FOCUS ON MARKING to the factory floor , environment and part surface quality . Ultimately , the solution chosen will come down to several factors including material , application , budget and time restraints ( if any ).
There are three basic types of marking methods that can be used for permanent marking on metal , which are listed below .
Laser markings on a saucepan ( image : TRUMPF ).
Etching
“ Etching can be accomplished with a number of methods , but each of them relies on disturbing the surface of the metal to a noticeable depth . The change in surface properties shows a contrast , which is the visible mark ,” explained Matt Martin .
The most common etching methods include dot peen marking systems ; laser ; CNC marking tools and hand-held marking tools .
Engraving
Much like etching , engraving relies on displacing the surface of the metal . When engraving or stamping , however , a much deeper mark is made into the surface . Engraving and stamping are ideal solutions for applications that will be subject to harsh environments and parts that will need painting or coatings .
Common engraving methods include impact presses ; steel type and holders ; steel stamps and dies ; hand-held marking tools and numbering heads .
Surface marking
Surface marking typically doesn ’ t remove any of the surface material . Instead , this type of marking method adds ink , paint or foil to the surface of the material .
Common surface marking methods include industrial inks ; inkjet printing ; hot stamping and stencils .
A selection of marking methods
‘ Marking ’, ‘ engraving ’ and ‘ etching ’ can describe different processes . Engraving is a technique that removes layers of materials away from a substrate . When you engrave a substrate , the top layer is vaporised which often leaves a contrast . Etching follows the same lines , but usually results in a lighter mark without as much depth . If etching something delicate , it barely touches the surface and you can hardly feel the difference .
Marking is often associated with engraving metals or polymers . Metal is marked typically for identification , tracking or branding . There is usually a change in colour , for example , marking a black serial number . Sometimes you may notice a colour differentiation , but it is more of a surface treatment .
UDI ( Unique Device Identification ) marking on medical tweezers ( image : TRUMPF ).
Electrochemical marking
The popularity of electrochemical marking technology is closely related to its versatility and flexibility . Since the process is fuelled by electricity and mild electrolytes ( marking fluids ), this marking method is suitable only for conductive metal surfaces . However , this covers a wide range of different metals and electrically conductive surfaces , including stainless steel , aluminium , brass , mild steel and titanium to name a few .
“ Electrolytic marking equipment is generally affordable and not associated with high maintenance costs . The marking machines themselves are portable and compact for clear marking results . However , although practical , electrolytic marking is still a manual process . Therefore , it may not be suitable if you are dealing with high-scale serial production where computer-controlled systems can secure more benefits ,” explained Cougartron .
Laser marking
Laser marking is a manufacturing process that uses a focused beam of light to permanently alter the surface of the workpiece . Unlike laser engraving , it changes the surface without removing material . It produces long-lasting high-contrast marks that can be easily read or scanned . Medical devices and instruments can be laser-engraved , laser-marked or laser-etched with logos ; UDI ; part numbers ; identification and tracking information .
It is an effective method that owes its success to technological progress . Unlike the electrochemical method , laser marking is suited to serial production since the equipment used is mostly stationary and not controlled by hand . The technique is usable on various materials including metal and plastics , explained Cougartron .
There are many laser marking methods available . Commonly used methods are annealing ; carbon migration ; colouring and foaming .
“ The main advantage of annealing is that the material surface remains completely intact : the marking is easily legible , long-lasting and resistant to abrasion . Annealing is ideal wherever a precision fit must be maintained or material bulging is prohibited . That is why this procedure is ideal for consumer goods such as cooking utensils or medical products , for example ,” commented sheet metal specialist , TRUMPF .
Compared to other marking methods , laser marking offers several advantages , such as higher marking accuracy / precision ( enabling manufacturers to target highly specific areas on the workpiece ). They also ensure a smaller environmental impact ( the process produces much less waste since it does not require the removal of material from the workpiece to create the desired marks ).
“ Laser marking also offers better compliance with industry regulations . The permanence and readability of laser-made markings make the laser marking process ideal for adding important information to manufactured components ( e . g ., barcodes , serial numbers and trademark icons ),” added laser marking specialist , Accubeam .
Laser engraving
Laser engraving is a manufacturing process that uses a focused beam of light to remove material from the workpiece to form the desired design ( e . g . text or image ).
ISMR March 2022 | sheetmetalplus . com | 39