Stencils are used everywhere where, but to produce them to perfection you need to pay attention to artwork you make. This guide will show how to make stencil artwork for laser cutting. Stencils can be cut with CO2 laser, fiber laser, CNC and blade vinyl plotters. regardless of what machine is used to cut them the all get cut and unlike a printer all cutters cut through material fully so all unsupported parts will fall off.
So lets say we want to spray paint this image below.
If you print out our image it will look perfect on paper, font is good size is good BUT if you send this art for laser cutting as stencil this art is not good and you will NOT get what you expected to be on paper. This font has letters B, oo, e,o that have inner elements. When laser cutting machine cuts out black area you get sign style letters that you can stick to something and you are OK but stencil needs negative space and as result all inner elements will get lost. Here is what happens when art is cut as stencil.
As inner elements of stencil were not supported by bridges ir tabs they got separated from main stencil body and when you spray that art you get big black holes in certain letters.
To avoid this, bridges or tabs need to be added to stencil artwork. This can be dome by cutting letters with eraser tool. So basically walls of the letters are separated and this allows main body your material to hold inner components. Example of properly setup stencil artwork will look like one blow
Same technique is used to make actual artwork with more complex thing then just plain text signs.
Another thing is to keep in mind about stencils is wall thickness of your bridges. If walls are too small then there us chance that bridge will burn out when lasered and inner part will be lost. Best to keep bridge walls to be at least same at material thickens though in many cases it can be smaller. For example if we would cut artwork above from 1/8″ (3mm) acrylic min wall thickness should be 3mm , bigger the wall more reliable it is. However if our stencil is very small day 6″ wide we can stil push bridges down to 1mm this will make stencil more fragile but its still usable. If we go less 1mm on acrylic parts will just brake.
LaserCutZ got request to produce mil speck metal id tag that can have photo laser etched to it. Goal of the project to make photo engraving that will not get scratched off, burn or gets washed away by chemicals. As need on sample our state of the art laser machine was able to engrave photo at 300dpi which is same as it would be printed on paper but this one is etched into black aluminum. Sample was requested by aerospace contractor so we guess it would be for pilots or astronauts. We choose black anodized aluminum as a metal for this sample, we also tried same thing on stainless steel 316L and photo engraving came out perfect on stainless too. In general LaserCutZ can engrave photo on ant kind of media.
When it comes to lasers two most important parts that affect your cutting results are laser beam aliment and beam quality itself. Laser sources such as Fiber lasers are pre-aligned at the factory with special tool and usually under microscope so output results are very good (with fibers we seen focused spot have perfect circle at 0.015mm) For CO2 lasers situation is not that easy and in most cases you need to have optical elements along the laser path to deliver laser beam. Any element you add to machine has some tolerance and end result gets degraded. No matter how good you are in tuning there will be some losses BUT proper tuning and setup to makes a big difference.
01
Laser Optics Aliment
Perfectly aligned laser optics will let your machine cut with maximum precision
So step one is to align your optics. If we build our own machine we make parts the go into each other, no option to move too much so that guaranteed best results. Cylinder inverted into cylinder will have less chance of moving around and it wil maintain a straight vector which is the same as your laser beam travel path. Once mechanical aliment is done, alwyas check optical results.
When we work with LaserCutZ custom designed components we always make parts that can be mounted or host mounting hardware. As seen on image above test gel is installed onto of beam expanded. Aliment jig has reference rig so we know it matches mechanical part and it has cross chair lines so we can see what quadrant laser will hit. Laser test jig is nothing more then acrylic that can be cut by any CO2 laser machine, but outing hardware needs to be part of machine. If your machine is lucky (engineered well enough) then you can align it absolute perfection. Either way once test jig is installed fire laser 10% 20ms pulse and you will see exactly where it hits. As seen on image above it had 2 spot, one was too low, and tube was adjusted and 2nd one is perfectly in the center of cross chair. This part is good. We can move to next aliment point.
Next test point is where laser existing the mounting fixture. If main glass tube was not aligned properly then exit point will not be exactly in the center (even though entry point could be in perfect center) So we mount new test plate on exit point and check. To make live easier and safer this time we mounted red laser pointer so we can see what we will hit. Lucky due to experience doing laser maintenance our exit point hit exact center of cross chair so no further fixing is needed.
02
Laser Spot Quality
Laser spot form your source affects cutting end results but we can always do some magic to it
All laser sources are not created equally! CO2 tubes have less controlled spot, RF tubes are little better, both need some shaping at the end. Why do I care about spot quality? Initial laser spot will be carried through optical path get more distortion and finally gets focused to laser cutting material. If we have bad spot initially, we will project it and get not perfect circular cutting kerf so you may se some ribs on edge of material or some times have perfect cut through and some times not or the cutting or engraving line changes thickness all the time. Those are small not always critical problems but they do make difference when you need something perfect. Very often this whats determines good machine form bad cheap one. As we are crazy about quality of cuts lets look laser spots in details.
Perfect Laser Spot after Modifications
This CO2 laser spot was generated after we tuned laser beam with sharper and beam expanded. As we see from picture spot shape is nearly perfect circle, such spot is easier to deliver though optical path and focus onto cutting material.
Distorted Laser Spot form Glass Tube
Spot in this section is not absolutely bad, in fact it comes from very good China glass tube but its not yet perfect. As we can see shape is not a circle and there are some outside sparks, if we will be doing paper cutting or scoring we will have hard time.
As we see laser spots can be different and they can affect quality, lets find out how to make them better. One way is to use beam shapers, those are just metal screws thta block little of the laser beam outliers and kinda make more circular shape. Downturn of this screws taht catch laser will generate heat and those laser beans can reflect some where (even back reflect to laser source) Better option is beam expanders that, those will take some energy form our beam but usually that is form outlier rays.
Expanding lens is installed right after CO2 glass tube exit point, instead of expanding beam we turned it to combining direction, as result original rays coming from tubes get compressed a little and forming absolutely perfect beam spot. Note as we compressed ray density, our maximum laser travel distance will be reduced but usually its not a problem as on most machines total thavel path is 1-1.5m which is ok, laser attenuation will not be too big while quality improvement is dramatic
Fix Your Laser Machine Today
LaserCutZ offers laser maintenance, repairs, installations and custom build machines. Emergency calls can be serviced same day if client is withing a drive time form NYC. Out of state service visits are possible too. Click button below to get in touch with us.
Even if your machine is perfect there always room for improvements to make it better or add additional functionality. This time we doing a handson modification to our own cnc by adding simple but effective tweaking to make it much more precipice. In general LaserCutZ provides lasers, cnc and electonic repair services to industrial equipment on east cost and NYC area
Cerakote is very often used for coating weapons but we decided to do a sample on structural stainless steel beam that we laser cut on our tube cutting machine. Crekote can provide environment friendly, high temperature resistant coatings, in most cases its a spary based alternative to a powder coating.
Carbon fiber parts are very popular for car modifications, real carbon some time hard to manufacture (and some times not needed) one alternative to real carbon if hydroprinted texture that can be applied almost to any shape. For example shpeed shape below shows carbon wave that is fairly realistic even when we compared to original carbon used in Mercedes AMG interior our speed shape looked fairly decent. Few projects back we made custom parts form real carbon fiber for Lamborghini, now looking back we could use hydroprinting to do the same part with much less efforts and get same visual reuslt. If your project requires carbon texturing use contact page to start your job
LaserCutZ took a challenging project to make something unusual. This art project was so unique client decided to send film crew to make a documentary on how project was made. This film shows how our laser machines engrave metal parts with extreme high precision on unusual curves. Film is now done and LaserCutZ is working on mass production of metal part needed by client.
Protecting employees and building guest is a critical task for property management company. To prevent spread of COVID-19 LaserCutZ developed upscale looking bathroom partition for sink countertops. Installing glass or acrylic countertop dividers will protect guests when they are in close proximity to each other and reduce risk of virus transmission. Our divider panels are designed to provide high end upscale look. They do not need any drilling into marble countertop or glass so installation is very easy and fast. Kit includes all mounting hardware and laser cut acrylic glass. Glass partition is elevated form counter which allows easy cleaning.
This Glock receiver from Polymer 80 was laser engraved our UV laser machine. Customer had made texture with hot iron and prepared grip area to be laser engraved. We could use either fiber machine or UV machine to do deep engraving into pistol grip. We choose to use UV as plastic used for this Glock seemed very close to ABS and UV laser is better for ABS plastic engraving. Low waves for UV produce less heat and so ABS does not melt making engraving nice and crisp. This handgun got 3 logos on it, which was Hulk Security as seen in picture along with Hulk body silhouette and radiation symbol on back. Vido of this engraving is posted on YouTube. Watch it here
What do you do when you need to get something that government considers non-essential during 2020 COVID-19 pandemic? Well it may be tough! Aside from our face mask manufacturing initiative we made few jobs like this custom laser cut orchid pot with breathing holes from soup cups. It may be non-essential and not critical for living but it can make people happy and that can be good measure against virus spread too. Well orchid will make people happy not the pot itself but we do add our part to that process.
