Analysis of the current situation of laser plastic marking technology
Decorative thermoplastics with laser marking took longer to be recognized than expected ten years ago. Nevertheless, laser technology has replaced ink marking technology (such as embossing and inkjet printing) in some applications, and the situation has changed. At present, the so-called "non aesthetic" applications are estimated to account for 90% of plastic laser marks. Some marks are made by carbon dioxide laser machines, including part model, manufacturing date and expiration date. Usually, these marks are black letters and numbers on a transparent or light background, or pure white marks on a black background. "Aesthetic" laser marking accounts for 10% of the market and has great development potential in replacing ink technology. This is a typical white mark on black engineering plastics, which is printed with a solid-state nd:yag laser machine. This laser machine is easy to program and is suitable for making clear marks on products of any shape
laser marking has been successfully commercialized in applications including ABS keyboards for commercial machines, HDPE, i.e., pet and PVC rigid containers and container covers, nylon and PBT electrical connectors for automotive and non automotive applications, and hood components such as fuse boxes and gas caps. There are other applications, including TPE ear tags for cattle and pigs, HDPE switch buttons on electrical parts such as cleaning and drying equipment, and PVC pipe fittings such as connectors and pipe fittings
the initial applications include light switch covers, cosmetics packaging materials, car interior buttons and door handles, and instrument panels. In recent years, the latter has become an important application market
in the last decade, the technological progress of computer programmed laser marking equipment has been accompanied by the development of more varieties of laser marking resins. Specially made colorants and packaging additives can be used in a variety of plastics, such as polyolefins, ABS, PVC, polyester, polycarbonate, nylon, polyformaldehyde and thermoplastic elastomers
nowadays, laser marking plastics have high contrast. Sometimes, they are a contrasting color rather than black and white. Even dark contrast is possible. According to Patrick schlather, the marketing manager of rofin baasel, the main supplier of plastic laser equipment, these diverse colors are one of the popular trends, which is causing people to have greater interest in laser decorative plastics
applications of laser marking include light switch covers, cosmetic packaging materials, automotive interior buttons and door handles, and instrument panels. In recent years, the latter has become an important application market, and also meets the development needs of printing a large amount of data on even smaller plastic parts. For example, a two-dimensional bar code with a data density of 10 times that of a traditional bar code has been developed. Compared with the previously used bar codes, printing two-dimensional bar codes requires more accuracy and higher definition. According to schlather, laser marking meets these requirements. Within the range of 0.001 inch, the size and position of points can be repeated - these properties are difficult to achieve by embossing or ink printing machines
environmental problems are another driving force for the development of laser marking. Laser marking does not need ink or solvent, nor does it need high-intensity energy drying process like ink marking technology. Schlather said that for a three shift printing label production, ink and chemicals cost $20000-40000, while printing plates cost $100000/5. When the pneumatic sensor is impacted by external forces or used in excess of capacity, it is damaged every year or more. In contrast, a three shift laser marking equipment costs less than $3000 in electricity per year, and other consumption such as lamps and filters costs less than $3500
basis of marking equipment
although there are many laser light sources for decorative plastics, such as yield strength and tensile strength of steel, sealed carbon dioxide lasers are the most widely used at present, followed by solid-state nd:yag lasers pumped by lamps and nd:yag devices pumped by diodes in recent years
most laser equipment adopts galvanometer marking technology with high-speed beam control. This control device scans the laser beam with a mirror or galvanometer controlled by two computers that can move in the Zang Y direction. "When the programmed laser path is completed, the new part is in place and this cycle is repeated. Since the laser mode completely exists in the software, neither the tool nor the mask is needed."
software that allows plastic marking with rotating beam control is also supplied by several laser equipment suppliers. This kind of equipment essentially adopts the same technology, but it is suitable for continuous rotation production, such as conveyor belt or substrate conversion. Barbero explained, "the advantage of this equipment is that it can be easily refitted to the existing production line to maximize the productivity. The coding is fed back to the computer, and the computer makes appropriate adjustments to track the moving target in real time." Schlather continued, "current devices use simple and clear graphics generation software, which is easy to program and print a single data on each and every rotating part."
in recent years, it is easier to program, standardize and troubleshoot laser marking, and the marking speed has also been greatly improved. Barbero said, "today's software is suitable for printing more than 400 units per second, compared with 40 units per second 10 years ago." Most laser machine software has the ability to print serial and multi model bar codes and texts of any model (including the company logo). With the "help" option of n1ndow base, the laser marking supplier has added service and standardization technology as well as fault removal software
another development is that two parts can be printed synchronously with a laser light source. Plus a deformation head and a programmed beam splitter, with the same information, a laser machine can print two parts at the same time. Schlather pointed out that this type of equipment can be used for printing large areas or large quantities of products without moving parts
cost is a key factor in the growing popularity of carbon dioxide laser equipment. A complete set of carbon dioxide turnkey equipment costs between $25000 and $35000, while a tube pumped or diode pumped nd:yag equipment costs between $60000 and $75000
the carbon dioxide laser machine etches the plastic surface, and the material is cleaned by evaporation. The contrast mark is obtained, but there is little or no real color change. PVC, ABS and most polyesters are suitable for carbon dioxide laser printing. Commercial resins filled with mica, such as those marked with carbon dioxide laser, produce frosty gray marks. Although the output power of carbon dioxide machine can reach 200W, the most common range for marking plastics is 10-25w, sometimes 50W (due to its high output), but there are also devices with an output power of 30-50w. YAG laser machines are generally used for high-quality marking of parts, such as electronic connectors, hood components, lock caps and surgical equipment. Schrather of rofin baasel suggested that processors should understand the required production capacity and the aesthetic requirements of marking when considering purchasing solid-state laser machines. For example, if you want high contrast, surface has not been measured to interrupt the mark, then high-frequency laser machine performance is the best. However, it depends on whether the low output power of the equipment is suitable for your productivity requirements
there is also a new type of diode, whose power is between 3-1000 W. the diode can be used as the light source of the laser machine to replace the electron tube of the electron tube pump equipment. It is said that the structure of diode is 50% more compact than that of electronic tube, and the energy utility is increased by 20% - 30%. The electronic tube equipment needs water cooling, while the diode type needs water cooling or air cooling. The electronic tube generally needs to be replaced every 1000 hours, and the service life of the diode is up to 10000 hours. The disadvantage is that diodes are relatively new and expensive. For example, the diode pump laser machine of foba50w is 10% more expensive than the electronic tube equipment of 100W, but foba predicts that the price of diode equipment may decline in the next few months, and they will eventually replace the electronic tube pump equipment
"environmental problems are another driving force for the development of laser marking. Laser marking does not require ink or solvent, nor does it require a high-intensity energy drying process like ink marking technology."
schrather of rofin baasel summarized the selection of YAG type: "if you want to repair every 600-800 hours, the investment of electronic tube pump is the least, but you can get the maximum productivity. If you can complete the desired marking with 3-60w diode pump equipment, then the cost of diode pump equipment 70 will be less than that of electronic tube pump equipment within 5 years."
formula for lasers
if you use the right additive formula, foba's bone said that almost any kind of plastic can be marked by any type of laser machine. The supplier of the formula or masterbatch needs to know the resin, the final application, and the type of icon required. For example, some plastics such as high-density polyethylene and polycarbonate can be printed well with YAG laser without any additives in some colors. On the other hand, the carbon dioxide laser machine cannot print these two kinds of plastics well without special additives
the limitation of the existing technology is that the ability to obtain color adjusted laser marking is limited, and the cost of laser optimized plastic is also higher than 10% - 15% of the market price, sometimes higher
bill Blasius, director of the master batch Technology Development Department of Clariant group, admitted that laser marking is limited in pigment selection and color transparency. He said, "we know more about how to use pigments and additives than we did a thousand years ago. We hope to make full use of chemical reactions when using laser lamps, which occur between special resins and some additives and pigments." Due to the development of compounding technology, we can get near flat white marks on black or blue acetaldehyde copolymers, or pure white marks on black ABS. With special formula and laser parameters, we can even get the adjusted color. Schlather explained, "in this way, the etched laser marking can be installed on the middle beam and adjusted to Pantone, Munsell or other industrial standards. The pigment in the resin determines the color and hue, while the laser determines the intensity or concentration." Many laser marking color/licking additives are based on surface treated mica, such as the popular afflair and laser flair formulations formulated by EM industries. However, other additives such as copper and antimony are also used in patented formulations
"although there are many existing laser light sources for decorative plastics, sealed carbon dioxide lasers are the most widely used at present, followed by solid-state nd:yag lasers pumped by tubes and nd:yag devices pumped by diodes in recent years."
companies that produce plastic that can be used for dry laser marking include BASF, Bayer, Ticona and RTP. The main suppliers of special pigments and additives masterbatches for laser marking are Clariant and PolyOne
first of all, focus on automotive parts. Ticona introduced two kinds of laser marking black acetaldehyde copolymers, Celcon LM90 and lm90z. LM90 is used to print engine hood and fuel equipment components, and lh90z is UV stabilized for interior trim, such as speaker grille and release rod. Tommiller's automobile marketing manager said that the additives of patented technology are most suitable for nd:yag laser machines
ticona's latest research product is Celcon uvl40lg, which is said to be the earliest low gloss laser