POWER

Each Kern laser system is specified by its laser wattage. The actual laser wattage emitted from the laser tube is known as laser power. The higher the wattage, the more power the laser machine has. Every Kern CO2 laser can cut MDF at full 100% power. At this full power setting, you will maximize your machine’s efficiency, or it’s ability to cut out the greatest number of pieces in the shortest amount of time.

Alternatively, you may only be needing to engrave the surface, mark a logo, etch a part number. In these instances, a REDUCED power setting may be best, resulting in a depth and color according to your desired look.

A final consideration with laser power is adjusting the PWM (Pulse Width Modulation). The Kern CO2 laser is a pulsing laser that allows you to adjust the pulsing frequency during the laser process. This frequency range varies from 100 to 50,000 Hz. I have found the peak cutting performance for MDF processing to be in a range from 3800 to 5000Hz. If you increase the pulsing to 10,000 and above the audible noise level will be noticeably quieter, but it will not be in the peak cutting performance range.

SPEED

The goal when cutting MDF is to complete the job in the least amount of time, with the highest quality results. A point of consideration for clean fast cutting is to push the speed as fast as you can and still get completely through the material. One of the problems with cutting too slow is that you will create more dark char or burning on the profile as well as dark smoky spots on the back of the material. This will require your operator to clean the honeycomb bed more often, as well as require a more detailed cleaning of the parts.

When it comes to engraving the MDF, a faster speed will produce more smoke and fumes so be sure the top-side engraving vacuum is enabled and pulling away any lingering smoke from the engraving process.

Sometimes a much lower DPI of the image or artwork will be sufficient when engraving MDF boards and panels. This decrease in picture resolution will allow your overall speed to increase, which will reduce the time it takes to complete the job.

VACUUM

When cutting the MDF material you will notice a good amount of smoke being generated by the lasering process. Most of our machines are equipped with two 2-3 HP blowers, and it is essential to ensure your vacuum system is in operation and running optimally.

One of the import steps when setting up your MDF cutting is to have a powerful suction holding your sheet of material down flat. Since you do not have any clamps to secure or keep the material from bowing up, you will need to be sure to have your vacuum running at full strength as well as sealing off any open area of honeycomb to ensure full vacuum potential.

When engraving with the OPTIFLEX or LASERCELL machines, the top gantry has a vacuum manifold built into the underside of the moving gantry. This manifold is connected to a vacuum unit that assists in the removal of smoke and debris. You will notice when you engrave a piece of MDF the white smoke will rise up into this manifold area and not be deposit back onto the material.

The most misunderstood aspect of cutting this material cleanly is assuring you have your material flat and held down so the nozzle will stay in its proper focus position.

FOCUS

The Kern laser systems have an adjustable tube that allows the movement of the lens assembly into the correct focusing position. Once the lens has been moved to the proper height using a lens spacer tool, the lens assembly has been focused. Now, the part of the beam with the thinnest width can cut the MDF material quickly and cleanly.

If, over time,  the material starts to lift up, or the honeycomb table is bent you may notice some wider lines during the cutting process. This is because the distance from the center of your lens to the top of the material has changed and it is no longer in focus.

Several times I have seen where the operator has assumed the lens assembly and the lens spacer tool spacing is correct, but it was not due to the material lifting or the bent honeycomb. Typically, this space is set at the factory so you can quickly place your cutting lens into focus, but in your shop there are other variables that can skew the accuracy of this focusing tool.

The best way to find your focus height is to do a focus test. This focus test can be found in our video library (also shown below) and you only need a a piece of paper or scrap wood. The goal of the focus position it to have the finest or narrowest beam width possible. This may require the operator raising or lowering the internal lens position OR the focus dial slightly to get the lens into the correct focus height.

AIR ASSIST

Finally, another important parameter when cutting this hard fiberboard is to use a good amount of assist air when cutting or engraving. Mounted on the lens assembly, you will find an air elbow. The lens assembly has a ¼” airline that allows for a steady stream of air flowing out the nozzle during the laser process.

The air compressor source will need to have a moisture and oil trap to prevent any contaminants from getting onto your lens. The best pressure to use when cutting MDF will depend on the nozzle size you are cutting with, but I have found the best cutting and engraving pressure with a 0.100″ diameter stock nozzle to be 40 psi.

Kern’s KCAM Laser Software has advanced settings to allow you to piece the material with one air pressure and then cut the profiles with another. The machines have two air gauges that will assist in getting the cleanest entry hole as well as allowing a clean look by pushing and spreading the vaporized MDF away from the kerf path.

If you plan on cutting MDF in the future, be sure to learn and review these five essential parameters to cut your material cleanly, smoothly, and with maximum speeds.

When equipped with the laser cutting option, Kern’s CO2 lasers are quick and efficient at mild steel cutting.

The following tips will help operators be successful…  

1. MATCH MATERIAL THICKNESS AND WATTAGE

As you likely know, the wattage of a laser will dictate the thickness of mild steel you’re able to cut, and the speed at which you’re able to cut it. 

Check out the manufacturing specifications of your laser’s system to see what thicknesses of mild steel different laser wattages can cut. While there may be some variation, the manufacturer recommendations provide an excellent guide. 

2. PIERCE YOUR MILD STEEL 

An important part of cutting mild steel is the moment when the laser first pierces the material. Keep in mind that the settings during the piercing process will be different than the settings during cutting. The pierce point requires lower power, about half the air pressure and steady contact for 1-2 seconds.  

3. DON’T CLIP YOUR BEAM

Laser beam placement is a key component of cutting mild steel. The goal here is to align the beam so that it goes directly through the center of the nozzle. 

The copper nozzle on Kern laser systems has an opening size of about 60/1000 of an inch. If the beam is not centered, the nozzle will clip the beam. A clipped beam spells all sorts of trouble for cutting mild steel. 

First, it will decrease the power, which can prevent the beam from having enough strength to pierce the material. Additionally, it will prevent the laser from making clean cuts. Instead, it will leave the mild steel with burrs and unclean edges. 

4. ADJUST YOUR FOCUS POINT

In order to effectively cut mild steel, the copper nozzle needs to be at a distance of 0.010″-0.020″ from the material being processed. This provides the laser beam with the ideal focus point for the laser to perform optimally. This also allows the assist gas to penetrate into the cut to help clear away debris and create a precise clean cut. If your nozzle is too high, not only would your nozzle be out of focus, but the assist gas would be dispersed over the cut leaving debris within the cut.

This same principle is in effect when using a magnifying glass to concentrate the sun’s heat. Making slight changes to the height of the magnifying glass affects how powerful the beam is, just like adjusting the height of your laser’s copper nozzle affects the beam’s power. 

5. CHECK YOUR OPTICS

A laser outfitted with bad optics is not going to cut mild steel effectively. Check your mirrors and your lenses to ensure they are free of debris. 

6. CHOOSE YOUR ASSIST GAS

When cutting mild steel, choose either oxygen assist or regular shop air. For thicker mild steel, choose oxygen assist with a lower psi. 

7. ADJUST YOUR POWER SETTINGS

Although it does take a fair amount of power for a CO2 laser to pierce and cut mild steel, too much heat will leave burn marks on the material. As a rule of thumb, less heat is better for mild steel. 

Instead of defaulting the power setting at 100%, try to figure out the lowest power setting that will still allow you to cut the material. The lower setting will help you prevent marks and dross on the back side of the mild steel. 

CUTTING 18 GA MILD STEEL

In this video, Jake Shaw will lead you through the basics of cutting 18 gauge mild steel with a 400W CO2 laser. 

DIFFICULTIES OF ALUMINUM AND LASER PROCESSING

When you project light onto a reflective material, it bounces back or scatters. So when the light of a laser beam makes contact with aluminum, the tendency is for it to bounce or scatter as well. This can make laser cutting difficult.

Solid and stable molecular structures are easier to cut through than softer ones. Because aluminum’s molecular structure is more malleable, the laser beam is not as effective at piercing through it and creating clean cuts.

Finally, aluminum is a heat conductive material. As such, it quickly absorbs heat, which is needed for clean cutting. Also, when you dissipate the heat it makes smooth laser processing difficult.

All of these reasons are why laser cutting aluminum is difficult. But just because something is difficult doesn’t mean we can’t do it. Over the years, we’ve fine-tuned our aluminum cutting capabilities to make it an easy and effective process. 

HOW TO CUT ALUMINUM SHEET

While it is reflective, soft and thermally conductive, aluminum can still be cut with a CO2 or fiber laser. High-speed laser beams make it possible to cut various alloys of aluminum, including aerospace and marine-grade aluminum alloys. 

USING A METAL CUTTING HEAD

When cutting aluminum with a CO2 laser, we’re using a metal cutting head, which is a different assembly than the one used when cutting non-metal materials like plastic or foam. 

The metal cutting head assembly has a protective window for spark reflection and a variable/adjustable focus knob. These features make cutting aluminum sheet much more effective. It eliminates the issue of finding the right focus position and setting the perfect height. 

CREATING A CLEAN-CUT ALUMINUM EDGE

In order to get a clean-cut edge with aluminum cutting, you want to focus on two things: high pressure and gas assist. These two combined will effectively eject any molten material quickly, preventing the buildup of a rough edge. With aluminum, the faster you cut, the smoother the edge will be. That’s also why higher wattage lasers will perform better when cutting aluminum. They allow you to push the kerf line faster. 

Unlike other options, like routers or CNC cutters, laser cutting aluminum is a fast, efficient process. It also allows for no contact cutting, so the only thing touching the material during processing is light. There is absolutely no need to clamp down or otherwise secure the material. Not only does this save you time, but it prevents any impressions or damage making its way into the material. 

What are some of the common mistakes laser owners and operators make that end up costing them in the long-run? Here are four laser engraving mistakes to avoid.

WRONG AIR PRESSURE

Setting the proper optic air pressure when cutting metal is a very important step, and you will notice the negative effects of incorrect air pressure almost instantly.

When it comes to engraving, air pressure commonly gets overlooked as most materials are much more forgiving, and the air pressure setting is not critical. However, there are certain engraving and etching applications where setting the air pressure correctly is key.

One of these applications is plastic etching—such as an acrylic sheet. Using a higher optic pressure through a small nozzle concentrates the air flow onto the area being processed and can leave a hazy ghosting or shadowing effect around the etched area. By simply decreasing the air pressure you might see a decrease in this effect immediately. Don’t turn off the air completely, as you do need some positive pressure to keep smoke from entering the beam delivery.

Another tip to go along with this is using a wider nozzle opening. Kern offers a wide nozzle that can be added to any S-FOCUS assembly.

SKIPPING THE TEST RUN

Before diving into a new project, it pays to run a little test cut on an excess piece of material, even when you’re relying on presets. The fact of the matter is, you never truly know what the final result will be until you see it. Material variation is a common problem especially in wood and stone.

One tip here is using a neat feature in our KCAM laser software. The “Position in File” feature allows you to move to any engraving line in your project. If there is a more critical area of your engraving with lots of detail, you can simply type in that line and the laser will start at that point. KCAM makes it easy and highlights the line you type in so you can get to the line you are looking for easily.

Notice the red and cyan line across the engraving file below. Generally, an inch or two of engraving will give you a good idea if your settings are correct.

TREATING ALL MATERIALS THE SAME

Laser engraving leather is going to be different from laser engraving glass. And the same thing goes for engraving acrylic or wood. These materials are all different, and those differences impact how they respond to laser engraving.

Taking the same approach to laser engraving regardless of material types is a recipe for disaster. There is no one-size-fits-all to laser engraving, because the variables—and possibilities—are endless. 

The KCAM software accompanying your laser system includes the ability to save your settings in a directory for future use. This works great for customers that process the same materials on a regular interval. Simply load in the settings file and you are back to the same great settings you were using a month ago on the same material. This helps to maintain consistent engraving from job to job, and it helps reduce startup time for each project. 

Over time, your settings directory will become one of the most important parts of your system!

FORGETTING TO CLEAN YOUR MACHINE

Are you noticing your laser engraver’s performance is slower than it used to be? It might be time to give your machine a thorough cleaning, with special attention to the optics. Like any piece of equipment or machinery, laser engraving machines require routine maintenance.

Depending on the materials you are engraving, dust and debris buildup may be a frequent problem. It is important to make sure your vacuum blower system is running efficiently. Ensure there is not build up in your vacuum hose lines and smoke/dust is quickly being picked up by the vacuum ports. As always, check your operator’s manual for tips on cleaning your machine and other maintenance specifications, especially if you’re noticing a sharp decline in processing speed.

One common mistake I see is when customers are using a known good setting but for some reason they are not getting the results they did previously. Most users instinctively increase the laser power to get back to the proper setting. However, most times that is the last thing you want to do. The best solution is to determine what is causing the drop in power. It could be a dirty optic that just needs a good cleaning. If you ignore these warning signs, the increase in power will only heat up the optic more and eventually it will crack.

For customized laser engraving tips and techniques, you can always connect with the team at Kern Laser Systems to discuss your approach to engraving. Oftentimes, it comes down to understanding your material, your laser system and how the two react to each other. Luckily, getting the hang of laser engraving is relatively quick and easy, especially when you have the support you need. 

AUTOMOTIVE

Fiber lasers and properly fitted CO2 lasers are used within the automotive industry to cut, engrave and mark. Here’s a look at some laser-cut automotive details. 

AWARDS AND TROPHIES

Laser cutting and engraving brings more unique elements to today’s awards and trophies. Commonly cut from acrylic, metal or wood, laser-cut awards and trophies are popular in corporate settings, athletic competitions and the arts. 

With lasers, etching text and images onto the award looks professional and lasts a lifetime. Here are some examples of awards made with laser processing: 

FOAM FABRICATION

Foam fabrication with laser systems yields much greater precision and much less waste than other methods like saw cutting or searing it with a hot rod. Foam box shadow tooling is perhaps one of the most popular forms of laser-cutting for foam. It requires only a low-power laser and yields precise results. 

For instance, cutting three-inch foam pairs perfectly with a 150 watt laser. If operators use too high of a wattage with foam, they run the risk of burning the material. 

HEADSTONES AND MEMORIALS

Laser cutting and engraving for memorials and headstones makes efficient work out of adding images, landscapes and inscriptions to natural stone. 

Businesses that provide memorial services, like funeral homes, cremation providers and pet memorialists all rely on laser cut precision to help create one-of-a-kind memorials for loved ones.

HEALTHCARE AND MEDICAL

The use of laser cutting, marking and engraving is widely utilized within the medical industry. Laser cutting lends itself to creating medical devices, especially as devices and products shrink in size and grow in intricacy. Laser systems provide the precision and speed required for medical device production. 

For instance, in the early months of 2020, the need for medial PPE surged. And in response, laser owners and operators from every area of industry pivoted their production efforts to meet this demand, producing face shields, face masks and other protective barriers.

JOB SHOPS

A versatile laser system is right at home in a job shop. Job shops are just that, shops that take on jobs of all shapes and sizes. Kern laser systems, with their ability to process a wide variety of materials with precision, can help job shops be even more successful. 

POINT-OF-PURCHASE DISPLAYS

With laser processing, companies can create custom displays for their products. For example, makeup companies with custom displays for their products will have the name of each product or the color number etched right into the display where the product is held.  

SIGNAGE

Laser systems provide an unmatched level of versatility within the signage industry. Laser cut and engraved acrylic, wood, plastic and metal materials are used to create signage. Signage is used in all areas of business, from local mom and pop shops to medical facilities. With laser engraving, signage can be etched to include words, room numbers, ADA lettering and more. 

TEXTILES

Laser-cut textiles are becoming more and more popular. Lasers do an excellent job cutting a wide variety of textile materials, from cotton and polyester to silk and nylon. Unlike with scissors or other cutting methods, laser cutters do not leave rough edges behind or cause fraying.

WOODWORKING

Woodworking and laser processing make a perfect pair. Lots of wood materials respond well to laser cutting and engraving, creating beautiful results. Here’s a look at some wood products created with Kern laser systems: 

This was a brief look into the ways laser systems are used in a variety of industries. Please know, this is not an exhaustive list. We work with customers from just about every industry imaginable to help them apply laser processing to support and strengthen their business.