RDWorks Learning Lab 26 A 10mm Acrylic project
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- čas přidán 8. 11. 2015
- 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
this is a great example of what can be done when you understand all of the variables of the machine. 10mm is pretty darn good! It's also funny that when you own a laser cutter, every task becomes a laser project.
+2020tesla
Creating 3D objects from 2D pieces has become a natural part of my design thinking. It was the cheapest and quickest way to create complex metal structures when I had 2 industrial lasers. Working with 2D CAD to design and then testing that everything fitted by building it in Solidworks was an extremely rapid way to get my commissions done rapidly and "right first time"
Really great work! Thanks a lot for all of your videos. I bought the same laser and and your videos made it much easyer for me to start. You saved me a lot of try and error...
Keep it up!
+Dominik
Hi Dominik
Its always good to know that others have benefited from my mistakes. My pleasure has been in making the videos as much as learning about the machine. If you have got as far as session 26 and done some practice along the way, you are "ready to fly the nest" Good luck with your own projects and discoveries.
+SarbarMultimedia Yes I watch every of your videos... Thanks!
I found that if you select each of the inside parts and group, it does help with the Cut Property ordering. A group becomes one element then you can select the bigger parts one by one or group them first and order fewer elements.
Excellent work! I 'm waiting for one of these days my co2 laser breaks (ebay 40w - 400 €) to buy the same as yours. I subscribed to your channel a few weeks ago and now everyday I take a look to see if you have uploaded a new video.
Thank you very much for the detailed and well explained videos.
Greetings from Spain.
Marco.
+marcocp91
Hi Marco
Thanks for your kind words. Glad you have been entertained by my discoveries and mistakes. I'm enjoying the whole experience.
What power do you have on chinese laser? power tube?
Where did you set your focus height for the 10mm stuff on top or middle of material
+Xairflyer
When I cut 15mm acrylic I set it about 2mm into the material. For 8 ad 10mm thick acrylic and ply I set it about 1mm in.
I can't work this out, when I go to cut out properties and set it up, it won't show on the preview or when I load it to the machine, how do you get it to save and refresh the changed order, now it thinks it has changed because when i go back to cutting order it still shows the changes I have made.
+Mentorcase
Hi
Very frustrating isn't it. I spent some time wresting with this problem and all is explained in session 20. Is your path optimise box still ticked?
SarbarMultimedia
Yes I just discovered the path optimized tick was tuck, lol and sorted it, thanks for the help anyway. Those 10mm acrylic cuts looked pretty nice.
Hello Russ, Your videos are very very helpful. Thank you. Can you please assist me with how to break a line in between the dots? Thank you.
Hi Heather
I never use the drawing tools in RDWorks because it's not a real drawing program, just a mix of tools for crude work and creating test programs. I do all my work in a CAD program. However there is another learning source that will answer your question
see
czcams.com/video/w3TI5A6Dxb0/video.html
All best wishes
Russ
Beautiful work as always. I'm curious, you mentioned 2 speed / 65 power was what you were able to successfully cut 10mm acrylic with? I performed your power test (which was helpful to realize that running at 80 vs say 68% power was not providing any added benefit. Now, I'm trying to figure out the pulse per minutes and other variables that actually help you achieve those cutting capabilities. Your wife needs to know she's lucky to have you. :)
+NFO Sec
Hi
Your stepper motor concern (which appears to have got lost in the postings) can easily be addressed if you plug your rotary axis into the Y socket before you power up (leave the rotary axis out of the machine). That way the machine will be happy because it can perform a head reset cycle and any programmed movement in Y will just make you rotary work but not affect machine coordinates.
Pulses per minute? I am just using the machine "as is". I think you may be able to adjust the pulse frequency of the laser tube but that's not an area I have explored.
Excellent as always! Looks like you are further along with your laser cut Christmas gifts than I am!
Regarding the tapered ends, this is my most recent problem. I've checked everything I can think of. I thought that the laser was focused but not exactly at the center of the lens and as a result was shining down at a slight angle. If that makes sense.. It turns out that that was not the case. I have spent hours trying to tackle this one with no luck yet.
It must be some sort of sorcery!
+CenterFireJewelry I have done some investigation already . Like you I mused on the fact that a laser beam offset to the lens centre will go off at a slight angle whereas if it is on centre but not perfectly perpendicular to the top lens face, it has little effect. Also the distance between the lens and the nozzle is sufficiently large that I was sure it would be impossible to generate the angular error I was seeing. Having identified the error as a back/front face problem, I put a square on my work table and found the nozzle (whole head) was tipped towards the back of the machine by 2 or 3 degrees and accounted for most of the problem. I even tried over compensating by a degree of two but in fixing that and trying to get the beam realigned I encountered another issue. All the ajdusters on the second mirror(on the end of the X slide) were almost seized. I managed to eventally get the screws loose and extracted and was able to grease them up. But when all the adjusters were out I found that the spring loaded "pull-back" screws were binding in their holes and preventing any real floating adjustment. Cans of worms inside cans of worms!! I have now opened up those "float" holes from about 5,2mm to 6mm and the whole assembly almost works like it should. Although I have put it back and struggled for a bit to get realignment I have got it reasonable close. Good enough to do my latest mode burn video. I have got to finish my Xmas cards tomorrow (all low power stuff) and then I will start a complete realignment exercise (on video of course ---problems, struggles and successes).
+SarbarMultimedia I look forward to watching that. I've tried to determine whether or not my machines head is off a bit but haven't had much luck. Instead of trying to reinvent the wheel I will gladly learn from your new exercise. Thanks as always!
After all this time I have discovered and fixed my off-angle cutting .See session 31 part 4 .
Happy Christmas!!
Russ
Hi!
Many thanks for your videos from which I learn a lot!
I'm trying to make use of a brand new chinese 80W lasercutting machine but I have an issue I'm not sure you addressed before (or later - from now, there is a large amount of videos to watch ;) ): the edges of my cut pieces are melted at the top.
Have you an idea of what is causing this? I supposed it was the power that is too high for a too slow speed, but with a lower power or a fester speed, the laser don't cut through.
I was wondering if a two-three-pass cut would do the job with a lower power but you shown in this video how it is a bad idea due to poor quality results... :(
Best regards and thanks again for your videos!
Hi Anoril
There is a basic golden rule for cutting all materials. 1 pass as fast as possible and with maximum air assist.. However, acrylic is the exception. Let me explain
With all organic materials (wood, card, ,mdf, leather etc) the cutting action is BURNING. That burning produces smoke which in itself still contains flammable materials. The other thing about smoke is that it is very absorbent of our IR beam of light. When the invisible IR light hits the smoke it gets absorbed and turns into heat which can ignite the smoke and produce charring in the cut AND because the smoke has absorbed a lot of energy , there is less power to BURN the organic material you are trying to cut. That is why it is essential to always have a THROUGH cut. If your air assist is efficient then it will penetrate into the cut and keep the smoke moving out of the BOTTOM of the cut and away from the cutting face. If you do not have a through cut the smoke runs along your cut channel and usually burns there causing charring of the edges.
With acrylic it is quite different. When your beam of light hits solid acrylic the energy is 100% absorbed and immediately turns to heat.. The heat evaporates the acrylic rather than causing it to burn. The vapour expands rapidly away from your cut area and also the vapour is less absorbent than smoke. It will ignite if allowed to build up and will also do the same as steam, condense back onto colder surfaces. One strange property of acrylic is demonstrated in learning lab #120 . The inside of your cut guides the light beam deeper than you can get with a burn, because of internal light reflection. It is essential with acrylic to again set power high and run just fast enough to get a through cut. Again the through cut allows the vapour out of the bottom of the cut where it will not condense on your work.. Now comes the problem. You need JUST enough air to keep the vapour moving out of the cut zone but not too much air or you will COOL the cut area and decrease its efficiency and also prevent the flame polishing of the edge that you can get when that balance of power and airflow are just right. Generally you need only a whisper of air assist to cut and even less for engraving.
The melting at the top of the cut and insufficient cut depth makes me believe you have your focus set incorrectly. Set your max power button to 15% and with a piece of thin card (like a cereal packet) try to find the distance between nozzle and card that produces the smallest spot when you just blip the pulse button. That is your focus distance that should generally be set onto the surface of your material. I suspect you will have been supplied with a 2" focal length lens. There are so many other possible reasons for your problem, such as loss of power because your beam is badly aligned or your beam is clipping the side of the nozzle hole. There is a lot to learn and understand.
I sadly suspect that your new machine is not what it purports to be unless you bought it direct from a Chinese manufacturer. If it was an Ebay or Amazon Marketplace machine it will probably be a 60 watt tube and a not very good quality tube either. Is the tuube perchance marked K H Laser?
All best wishes
Russ
SarbarMultimedia, many thanks for all this detailed explanations. I'll check all this, starting from the focus distance I've been told but I did not check by myself. Then the laser tube, then the mirrors aligments and so on, as you depicted in several videos! And yes, I watched various random videos of yours, including #120 which had a promising title ;)
Thanks again! I come back to tell if I managed to solve the issue!
Regards
We started to check for focus point and mirror alignments. The tube is actually a KHLaser, yep. A good point? :)
Maybe no. The Kehui factory manufacture machines but because they only sell to Ebay buyers via PRIVATE ebay sellers and there is no chain of responsibility back to them, they operate in some very unscrupulous ways. Thjey do not manufacture their own tubes despite the impression given by the KH Laser label. Instead, they trawl the major Chinese tube manufacturers for their reject tubes. They then retest the tubes to sort out those that work "in some way", enough to fool the naive Ebay buyer , put their own label over the original label and fit them to their machines. These machines are then shipped in bulk to warehouses around the world from where they are sold by private Ebay sellers for commission. Claimed 50 watt tubes are really 40 watts (800mm long) and 60 watt tubes are usually 50 watt tubes (1000mm long) and are not far off junk . They may last days or weeks and perform very poorly.
At 80 and 100 watts (actually 60 and 80watts respectively) you are likely to have a re purposed EFR tube. These tend to be at the other end of the spectrum and only have minor performance issues. I know of one such tube that is now 14 months old and still working well. But it does mean you must always be a bit suspicious about your tube. Why did EFR deem it unfit for sale with their name on it?
Best wishes
Russ
Hello Mr. Thank you for this wonderful effort, in which good benefit I have a question how it is used laser capability in boxing it possible to use any ability or is it specified
Hello Mohamad
There are no standard settings that apply to all machines because there are so many variables. How good are your mirrors? What focal length is your lens? how much air assist do you have? You may like to look at
czcams.com/video/m-buYn27MgU/video.html
Please ask more if this does not answer your question
Best regards
Russ
SarbarMultimedia
Video, attached with the answer in which good scientific accounts, but the problem is I am my Arabic and the languages of English is weak anyway, thank you very much for this information
مرحبا محمد
لا ينبغي أن يكون اللغة حاجزا حقيقيا لأن لدينا الترجمة جوجل لمساعدتنا. يجعل اخطاء ساذجة لكن يمكنك أن تشعر النقاش وطرح الأسئلة مريحة في laguage الخاصة بك
أطيب الأماني
روس
marhabaan muhammad
la ynbghy 'an yakun alllughat hajizanaan haqiqiaan li'ann ladayna alttarjimat jwjl limusaeadatina. yajeal 'akhta' sadhijat lkn yumkinuk 'an tasheur alnniqash watarh al'asyilat marihatan fi laguage alkhassat bik
'utib al'amani
rus
To learn how thrilled when I find a person carrying this beautiful spirit that interact to help those who help him ask the oldest beautiful greetings
Awesome
great video! but forget the laser tech for a moment... did she like it?
Hi
Yes and nearly 5 years later it is still in daily use. When I occasionally film in our kitchen you may spot it in the background
Best wishes
Russ
Russ
You mentioned that you get a jagged edge when you do the cut's twice.
I'm noticing a strange thing on my cuts but only in the Y axis.
The cut is ridged, with the ridges being about 0.3mm apart, and about 0.1 to 0.2 mm deep (its hard to determine the depth).
It appears that I'm not the only one with this problem, and some people experience it in both X and Y, but for me with acrylic and MDF I'm only seeing it in the Y axis. (i.e if I cut 20mm test squares they are smooth on 2 sides and rough on 2 sides)
Also, if I turn the power right down and try to cut card, I get a similar effect, except I get perforations, i.e a series of dots rather than a continuous cut.
I suspect the problem is in the mechanics of the machine and perhaps I'm getting vibration in the movement, and this is more in one axis than the other.
I intend to do some more tests to see if the ridges get further apart if I speed up the cut, and I may swap over the motor controllers between X and Y to rule out them from the equation.
I may also reduce the tension in the Y axis belt and see is this makes any difference.
But apart from that, I'm at a loss to what may be causing this problem, as I don't think its the laser tube or the power supply, it would not just occur in Y and not X.
+Roger Clark
Hi Roger
You may be ignoring the elephant.
Air assist.
This little puny jet does two things. Most importantly (in my opinion) its keeps a positive pressure in your nozzle and prevents fumes fogging up your lens. It's other function is to keep the fumes moving from the cut zone. Whether its smoke from burning wood/ mdf or the vaporised acrylic, if these fumes are not purged from the cut they will absorb the 10.6 micron energy very quickly and reduce your cutting efficiency. I have the luxury of a pressure regulator fitted to my little pump so that I can control flow down to a whisper. (which I do when cutting thin paper or card). The dynamis of what's going on in that cut zone is very complex. I did point out in this video about the way in which the bottom of the cut was a long way behind the top of the cut. I have not fiddled because it's not an area that I feel comfortable with but I believe you can change the operating frequency of the laser. I'm not sure that's the issue I would still focus back on air flow.. If you do some etching on MDF you will soon notice that the smoky residue settles back adjacent to your burn zone. Now you would think that scanning would drag the air flow behind the nozzle and and leave a predictable debris trail Does it? Unless your beam is dead central to your nozzle there will always be a biased air flow into your cut
Experiment a bit with this. Maybe purposely move you beam off lens centre to check difference.
Regards
Russ
+SarbarMultimedia
Hi Russ
Air assist is definitely something I need to investigate
As my lens is 51 mm the distance from the nozzle to the cut is almost 20mm, which means that the air pressure from the aquarium pump is a lot less strong at the cut than it would be with the shorter focal distance on your machine, i.e mine appears to be around 15mm further from the cut than yours is.
I do have a 2HP compressor but when I went to use it the other day I realised that the regulator had packed up.
So I will need to buy a new regulator (one that also has a moisture trap would be good), but I've not had time to work out the pipe fittings on my compressor so that I can get a regulator to match.
What's strange is that these ridges are much more apparent in the Y axis than they are in the X axis.
I did some more tests and if I change the speed from 10mm to 5mm the grooves are closer together and less defined. I estimate that the grooves are half the distance apart when I half the speed.
I also tried messing with the belt tension in the Y axis but it doesn't make any difference.
Re: Laser pulse modulation frequency.
I initially considered this as a possibility, but the figures listed in RDWorks are around 20kHz, which is far higher than would cause the sort of ridges I'm seeing.
i.e the modulation frequency would need to be something like 6Hz to account for what I'm seeing.
+Roger Clark
Hi Roger
Yes I have a 38mm lens and focus set is about 6mm below the nozzle, so your distance to the cut is much longer. I wouldn't hook your compressor up you will soon kill it (or your ears).Your compressor will just not keep up with the airflow. Because your nozzle is so far away, why not disconnect your air pipe and for a test just direct it at your cut manually to see the effects.
Russ
+SarbarMultimedia
Hi Russ
Good idea, I will rig up something to direct the airflow so that its much closer to the cut.
I probably have some thin bore metal pipe kicking round somewhere.
I don't know how much those aquarium pumps cost from China (probably not much), so perhaps a longer term solution is to run 2 of them, one to keep the nozzle clean and one as the actual air assist.
The air from the nozzle does make a difference, which I noticed when doing pulse tests and forgot to turn on the air pump, but its almost certainly not delivering enough air to remove the smoke from my cuts when cutting anything organic.
+Roger Clark
Hi Roger.
I know you have a 50mm lens and I thought I would pass on some interesting information as we were talking about lenses and I think I referred you to the Parallax site for some interesting reading.
I have been fielding several questions similar to that from Randy Pope below over the past few weeks, all are wanting to know what trick I'm using to cut 10mm acrylic and ply with only 30watts of power at the work piece. My dumb answer amounted to "just a good set up" But you amongst others that I speak to seem to have 50mm lenses fitted to their machines. My 38mm seems a bit of an oddity. That set me thinking and I went back to the Parallax website to read more about focal lengths and spot size. It turns out that your 50mm lens focuses down to a spot .004" diameter and my 38mm down to a spot of .003" diameter. Not a lot of difference there then.......until you chuck some numbers in and find the the power density ratio between the two spots is 8:14. I'm able to get almost TWICE as much punch as you can although my lens is more distance sensitive. That explains why I CAN WALK ON WATER!!! That, along with a few other odds and ends might be a good subject for another video.
Regards
Russ
Great video...I've upgraded my Chinese 40w laser to a 60w for the simple reason my power supply quit ,so I figured since I'm buying a new one I went to 60w and tube ,no different. So my main question is I have a heck of a time cutting through 5mm with 3 passes at 100% power and speed 2mm per sec let alone 10mm...so I'm thinking running it at 100% is actually chokeing it down.how do you determine that you get optimum power output at 65%? Question for anybody really.
Hi John
First of all a 60 watt tube has a recommended current limit of 22mA. If you do not have an ammeter fitted then it's a virtual certainty that you are over-driving your tube. Now, it depends on where you bought that new tube and power supply as to how it may perform. Was it from Ebay or direct from China or a local supplier? Is there any label on the tube?
A typical tube of any power will reach its rated maximum allowable drive current at between 60 and 70% power, but you shouldn't be using it because running over that will shorten the life of your tube. A good tube will have a steady increase of power all the way up to 100% but it's not there for you to use, it's there to keep your tube performing correctly at it's rated max power. If you have a "sub standard tube it may perform with a steady increase to 50% and then the power start to decrease rather than increase. I know because one of my ebay tubes was doing just that. There is a great visual presentation of the laser power mxing out at about 60% in this video
czcams.com/video/WbBPps42iHc/video.html
The other thing that may be different is that I was using a 1.5" focal length lens.
Best regards
Russ
Thanks Russ for replying so soon...it was both from China supplier tube and power supply together. ..im still watching all your vids. ..great job..what's that little black gaget you use to mesure the wattage ? Thanks again .john
Hi John
That's good to hear. Buying direct from China means you have a traceability trail and you will have bought what was advertized....a proper 60 watt tube and power supply
Take a look at this video to answer your other question.
czcams.com/video/lO9rWlobLZU/video.html
Best regards
Russ
Why not group all holes first ? I use Coral Draw have this program as a micro
This was early on in my learning journey A few sessions on I learnt the method i still use today
czcams.com/video/_3oUQ9gKjCk/video.html
You can set RDWorks to work from the centre and it will usually do all the hole first. I say usually because it has let me down on several occasions. It is also very random in its cutting order. I like to manage my cuts, and with turning all cut optimize and path optimize options off I can group and order very efficiently.
At the time your comment was entirely valid . Thanks
Best wishes
Russ
I have a 8ft x 4ft 120w laser Its great watching you learn as I went through the same learning curve as you, remember my first fire,,loll
Have you been here yet?
czcams.com/video/cVuYyfJmfTs/video.html
Russ
I have laser machine and it have same problem of cross beam angle cutting. Plz help me to solve that issue....
Hi
Your problem is all to do with beam alignment through your lens. Your beam axis and your lens axis do not coincide. See this video all about modifications I have made to my machine but the video is structured around the detailed description of how to set your beam The most important part is towards the en where I demonstrate the problem you get when the beam is off axis.
czcams.com/video/6aNwKhTRnd8/video.html
there is a footnote video to watch also
czcams.com/video/wS1qgmv8HTU/video.html
Best wishes
Russ
i deselect " cut optimized " and now it follow the right order
I cant get my to cut at all like this video what is your trick
+Randy Pope
Hi Randy
I wish there was a trick I could show you but it's not magic. I bought a 50 watt laser that I now find out was a 40 watt laser tube. Yep, I got scammed. However, it gets worse because the tube actually outputs 37 watts and at present my mirrors and lens are consuming 7 watts, leaving me just 30 watts at the cutting surface. So I'm cutting 10mm acrylic (very slowly) with just 30 watts. All my videos,(they are not staged you are watching me doing/struggling as it happens)) chart the stages of my learning and it's going to be a step by step fault finding exercise for you to track down where your problem is. The obvious place to start is with the laser tube itself. czcams.com/video/JfRpa9Y5Woc/video.html shows you how to asses what's coming out of your tube. Unless you want to invest in a power meter, there is no other way to get any idea of what's coming out of your tube. So that's the most important discovery you can make. If that looks good we can move on from there.
Good luck
Russ
+Randy Pope
Hi Randy
Just a thought on your problem Is your machine focus point about 19 or 20mm below the nozzle? if so I may have a clue as to what your problem is. Well its not a problem but a choice you may have to make to be able to cut like my machine
Regards
Russ
if your wife wants chef grade knives then she loves to cook. you cannot go wrong. but a chain mail vest would not hurt!