In electroplating, the thickness of the plating is typically measured in micrometres, which are also known as microns. The symbol for microns is μm, although it’s common to see it written as um. A micron is equivalent to one thousandth of a millimetre or 0.001 mm. To put this in perspective, the average diameter of a human hair is about 50 microns, while a ‘heavy’ deposit of silver in plating could be around 200 microns. This may seem like a tiny amount, but even this small increase in material can have a significant impact on the characteristics of the metal it’s applied to, improving its wear and corrosion resistance properties.
Here are some frequently asked questions about plating thickness in electroplating and their answers:
What is plating thickness?
Plating thickness is the measurement of the thickness of the plated metal layer on the substrate material.
Why is plating thickness important?
Plating thickness is important because it affects the properties and performance of the plated part, such as corrosion resistance, wear resistance, conductivity, and appearance.
How is plating thickness measured?
Plating thickness can be measured using various destructive or non-destructive methods, including X-ray fluorescence (XRF), eddy current, magnetic induction, and coulometric.
What factors affect plating thickness?
Factors that affect plating thickness include current density, plating time, bath chemistry, temperature, and agitation.
How is plating thickness controlled?
Plating thickness can be controlled by adjusting the process variables, such as the current density, plating time, and temperature. It is also important to maintain the proper bath chemistry and agitation.
What is the typical range of tolerance for plating thickness?
The tolerance for plating thickness depends on the application and the specification requirements. Typically, a tolerance of +/- 5-10% is acceptable for most applications.
Can plating thickness be uniform across a part?
Yes, plating thickness can be made uniform across a part by controlling the process variables, such as the current density and agitation, and by using specialized equipment, such as conforming anodes and shields.
What happens in case the plating is too thick?
Yes, plating thickness can be too thick, which can lead to problems such as cracking, peeling, and reduced adhesion to the substrate. It can also affect the dimensional tolerances and function of the part.
What happens when plating is too thin?
Yes, plating thickness can be too thin, which can result in inadequate performance of the part, such as poor corrosion resistance or conductivity. It is important to ensure that the plating thickness meets the desired specifications.
Why plating thickness is specified in range?
Plating thickness is specified in ranges for several reasons.
When it comes to technical drawings and specifications, achieving an exact thickness can be challenging due to the precision required in the plating process. Therefore, it is more practical to provide a range rather than a specific measurement.
The units of measurement involved in plating thickness, such as microns, are incredibly small. Achieving an exact thickness, such as 5 microns, can be technically demanding and may result in inconsistencies. By specifying a range, such as 5-8 microns, it allows for a margin of error and accommodates the inherent variability in the plating process.
Providing a range for plating thickness also offers flexibility. It allows for slight adjustments to be made during the plating process to ensure the desired properties and performance of the plated material. This flexibility helps to achieve optimal results while still adhering to the general thickness requirement.
Moreover, specifying a range takes into account factors such as plating uniformity, potential variations in the substrate, and the limitations of the plating equipment. These factors can affect the actual thickness achieved during the plating process. By defining a range, it ensures that the desired functionality and characteristics of the plated material are maintained, even if the exact thickness varies slightly.