About Finishes

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With Protocase finishes, you can apply chem film coating to aluminum, color the entire enclosure using powder coating, and add silkscreening or digital printing to print color text and images to the faces. You can also add dot peening, which does not use ink.

Powder coating is used to color the whole enclosure. For available powder coating colors, see Protocase Powder Coating. When specifying fully custom powder coat colors, please provide us with the RAL number. For examples of good and bad contrasting colors, see Contrast between silkscreen and powder-coat colors. Note that when printing text on powdercoat, colored letters on white powdercoat are legible to 6 pt for both sans and serif fonts. For colored letters on non-white powdercoat, the minimum font size is 10 pt for serif fonts and 8 pt for sans serif fonts.

Chemical conversion coating (also referred to as chem film, chromate coating, or yellow chromate coating) applies chromate to the metal substrate, is used to protect enclosures and metal parts from corrosion and to ensure that reliable electrical connections can be made to aluminum chassis and components. It is also an effective pretreatment for powdercoat. For details, see Protocase Chem Film.

Silkscreening is used to print simple images with up to just a few specific colors, shown on Protocase Silkscreening. For details on the silkscreen process, whether you use Protocase Designer to prepare the silkscreening or whether you send the images for us to prepare, see About silkscreening.

Direct digital printing, which will print any color, is used instead of silkscreening when images have multiple or gradient colors. Before specifying digital printing, please read instructions and important limitations in Adding silkscreening or direct digital printing using Protocase Designer. In particular, please note that direct digital printing will not stick to bare metal; you must use powder coating first. For an overview of the differences between silkscreening and digital printing, see Silkscreening vs. Direct Digital Printing.

Dot peening is a form of permanent marking on sheet metal parts, for traceability and identification to meet safety, warranty, or regulatory requirements. An alphanumeric pattern is first programmed into the dot peening equipment. The machine head is laid over the part while it is still flat (before bending and finishing) and a series of dots are then created by the impact of the pin. The end result is a readable, alphanumerical identification. You can specify alphanumerical identification as well as incremental markings, such as serialization. We can dot peen any of our materials, but there are considerations when using thin gauges. Specifically, when dot peening aluminum thinner than 0.051” or steel less than .048”, ghosting or witness marks may show through on the reverse side. This is only an aesthetic issue and in some cases may be perfectly acceptable. Therefore, in cases where dot peening is to be specified on these thin materials, carefully consider where witness marks might show up. Dot peening can be used on bare metal finishes or under powder coat, as the depth of the peening is sufficient to show through the paint. The presentation of the dot peened characters will vary from the different powder coat colors. For detailed specifications (including examples of dot peening under power coat), please see Protocase Dot Peening. Dot peening is not yet supported in Designer, but you can add the text to the design, then add a Note to that text requesting that it be done in dot peening.

Bare Metal Finishes are offered in "No Finish" and "Grained Finish" options for aluminum and stainless steel. "No Finish" means a part is deburred only; there is no additional finish or sanding applied to the metal. Minor scratches and blemishes are to be expected, with a consistent finish on both sides. With "Grained Finish," a part is deburred and scratched using a brush/sander to create a uniform grain direction on both sides. Grained finish is an ideal application for when powdercoat is not desired, but a uniform bare finish is still required. A grained finish can be silkscreened, but not digitally printed. The minimum dimension for a part with a grained finish is 3"x 5". For further details on these two finishing types, see Bare Metal Finish.

Secondary Finishes A primary finish is that which is performed on the case metal, such as a grained finish or the finish created by our CNC milling process. When this is the case, then digital printing, powder coating, etcetera, are secondary finishes. Because finishing processes affect surface finish (and therefore part size), we do not recommend applying secondary finishes to high-tolerance parts, as the finishing process can remove or add enough material to put the finished part out of size tolerance. (For a full list of secondary finishes that can be applied to milled items, scroll to the very end of the CNC milling page.) Please note that CNC Milling is not yet in Designer, but you can request it in a note you can add to the design. There is not a lot you can do with sheet metal, but if the front panel is thick (0.12" for example, as in a rackmount enclosure), that could be machined, such as adding bevels.