Mechanical Plating

Definition - What does Mechanical Plating mean?

Mechanical plating is a process that imparts a coating by cold welding fine metal particles to a workpiece. Mechanical galvanization uses the same process, but applies to coatings that are thicker than 0.001" (0.025 mm). Mechanical plating is usually used to overcome hydrogen embrittlement problems.

Mechanical plating can only be used on parts small enough to fit into a coating drum. The materials must be simple in design to ensure peening on all surfaces. Mechanical zinc plating is most commonly used on high-strength fasteners and other small parts not suitable for hot-dip galvanizing.

Mechanical plating is also known as peen plating, mechanical deposition, cold welding and impact plating.

Corrosionpedia explains Mechanical Plating

Mechanical plating is a metal finishing technique that protects metal parts through the application of a sacrificial metallic coating. It is, basically, a cold welding concept that applies the coating using mechanical energy at room temperature, without causing any lasting hydrogen embrittlement.

This method of plating can be used on a much wider thickness range than electroplating and can also be combined with many different top coats for a customized solution to meet a wide range of requirements.

The components to be coated are placed into a tumbling barrel containing glass beads, reagents and catalysts, which activate and prepare the surface. The coating to be applied is added in metallic powder form and glass beads of varying sizes "cold weld" the coating onto the activated surface of the component. Prior to drying the parts, lubricants may also be added as part of this process.

Commonly plated workpieces include:

  • Nails/screws
  • Nuts/washers
  • Stampings
  • Springs/clips
  • Sintered iron components

The mechanical plating process has many industry advantages, in both quality and cost. Mechanical plating does not produce hydrogen embrittlement and does not require a post-bake cycle. It more easily coats odd-shaped parts: from chains and flat parts, to complex sintered metal parts. It allows the utilization of one process for an array of applications and part types. Additionally, compared to hot-dip galvanizing, mechanical plating does not require threads to be chased after plating.

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