Diode Laser Special

[@p3d938]

Great lecture again, thank you Russ. High speeds and weight needs beefy motors, drivers and solid frame. Carthesian frame is for low speeds. CoreXY frame is working for many in 3D printing at higher speeds, the 2 motors work together. For tossing around a kilo at high speed you will not get away with a the common used Nema23 (24V, 2A) and 10-15mm belt on carthesian machines. That is 50 Watts at 20RPM but will be half at 400RPM. Nema 34, 6A+, 48V might do the job, now you have 150W+ at 400 RPM. The motors, drivers and PSU are not so expensive. A solid frame with 25mm quality belt is.

[@SarbarMultimedia]

Thanks for the great imformation. My current NEMA 23 motors, running with 24vdc, are capable enough for my present needs. If I start running faster as I discover more about the beam intensity profile, I may be running at 600 to 800 mm/s. I am sure the motor will do that but I will certainly have to back off the acceleration and accept bigger overtravels, Depending on how much of a compromise that becomes, I will decide if I need to upgrade motors and drivers. This is not a production machine so I have no cycle time pressures, just finished quality for my own satisfction. As you say, drivers and motors are not that expensive but chucking 1kg around at higher accelerations may require a stiiffer bearing and mounting system which could become a significant machine rework.. The good news is that the rigid frame I have at present is way better than any existing diode machine and is more than adequate for me to pursue my goal of decoding the minutiae of diode technology.. I am sure there are mant entusiats that would love to turbo charge their machines so both your warnings and advice may cause then to think carefully.

[@turboflush]

Another great video. My big thing with the diode desktop laser.. was the deceptive sales info. For any production work.. you need to add a lot of extras and have a dedicated spot. And the worst... was the danger it presents, from the exposed light that you can accidentaly look into or it could bounce off something. And then there are the fumes. I was running mine all day and i am sure 3nded up poisoned by the fumes. I had to shut down and go outside to fresh air and exhaust out the room the machine was in. After that... i went in search for a enclosed laser. I had plans on enclosing the machine and adding extraction and all this stuff. But a basic co2 machine comes with all that already. Boxed diode machines are for the weekend hobby guy that wants to make one item that day. Dont risk your health or life if you plan in running a laser at anything more than hobby. The co2 is way quicker also. Way!!!

[@SarbarMultimedia]

Your comments are so true and well described from a man who has experienced the "selling a dream" marketing tactics of diode lasers. There was a time when the little K40 desktop CO2 laser was the entry level into laser technology but cooling water, beam alignment, understanding lenses etc etc was not an easy dream to sell. Diode technology was a golden opportunity to dress up a pig and sell it as something else. I love the wide ranging material capability and cutting power of a CO2 laser but the response speed of a PWM controlled beam has tremenous promise. I have explored the PWM potential of CO2 RF technology that the "big boys" claim ot be the ultimate laser tool and its not the dream they sell either. Flying optics is their big barrier and messing with the raw beam via a beam expander destroys the intensity profile which in turn reduces the cutting capability. Diode technology has many great technical advantages but it comes with the penalty of VERY poor matarial damage capability because most materials are less than 10% absoptive of the 455nm energy. The tecchnology can only be made to work by using carbon as an energy absorber ( heat transfer mechanism). Despite these serious limitations, if I can decode the subtle details of diode technology, I really see potential for integrating it into one of my CO2 machines to fill in for those tasks that the slow response CO2 beam struggles with. Most people with diode lasers fear the blue light emitted during cutting or engraving. because they believe it to be the laser beam "coming to get them", even though they intuitively know that light travels in straight lines and that the laser light is doing just that as it points downwards to the work. As it hits the work it transferes it's energy to the material and then various chemical and physics effects happen to create a plasma that gives off random (non-laser) light. The only danger from that light is it's intensity. It is as dangerous as looking at the sun or at a welding arc ie you dont.....without dark sunglasses to attenuate the light INTENSITY. Constant inhalation of fumes or micro particles of any sort is bad for your long term health. Most bodyies are very capable of dealing with short term temporay exposure unless the fumes really are toxic. So, yes, these open frame machines can be dangerous in the hands of naive users who experiment unknowingly with "no-go" materials. That is not mentioned in the dream they sell. Thanks for sharing your wide ranging experiences.

[@patprop74]

The same headaches were and still are encountered when open source 3d printing began, At one point there was a lot of experimenting with a using spools and pulleys with heavy duty fishing line filament to replace the timing belts, but like everything, solving one problem often creates two new problems lol and eventually one has to come to the conclusion of cost factors over well enough, after all, hobby grade tools like laser engravers and 3d printers needs to be affordable.

[@krisknowlton5935]

People in the 3D printing industry have been fighting this problem for years. I have noticed the ringing in the pattern on the print has the same width as the tooth space on the belt.

[@SarbarMultimedia]

If the pattern is that obvious then turning the belt over as I have done to create a flexible rack and pinion system will likely solve the problem see this video from 45:00 kzbin.info/www/bejne/bJKxqH6eibehmpo You may have already watched it. A wider belt will also help reduce the issue . I know that most 3D printers run with 2mm picth 6mm wide "elastic bands"

[@krisknowlton5935]

@SarbarMultimedia of course, I have watched it. I watch all your videos. You teach people (whether you know it or not) how to look at problems from an entirely different perspective. I can always glean some good information from your videos.

[@ramhornnn]

I will also add how I solved the problem of these permanent stripes. Often there are not high-quality stepper motors (nema17) and they jam during operation. This can be noticed simply by turning the shaft of the disconnected motor with your fingers. If there is uneven rotation, then you can loosen the fastenings of the rear engine cover and gently tap the sides with a hammer until the jamming due to the misalignment is smoothed out. Then tighten the bolts. Sometimes engine jamming greatly increases the problem of structural backlash and people look for the cause in belts, pulleys, grounding, but after changing everything to a new one, the problem does not go away because engine jamming slows down the movement of the laser in certain places. But even if everything is fine, the bigger problem is the short operating time of the laser diode at constant power (after 1.5 hours of continuous engraving, due to the limitation of the diode driver in temperature, the power decreases and the lines become lighter than the previous ones). I am currently assembling a ceramic tile engraving machine from scratch using a laser diode. But now I have a question - is it worth using a diode for this purpose? The main task is to quickly engrave photos using Tio2. On a 5 watt diode, I achieved a good result (254 0.1) at a speed of 40mm/second of 80% power. On such parameters, engraving 20x30 cm takes more than 3 hours. Please tell me if it will be better and faster to engrave if I put a 40w CO2 tube and a short-focus lens.

[@daleshelley4887]

Very Interesting Russ so much detail & understanding ;-)Also supposed to be on retirement lol I enjoyed your Video's

[@JaakkoF]

Great analytical work and explanations, very much appreciated! Stiffness is easy to achieve with design changes, but power vs. velocity problem when it is accelerating is a different problem to conquer. Wondering if the control software/firmware could be modified so that it would modulate thhe power based on actual velocity?

[@SarbarMultimedia]

Hi The Ruida digital controller I am using was designed for both analog control of glass CO2 sources and PWM controlled RF CO2 sources and it has power modulation with velocity BUT that is for programmed velocity, not machine induced unpredictable velocity changes as produced by teeth engaging with the toothed belt or head "ringing". The Lightburn software has this power/velocity function but few diode users understand how it works . It's main function is to vary power per pixel but only when using the grayscale engraving function. For cutting it varies power into sharp corners as I demonstrate in this video kzbin.info/www/bejne/rXu7aYtqZblnjK8 For cutting with a diode beam it is not particularly useful but when you are drawing lines by cutting at higher speeds, sharp corners can get thick and dark. Careful use of the min power can fix this.

[@wadhamga]

Thank you for the clarity and understandings. My question is if the evidence from the x axis tests is able to show the issues in a new light what happens when the y axis is then tested and the two belts and different weights due to direction change are assessed? Is there a related effect which could be same effect with a different ratio? I saw elsewhere comments that people do their engraving on the y axis for the bidirectional passes and they get better image outcomes with photo images, they didn’t say much about speed but I think from memory they were slower than most people use. My tests for best photo image engraving has been at 60 mm/sec speed and power is dependent on materials such as painted MDF versus not painted or using baking soda and also using other timber’s. I generally x axis and if timber across the grain.

[@SarbarMultimedia]

LIghtburn is an amazing piece of multipurpose software that started as being just for CO2 lasers. Those machines never used any diagonal or angled X axis movements for scanning. The angular and cross hatch functions were added for galvo head fibre lasers that do not have the encumberance of different masses for different axes. The diode laser was the last addition to the package and thus new users of Lghtburn have assumed that all the functions available were good for their machines. In the same way, the matrix material test tool was designed for fibre machines and never intended for CO2 or diode use However, it's there so people use it. In reality unless you understand what the parameters you select are really doing, it gives VERY misleading results both for engraving and cutting, Although I have tackled this material test subject before in my series, (Laser Diodes ...Under the Hood), now that I have moved to my final 40 watt upgrade, I will be looking at these subjects afresh. I will never try to run my X axis at an angle because it greatly compromises the speed AND as I dmonstrate in this video, a singlre axixs stepper motor can induce resonance at low speeds thus usingt two steppers at slow speeds to create a diagonal scan seems to be inviting problems in two axes. Photo engraving is a specialized subject that requires a lot of understanding. For example if you dither a image and zoom in on the result you will find the dots are not random but coded in horizontal lines. If you start scanning diagonally across that pattern the "burnt" output will not replicate the original dithereing but will create some other weird (but probably acceptable) pattern. Again, photo engraving with Lightburn is a subject I will be dealing with when I have fully understood the capabilities of my 40 watt beam. At present the burnt dots I can make would only allow me to reproduce 127ppi images. I am hoping for at least 254ppi. With the right lens and materials I have ahieved a 508ppi image with my CO2 machine See this short video done at 200mm/s kzbin.info/www/bejne/iofKnqKEZtyfoNU Thanks for the comment

[@marouaneladjel1907]

My sincere regards, Mr. Ross. I just want to know if this type of laser can carve rubber material for making seals. Thank you for all your interesting and accurate videos. I am sure it is the greatest channel.

[@SarbarMultimedia]

Hi That's a great question. Most laser friendly rubbers are slicon based and grey in colour. They contain huge amounts of filler powder (usually talc) that is not going to be affected by the laser. This causes a problem because when you get much deeper than about 2mm, the powder falls in the way of the laser beam and prevents futher cutting The same applies to black EPDM rubber which is filled with carbon black. Yes, it can be engraved with a diode laser as well as the usual CO2 laser. Here is a video that you may find very interesting kzbin.info/www/bejne/oH6rYoSulJuqn6s

[@marouaneladjel1907]

@@SarbarMultimedia thank you mr. ross

[@skysurferuk]

Useful, thanks. 👍

[@cncdavenz]

Thanks 😁