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Cascade e-Ion Plasma™ Surface Hardening & Texture Control

Tuneable Ra 0.3-1-5um within minutes without the use of harsh chemicals. Treatment time with Ionic "Deburring" varies depending on the starting roughness, but is generally within a minute for most surfaces.

Surface harden with Nitrides, Oxynitrides, Diamond and Quech Techniques

Surface Roughness

  • Surface roughness is a measure of the texture of a surface.  The assesment of of texture depends on the resolving power of the probe employed. In an approximate sense, the resolution of the human eye is about 0.3 mm. The resolution of an optical light microscope is ~500 nanometer (nm) spatially and about a micron in the height direction.  In a scanning microscope it is about 10-100 nm dpending on the electron wavelenght. For a transmission microscope it could be less than 1 nm.

  • Commonly reported as Ra number (the absolute arithmetic average roughness of a surface). 

  • Or reported with a Rq number (root mean squared RMS value of roughness).    

  • More advanced reporting procedures include values for waviness, kurtosis, and surface skewness; however Ra and Rq capture the roughness property adequately.

  • Units:  The engineering units for both Ra and Rq are either microinch (u-inch) or micrometers (um).

  • 1 micron (um) = 39.37 u-inch

  • Peening or burring is the process of working a metal-surface to improve its material properties.  Ion Peening with the e-Ion Plasma is a relatively new processes that can be used for curved and complex shapes.

  • Cast surfaces display Ra of about 50-250 u-inch.  Sand castings display the higher roughness, plaster shell type investment castings and die castings show the lower values of roughness.  Squeeze castings also display a higher average roughness.

Participate in no-burr technology with the e-ion or with the use of GoldenBlue® tools


  • Surface roughness can impacts the look-and-feel of products (gloss and luster as well as friction and wear.  An inadequate roughness can effect the durability, fatique, bio-compatibility and reliability of the processed part.  Cascade e-ion information request.

  • Several quick machining operations leave behind burrs.

  • Roughness impacts life by impacting wear resistance, erosion resistance, fatigue resistance, creep-fatigues interaction and other material design parameters.

  • Roughness is called out for metallic, composite and ceramic parts used in turbo machinery, combustors, engines, cylinders and other engineering parts.

  • For polymeric and other soft surfaces the more commonly reported measurement number is related to specular reflectivity, the Ra and Rq are generally not called-out.

  • A bad casting finish can dramatically alter the energy efficiency in any fluid flow device e.g. a pump or turbocharger.  High roughness can cause turbulence. Roughness can be controlled with e-Ion techniques. Make casting surface harder or nitride complex surfaces.

  • For more information regarding surface roughness and surface finishing, see this site which discusses how coatings fill the voids between sand grains and can also act as a refractory, limiting the defects and loss of integrity that can occur with higher melting point alloys. Make casting surfaces harder and smoother.

  • The cascade e-ion is a cost effective method of altering the texture of a surface and thus altering several engineering properties including friction and wettability. Prevent slip-stick, improve color and luster.


Role of the Cascade e-Ion Plasma Plume

The Cascade e-ion Plasma is a versatile machine that may be used to impact the surface texture and roughness for metals (Cascade e-Ion source), ceramics (Cascade e-Ion EIZ) or soft plastics (e-Ion LIP).  With the e-Ion Plasma machine one may rapidly "deburr" or create new surfaces, depending on the ions used and other properly set conditions that change for specific alloy surfaces and temperature. Contact the manufacturer, MHI.  Nano scale features of texture and porosity that are now known to be important for surface bioactivity or roughness can be introduced.  Often some trial and error may be involved whether it is a titanium, steel, cobalt or PEEK alloy.


In its several modes the e-Ion Plasma™ can deburr, ionic co-deposit to alter surface porosity and be used simultaneously for thermal action in various combinations of use modes to obtain the best surface.  Numerous studies are underway for smoothening glasses, semiconductors and high hardness materials such as carbides, nitrides and borides.  Selective smoothening or roghening studies with composites and muticompositional alloys are underway also.  The initial surface conditioning plays an important and non-intuitive part in the surface action.



Every competitive "deburring" process has advantages and disadvantages. When comparing processes for a particular action, the comparison should include speed, reliability, tolerance, energy efficiency, chemicals and other environmental foot-print features including noise for comparison making.  Mechanical processing (such as drilling, grinding, stone-tumbling and polishing) may change or damage materials on account of focused stresses which then may lead to residual cracks, residual tensile stresses and/or changes in the microstructure; thus reducing the service life of the part.  Electro--polishing may require chemicals that need to be stored, replenished and disposed.  The e-ion on the other hand uses only air (or other gas of choice) and electricity as input to the machine.  High kinetic and thermal energy ions are used for deburring in the e-Ion Plasma process.  It is a noiseless yet controllable process and because of the small foot print of the cascade e-ion device, may be used on a table-top for almost all configurations.  The  Cascade e-Ion Plasma™ i.e. the CleanElectricFlame® can be used in a  continuous manner with a belt or robot part-handler. MHI provides all the high temperature holding accessories required by the user for addition to a standard part manipulators.  See also welding page.


Additional Benefits with the Cascade e-Ion

Although not all the benefits of a new technology like the e-Ion Plasma can be known at this point, several benefits may be anticipated.  For example, with the e-Ion Plasma, the rapid "deburring" step can be thought to be combined with a rapid surface niriding and bulk sintering step.  The ions do not require line-of-sight beam and the product does not have to be electrically grounded.   This type of sintering is called 4DSintering® which is a Trademark of MHI Inc.  Simultaneous ion peening operations can be envisaged. Similarly welding and weld smoothing may be anticipated as simultaneous operation.  The scale from welding and the chromium depleted layer underneath the weld roughness must be normally removed for example for improved stainless steel, sea-side corrosion resistance.   Mechanical polishing to match the finish on the parent material is often used but this must be done carefully so that cracks are not introduced which can lead to stress-corrosion cracking.   More Online Information. 


 Sometimes surface roughness is further reduced by deposition.  The e-Ion depositor attachment may be used with the same machine.


ExampleStarting from surface with a Ra = 20-40um, for an unsintered powder metallurgy produced alloy part for an alloy that sinters around 1700K, a Ra = 4um surface is easily obtained in minutes to an hour of non-line-of-sight surface e-Ion "deburring" operation.   Multiple parts can be made simultaneously. The production cost saving per part when comparing labor time for 1 hour vs. 3 days is substantial.  The savings from lessened environment degradation is substantial.  The energy savings per year could be thousands of dollars in benefit.  Please contact MHI for more precise calculations and to work with you to ensure best amortization cost for your specific location.  Please Contact Us for more information for the best surface-finish for metals, ceramics, glass, oxides, garnets, silicon carbide and many other materials that require nanoscale or microscale smoothening or manipulation. 



Grit   to    Microns































Note also that 1 micron (um) = 39.37 u-inch

Chart of Grid to Microns

Cascade e-Ion

A high energy and high velocity e-Ion Plasma™ CleanElectricFlame is shown below which can be used for in-situ

surface operations within seconds or minutes for the completed biomedical part (entire surface), casting, forging or powder-metallurgy fabricated parts.  Curved and non-line-of-sight regions can be treated. 


Scale of Texture

(Related to the resolving power required of the measurement probe, with light ~ 0.5 micron, with electrons, theoretically it is ~ 0.1 nanometer (nm))

Deepest ocean trench: 10.994 Km

Highest mountain: 8.850 Km

Human scale: ~1 m

Human organ scale: ~10 cm

Spoons and forks that fit a human mouth: ~1 cm

Pencil tip: ~1 mm

Grain of salt: ~0.1-1 mm

Human hair or dust mites: ~0.1 mm

Bacterium: ~1-10 micrometer

Phages (bacterial virus): ~0.1 micrometer

Large molecules or virus: ~10-100 nm

Atoms: ~0.1-1 nm

Water molecule: 0.275 nm

Nucleons: ~10^-6 nm

Electrons: ~10^-7 nm

Planck's length: ~10^-26 nm (smallest scale believed to exist in space-time)


The scale of hardness depends on the material and process conditions.  Contact MHI for high hardness, low distortion and tunable coefficient of friction.


Easy method to deburr steel tool steel and die steel

"Deburr" steel parts in a few seconds.  Simultaneously nitride or oxynitride as required.

On the left is nitrided and deburred.  On the right is the surface before duburring.

Typical Size/Footprint:   A typical ~ 14 kW Cascade e-Ion Plasma™ configuration fits on half a standard desk-top table.  Plug and Play type installation.

Expected operating cost is a few cents per part but please Contact Us for your specific application.



Biomedical screw


Microstructure Titanium Alloy Plasma Nitrided with Cascade e-Ion GoldenBlue(TM)Extremely low roughness Cascade e-ion Plasma Treatment of Titanium Alloys

Pictures above are hip/spine inserts and screws common shapes with magnification of 50,000X and 100,000X to indicate surface finish possibilities.

Easily nitride Ti-Al-V (Ti64) with the Cascade e-Ion Plasma Plume

The Cascade e-Ion is used for Titanium Alloys (including multilayer graded peening), Co-Cr-Mo type biomedical alloys,

Stainless Steel, High density plastics, dental alloys, gold alloys, superalloys, Nitinol oxide conditioning, Ni-Ti, Ti-Al, Ni-Al, castings, forgings and many others where roughness needs to be reduced or surfaces have to be peened.

Please Contact Us for your specific application

MHI offers complex part manipulators from robotic arms to continuous belts

Before and after pictures of Deburr Copper Zinc Nitride after GoldenBlue and deburr

Before e-Ion Ra= 20um » After treatment Ra= 4um surface shown above.  No burrs.

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