply Maximum
Hydrogen (optional): 200 PSI Supply Maximum
Nitrogen is an optional secondary gas.
Overall dimensions without cart: 46" wide x 18" deep x 39" high (116.8cm wide x 45.7cm deep x 99.0cm high)
Overall dimensions with cart (as shown): 46" wide x 30" deep x 74" high (116.8cm wide x 76.2cm deep x 118.0cm high)
Crated weight without cart: 650lbs. (295kg)
Crated weight with cart: 850lbs. (386kg)
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The Heat Exchanger, a 10-ton refrigerated chiller, is activated by and feeds its alarms directly to the console.
Requirements:
Electrical: 460VAC, 3 Phase, 60Hz 28.1 Amps
Blow-Out Air: 30 PSI Supply Maximum
Overall dimensions: 33" wide x 68" deep x 81" high (83.8cm wide x 172.7cm deep x 205.7cm high)
Crated weight: 2300 lbs. (1044kg)
To add this product to your quote request click here.
Thermach Powder Feeders deliver accuracy and repeatability and are highly customizable. Whether your requirements include high pressures, increased capacities, remote controllers, or quick-change canisters, Thermach Powder Feeders can be designed to meet your specs. Thermach Powder Feeders are built with an internal tamper assembly to assist powder flow into the slots of the powder wheel.
Closed-loop 0-15 RPM
90 PSI Maximum Canister Pressure
See the Thermach full line of Powder Delivery Systems here.
The SG100 from Thermach delivers:
Easy to maintain - self-aligning assembly
Repeatable coatings
Flexible powder injection; internal or external
A wide variety of anode, cathode, and gas injectors to match application requirements
Subsonic, Mach I, and Mach II spray velocities
80KW capability
Suitable for Production and Research
2086 and 2700 extensions are available in 12 inch and 24 inch standard lengths, and custom lengths from 6 inches to 72 inches. For interior applications down to 2.5 inches choose the model 2086. For interior applications down to 1.5 inches choose the model 2700.
To add this product to your quote request click here.
For all SG100 applications (with a few exceptions) the cooling water to the torch should be fed through the negative (black) cable into the back of the torch. Whereas the positive (red) cable is the return to the water chiller.
Delta T simply refers to the temperature difference between the water going to the torch and the water returning to the chiller.
It is important when running a given parameter, that the Delta T remain the same each time you run that parameter. It may fluctuate a few degrees, but if it continues to degrade in either direction, something is wrong and the system should be shut to perform trouble shooting.
All the Plasma torch manuals offer basic selections as to which anode, cathode and gas injector combinations will work together. View and download the hardware comparison chart below.
When doing Spec. coatings, they are dictated in that specific parameter. Torch hardware selection is also dependent upon powder selection. Most materials are sprayed using sub-sonic hardware. Other factors may dictate the use of a Mach I or Mach II components in the SG100.
If we do not have a published parameter for your specific needs, we can offer a close starting parameter to get you going.
Depending on the powder being sprayed, the mesh size of the powder, and the application, hardware builds for the SG100 vary.
Knowing the melting point of the powder helps determine the dwell time it needs in the plasma plume. If you need help determining your hardware setup, please contact a Thermach Representative.
The 2083 series of gas injectors are made from Boron Nitrite, hence the white color. The 2083 series is more easily prone to breakage and chipping. The series is still manufactured primarily due to the callout in spec. coatings.
The 3083 series of gas injectors are made from Corderite, hence the tan color. Although it can chip and break like any ceramic, Corderite is more robust than Boron Nitrite. It is also a cost effective alternative to Boron Nitrite.
Typically, Thermach suggests 80°F (26.6°C) from chiller to torch. This number can vary with your location and humidity. Warmer climates and high humidity will suggest a higher temperature setting to the torch. This is done to prevent condensation inside the nozzle, which can lead to ignition and powder feeding problems. A good rule of thumb is to set your “To Process” temperature at ambient or slightly above.
The “hardware set” of the SG100 consists of the anode, cathode, and gas injector. When selecting the hardware set, there are several factors that will influence this choice.
The first and most important factor is if you will be spraying a spec. coating. A spec. coating is one that has certain criteria to meet. Such as, the torch(s) that can be used to apply the coating or the hardware set that must be used inside the torch. The spec. can also dictate the operating parameters.
The material being sprayed, and the process gases being used, are the other factors that can influence this decision.
A material’s melting point can influence the anode selection. Materials that have higher melting points typically need to be injected closer to the arc attachment point. The opposite is true for lower melting point materials.
The process gasses also help dictate which series of anodes to use; there are a few exceptions. If using Argon only or a mixture of Argon/Helium, any of the anodes produced by Thermach and be used. When using Argon/Nitrogen or Argon/Hydrogen mixtures, the two best series to choose from are the all-copper 2083 series, or the tungsten bore 4083 series.
Cathode selection is less complicated. There are only two sub-sonic cathodes to choose from, the 843083129 (aka 129) and the 841083720 (aka 720). For parameters that are in the nominal gas flow range of 120 SCFH, either cathode will work. However, when gas flow parameters fall below the nominal range, the 129 cathode should be used, while the 720 should be used for the opposite side of the spectrum.
Gas injector choice can also be narrowed down to 2 choices. For Argon and Argon/Helium, the 845003644 is a good choice. For Argon/Nitrogen or Argon/Hydrogen, it is best to put a vortex on the gas using the 883083113 gas injector.
There are many anode, cathode, gas injector choices, this is a general rule of thumb.
Typically, Thermach suggests 80°F (26.6°C) from chiller to torch. This number can vary with your location and humidity. Warmer climates and high humidity will suggest a higher temperature setting to the torch. This is done to prevent condensation inside the nozzle, which can lead to ignition and powder feeding problems, such as spitting. A good rule of thumb is to set your “To Process” temperature at ambient or slightly above.
Use the highest pressure you can safely achieve; 9 gallons per minute minimum, even under sub-sonic conditions. The minimum for Mach II is 11 gallons per minute. Always remember that with this process, pressure is your friend.
Absolutely! The simplest way is using a Thermach powder splitter.
The most accurate way is to use two separate Thermach powder feeders.
Any number of things can cause a coating to fail. Did the part overheat? Part Temperatures should be held below 250°F (121°C).
Was the surface to be sprayed prepared properly? Coating adhesion is directly related to the cleanliness and roughness of prepared substrate. Prior to spraying, all parts should be cleaned of contaminants such as scale, oil, grease, and paint, and should remain that way until the spray operation has been completed. After the work piece has been properly cleaned, the part should be roughened so that the sprayed material has more surface area to interact with. Parts can be roughed by either grit blasting, macro-roughening, or bond coating.
There are a few things that can cause high oxide content in plasma coatings. The biggest issue is system leaks. When the system is pressurized but idle, a leak will force gas from the system. However, when running it can do the opposite by aspirating air into the system. Your system should be regularly tested and assessed for leaks.
If your system has been leak checked and oxides continue to form, Thermach offers an inert gas shroud for the SG100 that replaces the standard front cover. If you need to spray externally, Thermach has a shroud for that as well. For the 2086 and 2700 extension, simply connect Argon gas to the air jet assembly instead of using compressed air.
Spray Distance
Typical spray distance for most plasma torches is 3" to 3.5". If you are further than this decrease your torch stand-off distance.
Material
Certain materials naturally attract oxygen more than others. You may need to add an inert gas shroud assembly (Part No. 861000181). This will assist with encasing the plasma in an inert gas shield which will reduce oxides.
Cooling Wand
If you are using the Thermach Cooling Wand Assembly (Part No. 840000360) you'll need to cease using it for the material that is being sprayed and add more cooling to the back of the part. If the wand is being utilized to remove possible entrapments, simply changing the impingement angle away from the spray may provide a solution.
Yes! On the SG100 and SG200 it is as simple as replacing the front cover of the torch with an external feed front cover assembly. Currently the 2086 extension is the only I.D. torch that has an external feed capability. Contact Thermach for the correct part number for your application.
In fact, we do! Depending on the I.D. size, Thermach has three different I.D. torches.
The 2700, which can be used in diameters as small as 1 ¾”
The 2086, designed to be more robust than the 2700, it will fit in diameters as small as 2 ½”
The SG100-90, a true 90° version of the standard SG100, for diameters 6 ½” and larger.
Before lighting the torch, have carrier gas running (No Powder!) and turn on the air to the air jets. Those two steps will help cool the O-ring sealing surfaces. The carrier gas also aids in keeping any hot plasma gas from back feeding up the powder hole in the anode.
The first items to check are the anode and cathode. They should both be nice and polished.
You can clean the anode bore in a metal lathe using OOO, or OOOO steel wool. The other way is with a cordless drill. Using a ¼” X 6” wood dowel, cut a short slit in one end of the dowel with a hack saw. Insert a small piece of steel wool in the slit and SLOWLEY run the drill to get a few wraps of steel wool on the end of the dowel. Then use this to polish the anode bore. A wire wheel, or ScotchBrite wheel is used to clean the tungsten end of the cathode. Lightly steel wool the seating area of the copper near the threaded end.
Also, check the water temperature to the gun. Thermach recommends 80°F (26.6C) water temperature to the torch. If your “to process” temperature is too cold this can cause condensation inside the anode which can keep it from lighting. It is possible there is a problem with the electronics of the system. If that is the cause, give Thermach a call and speak to a technical specialist.
