Advantages and Disadvantages of Etching with Beam-Steered Laser

This year, over one-third of all material processing lasers will be installed for product or package marking applications. Since their introduction in the early-1970's, laser markers have evolved as an effective tool for manufacturers who require a combination of speed, permanence, and image flexibility not available from more traditional marking technologies.

Two marking system designs have emerged with notably different strengths and weaknesses. Careful consideration of these laser and imaging optics combinations can provide the optimum tool for a wide range of marking requirements. Process Fundamentals

Laser marking is a thermal process that employs a high-intensity beam of focused laser light to create a contrasting mark. The laser beam increases the surface temperature to induce either a color change in the material and/or displace material by vaporization to engrave the surface. Both marking system configurations utilize this principle of surface modification but differ in the method used to project the laser beam and create the marking image.

The beam-steered laser marker provides the greatest degree of image manipulation. To create the marking image, two beam-steering mirrors mounted on high-speed, computer-controlled galvanometers direct the laser beam across the target surface. Each galvanometer provides one axis of beam motion in the marking field. The beam projects through a multi-element, flat-field lens assembly after reflecting off the final steering mirror. The lens assembly focuses the laser light to achieve the highest power density possible on the work surface while maintaining the focused spot travel on a flat plane. The laser output is gated between marking strokes. This design offers the user the advantages of a computer generated marking image and utilization of the entire laser output for the highest marking power possible.

The mask or "stencil" marking system sacrifices image quality and versatility for significantly increased marking speed. The marking image is created by enlarging the laser beam, projecting it through a copper stencil of the desired image, and refocusing the beam on the target surface to "burn" the image into the material. A single pulse of the laser creates the entire image. If the alphanumeric characters must be altered part-to-part, (i.e., serialization, etc.), computer-controlled rotary stencil wheels index the characters. This technique is aesthetically limiting in that images exhibit a "stencil" appearance with breaks in the marking lines. Since the mask blocks a high percentage of the laser beam, marking power and resultant surface penetration is limited. Laser and Imaging Combinations

Beam-steered Nd:YAG

The combination of the Nd:YAG (Neodymium:Yttrium Aluminum Garnet) laser and the beam-steered delivery optics marks the widest range of materials and provides the versatility of computer controlled image generation.

Nd:YAG lasers amplify light in the near-infrared at 1.06 mm. Metallic materials absorb a comparatively high percentage of the light in this region of the spectrum. In the pulsed mode, the Nd:YAG laser produces peak powers considerably higher than the normal continuous-wave output. A 90 watt CW Nd:YAG laser, pulsed at 1 kHz, will emit a train of pulses with peak powers of 110,000 watts. The Nd:YAG lasers ability to emulate an "optical capacitor" provides the power necessary to vaporize metallics and other materials. The high peak power will vaporize material up to 0.005 inches deep in a single pass or greater with multiple passes. The non-metallic materials normally associated with the far-infrared wavelength of the CO2 laser are usually highly reflective to the Nd:YAG. However, the high peak power of the Nd:YAG can often overcome the higher reflectivity. Some overlap does occur among many plastics that absorb both wavelengths equally well.

The beam-steered marker can duplicate virtually any vector graphic image including variable line widths and images as small as 0.010 inch or less. In addition, the computer can instantly change any graphic element or the entire marking program before a new part is positioned for marking. The Nd:YAG laser offers a greater range of adjustable process variables to achieve a specific material modification but at a correspondingly higher purchase price than the CO2 laser.

Beam-steered CO2

The continuous-wave CO2 laser can also be combined with the beam-steered delivery system. CO2 lasers emit a narrow bandwidth of light in the far infrared at 10.6 mm. This wavelength is most suitable for organic materials such as paper and other wood products, many plastics, removing thin layers of ink or paint from a substrate, and for marking ceramics. It does not produce high peak powers when pulsed.

Typically utilizing laser powers up to 50 watts, these systems combine the far infrared wavelength with the image control and flexibility of beam-steered image generation. Typical uses include serialization of ceramic and plastic products that require high-quality graphics such as company logos and/or significant amounts of additional alphanumeric text. The lower power CO2 marker does not provide the power to "engrave" substrates but, due to the comparative simplicity of design, can be purchased at a lower cost than the beam-steered Nd:YAG marker.

Mask CO2

Applications that require high speed but not high power and do not vary the marking image except for alphanumeric text (i.e., serialization, date code, etc.) utilize the mask CO2 marker. The CO2 laser is pulsed at rates of up to 1,200 pulses per minute. The high repetition rate provides marking of parts "on-the-fly" at high part-transfer speeds. Computer controlled masks can alter up to three lines of text at speeds of up to 720 parts per minute if the alphanumeric code must be changed.

Advantages and Disadvantages

Beam-steered Nd:YAG

The beam-steered Nd:YAG provides more marking power and far superior imaging than any other laser marker configuration. The available high peak power can mark or engrave a wide variety of materials including hardened metallics. Present computer technology produces highly intricate graphics with linewidths and accuracy's of less than 0.001 inch. Because “drawing” with the laser beam creates the image, the marking time is dependent on the amount of text and the complexity of any graphics. The Nd:YAG laser marker is the most costly of the three system configurations. The beam-steered Nd:YAG marker frequently replaces acid and electro-etch systems, stamping and punching systems, and those other marking systems which permanently mark products by imprinting or engraving. It also replaces ink jet and other color printing systems. Typical applications include marking pistons, bearings, valves, gears, and a multitude of other components in the automotive industry; heart pacemakers, replacement hip joints, and surgical tools in the medical industry; computer chassis, disk drives, and integrated circuits in the electronics industry; tool holders, drill bits, and cutting tools in the tool industry; and writing pens, nameplates, and golf club grips.

Beam-steered CO2

The acquisition and operating costs of the beam-steered CO2 marker are lower than the Nd:YAG marker due to the relative simplicity of the laser. Image generation is equal to that of the other beam-steered system while speed and depth of penetration are considerable lower due to the lower power of the CO2 laser. Although not as popular as the beam-steered Nd:YAG and mask CO2 markers, the beam-steered CO2 system is frequently used for marking general plastics and plastic and ceramic connectors and packages within the electronics industry.

Mask CO2

Although the mask CO2 does not offer the imaging capabilities of the beam-steered design, it is far superior in speed. Because a single pulse of the laser creates the entire image, throughput is typically limited only by the pulse rate of the laser and the transfer speed of the parts handling system. While the part must be stationary while marking with the beam-steered design, parts are marked in motion with mask systems. Depth of penetration is less than the beam-steered CO2 marker since the laser output is spread over a large area with correspondingly low power density.

Masked CO2 markers most frequently compete with ink-jet marking. The mask CO2 laser is often the marker of choice for sequenced coding, batch coding, open or closed date coding, and real-time coding of paper or cardboard, ink or paint coatings, glass, plastics, coated metals, and ceramics.

While the beam-steered design provides superior imaging and material penetration and the mask design provides superior speed, either system provides a better combination of speed, permanence, and imaging flexibility than other marking techniques. Many users also benefit from the non-contact nature of laser marking and the elimination of additive materials such as inks or paints.

The development of a successful marking application requires careful consideration of the laser output characteristics, the design of the optical beam delivery and image generation system, the properties of the target material, and the aesthetic and physical properties of the desired mark. Industrial laser marking systems provide prospective users with several system designs from which to choose to match the optimum marking performance with the users unique requirements.

Richard Stevenson is the Sales Director for Control Micro Systems, Inc. a manufacturer of beam-steered laser marking systems. He has published and presented numerous technical papers and articles on laser marking in trade publications. For information on Laser Etching, Welding, Engraving, Cutting, Etching or Marking call 407-679-9716 or email sales@cmslaser.com

Digital Camera LED Laser Etching Trick

It’s a common scene no matter where you go, everyone is taking pictures with their digital cameras. Part of the intrigue of digital photography is the instant feedback; after all, with a digital camera you can check and see if you need to re-take the photo. You might even feel a little creative and start changing some of your cameras setting to reflect your inner artist. That’s what makes digital camera so much fun; you can experiment and witness the results instantly.

Make sure and visit our site using the link at the bottom of the article. You'll be able to see photo examples!

Our digital camera LED Laser Etching Trick is super EASY to do and will create some truly creative photos. We’ve used it many times and each time people look at the photos with a bewildered look trying to figure out how the photo was created.

To the rational mind this type of photo tends to violate our sense of order. Cameras record objects, whether they are moving or stationary. Once we press the shutter our brains are fully prepared to see whatever we took the picture of, frozen in time. What our brains are NOT prepared for is to see a photo where the camera has frozen AND recorded the “track” of an object, which in this case is a simple LED light.

I have even had experienced digital camera owners look at an LED Laser Etching Trick and ask, “So you didn’t use video to do this?” When it comes to digital photos most people think in a linear manner and the LED Laser Etching Trick is cool because it forces our brains to think dimensionally.

If you try to explain the trick to someone without showing them an example they’ll act like they understand, but in reality, they really don’t. On the other hand, if you show someone an LED Laser Etching photo, they will be INSTANTLY intrigued, no matter what level of photographic experience they might have.

You see the fun part here is when you show someone an LED Laser Etching Trick you don’t need to say anything; the response is ALWAYS the same…

Wow, how cool!

And the next question is always…

How did you do that?

In fact I was at a party the other day and I pulled out my compact digital camera and then handed a small LED light to one of the guys and just said, would you help me with a trick? I gave him a cursory explanation and he was simply not impressed, period.

You see in his brain it was going to be a stupid photo of him standing there pointing the LED at the camera, big deal. That’s because his brain has been conditioned to the idea of how digital cameras work, no mystery here.

Until…

I showed him a photo that looked as though he had etched it in the air with a laser beam.

OK, so here’s a guy that initially was less than interested…

Now he’s running back and forth to the camera to see his latest laser etching creation.

This guy went nuts! Once he saw how cool it was he wanted to try all sorts of LED laser etching designs. Smiley faces, Christmas trees, the legendary Zorro “Z”, a crown, he went on and on. In the mean time more and more people were aware of what was going on and after a while literally EVERYONE wanted in on the fun.

Here’s the trick

I used a point-and-shoot digital camera and a cheap LED key ring light, or in other words, no fancy equipment.

My camera was set to “Fireworks” and since I didn’t have a tripod I winged it and just held the camera as steady as possible.

Note: For more consistent results it would be best to have secured my camera on a tripod.

Next, I went into a room that was fairly dark and handed the guy the LED light told him to point the LED at my camera and for a test just do a bunch of “squiggles” in the air. This was to give him an idea of how much time he had to “write in the air.” Since this was a basic point-and-shoot digital camera the only control I had was to set it on “fireworks.” No manual controls, nothing, just a plain old digital camera.

However, I knew with the “fireworks” setting the cameras lens would stay open longer than usual, long enough to record the LED light moving through the air. Now I know there are going to be people say that because it was hand held for so long the background AND the guy were going to be blurry.

Hey, all I was after was a neat looking creative photo; I really didn’t care if everything in the background was blurry.

I just wanted to record the motion of the LED light.

Then I held the camera up, told the guy to get ready, took a deep breath, pressed the shutter, and told the guy, GO.

Remember no flash, just nice and dark.

It took a couple of test shots for the guy to see just how much time he had to write. As I said though, once he saw the results he wanted to try all sorts of designs.

Ideas to try:

• Use two different colors of LED lights at the same time.
• Have 2 or 3 people with multiple lights at the same time.
• Use a larger standard LED flashlight.

In Summary

This technique is for standard point-and-shoot digital cameras with basic settings. If you own camera that has manual settings you can hold your shutter open for much longer periods of time for more creative flexibility.

Either way, auto or manual control this is just a fun trick and impresses absolutely everyone, give it a go!

http://www.digitalcamerau.com/2006/12/26/digital-camera-led-laser-etching-trick/

Etched Glass: Etching Beauty

Etched glass is a wonderful gift to give those that you love. The method of actually etching the glass can be done by you or by a professional. No matter who does it, by digging into the first layer of the glass, a shine and detail can be added to the glass, transforming it from a simple gift into something truly beautiful. But, why should you add etched glass to your list of things to purchase and give? There are actually several ways that this type of method can dress up your gifts and create a very unique and special look.

Etching can be done on many types of glass and other materials. For example, if you want to dress up the look of a mirror, you can etch the glass in a pattern. In a circle framed mirror, etch an intertwining vine long the edge of the frame, leaving the center completely open for viewing. It adds texture and depth to the look so that you get a more interesting piece to hand on your wall.

Etched glass can also be an ideal way to add element to your framed pictures. You can use etching to dedicate a picture or message. Or, you can use etching as a way to communicate with others the date and time of what happens in the photo. You can etch a poem onto the glass that is only visible if you really look for it. These things can help to transform an average piece of glass and an average frame into a meaningful, beautiful sentiment to the memory being depicted.

You can find professionals that sell ready made etched glass products. You can also find a number of different products on the market to purchase to help you to create your own etching. Whatever you do, find a way to create a beautiful image with the help of etching. You will adore all that it can provide to you.

For more observations about picture frames from Chad, click the link.