Yes. PVD is a line-of-sight process. Only the surfaces of the components exposed to the target source can be coated. Depending on the size and shape of the components, they are subjected to a planetary motion (part rotation along an axis for uniform exposure to the target source) within the vacuum chamber to ensure uniformity of the coating across external, exposed surfaces.
A general thumb rule or ratio with this line-of sight process is 1:1 in terms of coating penetration to the diameter of the opening. This ratio can vary depending on the orientation of the component in the vacuum chamber and the critical surfaces requiring the coating. HEF can evaluate this case-by-case based on component geometry.
Yes. It is possible to mask certain surfaces that do not require PVD coating. Components are also held on certain surfaces using special tools within the vacuum chamber that do not get exposed to the coating. Customers are requested to specify on part drawings the following:
Non-critical surfaces will be utilized to fixture the part for the coating process.
Yes. PVD coatings can be applied on steel, titanium, copper-beryllium, aluminum alloys as well as certain plastics, elastomers and glass.
Absolutely! Pre-cleaning is essential and an important step of this process in order to ensure a good adhesion of the PVD coating on the component surface. HEF offers cleaning solutions for parts shipped to us with light rust preventative oils or machining coolants as part of the process.
Surface finish primarily depends on the application and performance requirements of the component. Ra, Rpk and Rz are typical surface roughness parameters that are looked into depending on the application. However, it is important to ensure that the parts are provided in a good surface condition without any imperfections/defects and contamination (rust, scaling/oxides).
PVD coatings generally duplicate the incoming surface finish of the parts. However, HEF offers certain pre-blasting and pre-polishing capabilities for applications that require a specific finish.
Yes. PVD coatings (depending on the type) can be offered in different colors such as gold, silver, grey and black to list a few.
Yes. PVD coatings can be removed or stripped if required. This requires components to be immersed in a special chemical solution for a certain time period to ensure the entire coating thickness has been removed. However, special attention needs to be given to ensure these de-coating chemicals do not affect the substrate material. The components may require additional polishing before recoating. This is generally discussed with the customer on a case-by-case basis. HEF has the capabilities to offer these services, if required.
PVD coatings are currently used across a diverse range of industry segments and applications. Some of these include:
DLC Coatings: Processing Details and Applications
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