Engraving stainless steel is a process that cuts designs such as lettering and logos into the surface of stainless steel to produce signs, labels, and nameplates. Traditionally, this has been done using rotary cutters which cut one letter at a time, and then the engraving is filled with paint to make it visible.
Engraving of plastics and other soft materials, and even some metals such as aluminium and brass, is relatively easy, but engraving stainless steel requires more skill, knowledge of cutters, and more robust machinery. As recently as twenty years ago, most towns and cities in the UK had local engravers with the skills and equipment to do this work, an invaluable service for manufacturing signs and labels in a hurry. Unfortunately, with the decline in British manufacturing, most of these engravers have closed down.
Over the last fifty years, most engraving into stainless steel has moved from rotary cutting to chemical etching, which is quicker, produces a much higher quality product, and enables more intricate and sharper designs than can be achieved by a rotary cutter. Both processes produce the same end result; detail cut permanently into the surface of stainless steel, there are, however, some important differences in the way the two technologies work.
Engineering companies requiring an equipment nameplate would typically cut and finish a blank plate, then take it to their local engraver. Stainless steel valve tags and asset labels were produced in a similar manner, the engraver buying standard pre-cut blanks, then simply engraving the individual details onto each one. This worked well for engraving, but is not appropriate for chemical etching.
Chemical etching works in a different way. Sheets of material are etched, and are then cut into individual signs and labels. For most jobs this makes no difference, but it does have implications for the design of some products.
It is not practical to etch pre-cut pieces of stainless steel. It can be done if there is a particular need to do so, but is slow and expensive. It takes more time to etch one small nameplate than it does to process a panel of ten or twenty nameplates, extra time being involved in alignment of the image to the cut piece, and in protecting the edges through the etching process.
For making equipment nameplates, this means it is no longer sensible to cut a piece of material, then to have it etched or engraved. This may affect the design of nameplates that previously may have had studs welded or other fabrication work prior to engraving. It can also affect the thickness of stainless steel used, because etching in sheet form and then cutting into individual labels only works up to a thickness of 1.5mm. Stainless steel thicker than this needs to be cut on bigger machinery, which will not allow alignment to the etched image.
For other items such as valve tags, it affects the costs and practicalities of cutting certain shapes. Cutting of straight lines in sheet metal is quick and efficient. Cutting of discs, for example, becomes slow and time-consuming, and therefore much more expensive than the same size squares. People have become used to specifying discs with one hole for such jobs, because this has been an industry standard product for a long time, but it is no longer the simple option, and discs rarely work well for displaying linear information such as text and numbers anyway. It is better to design such products as squares or rectangles with radius corners, which are quicker to make.
For most jobs, the change from mechanical engraving of stainless steel to chemical etching makes no difference, and the likelihood is that products such as labels and signs that people think have been engraved have actually been made by chemical etching anyway. Engraving of stainless steel is such a slow process, and the surface finish of the engraved areas unacceptable even when paint filled, that most such jobs have been manufactured by chemical etching, also known as chemical engraving, for more than half a century.
If you want to find out more about how the chemical etching process works to help with designing your project, read our Chemical Etching Guide.