Deep metal marking is a critical requirement for industries today. Surfaces with protective coatings or paint; or objects that will suffer from wear and abrasion often need deep identification marks. With the ever-increasing demand from the manufacturing world, the engraving and marking world is developing robust tools to deliver the much-needed arsenal. Two major methods dominating today’s markets are mechanical and laser dependent technologies. Laser etching or engraving and dot peen marking machines are essential tools, serving the industry.
Laser technology came into existence in the 1960s and its commercialization took further time. However, the industrial revolution had begun by the 1920s and 30s. Assembly lines streamlined production and increased efficiency. However, to maintain quality, traceability became an integral part of every manufacturing and similar process. Any defects found downstream or with end-users lead to recalling or re-manufacturing of goods and parts. Tweaks were made to the assembly or manufacturing process and the process then followed its usual flow. Traceability and tracking have been serving process-flow driven industries in general, and manufacturing industries in specific, multiple fold benefits. Machine operators can detect equipment defects and air-crash investigators can conduct thorough investigations because of this function.
To this end, the industry initially resorted to mechanical and chemical methods. With the introduction of the laser, many industries moved on to this newer technology.
Laser Engraving or Laser Etching
Laser engraving and etching are terms often brought in use without distinguishing between the two processes. The final results can be very different for both processes hence knowing the distinction is important.
Laser engraving is a process where a high-intensity laser beam cuts through a material, removing the surface in the process. The exposed cavity appears as an image to the eye. Laser etching machines on the other hand melt the material. In doing so, it alters the reflectivity of the surface and increases contrast. The melting process does remove material but is of the order of .001”.
For deep metal marking, a laser engraving machine is an obvious choice. Laser etching and marking machines are not designed to cater to requirements of greater depth.
Dot Peen Marking
The industrial revolution took place much earlier than the development of laser technology. Consequently, the requirement of deep metal marking arose much earlier than the development of laser tools. Mechanical solutions filled this gap.
The dot peen marking method is what lead the industry then. Its simplicity and further automation as well as an increase in sophistication make it a tool that is still in use today. Initially, metal stamping was done by hand. In metal stamping by hand, a hammer strikes a stamp which can be letters or patterns. The striking action leaves an indent of the stamp’s design on the metal’s surface. This process has further grown and is now done using machines.
Making use of dies and stamping presses to transform sheet metal into different shapes, metal stamping is a cold-forming process. Blanks, or pieces of flat sheet metal, are fed into a metal stamping press. The press uses a tool and die surface to form the marking on a surface. Production facilities and metal fabricators will place the material requiring stamping between die sections, where pressure from the die will shape and shear the material into the final shape for the product or component.
There are three common types of stamping presses in use but the industry. They are mechanical, hydraulic, and mechanical servo technologies. Conventionally, presses have a connection to an automatic feeder that sends blank metal through the press.
Comparison: Dot-Peen, Laser, and Stamping for Deep Metal Marking
Due to the technology upon which dot peening is based, it is often used for the marking of rigid materials such as metals or hard plastics. Machines handling hardness up to 60 HRC as well as on plain, curved, round, and rough surfaces are commercially available. Thus, this technique is frequently found in the automotive and aeronautics industries.
Similar to dot peen, metals tend to maintain their malleability and ductility after stamping. Metallic materials for precision stamping usually range from soft to medium hardness and have a low coefficient of flow. Following are metals commonly marked using stamping methods: Precious metals, such as silver, gold, and platinum; Ferrous metals, especially iron-based alloys like stainless steel; Non-ferrous metals, such as bronze, brass, and zinc; Non-standard alloys, such as beryllium nickel and beryllium copper.
In contrast to dot peen and stamping, laser marking systems can be optimized for several materials. Laser engraver manufacturers can control several parameters to extend the capacity of a machine. Factors such as the wavelength and the power of the laser beam allow for flexibility in the application of the equipment for marking purposes. This allows laser markers to be effective for a wide variety of materials such as metals, ceramics, wood, and plastics.
DPM vs Non Contact
Dot-peen marking and metal stamping is a DPM or direct part marking method. It is a contact method where the stylus or press and die must contact the surface to mark. This is a major difference between these processes and laser marking. Moreover, the process of marking with dot peen machines does not produce as much heat as a laser marking machine. Laser marking generates large quantities of heat and fumes in the process, which can be hazardous for the user.
Furthermore, the mechanical motion allows dot peen marking machines to produce deeper marks on metals than laser marking devices. Also, when handling irregular surfaces, dot peen engraving machines perform much better than laser marking machines and create clearer indents. Apart from uneven-ness, marking on a dirty or wet material surface with dot peen machines will create clear signs regardless of the surface conditions.
Laser engraving, on the other hand, is a non-contact process. This eliminates the worries that may arise due to mechanical tooling and consideration of material stresses. Furthermore, there is nothing to wear out. Hence, the engraving pattern is highly accurate and repeatable. A stylus that becomes blunt during the marking process can lead to many difficulties. Also, the laser allows access to areas of the workpiece that are difficult to reach mechanically. By focusing a laser beam, odd angles and locations can be dealt with.
The use of dot peen systems is especially suitable for the writing of alphanumeric serial numbers or 2D barcodes such as data matrix codes. This technique, however, is not widely used for the writing of 1D barcodes. This is because of the fact that 1D barcode readers need a higher level of writing contrast than 2D barcodes and dot peen marking machines are unable to provide requisite contrast levels.
Laser marker systems stand out with their ability to do different types of tracking codes and markings ranging from alphanumeric serial numbers to 2D barcodes.
Stamping is used in a variety of applications, especially those involving three-dimensional designs, lettering, or other surface engraving features. Such stamping products are commonly produced for home appliance manufacturers, automotive companies, the lighting industry, telecommunications services, military and defense, aerospace industries, medical equipment manufacturers, and electronics companies.
The Machines for Deep Metal Marking
Fiber Laser Engraving and Etching
Simplified Marking And Real-time Traceability is a range of fiber laser solutions. This Fiber Laser Marking System allows manufacturers to mark or engrave serial numbers, bar codes, 2D Data Matrix, and graphics on the widest variety of materials, including metals, plastics, and ceramics. The Fiber Laser is a referenced product in the Rockwell Automation Partne rNetwork that integrates into factory automation networks using native EtherNet/IP protocol and embedded controller technology.
It has a Ytterbium-doped fiber laser. The company offers a range of output power for the laser it integrates in its products. The lower power lasers are better for etching whereas the high power lasers are good at deep engraving and cutting. It has a galvanometer scanning setup and has a 7000mm/s engraving speed. Normally The laser supplier offers a 2-year warranty on the product.
Dot Peen Marking Machine
For factory automation environments, Heatsign offers dot peen marking systems allowing for easy integration of automatic pin marking for machine builders and OEMs.
The machine in the picture above is the HS-DE01 Dot Peen Direct Part Marking. It has a marking window of 120 x 80 mm. It is a pneumatic machine which has an operational speed 30-40mm/s.
This is the A-3000 SERIES air press. This press is ideal for assembly, punching, shearing, and staking of metal or plastic. The column height can be increased by adding a riser block between the base and the column. The A-3000 series pneumatic press has multiple built-in features for an increase in utility. Such as a T-Slot base for easy fixturing, dual hand anti-tie-down/anti-repeat controls, and a three-inch stroke length. An adjustable down stop/anti-rotate mechanism comes standard.
Practical Considerations for Deep Metal Marking Machines
A major advantage of dot peen systems is their low price. These systems have a price ranging from 8,000 Can$ and 15,0000 Can$. Consequently, return on investment on such equipment is achievable in a short span of time. However, due to the physical contact between the system and the material, the marking tip has a high deterioration rate and often needs replacement. In business terms, this implies a recurring cost and a constant maintenance requirement of the dot peen marking system. But a contact method does have its advantages. The profound permanence of the marking that one can create from these methods can survive extreme usage, storage, and transport conditions. On the flip side, such deep markings lead to low-speed writing because the tip needs to scan the whole marking region and at times, multiple passes may be carried out.
The metal stamping process tends to be relatively less expensive to execute and maintain than those used in other common processes. But a major issue of stamping is the higher cost of presses. Furthermore, the dies must also be bought or made, and producing custom metal stamping dies is a long pre-production process. This can have a significant operational impact considering situations where dies may need changing due to an alteration in design during production. Furthermore, there are secondary costs, such as cleaning and plating. But these are cheaper than similar requirements for other metal fabrication processes. Automation of stamping machines is relatively easy and machines these days can employ high-end computer-control programs. CNC marking machines come with the advantage of greater precision, faster production, and quicker turnaround times. The high level of automation also lowers the cost of labor.
The flexibility and ease that laser markers offer come with a much higher price tag. Conventional laser marking system prices start at 30,000 Can$ and can go up to 100,000 Can$. The price will depend on the power, the laser type, and the industrial-grade requirement for your application. This high upfront cost does not necessarily make it a deal-breaker as the laser engraving and marking systems come with cost-effective benefits operationally. For instance, there is no use of consumables and requires a low-level of maintenance. The method itself is fast and has a high resolution. A faster speed means higher throughput and increases productivity. Higher contrast is achievable allowing for greater marking ability in terms of graphics. These factors make laser engraving and etching systems a profitable long-term investment.
In a nutshell, laser, dot peen, and stamping have their positives and negatives to offer when in use for deep metal marking. Deciding upon which technology and which machine to adopt falls into the user’s lap. Which technology is right for an intended deep metal marking is highly dependent upon existing infrastructure.
Particular processes will need specific solutions. For instance, dot peen will be better for temperature-sensitive materials or environments. The laser will best suit brittle materials as direct contact methods may lead to material failure. Speed is another factor. If deeper engravings in a shorter time span are of need, dot peen can deliver the requirement. But so can laser. This can be offset by cost. The laser has a higher upfront cost but is low on maintenance. Does a lower maintenance machine make more sense or is recurring maintenance expense a more feasible option as is the case with dot peen.
Keeping these factors in mind, users can delve into the market and select the machine that will fulfill their needs. A one-stop-shop for marking and engraving needs is also available at Heatsign for the best laser engraver. They offer marking and engraving machines using these technologies and have multiple resources available for a better understanding of deep metal marking products.