RDWorks Learning Lab 60 Lens Orientation
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- čas přidán 23. 04. 2016
- If you own a Chinese laser cutter this little series of videos about me learning how to use the free software provided, may solve the problem of trying to learn from a virtually unreadable manual.
I am nothing to do with RD Works, I am not an instructor and I am no expert. This series will document the essential bits of many hours of trial and error - Věda a technologie
I really like how instead of taking things for granted you actually figure out the right answer!
I would really like to thank you for putting out these videos, I ordered the same laser cutter you have and it will be here tomorrow. The feeling of relief I have from watching your videos is great. I just wanted to say how happy I am that there are people like you in this world that share their knowledge so freely. You sir are a great guy.
+Bob Walters
Hi Bob
I'm 80% retired with a the plan of keeping my hand in for some spare cash and to keep contact with a few non-demanding long-time clients. I have just stopped for a cup of coffee to answer your comment because my plan to expect the remaining 20% work to be evenly spread throughout the year has failed. I have got to complete about 15% in the next two weeks before I go on a planned break. It pays well but annoyingly has curtailed my "play time".
After my wife, there are two loves in my life (I hope she never finds out their names!!) but seriously, they are engineering and video. The opportunity to use my learning experience with this little Chinese dragon as a focus for hobby number two was too good to miss. So you get a chance to look over my shoulder as I struggle from problems to success via lots of mistakes. Hopefully you have seen where I went wrong and will avoid those problems and be up and running much quicker. I'm in this for FUN and not any sort of business so there's no pressure on me. Although there is a general progression to my learning I can easily be side tracked by something that I observe but don't understand or something that makes an interesting interlude. There are still lots of dark corners to this technology that need investigating and that's where the real pleasure comes from. I've only just started on 3D wood carving but that has already thrown up a whole handful of questions that need investigation. As you rightly observe, there's not much information and help out there for us learners because the seasoned pro's are keeping their hard won knowledge secret. If we all had that attitude we would still be living in caves! There are lots of videos out there showing the machine doing something but that's not interesting that's just showing off. Part of the fun I get from making these videos is the uncertainty of what I might find, I don't secretly experiment and then show you what I've found, it's generally all "as it happens" with the expletives edited out.
Thanks for your appreciation
Best regards
Russ
Russ, thanks, this is a great little test, I turned around my 2in lens, the beam is in focus for much longer, and the focal length shortened by 1.75mm.
otto
As always excellent informative content. Following with great admiration and respect of your works. Can you advise if there is a definitive size of key for setting the laser head from the work piece (focus) The one supplied with my machine ( same machine as shown in the videos ) is approx double the size you use. I need to understand if I'm maximising my focus.
Hi Russ,
I don't even own a laser cutter but thought I'd drop you a line stating just how much I have enjoyed your series of tutorials. Regards.
+Telchi Nua
Hi Telchi
Thanks for writing with kind words. You may think of these sessions as tutorials but they are not really . I am not a teacher and there is no structure to these sessions. They are a record of ME learning to use this little "Chinese Dragon" As you will have seen, I have had lots of problems, made lots of mistakes and ultimately had lots of successes. I have owned the machine for 10 months now and it's only about 2 months ago that I managed to extract the maximum performance from the poor tube that I had in the machine. I have now "house trained" my little dragon and am just beginning to find out what tricks it can perform. I have still got lots more learning to do , so perhaps with seeing me make mistakes and overcome problems, it will give you courage enough to buy your own machine and participate in the enjoyment.
Best regards
Russ
I agree, that all the published info I could find said the lens should be installed with the curved side up (away from the work), and my machine had the lens installed backwards as well from the factory. You don't need a special jig to remeasure your focal distance. Just a flat piece of cardstock or wood placed on a block to create a wedge shape. Move the laser beam down the wedge shape, and then use a vernier caliper to measure the distance from the table to the top of the wood or cardstock at the sharpest point. Subtract this from the distance from the table to the bottom of the laser tube. The result will be your focal distance which you can use to make a focus gauge block to quickly set up your work.
Over 40 years ago I built a CO2 thick film hybrid laser trimmer using a zinc selenide lens. It worked fine to start with, then mysteriously the trimmed resistors started drifting after trimming. Drove me nuts. Finally I noticed the lens had been turned over. My thought is that you need to consider that this is a diffraction limited system and that as you noticed, even at the focus, with an inverted lens, the cut wasn't as clean. In my case this resulted in a wider spot causing re-melting of the thick film and later heat stress relief cracking. So two thoughts; 1) the longer focal length of the wrong lens face is also theoretically going to lead to a larger focused spot; 2) Consider that the parallel laser beam entry angle and exit angle to the lens surface are about equal in the proper lens orientation, but zero on entry and 2x on exit for an inverted lens -- this will lead to a form of lens coma distortion.
good info on this lens orientation. my 100w laser is arriving next week and hopefully it work well😊. but vids are a great source of insights👍
Hi Russ, great video again, thanks for the credits, and yes you have pronounced my name just fine. I have not been able to spend time on the lenses since we have talked about it, due to being preoccupied with making my tube clamps. As you describe in your video, that's exactly what happen once I flipped the lens over to convex down my gauge put the head at the correct focal point and my paper cutting started coming out nice and clean. Now after watching your video I need to go back and cut new gauge for the correct lens position convex up and I should be all set. Also I got a set of all 1", 1.5", 2", 2.5", 3" and 4" lenses and will be testing your concept with all of them pretty soon. Thanks again for all the info you research you do for all of our benefit!!! Tad Bojanowski
Tad Bojanowski
Hi Tad
Unless you make a special nozzle I doubt you will be able to use the 1" lens, but all the others will be fine. I like using the 1.5 for paper cutting because at low power values you can get a really fine cut and produce really exquisite details.. Thats why I'm interested in the slightly wider usable focus range for the flat side down.
Thanks again for your input
Best regards
Russ
Hi Russ, Yes I'm planning on machining out a nozzle for that 1" lens probably out of some soft metal like copper or aluminum. If that goes well, I'll make more for the rest of the lenses. Otherwise I'll retrofit something to make it work only for that 1" and extend the air hose for the rest. I'm really interested in getting the full range out of this set. Tad Bojanowski
Hi Russ,
another fact i realized when i tried to work out 3D carvings ... i also mentionend that i have better results with the round side up but i did not realized that the focus length also changes ... i will test this myself again with 2" and 3" lens and will see what happens ...
Hello Again Russ. I haven't yet watched this video, but I intend to, as I've watched and studied all the rest of them. We've had our machine for a week now so that's been keeping me busy busy for sure. I wanted to ask you what focus lens you replaced into your machine. The one I have seems like it's already showing a scorch mark on it and I cleaned it gently with alcohol but not too hard as I was afraid of damaging it further, but it looks as if it is indeed scorched a bit. Should I rub harder, or will this damage it? Or, is it just a cheapie cheapie and I need to get another? Thanks again, my friend in England!!
+Christopher Miller
Hi Chris
These machines are normally supplied with a 2" focal length lens. I have a 1.5" lens and find this to be very powerful. I have experimented with others but but for most applications that's what I use. The orange zinc selenide material that the lens is made from is only about 70% transmissive to IR light. Not because it absorbs the light but because it reflects off the surface crystal structure. They put an anti reflective coating in the lens to improve this transmission. A cheapie coated lens will get you up to about 95%. There is a multi coating technique by a USA company that's a bit like the Coca Cola formula (very secret and protected). This is usually described as an HQ lens and has this coating which can improve transmission to about 99%. .
The important point I am making here is that you should be careful not to damage the coating. If alcohol and Qtips wont shift the "bloom" you could try something a bit more aggressive than alcohol, acetone would be OK. I would get another standby cheapie lens in place whilst you are learning about your machine but also think about an HQ lens for when you want to get the best from it. In the meantime, if you do damage the surface coating I would try fitting it damaged side to the work until you can get a replacement.
Hope this helps a bit
Best regards
Russ
Wow, well done!
Just brilliant!This is an invaluable resource that I see myself using as standard way for testing materials before cutting. You are sparking my creativity, I will probably modify the design and include several lines to test different levels of power and speed. I'm a bit concerned about the crispiness of cuts my yet to arrive machine will produce cutting paper. I opted for a 80W laser tube instead of 60W or even 40W knowing that I would sacrifice a bit of resolution due to the wider beam. After seen this video, I will use this to extract as much resolution as I can from my cuts.
+Abraham Saenz
Hi Abaham
The crispness should not vary with power as the beam will still be about 6mm diameter before it passes through the lens. The lens will shape your beam regardless of its power. What you may find is that more power is more difficult to control at lower powers. For example, lets assume the power characteristic is linear (which it will not be) the I have between about 10% and 65% ie 55 divisions to divide a 50watt tube into ie about 1% per watt power. Now if my tube was 100 watts then the same percentages will apply and I now have 1% power=2watts. You appear to have only half as much control....quite important at low powers for cutting paper BUT fear not because something I never used until my 60 watt tube was the 0.1% power selection. Yes, you can change those 55 divisions into 550 divisions to control the low powers.........something I ignored with a low power tube. You will barely need your tube whispering at about 12% for paper.
Best regards
Russ
+SarbarMultimedia Thanks, do you think I will benefit from using a 1.5" or even a 1" focus lens for cutting paper? I've seen some "high resolution" laser heads produced by thunder laser ( haven''t seen them avaliable anywhere else) www.thunderlaser.com/features/high-resolution-laser-head.html, since they are very shallow, I believe they are designed for 1" lenses. Have you researched on those?
+Abraham Saenz
I have looked in passing but I think I have the best of all worlds with my 1.5" lens flat side down. It gives a very fine cut with some depth tolerance. The 1" lens will have to be pinpoint accurate on depth to get a small advantage. The trick is to balance speed and power, but with paper, because I am using a pin bed support I also have to control my air assist to just a whisper otherwise it can push the paper out of focus. If you have a honeycomb table, every time you pass over a piece of metal you get a reflection and a small burn mark. With my flexible pin table I can set my pins to stay away from the cuts. I am currently working on a Christmas card design commission for my sister who belongs to a worldwide ladies organization called the Red Hatters. Go to my You Tube private messages and send me your email and I'll show you what I'm doing.
Best regards
Russ
i spend hours dealing with this. It turns out China send the lens "convex down" and yet sent a 20mm plastic gauge. It was never "right" well I flipped my lens and now the gauge is actually correct! Thanks for the great video!
It will be worth checking the focus point. Use a piece of mdf/ply/acrylic and set the max power button to about 25%. Set the speed button to about 200mm/s. Maker the piece of ply about 150mm long in X. Prop one end up with a 5 or 6mm spacer to make a ramp. . Move you nozzle to the middle of the ramp and set the distance with your 20mm setting piece. Move the head clear of the ramp by about 50mm. Now simultaneously press the arrow button and the pulse button to draw a line up the ramp.. Examine the line (look along it at eye level) to find the narrowest part of the line. That is your correct focus. I suspect that it will be towards the top of the slope because turning the lens the correct way decreases the focal length by at least 1 to 1.5mm. To make sure you have the focus on your slope you really need to see the line go thick, thin and back to thick.
Best wishes
Russ
@@SarbarMultimedia Hi Russ. Out of frustration on some unrelated matters, I decided to flip my 2" lens to have the curved side down. To my delight, the edges on my plywood cutting were much straighter. Apparently there's less of a beam shape change from "in focus" to "out of focus." However, the kerf and spot sizes are a bit larger.
@@1888scanvan
Hi te#here is no right and wrong way for a plano convex lense it works both ways but in general you get deeper or faster cutting flat side down and more precise engraving flat side up. On a 2" lens the focal distance changes by about 2mm. It will match the gauge the Chinese sent with the machine if you use it flat side up. It's really whatever works best for you.
Best wishes
Russ.
my table is 1300x2500mm and it is completely twisted. i cannot cut one big piece without ruin it.
i have the live focus system, that suppose to correct the focus automatically while cutting.
unfortunately i am using in manual mode because it is completely not regulated. no manuals and the settings menu is blocked by a password.
do you know something about the "live focus" system? it has a inductive sensor to see the metal... glad if you can help
Hi Ricardo
Out of interest I already have this document downloaded because I was interested.
en.rd-acs.com/Private/Files/8f6cb094a457cb7b.pdf
I'm sorry but I do not have any knowledge or experience of the bigger Chinese machines.
You may wish to join the "Fellow Chinese Laser Machine Sufferers" forum at www.rdworklab.com. There maybe other there with a similar machine who may be of assistance.
Best wishes
Russ
Could I get a copy of your file to test my k40. Thank you
Sweet. I know this is an old video, but I just got my 700x500 laser last week and after cleaning everything (amazing how dirty a "new" laser is) I discovered that the convex side is facing down and was questioning this myself as I thought it should be facing up. A Camera lens has the convex side facing away from the film, so shouldn't it be the same with the laser? Looks like you answered that question.
Hi
Flat side down makes logical sense but as my experiments are showing (and I still have a lot to complete) Flat side down with more spherical aberration (less focus) ahd reduces the focal length by 1 or 2 mm and gives better cutting result Flat side up gives a sharper focus that is closer to the claimed lens focal length. This is better for some types of engraving but is less efficient for cutting. That is why most people claim that flat side down is the correct way to have your lens. So surprisingly the lens works both ways but you need to understand which orientation will best suit your job.
Best wishes
Russ
@@SarbarMultimedia For the most part I will be cutting Balsa and lite ply, so knowing this is a huge benefit. Thank you.
Hello, Thank-you for this nice video. Is it possible to find or receive the plan of the ramp ?
Hi Daniel
You can either send me your email address via the you Tube private messaging system and I get a copy off to you or you can join a recently formed forum specifically for Chinese Laser Machine Sufferers It's at www.rdworkslab.com. To make sure you are not a computer you have to answer a simple question. The answer is russ. All my published DXF files are there for free download along with a detailed index of all my videos.
Best wishes
Russ
Thank-you very much. :-)
Does anyone have the link for this file?
Hi
You will find all my files posted at www.rdworkslab.com. If you have any problems add your email to another comment in disguised form (timatgooglemaildotcom forexample) and I will send you the file and then delete your comment.
Best wishes
Russ
Anyone still have a copy of the file he uses here?
Hi
It is available to download at the www.rdworkslab.com forum or you can add your disguised email (johndotsmithatgmaildotcom) to another comment and I will send you the dxf file.
Best wishes
Russ
i saw a bosslaser alignment and the technician when he was setting up the lens, he specifically said the flat side facing down to the material.
Hi Cary
Flat side down is recognized as the "better" way to run a lens. So Boss Laser are working to that convention. The designed orientation for the lens is flat side up and that is how my machine (and most machines) was shipped out of China. The setting piece supplied with the machine will be wrong if you turn your lens to flat down because flat side down gives a shorter focal length. However, I run my lens flat side down but with the corrected setting piece and it works well for me.
Best regards
Russ
+SarbarMultimedia will check my lens tomorrow. the spacer that came with the cutter is a 8mm thick acrylic piece. the FL of the 20mm lens is 50.8mm. i was thinking if that is wrong but then i finally realised that i am suppose to measure 50.8mm from the lens and not from thr tip of the laser head. so based on their spacer, the distance of the face of the lens to the tip is 42.8mm. will double check that on my laser tomorrow😊
Hi Cary
There are only going to be 3 possible FL lenses we can use . 1.5" (38mm) 2" (51mm) or 2.5" (63mm). If you poke a Qtip or drinking straw up inside you nozzle (it must be soft so that you don't scratch the lens) and mark where it appears out of the nozzle, add the Width of your setting piece to that dimension, it should be pretty close to one of the 3 standard lenses.
Best regards
Russ
+SarbarMultimedia thanks for the tip. will do that to check. just wondering on the air assist, how strong is it suppose to be or it just a soft moving air just to prevent smoke from going into the tube?
Hi Cary
Air assist is always important to ensure there is flow out of the nozzle, even a whisper, because that keeps your lens clean by preventing fume ingress. For acrylic it needs to be gentle because too much airflow cools the cut and r educes cutting ability. I have done several test that prove this. However for cutting any wood products or leather you need to get as much air as possible right into the cut grove to keep the cut face clear of smoke and fumes. Smoke and fumes absorb the IR radiation and decreases the cutting effectiveness
For engraving of any sort it is less critical because there is w adie open expanse on the surface and smoke will be blown off quickly. The standar 2" lens fitted to most of these machines is not the best fro cutting unless you have a 60 watt plus laser. Not only is the lens energy density almost 50% down on a 1.5" lens but the distance you have to be from the work surface (usually about 20mm means pathetic air flow into your cut groove) The 2" lens is basically a general purpose engraving lens. With thick materials I can set my nozzle about 2mm above the work so there is no problem with good air flow into the cut.
Best regards
Russ
i just bought one chinese machine with doule heads (260w and 80w) .
Hi Russ, would you please send me the dxf file you use in this video for your ramp test? You should have my email already. Much appreciated. Merry Christmas.
Hi Russ,
This is a good tutorial stating how to clean the lense and which direction to fit the lense.
www.eurolaser.com/customer-service/faq/cleaning-the-focal-lens/
Hi Russ Falk here again. Can you please send me the dxf file for the ramp please. You got my email lasertony......... Thank you so much for your help!
thanks for sharing. giotmucdden at yahoo
thanks again.
+Trực Chính
Hello
Was that a request for the dxf file or just a nice comment?
Many thanks
Russ
+SarbarMultimedia Hi Russ. First thanks for the great tutorials! Can I ask a question. I bought one of these "beasts", but for now it can't make a straight circle ... maybe some problem with the axes... Did you encountered such a problem in the beginning?
All the best!
Dimitri
+Dimitri Dimov
Hi Dimitri
The simple answer is no, I have never had this [problem......but have had other people speaking to me about it. The problem with this open forum is that you cannot include pictures. I might be able to pass on other peoples experience and solutions but to do that you will need to send me you email via the CZcams private messaging system and we can chat off line.
Best regards
Russ
SarbarMultimedia Thanks Russ, here is one: dimov.dimitar(at)yahoo.fr