Laser Plastic Labeling Technology Application (I)

Laser marking technology application

Currently, laser technology has replaced ink marking technologies (such as imprinting and inkjet printing) in some applications. Laser marking has been successfully commercialized in applications including ABS keyboards for commercial machines, HDPE, PP, PET and PVC steel. Containers and caps; Nylon and PBT automotive, non-automotive electrical connectors, hood components such as fuse boxes, air caps. There are other applications, including TPE ear tags for cattle, pigs, etc., electrical devices such as HDPE opening buttons on washing and drying equipment, and PVC fittings such as connectors.
In the last 10 years, technological advances in computer-programmed laser marking equipment have been accompanied by the development of more varieties of laser-markable resins. Specially-made colorants and packaging additives can be used in a variety of plastics. , such as polyolefins, ABS, PVC, polyester, polycarbonate, nylon, polyoxymethylene, and thermoplastic elastomers.
Today's laser marking plastics have a high contrast ratio. Sometimes it is not so much black and white as a contrasting color. Even dark contrast is possible. These colorful variations are one of the trends that are giving rise to greater interest in laser decorative plastics.
Laser marking applications 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 while also meeting the development needs of printing large amounts of data on smaller plastic parts. For example, two-dimensional barcodes with a data density of 10 times that of conventional barcodes have been studied. Compared with previously used barcodes, printing two-dimensional barcodes requires more precision and higher resolution.

Laser marking technology equipment requirements

Although there are many existing laser sources for decorative plastics, sealed carbon dioxide lamps are the most widely used at present, followed by lamp-pumped solid-state Nd:YAG lasers and diode pumped Nd:YAG in recent years. Device.
Most laser devices use high-speed beam-controlled galvanometer marking technology. This control device is controlled by two computers and can scan the laser beam on a mirror or galvanometer moving in the X or Y direction. “When the programmed laser path is completed, the new part is in place and repeats this cycle. Because the laser mode is completely in software, tools or masks are not required.”
Software that allows plastic marking with rotating beam control is also available from several laser equipment suppliers. This type of equipment uses essentially the same technology but is suitable for continuous rotary production such as conveyor belt or substrate transfer. The advantage of this type of equipment is that it can be easily retrofitted to existing production lines, maximizing productivity. . The code is fed back to the computer, the computer makes the appropriate adjustments, and the moving target is tracked. The current device employs a simple and straightforward graphics generation software that is easy to program and print a single piece of data on each rotating part.
In recent years, the proceduralization, standardization and troubleshooting of laser marking have become easier and the speed of marking has also been greatly improved. Today's software is suitable for printing more than 400 words per second, but only 40 words can be printed every second 10 years ago. Most laser machine software have the ability to print serial and multi-model bar codes as well as texts of any type (including company logos). With Window's “help” option, laser marking suppliers added services, standardization techniques, and troubleshooting software. Another development is the use of a laser light source to simultaneously print two parts. In addition to a deformation head and a programmed beam splitter, a laser machine can print two parts at the same time with the same information. This type of device can be used for large areas or large quantities of parts that do not move parts. The printing. Cost is a key factor in the ever-popular CO2 laser equipment. A complete set of CO2 turnkey equipment is priced between $25,000 and $35,000, while a tube-pumped or diode-pumped Nd:YAG device costs between $60,000 and $75,000.
The CO2 laser etched the plastic surface and cleaned the material by evaporation, resulting in a contrasting mark but with little or no real color change. Plastics suitable for printing on carbon dioxide lasers are PVC, ABS and most polyesters. Mica-filled commercial resins, such as PP, are marked with a CO2 laser to produce a frosty gray marking. Although the CO2 output power can reach 200W, the most common range for printing plastics is 10-25W, sometimes 50W.
In the coding process of the bottling line, speed is critical, or large letters are also needed, and carbon dioxide lasers are generally used. Steve bone, president and chief executive officer of the FOBA North American Laser Equipment Group, said that carbon dioxide machines use matrix printing marks twice as fast as Nd:YAG machines, albeit only a few seconds faster. Today's laser marking plastics have a high contrast ratio. Sometimes it is not so much black and white as a contrasting color, even dark contrast is possible.
Control Microsysterns' main market focus has always been on car hoods and electronic/electrical devices. Stevenson, the company's company, said that considering a plastic marking process, the first thing to do is to use a carbon dioxide laser to print. If you do not get the required contrast or get excessive melting, go to the YAG laser.
Solid state Nd:YAG laser heating plastics will cause thermochemical reactions (such as foaming), but also produce more color changes. Since the wavelength of the laser light generated by this laser is short, high definition can be obtained. The shorter the wavelength, the less heat is induced by the plastic substrate (cold print). The 100-watt Nd:YAG device for plastic marking is currently popular (due to its high output, but the output power is also 30-50W. YAG lasers are generally used for high-quality marking of parts, such as electronic connectors. , Hood elements, lock caps and surgical equipment.
Processors consider buying solid-state lasers to understand the amount of production required and the aesthetic requirements for printing. For example, if you want high-contrast, unmeasured break marks, the high-frequency laser performs best. However, this depends on whether the device's low output power suits your productivity requirements.
There is also a new type of diode, with a power between 3 and 100W, which can use a diode as a laser light source instead of the electron tube of a vacuum pump device. Diodes are said to be 50% more compact than electron tubes and energy efficiency is increased by 20% to 30%. Tube equipment needs water cooling, and the diode type needs water or air cooling. The electron tube generally needs to be replaced every 1000 hours, and the lifetime of the diode is 10,000 hours. The disadvantage is that diodes are relatively new and expensive. For example, the FOBA50W diode pump laser is 10% more expensive than a 100W tube device. However, FOBA anticipates that the prices of diode devices may fall in the next few months, and they will eventually replace the tube pump equipment.
Environmental issues are another driving force for the development of laser marking. Laser marking does not use inks or solvents, nor does it require high-intensity energy drying processes such as ink marking. If the maintenance is to be performed every 600-800 hours, then the vacuum pump investment is minimal, but maximum productivity can be obtained. If a 3-60W diode pump device can accomplish the desired printing, the diode pump device will cost less than the tube pump device in 5 years.