Laser Diode___Underthe Hood 12
Vložit
- čas přidán 29. 04. 2024
- I have already learnt a lot about this diode laser system and quickly reached a conclusion about its puny cutting capability. I can understand those that have invested in one of these machines being prepared to jump through all sort of inconvenient hoops to make it do as much as possible. I apologize but I dont have that patience to demonstrate that if I stand on my head, sing the national anthem and drink a pint of bear at the same time then I can make my machine do things it's really almost incapable of doing.
The purpose of my exploration into this subject is to find what it MAY be good at. With the aid of super focusing the beam to enhance its INTENSITY, I have increased its potential for certain types of engraving. One of those is dithered engraving and in this session I try to find materials that will respond to the most difficult SINGLE PIXEL engraving required for photo replication. I know that the reduce quality required for IMAGE engraving (which most people do) is a much simpler task for the diode laser and will be examined in the next session. - Věda a technologie
Russ, I watched this video today, more than once, and downloaded your test file. I decided I would try some photo replication. It exceeded my expectations. The media was black poster board from Dolar Tree. It worked very well the first time out even though I was using a 55 watt Cloudray CO2 laser. Tomorrow I plan on giving it a go on glazed tile using the Nick Norton method. I will try it both on the CO2 and the fiber laser.
Back few years ago I bought a small 15W diode laser engraving machine from China. Just a simple square frame out of extruded aluminum. That unit was claimed to mark on steel and to my surprise it indeed was capable of doing so. So I believe that with one of these diode lasers one could attempts photo replicating on steel/stainless steel. SS is absolutely not a binary (as you define it) material and you had to run it fairly slow to get decent contrast. That diode laser died long ago for me.
Other than that, I had access to a fiber laser marking machine. The one with the wave length designed for marking metals. That machine was capable of doing photographs on metals in an extremely fast manner.
S6ainless steel,is an interesting material because of its very high chromium content. There are generally three ways to mark stainlees . One is to add a surface coating (generally one with a high sulfur content) and heat it up. This causes a chemical reaction where the oxygen in the coating bonds to the chromium in the stainless to create black chromiun dioxide...leaving a permenant mark. This is all you can do with a CO2 laser. Despite my intensification of the beam with a com[ound ;lens I was unable to achieve this type of marking with the 5 watt diode.
I have owned both a MOPA and a Qswitch fibre lasers operating at 1064 nm. . With these there are two other marking strategies. The MOPA allows you to do micro machinngi of the marerial surface in different ways to produce a range of refraction colours that are rather fragile in that you have to catch thenm in the right light and at the correct angle to see the colours They also cause tyhe steel to go rusty afre a wek or two. A limited pallette of these colours can be obtained with a Q switch fibre laser but i the minimal range of pulse control limits it's ability at surface management . So with that in mind I will agree that stainless is not a binary material. I think with a more powerful diode laser a range of temper colours may become available on thin steel where heat conduction sideways is limited. These colours are produced by yet another mechanism, where a varying thickness of heat induced oxidation causes thin film intereference causes the colours you see with an oil fil on water or bubbles.
At the moment I am investigating the diode laser principle with a single 5 watt diode so as to remove the problem of the internal optics required to set the multiple beams onto a single lens spot. I have a two diode 10 watt head and also a 4 diode 20 watt head that I will be testing in the near future , so I may be able to do some of these things faster,
The one pixel for one dot principle of photo replication works on a CO2 RF laser as well as the glass tube. It also works with hgiher resolutions on MOPA and Q switch fibre lasers (much faster as you say) . I was only slightly surprised at how well (and relativerly fast) a 4 watt diode laser could work, albeit on a VERY limited range of materials.
@@SarbarMultimedia Right, I was fascinated too by the ability to do any damage to materials with diode lasers as low power as few watts. This was what led me to buying one of these. By the way, I have seen they were even making small portable devices with those diode lasers, which you could use in a manner you would an image projector, marking various surfaces.
@SarbarMultimedia. Hi I have been watching this series of videos and learning lots, thanks.
I have an Atezr P20 and have been trying all sorts of methods to engrave and cut. It is not to make money and I am disabled (MS) which gives me a hooby and distraction from symptoms and mobility problems.
One thought I have is my present experiements to achieve a 2.5 or 3D photo image on timber or other material that is man made rather than fibre, grain density, and other variations which alter the effect of the visual results has been to match the image, the settings and also to use methods to give the material a chemical change to give color contrasts when burnt.
Basically I have modified Nicky Norton methods, such as using baking soda mixed with water to soak the material first and let it dry naturally. Then light sand to smooth the surface and add a mix of acrylic undrcoat and baking soda and again air dry then light sand to level surface. Doing this gives many things like cardboard and also timber a darker tone and it does mean some depth can be achieved and retain the burn color. So deep or light the settings are so important, many fails and many very good results.
I use Lightburn grey scale and have tested to get settings to achieve the results I like. Photo images are my goal at the moment. Most of all the ones I have taken over years. I am trained in Falconry and I am very passionate about NZ falcons most of all.
My observation is that a dither such as Atkinson or Stucki or Jarvis give results that require more image adjustment to achieve the best results which are image specific. Different image requires more prep and can't just have same as another.
Greyscale is unique in it's requirements when adjusting the image and most importantly is when lasering the speed is not constant, it changes as an x axis pass is happenning.
Is the modified controller you use also changing speed as it does x axis passes in greyscale?
Have you tried scratch paper?
I have seen many images done on stratch paper by Nicky Norton so I have ordered some.
Hi Nigel
Thanks for the interesing comments It seems our life paths have intersected at quite a few points. My late wife was a victim of MS so I understand your situation. I spent 3 months travelling around NZ (2 in the south island) and am fascinated by raptors (not to your passion)ate extent) and encountered many swamp harriers eating road kill as we travelled around NZ, It's an amazing country. We have lasers in common as well . Having spent time experimenting with fibre and diode lasers I have limited patience for each because I am aware of how easy all the things you (and currently me) are trying to do, can be achieved with no fuss using a CO2 laser. That is why I am testing materials and processes quite quickly in this series. I have leant that undestanding the the characteristics of the damage profile that a focused beam makes, predicts what sort processes/materials it is best suited to.. Hence my intial determination to find how the diode beam enerters and exits the lens. It uses a completely different part of the lens geometry to that used by a CO2 and a fibre lasers. in fact it uses a very poor focusing part of the lens, hence the very long thin nearly parallel beam profile. I can already see how keeping that same beam profile but stacking more lasers into the same profile will create a much higher intensity profile and thus do more damage to materials quicker.. The limited range of materials it can affect will not change, but I anticipate less frustration as I move on to 10 and 20 watt heads in the very near future. Your patience with greyscale is praiseworthy but th basic facts tell me that surface engraving is near impossible (much like CO2... and for the same reasons). Yes you can infuse celulose based materials with chemicals (such as baking powder and salt soloutions) and you can create damage thresholds that allow different exposure times to create tonal changes to the metallic salt much like those created in photography with silver iodide. Cellulose is so poor at absorbing 455nm light that very little light energy is convereted into kinetic (heat) energy. It seems that the little that is absorbed (given enough time) will change the chemistry of the wood/card/paper so that it can convert more light energy to heat. It seems like its a chain reaction that probably accelerated by the addition of external chemicals . I expect this natural reaction to get faster as I step up the power (light intensity)..
My next video demonstrates how using the different power per pixel capability (thanks to PWM) allows you to do proper 3D engraving with just 4 watts !
Although my enthusiasm for the very limited capability of 455nm technology is muted, I am nonetheless ascinated and surprised by its process capabilty on certain materials. I have that failed glass coaster on my desk and in certain lights those crystal cleaer eyes are stunning. With more power I feel confident the TiO2 white tile method will work well.
Discovery and new knowlwedge is always exciting so despite it's limited capability, diode lasers have a lot to teach me.
@@SarbarMultimedia Thank you so much for the reply. I have been using timber because I am able to get offcuts and even machine and sand firewood timber, plus pallets. All this is because I have no income and I had to experiment with these scraps and then get better pieces as the outcomes improve. In a nut shell timber or even man modified timber, card and paper have not performed as I hoped. Using Nicky Norton's methods and modifying them to improve them such as the ceramic tile method I use is not with spray paint but a mix of PVA glue, water and TiO powder applied with a paint sponge, not a brush or spray. The results are much better and my method does have some more issues to solve but the finished tiles are amazing.
Using the Nicky Noton method to get the timber to colour better and also soaking that Baking soda mix into the timber before putting the undercoat baking soda solution is also a modified technique that is better and the wood quality issues I have due to budget are minimal.
I haven't researched this but I read that my Atezr laser head has 6 diodes so what that means regards spot size and focus depth appears to be important because changing the focal point depth in tests I have done to check from 6mm above to 4mm below have not shown improvements. When I read about people with Xtool and many, many other lasers that they have needed to adjust eg 4mm higher for some and 1mm lower for others appears to be the method using a flip-down tool is the problem and wasn't the correct length by the manufacturer?
Does need checking on every laser but it ain't broke don't change it!
Hi again. One thing just came to what is left of my mind regards using timber.
If you prepare wood as end grain rather than side grain, OR dark versus light timber, OR growth rings, OR grain changes you have multiple effects when the burn happens. That plus resin and sap content makes so much difference which means it can be used with sklls to enhance the outcome whether vector or image each has diferences that can be maximised by timber type and end or length preparation.
Hello yet again, my mind has farted out another comment.
If you do an image or vector with one bi directional pass and then a second pass or second pass as a cross direction of the first you change the image or vector visual effect to be light shading and I assume it is because you remove the carbon or burn residue and the natural timber is left but a deeper engrave?
The result is a lighter shade than the single pass.because of the engrave or etch of material and remaval of the carbon type effect? You do get a slightly deeper result but not visually better result when you eye processes the result, which is not as easy to pick up.
@@wadhamga Hi Nigel
6 diodes at 6 optical watts ech could mean 36 watts but there is always some efficiency loss so it could be as low as 30 watts, but that is still a useful machine. I will eventuallu be testing a 4 diode 20 watt head but next it will bw the 2 diode 10 watt head.
Take a look at some of the test I conducted to evalute the beam performance. Because the beam is very small it is using the least refractive part of the lens and tends to be nearly parallel That means there is a fairly uniform intensity profile within the beam and although there is a point where the beam is at its smallest and most intense. the change of beam diameter will be fairly slow so there will be several mm where there is little change in the apparent focal spot. It all depends on the nominal focal distance of the lens used in your head that will determine if your beam perfforms the same as another manufcturers head.. Unlike a CO2 laser with a Gaussian beam profile , the one I have used so fay doesnot change the focal distance because of spped or power but it does seem to vary between materials
For those wanting to use the dot test I used in this video , you can down load it here
workdrive.zohopublic.eu/external/32aaa1ca80215714ed29e7eb1ed473de1c276af9b9cf88d21fd7bad49dc391d7/download
Thank you this I was trying to find it on other posts in this series.
One question is pass throught percentage/distance.
If that is too short the the x axis dots row will not aline with the y axis line of dots and therefore an image is going to have issues and if an image is cropped boarders and a background is added then there is another level of the same problem going to happen? An image will show that edges are not lasered and have an unlasered frame effect.
Using greyscale with its speed settings being contoller variable will have some areas needing more buffing from pass through being too low and image quality will show the misalinement as well of pixel rolls as well?
@@wadhamga
Hi Nigel
I am not sure I fully understand your question about pass through percentage distance. I was involved with testing the graphics tools in Lightburn when it was in its prototype state. Because I could not get Lighytburn to output (or display) my test patern single pixels. the "pass through" switch was added so that anything youcreated in an external package would not be interfered with by Lightburn. Obviously this meant that you could not access the DPI or line spacing because that was defined by the resolution for image that you were "passing thhrough". The one major issue that happens with Lightburn is that the burnt dots (DPI) will be sqaure, just like the pixels. As I have demonstarted, the faster you scan the thinner the lines so instead of producing dots, for single pixels you produce dashes. In some instances it would be nice to pitch the Y spacing to something other than the X resolution. You can do this with RDWorks but if you are runnning a GRBL controller then this option is not available to you. Because I am running the diode heads on a CO2 machine, my Ruida controller has more features than yours.
I think your understanding of greyscale is a bit off. Your controller does not change speed during scanning of a greyscale image. instead it has the ability to varythe power for every singlre pixel whist running at a constant speed. Hmmm..I say constant speed but that is not 100% true. Your head is driven by a stepper motor that is "on average" running at a constant speed but the stepping pulses are always present and can cause problems at low speeds when the steps become more obvious.. On a small diode machie I suspect your X axis is driven directly from the stepper motor via a very small (maybe 16 to 24 tooth?) pulley. When the stepper runs at high revs the inertia of the rotoer damps out these steps but at low revs they become a nuisance.
I hope I have interpeted your question correctly
@@SarbarMultimedia Hi, thanks for the reply. The reason I have attempted to describe that the speed of the laser is not constant when in greyscale but is constant in a dither mode is because of actually watching x axis passes and observing the speed change as the head moves left to right and back to left. The time to laser the same photo in greyscale mode versus a dither mode is very different. I have used the same image in both modes and all I do is change the mode. I do have to adjust the speed and power a little to get the best burn color but the change of speed during a greyscale pass stands out like the proverbial dogs balls, unless it's neutered!
It seems an example of actually doing the method to prove the point because theory is not matching the effect?
@@wadhamga If you are using Lightburn then I know absolutely that the X speed is supposed to be constant and the power changes with the grayscale value. I have seen this happenong with ocilascope traces on my CO2 glass tube machine and my RF co2 machine that operates with a PWM system. Lightburn is a reverse engineerd version of the Ruida control software called RDWorks.. Yes this has been re written in places to suit diode lasers but I cannot imagine the principle of greyscale operation has changed.. If you think about it logically it is an impossibility to make the head jump INSTANTLY from one pixel to the next and hold it in a position for a time period proportional to the greyscale number. The inertia of the head combined with the lack of stiffness with a belt drive makes this task absolutely impossible. Switching ther power on and off at lightning speed is just an electronics problem where no mechanical issues are involed . Thus a constant speed and power switching per pixel is the only possible grayscale operating mode. I am not disbelieveing what you see but I would suggest this may indicate there is something wrong. please don't take my word for it , send in a question to the Lightburn forum. If your machine does not use LIghtburn then I have no idea how the grayscale output signals are configured. As for different timings on the same image, ,yes they could be diifferent. When you dither an image , depending on the background colours, the scan will stop at the last black pixel on that scan line. If there is a border then the timings should be the same but with no border the last pixel may not always be at the full extent of the grayscale original. The grayscale will always scan to the full extent of the image whereas the dithered version may not, thus finish ing in a shorter period.