FOCUS ON MARKING
The resulting marks are durable and resistant to falsification . The three main laser engraving methods are laser etching , laser engraving and laser ablation . The key difference between etching , engraving and ablation is :
■ Laser etching produces shallow marks .
■ Laser engraving produces deep marks that can withstand exposure to harsh operational or environmental conditions .
■ Laser ablation produces marks by removing surface coatings ( e . g ., painted or anodized layers ) to expose underlying layers .
Laser engravings are often used in the automobile industry or in electromechanics . But laser engraving is also often implemented to create markings and deep engravings in rapid prototyping and rapid tooling .
“ When laser engraving metals , oxides are formed by the interaction of the melted basic material with the atmospheric oxygen which differ in colour . The usually quite rough surface absorbs a lot of light which is why the marking usually appears to be black or dark grey ( aluminium ) or dark brown ( steel , brass , copper ), depending on the material ,” said TRUMPF .
Laser engraving offers a variety of advantages over other marking processes , such as a broader range of depths . Laser engraved marks can be made to varying depths , from shallow to deep . It also offers better durability . The laser engraving process can produce marks that remain highly visible , even after being exposed to harsh conditions . Greater marking speed is also an advantage ; laser engraving is a rapid way to produce lasermade markings .
Dot Peen marking
Dot Peen marking or engraving is a pin marking application that allows manufacturers to make deep , permanent impressions in a variety of materials for identification and traceability . Also known as pin marking or pin stamping , this efficient marking process involves a carbide or a tungsten carbide pin that directly impacts a material to create a mark . Automated dot peen marking delivers high-speed marking as well as deep , permanent engraving capabilities .
Dot peen marking involves stronger contact between the equipment and the metal surface . In fact , this process is more similar to engraving . The name of the method is partially derived from a dotted pattern that is left on the surface via a special marking head , better known as a ‘ stylus ’.
Dot peen engraving is useful for marking a variety of mechanical parts in different industries . These include tools ; gears ; metal tubes ; pumps ; fasteners ; valves ; drive shafts ; engine blocks ; cylinder heads and so forth . Dot peen ( ing ) can also generally be used on thicker metal surfaces due to the nature of the process .
Electric dot peen marking , also known as vibro peen marking , is useful in the automotive industry for durable engravings at high marking speeds . Vibro peen automotive engraving is also resistant to chemical compounds , abrasives and temperature changes .
Inkjet marking
Continuous inkjet ( CIJ ) is a common marking technology for metal components . CIJ printers offer easy integration for printing on a wide variety of metals and are suitable for printing on curved or indented surfaces . Printing can also be done without damaging surface treatments such as rust-proof painting and plating
Inkjet marking is a customised printing process that results in semi-permanent marks on the metal ( and plastic ) surface . It is possible to achieve high-resolution marking results using inkjet marking machines , but you have to be careful when choosing your equipment .
“ Labels created using this technique are the least resistant to external influences and are therefore quite prone to fading . The pressurised ink is responsible for changing the colour of the surface , but it does not significantly affect the microstructure of the base metal ,” commented Cougartron .
Impact presses
For higher-volume marking requirements , a common marking method is to employ an impact press . Presses come in many sizes and can often be integrated into a production line . These presses are commonly used for adding traceability information to parts , but can also be used to stake , rivet , crimp and more .
“ Custom shank stamps and type holders with interchangeable steel type can be employed for part marking requirements where one or more lines of copy are required . Numbering heads are also available for serialising parts . Pneumatic controls are available for higher-volume marking requirements ,” added Durable Technologies .
Marking / etching tools
Sheet marking tools permanently mark , etch or inscribe sheet metal parts with assembly codes , serial numbers , names and etchings for part traceability using data such as pallet number , machine number , sequential serial number , time and date .
Selected tooling specialists can provide these tools , which can be used during sheet metal manufacturing processes such as metal punching .
Hand stamping
Hand stamping is a popular , low-volume marking method among hobbyists , craftsmen and artists . Requiring only a hand stamp and a hammer , hand stamping has a very low barrier to entry and low upfront costs .
“ However , while hand stamping is an excellent solution for applications with low volume and simple marking requirements , it is not an ideal solution for applications where the requirements specify changing data , medium-to highvolume or certain materials like glass and some plastics ,” cautioned
Durable Technologies .
Left : Pin stamped part . Above top : Dot peen marked part . Above : Inkjet-marked part ( MMS Metal ).
The intricacies of product marking and choosing the right kind for your product may seem daunting , but understanding the differences between marking types can help you determine which metal marking method would be most suitable for your product . n
40 | sheetmetalplus . com | ISMR March 2022