Rocklin Manufacturing Blog

Posted by Ross Rocklin in Rocklin Mfg on 5/18/2022

What coatings or surface treatments does your company specialize in and what are its advantages?

The ROCKLINIZING process is a method of electronically transferring tungsten carbide, titanium carbide, and rockhard electrode material into and onto steel surfaces. Advantages are many due to the flexibility of the equipment and the applications to which carbide impregnation is applied. The user has freedom to experiment with various deposits and applications. Whereas other coatings offer greater lubricity, the ROCKLINIZER electrospark deposition process provides extreme wear resistance. The hardsurfacing process is a method of alloying tungsten carbide with steel, yielding a coating finish which shares the benefits of both.

If yours is a high-temperature process, what problems arise and what are the solutions for maintaining critical dimensions?

Most items which are ROCKLINIZED may be held in the hand since the electrospark deposition system is quick air quenched and little heat is generated. In many applications, ROCKLINIZER electrospark deposition equipment is exclusively used to correct dimensional errors and reclaim tolerances. With flexibility to deposit up to .010” controlled within .0001” by machine dial setting, the equipment has many benefits. A totally unique property of ROCKLINIZING hardsurfacing is that a similar amount of wear resistant material is impregnated beneath the surface as deposited above, leaving a two-fold wear protection surface.

Rocklinizer 950

In what increments of measurement can the treated surface be controlled?

The treated metal surface application is so finely controlled by machine setting that it can be controlled in small increments of ten-thousandths of an inch. In fact, before a ROCKLINIZER is released for use, a test bar of tool steel is covered across the range of power settings in addition to hours of automated testing.

What effect does Rocklinizing have on the surface finish?

The question of surface finish is key when one considers the ROCKLINIZING process application. Since the spark discharge in infinite amounts actually melts particles of the material’s surface, usually a mottled appearance exists. However, we are able to control the minimum deposit output to such a fine point, such that even when the hardsurface coating is applied one can observe the grinding marks from the original surface.

The heavier the discharge, the rougher the appearance. This doesn’t always mean the finish is rougher – it only shows where each spot of hardening occurred.

Isn’t a bright polished finish required for tools, punches, and dies?

The question of the necessity of a bright or super polished finish on tools can be directly related to the deformation of metal which exists in all stamping processes, as this work results in heat generation.

To exaggerate this condition in order to bring this presumed bright finish into proper focus on heated surfaces, we relate ROCKLINIZING when used with hot metal on a highly polished core pin of a diecaster’s die. This high polish was previously considered a necessity. One user of ROCKLINIZING hardsurfacing sums it up as follows: “When carbiding cores, it will appear that the core is awfully rough for releasing the casting. This roughness is so shallow that the core actually makes the casting smoother because the aluminum will not adhere to the core as much as it does to the core that has been stoned to a high finish.” Hot steel reacts the same.

Can a heavier deposit be made and a finishing operation used to decrease the roughness?

One can secure a smoother finish after making a heavier and rougher deposit by reducing the power to a lower setting and going over the part, thus getting a smoother surface. This result may also be achieved by adding titanium carbide coating onto a previously applied tungsten carbide coating.

Honing or grinding should only be utilized as a last resort. However, with the ROCKLINIZED surface so finely applied in thickness, unless one uses just a few hand passes of an abrasive cloth, one might go through the thin applied surface and expose the base metal. In other words, don’t polish off the applied hard surface with a wheel to attempt to get smoothness which may not even be necessary. Why not try the surface part first to see if the appearance really is a disadvantage? You might be pleasantly surprised.

What is the resultant tool hardness surface after Rocklinizing?

Normal methods of hardness reading, using diamond or point penetration, associated with Rockwell or Brinell testing do not give proper readings because process points penetrate the thin ROCKLINIZED layer. The resultant reading, therefore, is usually the base metal reading. ROCKLINIZING by applying known hardness material is a process to provide longer tool wear. Practical use is a better meter of effectiveness. On T-8 tool steel, compared hardness is ~80 Rockwell C (HRC) for titanium carbide, ~70 HRC for tungsten carbide, and ~60 HRC for the Rockhard electrode.

Rocklinizing apparently only affects the surface – are there any other considerations?

As a paint manufacturer once said, “Save the surface and you save all.” ROCKLINIZING saves surfaces.

Simple Operating Instructions are included with the ROCKLINIZER. One can within a few minutes master the techniques necessary for ROCKLINIZING. However, operation and process questions may arise.

ROCKLINIZING provides a thin layer application of tungsten carbide to tool steel (drills, reamers, taps, etc.) These tool surfaces should have already been properly ground and sharpened and ready for use.

The purpose of ROCKLINIZING is to provide greater wear and longer cutting tool life to tools between regrinding, or extend longer wear to other surfaces which are subject to wear.

What governs the power setting for desired thickness or the technique for electrode use?

There are countless Rocklinizer use cases, and there is no one best way for Rocklinizing. Technique may be a matter of “trial and error” when getting started. As an unusual example, when applying ROCKLINIZING to a needle point to attempt to give it greater wear, infused arc discharge from the largest setting could alter the metallurgical structure of the point metal itself. In this case, the lowest power setting would be used. Similarly, for knife edges, if one would use point to point contact of the electrode to the knife feathered edge, this might actually dull the knife edge. A hand control technique exclusively developed for ROCKLINIZING uses the arcing side of the electrode. This also would require the lower power setting so as not to dull the edge.

Larger surface applications such as coating wear areas on die casting dies or adding grip to tube bending dies may require the use of higher power settings. For more info on common applications, see our “How and Where to Apply” resource page.

How much area will one electrode cover?

The extent of use of electrodes as to specific coverage and life is minor. The electrode rate of erosion is sometimes not apparent with each coating. Consumption is exceedingly low. In cost relationship to the work accomplished, it is an insignificant factor. ROCKLINIZING electrodes, contrary to regular arc welding electrodes, are not used up to fill metal into space.

How much time is required to Rocklinize?

ROCKLINIZING required is related to the individual operator, the precision required for the area being coated, and the ROCKLINIZER model used. For example, nearly 5 sq. inches can be coated in one minute with the fastest Model 950 ROCKLINIZER. Moreover, new automation options including Rocklinizer Automation and Robotic Rocklinizing can deliver even greater efficiencies.

What are the main purposes for Rocklinizing?

The main purposes for ROCKLINIZING are to reduce metal-on-metal wear, to increase tool and die life, and to optimize grip. By adjusting the power settings and the electrode material deployed based on one’s application needs, all of these objectives can be achieved. With full portability supporting high-speed coating, downtime, setup time, inspection, excess inventory, and rejects are materially reduced.


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