Coating Machine Part Surfaces

Armoloy Coating Beats Wear and Improves Mold and Machine Part Surfaces

Many frustrating problems involving premature failure of metal wear parts are being solved on a routine basis by a unique hard-surface coating process trade named Armoloy. This controlled proprietary process in which an extremely hard corrosion resistant chromium coating is applied produces a superior degree of adherence and uniformity not obtainable by conventional chromium plating. Amazing results have been achieved with Armoloy including increased parts service life from two to ten times that of unprocessed parts. All this is accomplished with a size change of less than .002' coating thickness. Applications in a number of industries include tool, die, machinery, and equipment builders.

  • What is Armoloy
  • Armoloy is a low-temperature multistate process of electrocoating based upon chrome-plating technology. Instead of normal chrome-plating solutions, however, the national and internationally franchised operators of the process obtain their chemicals directly from the technique's developer. The proprietary coating solution and procedure is rigidly controlled to produce superior results.

    The process involves clearing and removing the matrix on the metal's surface by chemical and mechanical means. The proprietary process causes the metallic elements to permeate the pores of the metal, actually becoming a part of the metal itself and insuring a positive, lasting bond between the basis metal and the hard Armoloy surface.

    Armoloy coating can be applied to all ferrous and nonferrous metals, but is not recommended for aluminum, titanium, or magnesium; metals not commonly used in the construction of molds or machinery for plastics processing. The process has no effect on the basis metal to which it is applied, nor does it build up on corners or sharp edges in the manner of other plating materials. Based on the substrate metal being coated, the deposited Armoloy has an equivalent hardness value of 78Rc. The use of similar or identical materials as opposing bearing surfaces is acceptable due to this high hardness rating.

    Hydrogen embrittlement, which is a factor in some plating processes, is not likely to occur with Armoloy corrosion resistance coating. Armoloy surface preparation and processing control prevents the embrittlement phenomenon from occurring.

    Armoloy thermal shock tolerances are almost unbelievable - from -400°F to over 1600°F. At elevated temperatures above 1200°F, Armoloy will react with certain materials such as carbon monoxide, sulfur vapor, and phosphorus. However, for the tool making industry, these do not represent any problem. At temperatures above 700F, hardness and wear resistance will change to some degree, but this is not a factor in coating cavity parts for die-casting molds.

  • Applications
  • Armoloy's corrosion resistant coating is used to protect both metal and plastics molds, even though the continuous effects of hot metal injected into die-casting molds represent on of the toughest wear problems. Even the hot work series of alloy steels (H-13) are not able to stand up continuously to the effects of the heating and cooling cycles demanded of the mold. In addition, the use of mold releases can cause a build-up of release residue on the cavity surface to the point where the mold must be removed from the press and cleaned and polished. Armoloy improves the lasting qualities of the mold on both problems: heat checking and release build-up.

    The inherently hard Armoloy surface is corrosion-resistant and lowers the coefficient of friction between the Armoloy surface and other materials which helps reduce galling and pick-up between sliding metal parts. The satiny-matte, micro-orange peel finish of the Armoloy coating tends to also prevent mold release drips and runs on the cavity surface. Polishing and grinding requirements prior to coating with Armoloy are the same as that with standard chrome plating.

    For thermoset materials, alkyds cause considerable maintenance problems requiring periodic leaning of mold surfaces and recoating. Armoloy coating reduces maintenance requirements and extends mold life up to ten times that of normal molds without Armoloy.

    Standard chrome plating over nitrided surfaces can best be described as sporadic. Adhesion is definitely a problem and the flash-plating is liable to peel off. Armoloy solves this problem with a special cleaning technique that provides a secure Armoloy bond to the nitrided surface.

    Automatic unscrewing molds for threaded closures have a wear and galling problem between the rotating core and stripper ring. Ideally these running surfaces would be lubricated, but this is not always possible due to the close proximity to the molding area. Tests indicate that the siding coefficient of friction when one surface is Armoloy coated is reduced 20 percent and when both surfaces are Armoloy coated, friction is reduced in excess of 40 percent compared to steel against steel contact.

  • Machinery and Equipment Applications:
  • In addition, Armoloy can be used to protect working part surfaces on scrap grinders, grinder blades, cheek plates and rotors, improving part life up to two to three times that of uncoated parts while reducing common maintenance problems. Wet parts and runners from water-bath cooling set-ups may be put directly into Armoloy protected grinders without concern about discoloring the plastic due to rust of corrosion. Of course when using a grinder for wet material, some type of protective coating should be used on the scrap bin and grinder body as well.

    Severe corrosion and wear problems common to extrusion screws and non-return valves also can be significantly reduced. Since Armoloy coating will adhere to nitrided surfaces, extrusion barrels may benefit most from corrosion resistant technology.

    For thermoset materials, alkyds cause considerable maintenance problems requiring periodic leaning of mold surfaces and recoating. Armoloy coating reduces maintenance requirements and extends mold life up to ten times that of normal molds without Armoloy.

    Perishable tools, such as drills, taps, and milling cutters, benefit from the corrosion resistant Armoloy surface coating. In some cases, Armoloy coated high-speed tools can replace expensive carbide tooling. For molders of thermosets with secondary machining problems, Armoloy coating may cut tool expenses with improved tolerances due to the greater wear resistance solution for tooling.

    The applications where Armoloy's corrosion resistance coating increases parts life by reducing wear and corrosion extends throughout the plastics and machinery industry - yet the cost of processing is not high - and tits in virtually everyone's budgets.

    For more information, call the leader in corrosion resistant coatings at: 412-823-1030.