Machine- Monport Reno 65 pro
DSP
Lightburn 2.0( 30 day trial)
I am new to Laser engraving and would like to ask, what would cause my laser to start cutting numbers good at first, then not finish them. I am cutting numbers for a couple of clocks. I used the settings from a guy on Youtube who had the same machine. However, his settings did not cut through all of the numbers. Started with 30mms, 60% pwr. Then 25mms,65% power. Any help would be appreaciate. Thanks, John
Hello John… Welcome to the site. 
If you have
- properly working tube
- clean and aligned mirrors
- proper focus
They just work.
It’s always best to recheck for any alignment of focus issues. Focus is usually the issue.
If you are making the clock faces out of 2x4" lumber, I might have a different opinion of your settings. Might clue us in on the type and size of material, lens you’re using and a link to the video you’re attempting to duplicate.
All of these machines vary, especially how the co2 reacts, so his settings are likely a good ball park area to start with.. Unlikely to work absolutely correct.
Hello JKW. I am making 3" tall letters out of 3mm basswood. I have not cleaned or aligned mirrors. There seems to be a problem at the bottom of the board. I will watch some videos on mirror alignment if I can find some. Here is the ling to the video. https://www.youtube.com/watch?v=vy1DV_2QBOY&t=729s
You can try setting your focus a couple mm lower than the surface of the materials.
That can help keep your laser in focus as you cut deeper into the materials.
What focal length is your lens ?
Hello Soniclab, Thanks for responding. Think of me as an infant in laser engraving. I will have to get back to you on the focal length of the lens. I decided since I needed to get the letters cut for my clocks, I would just cut in 2 passes. It worked at 25mm/s and pwr at 65%. Thanks for your help. I will try to get more information on my machine. I will get back to you.
If you’re running 25mm/s using about 60 * .65 is about 39W for 3mm basswood.
I run 11mm/s using 43W * .45 is about 19W to cut 5mm sub flooring using a 2" (50.8mm) lens.
Half the power and 2mm thicker at half your speed.
I think your machine is in need of an alignment, just my opinion.
IMHO, anytime you make multiple passes, things such as residual debris effect how subsequent passes work.
I have always used the fastest speed at the highest power to cut through in one pass. I would expect yours to rip through 3mm basswood with no problem in a single pass.
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Hello again. I have watched a couple videos on alignment. However, when I turn on my laser and chiller, I cannot see water in the laser tube. I can feel cool water in the hose going into the back only. I really don’t want to ruin my laser tube, so if you or anyone has experience with the Monport Reno 65 pro, I would appreciate all help. Thanks again, John
It has to be, not only going, but coming back out or your machine would be full of water.
You can usually see a coolant in the tube, running or not. Many of them have a few small bubbles at the cathode end, where the water and laser beam exit the tube.
I’ve checked mine, by pinching the flow off, the laser should halt or show an error message for coolant not flowing. The machine needs to be executing a job, I just turn the lps off when I did this.
I have pinched my coolant tube and after a few seconds the alarm will sound on the chiller. Can I assume water is in the tube and actually flowing. I will look for bubbles. Thanks for the help. John
Bubbles are not nessarily a bad thing. I’ve run additives that make the coolant white from so many bubbles.
What matters, is the inside tube where the lasing takes place to not have any bubbles of any size stuck here. If it’s large enough, it insulates the heat and the glass may not be able to handle the change over such a small area.
I was pretty sure it was flowing as it was going in, according to you.. if it goes in it must come out somewhere…
Good luck.
I have found that if I am cutting a piece of wood placed on honeycomb, the cut may not go through where it is touching the metal. Solution: space the material slightly above the honeycomb. This also has the benefit of letting the part drop out when it is cut successfully. Just be sure the cut is done AFTER any engraving.
I actually saw the water moving in the tube today. I cut some 3mm basswood numbers for a few clocks I am building. It seems that when the laser cuts the numbers lower on the board, they don’t always cut through. I had the settings at 65 percent power and 15 mm/s. later I slowed to 12mm/s. Thanks for the hlep. I happy to know I have experienced people to talk too. John
Thanks FixitMike, That is a great idea. I will space it with small pieces of basswood or some other kind of spacer. I may just burn with the slats in and no honeycomb. Thanks for the advice. John
It’s also worth noting that as a laser tube gets warmer, the output power is reduced. I’ve noticed that if my tube starts cold (say, 10 degrees C) then I start a large job, the beginning will be overburned then, once the tube is up to temp, etching will stay consistent as my chiller keeps up.
Is it possible that your laser’s water circuit is starting cool then getting hot?
Thanks for the help. I have slowed down the speed and it seems to be cutting better. I have a couple of Halloween downloads from Etsy and I will test them today. Thanks again, John
You are aware of the Ruida Start Speed and how that works? You are running in an area that this could be an issue.
Smoke extraction can make a difference too. If smoke is not effectively evacuated it can negatively impact on the power level required to cut through things. It’s a bit like shining a torch light through fog.
I experienced this on my own machine, where the air intake was not large enough to allow sufficient air flow through the exhaust. My fix was low tech but is outside of the scope this discussion.
I have not heard of that. I welcome any info that can help me. The machine seems to be working good, I just need to learn to import, extract files from Etsy downloads and discover all the things possible with my Monport Reno 65 pro. Thanks for the help
Hello Marius. I made a poor mans extraction fan using a bath fan from lowes. I built a small box around the fan and created a port for the hose to go into. I used it once yesterday and still had some smoke smell in the house. I am going to check all the tube for leaks in the morning. Thanks for the help, John
I had a smoke accumulation problem inside the machine (poor machine design- the only air intake is the louvres in the electronics bay door which led to inadequate air low through the machine).
The incomplete cuts would typically happen in this smoky environment when the cutting head was furthest away from mirror 1.
FWIW and just for comparison: I just replaced my tube so it is new like yours should be. I cut through 3mm Birch ply in one pass at 25mm/sec using 44W of power as set by the controller and software.
Also, after I have done test cuts to determine power and speed, I usually bump the power by 3% (arbitrary value, insurance if you like) because no two pieces of plywood will have the same density. You can achieve the same thing by lowering the speed a bit.