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Hi If your spot is just burnt on fumes then soak it for a few seconds with IPA and try to remove the spot with circular rubbing using a cotton bud. The antireflective coating is pretty duarable. Howver, if the debris has ben on there for a few minutes then the debris will absorb laser energy and heat the surface of the lens. That process could bake the fumes into the AR coating and the lens is likely to overheat with use and a cental star crack will happen. Lenses are the most vulnerable part of your machine, thus you should always have a spare lens. The 50/60 watt tube supplied with your machine may not be what you think. . A typical 50 watt tube will be 1000mm long and 50mm diameter. It may claim to be 60 watts because that is waht it was test at innthe factory .... but that is not for you to use as it will shorten the tube life, 200mA is the max to run a 50 watt tube at. However, that 50 watt tube is almost certainly a B grade tube with a poor intensity profile. B grade does not mean crap but if you watch part 2 of this video you will see me running a B grade tube in one of my machines. Because I now understand how lenses and laser beams interact I have paired this 70 watt beam with a 2,5" GaAs lens and it cuts very well. Your question about tube upgrade is an intersting one. AS the power of a tube increases so does the beam diameter. This could mean the the intesity gain is not proprtional to your expectations. I have found that the best "jack of all trades " tubes are in the 70 to 80wttt range. Steer clear of Reci (despite their good reputation). I have ssen far too many that are rubbish at low power Why pay twice the price for something that does not deliver across the range. Amongst the rest, Yongli, EFR and SPT, I would rate SPT as the best value for money. You can buy an A grade SPT rebadged (officially) as a CR70 or CR90 from Cloudray.. Fof a small kerf on thin material I would use a 1.5" (38.1mm) meniscis lens. There are all sorts of "opinions" about lenses and getting what you pay for, The facts are simple, The geometry of a lens logically has to be the same no matter who makes it and how much ir costs. Cost is generally related to the quality of the material and the materials manufacturing process, USA on a lens description means it is made with CVD ZnSe which is bright yellow and can withstand power in excess of 200 watts. The brown honey coloured material is Chines manufactured PVD ZnSe which ir rated at about 80 watts. That's another reason for staying below 80 watts with your tube, you can use cheap lenses. I have tested the power transmission and cutting performance of almost every lens available and higher cost does not get you better performsnce, One final point (myth) about lenses. A bright yellow CVD lens looks crystal clear to our eyes whereas the brown Chinese PVD lenses look rather dull and unexciting. OK. if that is your judgment of lens quality, how do you explain the BLACK galliun arsenide lens? We "see"in the 400 to 700nm wavelength range the light passing through these materials is at 10,640nm. So what you see is not what is actually happening. At that wavelength my black gallium arsenide lens is transparent Weird? Best wishes Russ

@@SarbarMultimedia Thanks Russ. I rarely hit 18 mA on mine and have the power turned down to 80% max at the controller, so 100% in lightburn is 80% at the machine. Tube still going strong 5 years now. Reason to step up to 100W is to cut thicker material in the 1/4 to 3/8" range for some projects. Also great info on Reci tubes, so I will look into the other tubes at Cloudray. I also replaced the Chaser lens soon after watching your earlier videos on lenses, and put a lot of what you taught to practice. Right now I just want to get a tighter cut for a couple projects, so will look into the 1.5" setup. Will also see if that is just a surface spot or actual damage. Going to tie the pressure switch into my relay setup that turns air on and off, so the tube wont fire if there is no air pressure, I missed that somehow. I've also put your acrylic cutting and etching to good use, and yes, keep the machine clean, don't want a grid fire. I appreciate all the work you put into these videos.

Hi Malcolm I never stop learning or stop searching for better ways to do things. In a more recent video I have found there is a logical flaw in the way we have all been taugh to set machines. I modified my machines many yeats ago to make the heads adjustable in Y and Z. The principle I demonstarte in this video works for all machines , however if you do not have the adjustments that I have it will be more difficult to achieve. see ruclips.net/video/tvNfAg-cOLA/видео.html

Hi Jean Even though I am supposed to be retired, I have been involved with paid work for the last several weeks and my hobby has been on hold. Howvere I am now back on the diode learning journey and am in the middle of video 17. which deals with some loose ends that I created in this cutting video and the grayscale video. I will take a few moments to carry out the test that Jerry and yourself would like to see. Best wishes Russ

Hi Max I was loaned a 20 watt MOPA fibre laser for about a year by a local company that builds bespoke laser systems for industry It was about 5 years ago when such lasers were rather rare and the company didn't have recources to explore the limits of the technology. That had a galvo head and an F theta lens. It was during thr period when I was trying to understand how a normal single lens with an expanding beam below the focal point could burn deep parallel cuts.. Ther F there lens was only ever designed to keep the OPTICAL focal point on a flat plane over a very limited area. Such machines are designed for MARKING the surface of materials and never cutting although deep engraving is possible to a limited extent. In nprinciple this lens is a brilliant idea because it means the beam can be made to scan across the material rather than trying to move the material acosssa static beam. As I said, this was long before I fully understood the weird relationship between laser beams and various lenses. or the fact that the OPTICAL focal point that all lenses are designed for is not the same point as the INTENSITY focal point. In the same way that speed and power change the position of the most efficient focal distance with a single lens, I noted the same characteristic witht the F theta lens. I had not yet understood the concept of spherical aberration and therfore this issue was just something I noted for future investigation. There are several bits of optical trickery used in fibre and RF lasers to modify the beams before passing into the final focussing lens. One such device is the beam expander, an optical device invented by Kepler and Gallileo in the 15th century to improve telescopes. The principle being to change a small non-parallel beam of light to one which is bigger and more parallel.. This is an essential requirement for expanding the very small output beams from RF and Fibre laser soiurces. I draw your attention back to Diode Laser video 03 where you see me demonstrating the effect of UNIFORM intensity sunlight focussed through a normal lens. You can clearly see that the outer part of a lens is where the spherial aberration effect is LEAST and the refraction concentrates the light into a single focal zone. The central part of the lens still refracts the light towards focal points BUT those focal points are spread beyond what we see as the OPTICAL focal point and because they are not acting in unison they are not concentrating the light INTENSITY sufficiinetlyto do damage. Lenses are designed to transit images and not to concentrate INTENSITY so we can do damage with it. The RATE of doing damage to material is directly related to the intensity ALL laser sources have an output intensity profile that is near Gaussian. That means the area around the beam axis will naturally be the most intense and most damaging.. Howewver send this beam through one or more lenses and at each lens , spherical aberration takes its toll and eventually destoys any semblance of a Gaussian intensity distribution . WE are almost back to a very low but UNIFORM intensity. Logically this means that in the same way that I was not using at least 50% of the sunlight to damage material, I am probably wasting 50% of the laser beam's potential with the optical trickery BUT the end result is a concentrated SOPT that is great for engraving/marking but useless at cutting. Although my interest in the diode laser was close to nil as a useful technology, the optics for harnessing the very low power of the laser beam is fascinating . It appears that designers are exploiting the many spread out and useless focal points that result from the low refactions around the lens axis but are stacking multiple lasers beams through this area to efficiently increase the intensity of the poorly focused small diameter. I am unsure if this is designed or accidental based on all the tedchno babble I read or hear as they try to sell these devices. Yes, it works but there are also many cosequential negatives that happen as well. It has turned out to be more interesting that I had originally imagined. Best wishes Russ

+ Hi Jerry Your ideas are thought provoking but you must not lose sight of two important facts of physics. First, light travels in straight lines or to imagine it another way, the little photon bullets are travelling in straight trajectories. Secondly, it is only the density of those bullets (light intensity) that can cause damage. Although we have two cones of light coinciding at a point those cones are not filled with uniform intensity light.The light is weakest at the surface of the cones.. Imagine those two cones just touching each other then where they touch will be a vertical beam of two combined weak rays.. Logically it must be these combined vertical stream of photon bullets that are responsible for the deep narrow straight cut. This is just a concept, in reality the cones are overlapping but it must still be some combination of VERTICAL photon bullets that are responsible for the cut. There will be some small element of non vertical photons that aremaking it through the cut entrance are causing the balloooning erosion effect near to the top of the cut. Watch the circular cuts and you will see no evidence of cut width change or cutting loss depending on the direction of the cut. I will try to do the test you are intersted in and send a picture via email (is it still "homecall"?) Best wishes Russ

@@SarbarMultimedia yep its homecall. That's very kind of you but don't let me interfere or take up your valuble time.. a small amount of time is all we have left .... Jerry

of course , if the beams are not aligned along the x axis or Y axis but are canted along the nnw or the ssw direction then cutting on X and Y direction will show the same. but as Jean describes far better than myself it would show up doing a full circular cut. I envisage it as the system the dam busters used to get there height correct using converging light beams.. Jerry

@@JERRYIRWIN41 Hi Jerry Yes the dam bustsrs heigh detection system is an exact analogy . However the fact that I cannot getthe beams to perfectly merge to a thin line means there is some "crud" of alsmost equal intensity at that intersection point that prebvents an ideal focus. . In a weird an fortuatous way that may help to "fatten" my dots when it comes to ditherdengraving.. Something I will be exploring futher in session 17.

@@SarbarMultimedia Many thanks again for your in depth replies. Jerry

Hi Malcol Thanks for your interest. and welcome to the fascinating world of laser technology. There are many experts (amateur and professional) that will tell you the best way to run your machine and the things you can do with it. None seem to take any interest in finding out how and why the technology works. The biggest problem I encountered that no one seemed able to answer (even laser physicists) was how it is possible to "burn" a deep parralel kerf with a beam od light that is expanding and loosing its intensity once it gets past the focal point see this thought provoking example which I sent to many optics and pysics professional. ruclips.net/video/vTEAm-01E1Q/видео.html I had zero meaningful explanations . I thought I understood a bit about lenses 6 years ago when I created this video. but in reality I understood very little. Yes I managed to find a magic combination of lenses to create a very small focussed spot but that lens type was rubbish at cutting....but why? I had to spend about 3 years of further experiments and observations before I fully understood how lenses and laser beams are really incompatible . However, despite this incompatability. manufactureres have been able to bolt proprietary items together in a way that wooks. I am convinced that machune builders are unaware of the real science theyare selling. A more upto date review on this subject can be viewed at ruclips.net/video/7N8Th1-IF4s/видео.html ruclips.net/video/v7-VArJbJTs/видео.html There are no books or learned papers on this subject, it's all about experimentation and self education. Good luck for your journey.

@@SarbarMultimedia Sorting through the "so called experts" and people who actually know what they are talking about is difficult. I'm glad I found your website and appreciate your methodical approach, rather than the anecdotal information RUclips is rife with.

@@MalcolmProductions1 This technology is riddled with myths, and techno babble . I did a more recent series called CO2 & Diode Laser Myths and Misunderstandings mwhich you will find on this channel

Yes there are several videosdscribing how a laser tube works . However let me summerise the facts because ther are many that create plausible techno myths to explain what they dont really understand The laser tube (rf or glass) is filled with a mix of 3 basic gasses. Crudely there is 10% carbon dioxide, 10% nitrogen and 80% helium.. Heluim does nothing except act as a heat conduction medium to carry the heat away from the pink ionized nitrogen. In a glass tube this ionization is provoked with high voltage and in an RF tube the ionization is stimulated by very high frequecy. In both cases the atoms in the nitrogen are made to vibrate very fast. so that collisions with the CO2 molecules creates the laser beam (I wont go into the physics this is just the crude principle). Lets change subject for a minute and look at the HV power supply used with a glass tube. 100% power is a misunderstood concept because it has nothing to do with WATTS. IF you look at the specification for your HV power supply you will find it has a maximmum current output. Let's say 28mA. The greater the current flow through the ionized nitrogen the pinker and more intense the beam will appear. So current flow is used to make the nitrogen vibrate faster. %power is a lnear measure of the current flow through the ionized nitrogen. and NOT watts. 100% power = 28mA for my example, 50% power is 14mA and 25% power is 7mA . The excited nitrogen is acting like a cue ball and supplies extra energy to the CO2 molecule as it collides with it. If you add sufficient energy to the nitrogen by increasing the current flow (%power) ithere is a critical point wher the nitrogen has sufficient energy to break away one of the oxygen atoms from the CO2 and changes it to CO and O (carbon monoxide and a free oxygen) Neither will produce a lasing action. So your carbon dioxide is like ink in a print cartridge . Yes the CO2 will eventually be consumed by this destructive action. However, the manufacturer advises on a current level that will reduce this destruction to VERY low levels and a typical glass tube can last for 5 to 8 years. The watts output is not linear and ther eis no fixed relationship between %power and watts. It all depends on the tube brand . Typically you may find that you will achieve 60% of the promised watts at as littlre as 30% power.....very non linear. So, in answer to one of your questions, yes, you can dramatically shorten a tube's life by "over driving" it with too much current .Stay below the recommended current and it makes little difference to the tube life even if you try to run at low powers. It may sound counter intuitive but running a tube at less than the recommended max %power can often result in faster cleaner cutting. IThis is due to the complex relationship between the intensity distribution in the beam and the shape of the lens you are using.. As you reduce the %power that intesity profile changes and there is an intensity sweet spot for each focal length lens that will rarely be at the full allowable power. You cannot overdrive an RF tube because it works with a different control principle A 30 watt RF tube has zero power adjustment. Instead it's like a light bulb, its either ON ( and delvering 30 watts ) or OFF (delivering zero watts). The ratio of ON to OFF is called the dutty cycle and for example a duty cycle that is ON for 50% and OFF of 50% is assumed to be doing 15watts worth of damage. The RF tube manufacturer has fixed the SAFE current flow to create 30 watts and you can do nothing about it. That is the main reason why Trotec and Epilog make silly life claims and comparisons between the two technologies. By the way diode lasers work in this manner also. If you know the safe current limit for your tube and you have an ammeter fitted, you can test the % power to find the number that allows the safe current flow for your tube.. There are fancy ammeters that allow you to limit the current so that you can use 0 to100% without overdiving your tube . However you can achive the same level of protection by setting the % power you discovered in the vendor settings of Lightburn or RDWorks.

Thank you Russ for the detailed explanation. So, my 30 watt Trotec will not be negatively affected by operating it at 100% power - I believe the tube is a Synrad brand - will have to look inside to verify. There is no setting to adjust my power by mA. It does not operate using Lightburn or RDWorks. In my Trotec Job Control settings, I can adjust the supposed power (by percentage) but also the PPI/Hz. So would this mean that in reality my settings only allow an on or off condition which can be XXXX number of times within a particular distance -? For example, a 1 inch long black line would have all pixels "on" when set at 100% power but only half of the pixels "on" when set to 50% power? Presumably my black line would not turn out as black at 50% power unless there was sufficient DPI to cause overlap of the "on" dots? I should probably revisit your videos on dots and pixel size and PPI. Incidentally I can also separately set a fixed number of dots per inch within their print driver while in Corel Draw, such as 125, 250. 333, 500, 600, 1000. Corel Draw then sends this info to Job Control.

@@DesignCutters Hi You are correct. Your RF tube has no current control because that is set to a VERY safe level by the manufacturer. Your tube can ONLY EVER deliver 30 watts or nothing depending if it is switched ON or OFF. The ON/OFF is controlled by the PWM system and 100% power means it is ON for 100% of every PWM cycle. Remeber that there are two basic types of scanning (engraving) If you have vector letters for example. for every scan line the controller knows where thre starting edge of the letter is and turns the beam ON until the other edge of the letter tells it to switch off. If you have your %power set at 100% , then regardless of the PPI, there will be no pulses in the burn signal because the duty cycle is 100% (ie a continuous burn). In normal graphic terms PPI =pixels per inch but on a Trotec machine I have heard the machine demonstrators describe this parameter as PULSES per inch. This brings me to the other type of engraving that involves a BITMAP image . Such images are made up of individual pixels Let's assume your image has a resolution of 254 PIXELS per inch. First of all, PULSES per inch is meaningless if you specify 100% power. You can only get pulses if you specify 99% power or less (99% ON and 1% OFF). I suspect you have no control of frequency if the PPI means PULSES. The 254 PIXELS per inch example means that each pixel is 25.4/254 =0.1mm square. Looked another way that is 10 PIXELS per mm If I want to engrave this image at 200mm/s. If I want to run my image at 200mm/s then I need to create 10 X 200 = 2000 BURNS per second but only if they are PULSES that are switching the beam on and off 2000 times per second. ie the PWM is set to 2kHz. At 400mm/s the PWM needs to be set to 4kHz. This calculation may be confusing for many people so I think Trotec has bypassed this issue by asking you for the image resolution. If you say 254 PIXELS per inch and a certain speed then Trotec appears to be calculating the ideal PWM frequency to create 254 BURNS per inch. Single isolated pixels are the most difficult things to create but in theory the PWM system is capable Here is my little test pattern to see how good yoiur machine is at creating 0.1mm dots from o.1mm pixels. workdrive.zohopublic.eu/external/32aaa1ca80215714ed29e7eb1ed473de1c276af9b9cf88d21fd7bad49dc391d7/download Change the %power (pulse width) to see how this affects burn size.. I am sure you will be surpised. (by the way set your PPI to 254) Note your concept of how PWM works is incorrect as this pattern will demonstrate. 50% power does not mean you will lose half the pixels They will ALL be there but will be shallower (thus thinner) becuse you have halved the EXPOSURE time for each burn. Also your thoughts about PIXELS per inch in CorelDraw are also leading you astray. You can specify1000ppi in CorelDraw (that's a pixel siize of 25.4/1000 = 0.025mm square) but If you use a typical dither pattern such as Jarvis, Diffusion or Stuki then you will just get an overburnt mess. If you use newsprint or halftone then the image will be much cruder but may work. It certainly will NOT be a 1000ppi image That is why you must understand what your machine is capable of. Sadly there is one big issue with an RF beam which you will see with the dot test. Do the test in the corner nearest to the tube and then run the same test with the same parameters at the diagonally opposite corner of the machine. Are they the same?

Hi Joseph. As you work through my videos you wll seet that at one stage I tried to amplify the inensity effect of a beam by using various pairs of different focal length lenses. In the case of creating a super small clean dot, I succeded but when I tried to use two lenses for increasing cutting speed/depth I came across a brickwall. Lenses are designed with a focal distance based on the assmption that the rays entering the lens will e parallel. If you use one lens to focus the beam down to a smaller size then two issues ensue. First the rays are now converging at the second lens so this automatically reduces the focal length of the second lens. The smaller beam hitting the second lens is now not a Gaussian distribution (because of spherical aberration) and is being poorly focused by the less refractive geometry at the centre of the second lens. If the lenses are touching (as with the short focussing compond lens system I designed for photo engraving) this effect is not important, however putting distance between the lenses does not have the expected intensity amplification effect you would imagine..

Ok I have a question: What type of lens ie. ZnSe,GaAs,Ge,CVD-ll-vl Znse for photo engraving is ideal.? I believe 1.5 is a good length but don't understand the types. Do you have a video on this subject. Thanks Joseph

@@josephlovell6951 Hi Joseph Yes there are several videos on lense but it is all summed up in these two videos. Forget germanium as a lens because after about 12 watts the power changes the crystal stucture of the lens and it becomes opaque for CO2 light. The lenses we can buy for our machnes regardless of price or material, ALL possess an unbeatable physics property called spherical aberration. In normal lens use for telecopes . projectors, camaeras etc the light is always uniform intensity as it hits the lens.with parallel rays. Under these circumstances the standard laws of lens theory apply. However.we are not sending a uniform intensirty beaminto the lens and we are not trying to project/capture an IMAGE. Instead we are tring to intensify the intensity of the bean to damage material. An the golden rule for damaging material is " the greater the INTENSITY the FASTER you can do damage". There are two lens forms we can buy. One is plano convex which has significant spherical aberration properties and is designed to be used flat side towards the work. The second type is a meniscus form where the lower face of the lens is concave,. This reduces the spherical aberrationeffect by about 90% and produces a pretty small concntrated spot size. This form of lens is ideal for engraving whereas the plano convex form, with its HORRIBLE optical properties. is actually more efficient at cutting. There are basically only two types of lens material we can use . 1) Zinc Selenide All ZnSe material is poor at transmittong CO2 light (about 70% efficient) and is toxic to handle. However, in the same way that you see a blue/mauve hue to camara and binocular lenses which is there to improve light transmission, so it is with ZnSe lenses. They are coated with several layers of exotic materials to provide an anti reflective coating to improve light transmission to 98% or better.. Althnough ZnSe can occur naturally it is always grown in a laboratoty (jusyt like silicon chips) The Chinese use a manufacturing technique called Physical Vapour Deposition (PVD) whereas the USA uses a process called Chemical Vapour Deposition (CVD). The PVD materal is limied to about 80 watts whereas the CVD material can handle up to about 200 watts . The ll-lV material is always CVD material and has a slightly more efficient anti refection coating. ..... but you pay a lot more for that 1 or 2% transmission improvement. Remember that ALL these lens types are designed and made according to factors defined by conventional lens theory so there is no significan difference in the GEOMETRY between any of these ZnSe lenses, they all perform the light intensification function in exactly the same way regardless of manufacturing process or price. By the way, the AR coating on the ZnSe makes it safe to handle but be careful if you break a lens. 2) Gallium Arsednide This is a weird material because it is black and you cannot see through it. So you wonder how can it work as a lens? Light is equally unfathomable because at 12.640 nm wavelength this black material is transparent and allows the light through. This materail is even less efficient at transmitting light (about 60% efficient) but by adding exotic materials to produce an anti reflective coating, the transmission efficiency is again about 98% However there are two properties that sets this materiial apart fro any of the ZnSe products. First. it is mechanically stronger and will easily handle powers in excess of 500 watts . Second, it has a different refractive index that means that for a given focal distance the shape of the lens geometry is "flatter". As I show in these two videos. the focussing effiiency of a lens is not constant, it depends on the INTENSITY distribution in your beam. For your RF machine the situation is very complex because your beam is being modified by a beam expander as soon as it exits the tube. This basically destroys the nice Gaussian intensity distribution and what is sent aroind your machine is an unpredictable intensity mess, The RF machine is pretty efficient at engraving (if you find out how to control your dot size) but it is very inefficient at cutting (yes I know it cuts) but the spherial aberration property of the lens can only be exploited by a decent Gaussial intensity distibution. Finally if you are looking to produce the smalles dot you need a special compound lens with a very sort focal length (about 20mm) that I develoed and is on sale at C;loudray see this www.cloudraylaser.com/collections/nozzles-lens-tube/products/cloudray-n04-universal-compond-engraving-nozzles and scroll down to see lots of detail. Sadly , Trotec have locked you into a rather expensive and inflexible lens mounting design and a high definition lens arrangement was never on their design radar. This means doing the best you can withthe shortest focal length lens available and see if it can be of meniscus form.

@@SarbarMultimedia thanks that is helpful

Hi Joseph How lenses and laser beams interact has taken me a long time to understand. Thus my knowledge of lenses from 5 years ago has changed a bit. You may like to update by looking at these videos ruclips.net/video/7N8Th1-IF4s/видео.html and ruclips.net/video/v7-VArJbJTs/видео.html

@SarbarMultimedia I have watched many of your videos over the last week. I love how you keep digging into them . Although sometimes your concerns are not clear. But I get it you need more data before you can make that leep. I did subscribe so I can stay up to date. I just got an older co2 laser 50w that I have updated to 70w tube and power supply. But looks like the controller is very old so I need to learn RDWorks

@@josephlovell6951 Hi Joseph Always bear in mind that these videos are not rehearsed and that you are looking over my shoulder as I experiment and discover. This is a record of a learning journey and as such some sessions will be very much "follow your nose". It may take many sessions to arrrive at a sensible conclusion. It took me about 3 yeas to discover exactly how lenses managed to focus the beam to produce a deep parallel cut. There is no need to learn RDWorks if you are used to using Lightburn. Lightburn was created 7 or 8 years ago because a very capable software programmer who was also a laser hobbyist, became aware of the limited capability of RDWorks and it's very clunky interface. He set about reverse engineering RDWorks to create Lightburn. So with just a few exceptions, everything in Lightburn is in RDWorks but the usability and features of Lightburn are from a different planet.. Lightburn has now been developed into an industry standard package where it can be used with any type of laser or laser controller using Linux. OS or Windows. RDWorks is still Widows only.

@SarbarMultimedia thanks for the information I have a morn 3050. It has a RDL8082 B main board. That I can find any thing on it. So unless I can contact to it. Witch I have not tried at this time. Because I fear I won't have the driver's for it. So I will cross that bridge when I get there. I have parts on order to fix the cooling system. Just trying to get as much knowledge as I can for now. I'm hoping I can make it work and not have to spend 400 for a new contractor. Still think your work is brilliant. I bit surprised at some of the rezol

@@josephlovell6951 Hi Joseph I think your machine will be fitted with a RDC6442 controller see www.google.com/search?q=RDC6442&oq=RDC6442&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIGCAEQRRhB0gEINTEzNGowajeoAgCwAgA&sourceid=chrome&ie=UTF-8 If so then either Lightburn or RDWorks will be OK and there is no need to upgrade.

hi In the past three yearsI have learnt a lot more about the interaction of light waves with various materials and I now understand how this effect happens. In fact I recently reproduced the same bubble effect during experiments with a diode laser see ruclips.net/video/pvNKf2T-op4/видео.html from about 20 minutes The bubbles are random (ish) because there is a zone of light intensity either side of the focal point which is sufficient to ineract withthe few acrylic molecules that happen to be in the path of the photons

My apologies for late reply, I am currently on a vacation. However to get all the data (and more) you need to contact me privately so that I can send you what you requested. Please use this contact form forms.zohopublic.eu/ndeavorlimited/form/K40XtreeemLaserCutterContactRussSadler/formperma/k2Cn0QN5ChpazfTMAUw25lZ-FKpjZa96TQWHjv3ntOg Best wishes Russ

hi The simple answers are yess. all brands have this beam alignment issue but there are a few machines that have now tried to deal with this setting issue by making the head mounting bracket crudely adjustable in Z but the emphasis here is on crude.. However, one company did recognize the merit in all my modifications and the blue machine you see me using is a prototype machine that Cloudray designed , that is a copy of my original modified 300x500 machine.. My original machine did not have a programmable Z axis but this Cloudray version has a super smooth table mechanism. see this product www.cloudraylaser.com/collections/laser-cutting-machine/products/flash-sale-cloudray-cr-series-russ-oem-70w-co2-engraver-cutting-machine-with-working-area-20x12 This is exactly the machine you see me using. ;

I am not a chemist but from everthingi know and have experienced, acrylic is very analagous to H2O. At room temperature it is a clear solid just like ice. At 1C ice changes state to lquid water . At 160 C acrylic changes from solid to liquid acrylic. At 100C water boils off into micro liquid particles (steam). In the same way, liquid acrylic boils and evaporates as Methyl methacrylate, micro particles . Steam recondenses on a cold surface so does acrylic . If you blow it back onto the material surface with air assist the hot vapour will stick to the surface as it cools to a solid . Under the correct circumstances it is possible to cool the acrylic vapour before it hits the material surface and ithen just settles as a thin film of solid dust that can be wiped away with a dry cloth. I know that you can use acetone to dissolve acrylic but an not aware that any by-product of acrylic decomposition creates acetone. Quite the contrary. Acetone is used in the prodcution of acrylic (MMA) and is therefore most unlikely to return as a decomposition product.. Acrylic is basically a hydrocarbon and if you reheat the vapour to higher temperatures then it decomposes into combustable products. Great question Thanks

Hi Max and Min are equal because this is not normal constant power cutting. Enen though you still slow down forthe corners, the very short high power pulses do not cause burning because they are always instantly vapourising the card. Reducing acelleration to achieve staright cuts sounds like a mechanical issue. If you wish to contact me privately so that we can try to sort this with email and pictures/video then use the following form forms.zohopublic.eu/ndeavorlimited/form/K40XtreeemLaserCutterContactRussSadler/formperma/k2Cn0QN5ChpazfTMAUw25lZ-FKpjZa96TQWHjv3ntOg

Hi I understand your frustaration about RUclips videos. Everyone want's to share what they can do with their laser but nobody is taking the time to understand even the basics of what makes the technology tick. Having spent many years experimenting to self-educate myself on various types and wavelength lasers, I am a latecomer to 455nm lasers because they are low power, slow and have a very limited range of materials they can damage. They seemed very uninviting and I thought it would be simple to trasnsfer my other knowledge to this technology. However there are still some surprises that I did not expect as I dig deeper into how these devices actually work. Lense and laser beams are like a marriage made in hell. On the surface they seem to work ok but when you understand what is really happening, things are far from efficient. I am still a student exploring so I will let you catch up with the series to find out what I have discovered so far. Thanks for the interest

. Two problems with your thought. First you would have to flip the program and second how would you guarantee perfect alignment with the first cut.

I hope it works as well for you. Special problems require special solutions

Hi David No, I have several machines and only one HV PSU has ever failed. There is nothing in between working and not workin Unlike the tube. That is just like an ink cartridge it will work well with no loss of performance untill the ink has alsmost run out. In the case of a glass tube it is the CO2 gas that gets transformedover time to CO. You will notice the loss of power a week or two before it drops to zero output. The pink beam will no longer be a bright pink but the beam will still be there so people are puzzled as to why no power. It is the ionized nitrogen in the gas mix that glows pink but when it becomes contaminted with some of the oxygen stripped from the CO2 it becomes an almost white beam. A sure sign of a dead tube. A marginally bettter tube could be a sign of replacing a B grade tube with another (newer) B grade tube. Thereare many of f these tubes available and unless you know what you are looking at or buy from a reliable A grade tube source , it's a real lottery. A simple test that will tell you if your tube is a factory reject is demonstarted inthe his video You will need tome thick (say 10mm acrylic. If you do not have this but maybe have 3mm acrylic then cut 4 sqares 25mm and superglue them into a block A pointed trumpet shape is what you should see but a blunt bullet shape indictes something lass than ideal ruclips.net/video/naPzFsuvURU/видео.html

Hi You are learnong well about preionization. If you run the video again you will hear that the fox , which is a dithered image is being done at 18%. That power is towards the upper limit of preionization for this tube because at 20% it becomes a stable beam. Yes I did run faster to test the acceleration limitations..Althought the results appeared reasonable at the higher power there was a lack of crispness and as I pushed on to 1000mm/s the problem becacame very obvious. This was an experiment that sort of worked but didn't meet my normal standard for photo engraving. So please stick to the safe preionization zone for photo engraving. There is a follow up video that may interest your where I do a deep dive into the limiting factor of engravinbg with a glass tube...the HV power supply. see ruclips.net/video/Cgkze6gPI8M/видео.html Here you will see me doing super quality photo engraving at 18% but at 600mm/s. However, this is no longer guess work, I am exploiting certain properties of a specific HV power supply. Be suprised. You are also very observent re the closed loop feedback steppers on the Lightburn machine. No it cant loose steps but you can still drive it too fast and it complains. The only time you need the torque from the stepper is during acceleration to scanning speed. The faster your choose to run a scan the greater the torque required to get there quickly. As you rightly say, the torque drops off with speed, thus faster your scan speed the less toque is available as it aproaches that scan speed. Hence, as I push the scanning speeds higher, I have to back off the acceleration to prevent step loss. Its a balancing act . The aim is always to achieve the fastes overall run time and sometimes running at 600mm/s achieves a faster cycle time than running at 800mm/s. At 800mm/s the acceleration has to be backed off and that causes the overun at each end of the stroke to be longer. Thanks for the gear comments as this allows me to explains something interesting forothers

​@@SarbarMultimedia Thanks a lot for clearing it up for me. Thank for the link to the other video as well. It's really interesting to see the actual signals behavious on the screen. Just recently have I found the additional settings of cutting and scanning parameters under the "user" tab in RDworks. Up until then I had only set the paramerters for accel and speed under the "vendor settings", but I was not able to get good quality of intricate detailed cardboard cuts nor engraving. Under the Cut Parameters had to set Max Acc to 2000 and Min Acc to 100, back off Start Speed to 5 and Speed Factor to 20 in order to get acceptable results. Not perfect, but a lot better. For the Sweep Parameters had to reduce X and Y Starts Speed to 5 X Acc 4500 and Y Acc 2000, Line Shift Speed 10. Sadly, these parameters are nowhere near your insane accelerations.

@@DYEngineering Hi The vendor settings are just limits that the machine builder sets They are almost meaningless if you wish to experiment. For example you can set the vendor X acceleratoon to 100.000 and that is the max value that you can set in the USER settings. However long before you reach that limit your stepper motor will complain and maybe 40K or %)k is the max the machine will tolerate There are no specific dangers to setting the values high. Be adventurous However a word of warning. SAVE your Vendor and User settings as a file before you make any changes. Everytime you are happy with a change you have made, create a new set of files just incase you want to go back a step.

Hi Dwight . Thanks for the kind. thought. I'm still learning new things

Hi That is a good suggestion for those that relly want to fit a big compressor ( I already have such equipment) but the point of this videeo is to show that it is unecessary to use high flows and high pressure. I have done a furhter video on this subject that may interest you see ruclips.net/video/QwOkOLBp1pE/видео.html

@@SarbarMultimedia I will watch it for sure. Your tests confirmed my suspiction that air flow is important throughout all processes: cutting and engraving. The general theory wants air assint not necessary while engraving, even counterproductive. Your test with the lateral air blow shows exaclty the opposite. How about using both for engraving? a tiny blow from the nozzle and from the side to blow debris away?

Hi Welcome to the fascinating world of lasers. I deduce that because you are "waiting for a bed" that you have started with a diode laser.. I have spent many years "playing with" and self educating on how this technology actually work at 10640nm wavwelength and how fibre lasers work at 1064nm, I have recently stsrted a series investigating diode laser that operate at 455nm. You migh like to see my honest look at how diode lasers really work and how limited their capability really is (despite the flashy videos and adverts). see the first in the series . ruclips.net/video/wermWuSbK4w/видео.html Understanding the science behind what you are just about to embark upon will be very useful. There are no books on this stuff, just lots of armchair experts who spresd myths because they do not inderstand the underlying physics principples. Sadly these very early videos show my naivety when I look back, but to be fair they are a documented trail of my learning journey Best wishes for your new adventure.

@@SarbarMultimedia Thank you! I got this for free, so I'm happy with whatever it does, but I'm definitely trying to make sure I know what _not_ to do before I do anything. I guess I don't know what kind of laser it is, so that's something I'll need to check on right away. I'll definitely be checking out more of your channel!

Hi Jerry Lots has happened during the interevening 8 years since this video. The good news is that this tube is still running as good as new. However things have moved on a lot and I have bought several new tubes and know a lot more now that |I did then. It may be easier to contact me privately so that we can use email rather than an open forum to discuss your upgrade options The following fom will allow you to contact me forms.zohopublic.eu/ndeavorlimited/form/K40XtreeemLaserCutterContactRussSadler/formperma/k2Cn0QN5ChpazfTMAUw25lZ-FKpjZa96TQWHjv3ntOg Many thanks for the support and patience as I picked a zig zag path to understanding how this whole technology worked.

This is a very old vido and after 8 years I have no regrets. This particulat first machine is stilli n regular use. In fact I have 3 similar machines that I have modified to make them easier to use and set the beam. If you skip through the series you will see the evolution. Lots to learn about this technology if you are interested but perhaps, like most, you will only every use the 20% that gets you a result. Best wishes for yourn journey.

Hi Cloudray sells the adjustable YZbracket for top bering rail machines but the bracket only fits 15mm bearing blocks. Although I offered the lightweightbhead to Cloudray they were too slow in answering and demand was high so I had to make it myself.. Demand is steady from new people and old hands wanting to upgrade so I continue to manufacture batches, I have just restockeda nd the new price id now £45 inc normal postage If you wan to purchase, let me know if you are fitting to a 12mm bearing railmand I wll add an adaptor for free. The bracket is still available from Cloudray see ...........oops I have just looked and it appears they are no longer selling it.!!! I will have to check with them if this is just temporary . If not I will have to make a small batch myself.

Hi I can promise nothing but send me pictures of your machine and I will see whats possible. If you do not already have my email then contact me privately with this contact form forms.zohopublic.eu/ndeavorlimited/form/K40XtreeemLaserCutterContactRussSadler/formperma/k2Cn0QN5ChpazfTMAUw25lZ-FKpjZa96TQWHjv3ntOg

Hi Thanks for the thought. I have already been there and tested it. Yes, it works but there are better ways to achieve the same results. You may like to watch this video and specifically at 45:29. I hope I am not appearing to dismiss your comment because that fact two people can indepenently invent the wheel is just the way the world works and is a demonstration of how independant thought works. see ruclips.net/video/79VZjMdfBmI/видео.html

@@SarbarMultimedia No worries about dismissing 😊 I'll have a look at the video you mention, and I guess you've thought about a lot in this domain. I'm grateful you share your knowledge since I'm not going to do these deep investigations you do, but I'm interested.

Hi There was a time when new laser users started with a 40 watt CO2 laser but in the last few years diode lasers have swept new users up with slick advertising and the promise of doing so many things at a budget price and with almost zero knowledge. It is the limited knowledge requirement and the word LASER that captures newcomers imagination. As you have now found out, there are serious material limitations to working with light at 455nm wavelength. Thanks for jumping into my video but this is the wrong place for you to be. I have never been a big fan of diode lasers but just recently I decided that with so many people interested in the technology and so little REAL understanding available,I have decided to disect the technology in detail so that you can do more than fiddle with parameters and watch videos to see what others have achieved by blind experimentation.. If youunderstand the science behind the technology you are using you may be able to gain more form it and make sensible decisions about materials and parameters.. Can I suggest that you search for Diode Lasers...Under the Hood on you tube. Start at number 01 and work through with me. . From all my experience with CO2 and Fiber lasers I have a good backgound knowledge about laser technology, materials and lenses but I am a student when it comes to diodes but I have no interest in the trickery that people use to try to achieve results despite the materials saying "NO!!!". Your problem with clear acylic is typical of the sort of problem people encounter. Your solution is the sort of experimentation that many hav unsuccessfully tried because they fail to undersatnd the basic principles of damaging material with light. The first 3 sessions in my diode series expain the science in simple terms. This may not be scientifically perfect but it's the ideas that are important. Understanding that the laser beam is NOT a beam of heat but a beam of light that has no termperature is a difficult concept to accept when you clearly see that damage is caused by heat. Watch the seies so far and then please ask questions see the first video here ruclips.net/video/wermWuSbK4w/видео.html Good luck and welcome to your journey into the world of lasers.

@@SarbarMultimedia I see your point and agree to a large a extent. Though I'm not very experienced in laser cutting I'm not totally ignorant with technology. I've already seen that you have a d diode series but I have still to watch it all. My suggestion was simply an idea that I got when you explain how acrylic is actually "boiled" away, and that this could be utilised even on a diode laser, since some materials and settings produce a lot of heat - some "air jet" with that could possibly make some (probably not very pretty) rough cutting in clear acrylic, but experiments are off course needed, and failure is a very possible outcome 😁

Hi Keith It's a great question that is nearly impossible to answer without knowing more about your system. You may not have the flexibilty with your lens tube and lens holding system to overcome the problem. The simple principle is to have a large air gap below your nozzle, a large hole in your nozzle, very little air assist flow and a cutting speed that ensures you cut through cleanly with a single pass.. Cutting acrylic is always one of the most dangerous materials for cutting on a CO2 laser.please watch these two videos ruclips.net/video/n54uNRs8Ydk/видео.html and ruclips.net/video/eaz9ZEjwjfs/видео.html This is meant to be cautionary rather than terrifying. Just understand and respect the material. Any upwelling fumes are reheated by the incoming laser beam and can ignite so it is important to either blow them away with CROSSFLOW air or send them out of the bottom of the cut.. As the two videos show, out of sight is not necessarily 100% safe. Here is a short video I did for another guy to show how a big airgap can be used to reduce surface browing on plywood. The same principle applies for acrylic. ruclips.net/video/HwVw_TzyGrM/видео.html Please shout again if you need more help Best wishes Russ

Hi Tomas That sounds nice on a sunny day. However, this is my initial understanding of Max and Min. As my knowledge grew with time I was able to sort ot the real details of what was happening. please see this video ruclips.net/video/wJX8X40T4VM/видео.html