80w EFR Tube Engraving Quality and Beginner Questions

[Mike Lysov]

Hi Guys,


I have been browsing for a while and just got my laser setup a couple weeks ago. I have a lot to learn. So far I have played with a bunch of different speed and power settings with a few different types of low quality plywood just to get me started. I know the plywood I am cutting through is crap so that is mostly why the edges are so badly charred. I cut some higher quality plywood and the edges did look nice.

Questions
1
What psi do you run your air assist at? I am getting a lot of burning and I am guessing it is do to the low air pressure from the supplied air compressor. Do most people just use whatever compressor is in their shop or are their compressors more specifically for laser machines?


4
If the laser is aligned perfectly does your cone ever get hot while running the laser? I think my laser might be hitting the side of the cone a bit as it does get a bit hot. It is hard to tell how to adjust it since the mirrors each have the spot pretty much in the center and the spot shape looks different at different heights. Sometimes it looks almost exactly circular and others it looks more like the sharp ellipse. Do you just guess adjusting the last mirror until the spot is perfectly circular?


Steve

H Steve,

I can help you with these two only from my experience.

1) This question is relevant to a distance from the tip of your cone to a material. If distance is small you may not need too much air pressure, if distance is big you will need much more pressure.

With my stock cone for my Spirit GX the distance was about 2cm and the air pump(airbrush small compressor was supplied with the machine) I had a lot of residue around cutting lines. No surprise as air is supposed to blow all smoke away before it sticks to a piece but with about 15psi from that compressor could pump and such a huge distance it was not happening. Then I made an extra tip for the cone from a metal ballpoint pen tip decreasing the distance to about 7-8mm and started using a normal air compressor. Now it runs at 30psi and no residue left on cut pieces.

4)If something is heating then it is not aligned or your tube is not working properly.
I did not have any problem with any parts heating up when my laser was brand new but then I started to notice that my laser head was heating up to 50-65 degrees Celsius on 20 minutes jobs.
I was trying to find what was the problem and I could not until I tried to align my tubes again(I have a double tube laser) and noticed that one of the tubes produces two burn marks instead of one. Then this tube died.
So in my situation I can guess it was the dying tube with abnormal beam profile that was responsible for the head heating up.

It may be not your case and may be your beam is not aligned very well at the head resulting the beam coming not through the center of the hole in your nozzle, hitting its walls and heating the whole part. However it is still good to keep in mind that even when everything seems to be perfectly aligned and it still heats up some parts there is also a possibility that it is a bad tube doing all this bad stuff.

[Matt McCoy]

Speaking of tube power... do you guys recommend 80% of max continuous power or just less than or equal to max continuous power (so 25mA for EFR zs1250). I too have gotten confused by the %'s. For the reference 95% on my machine is 25mA if you are looking at my settings. I didn't check what the 17% cut in mA was yet.

I don't know if it helps, but the operating current of that tube is 28 mA.

[Steven Taitinger]

That is the max peak current. The max continuous current is 25mA. It is in the second chart.

http://efrlaser.com/2-co2-laser-tube/200477

[Matt McCoy]

That is the max peak current. The max continuous current is 25mA. It is in the second chart.

http://efrlaser.com/2-co2-laser-tube/200477

Thanks Steven.

[Steven Taitinger]

However at the bottom of that page they mention the warranty being void if you go over 75% of some value and says refer to the manual. I have emailed them and asked for the manual.... I am rather curious what the difference between guarantee and warranty is in their mind.

Edit
I totally misread that. I am sure they mean if the max power output of the laser goes less than 80 or 75% of the rated power then they will replace it. They do say here though that the "optimum power" is 80% of the rated power whatever that means http://efrlaser.com/profile/technical-support/200475/0. My guess is that is just related to power efficiency but I guess I will try and stay less than 80% if I can. That gives 20mA.

[John Lifer]

I try and keep below 75%, will go to 80% Roughly 25ma at 75% and 28ma at 80% At least on my machine.

[Bill George]

How would they know? In any event your going to be blamed for going over the mA if you did or not.

[Steven Taitinger]

I guess I'm not as worried about warranty as just treating the tube right since I can't afford to replace it right now! I would also tell the truth if asked which I guess is my problem lol.

[Erik Goetheer]

Hi Steven, I have the same tube as you, still pretty new on my 4-months old 9060 machine. When I got the machine started, first thing I did was a laser power test with a thick acrylic block. It appeared that max power is given at 70%-75%, (I tested with steps of 5% from 30% to 95%), so I have 75% as maximum power in the settings. In practice I hardly ever go over 65%. Of course, water temperature is also important for the performance and I try to keep it around 19-20 degrees Celcius.

My max. engraving speed is 300 mm/s. I could probably go higher, but I also never drive my car to the max, bad for the engine in the long run. At least, that's what I like to think. And the time advantage of even higher engraving speed is very littlte, especially when you do smaller engraving with lots of changes in direction.

And my tube still fires at 8%, but I mainly use 9% (and 125 mm/s) if I want to have very thin vector lines in a sign for instance to mark the places where lettering and such must be glued.

[Jerome Stanek]

Percentages mean nothing 80% of a 100watt power supply is less than 50% of a 300watt supply. You need to go by the Milamps on your meter

[Steven Taitinger]

Erik do you know what mA range 8% to 75% is on your machine? Thanks for listing you temperature on the chiller. The default is 25C so I have been wondering what to set mine to. Did you test different temperatures or just pick that one?

[Erik Goetheer]

25C is the default (manufacturer) temperature setting. Most experienced users find it pretty high, so I've read, and they advice somewhere around 18 - 21 degrees. I guess that your chiller is still in the intelligent control mode, which is also default. I changed it to constant temperature control mode, set the constant temperature to 19C with the allowed low on 18C and the allowed high on 21C. This will keep the tube nice chill. Beware of condensation though.

I will check mA range for you tomorrow.

[Erik Goetheer]

Erik do you know what mA range 8% to 75% is on your machine?

8% > 4 mA
75% > 23.5 mA

[Steven Taitinger]

Well things have come a long way in the past few weeks. If anyone else sees this and doesn't have photo quality results yet I would like to share a picture and a few tips. The most important thing to know is that when you are learning your machine, DON'T start with photos. Start with a 10 pixel square with 1 pixel borders on the bottom and left and 2 pixel borders on the top and right and with 1 pixel in the middle (black with the rest white). Save it to each dpi you want to test. Import into rdworks and test all the different speed, power settings, reverse interval etc. That will tell you everything you need to know in order to get good photo quality pictures pretty much and with not worrying if it is your photo editing skills to blame. Make sure you write down each setting you changed like I did below. Then you can tell in one super fast test for each combination at least the following factors
-if you have the correct reverse interval at that speed
-if single pixels will get skipped (skipped single pixels makes washed out engraves without the smooth shades)
-if it takes more than 1 pixel to ramp up to full speed the right edge will be darker than the left edge (not having enough ramp down time for laser power makes for nice shades but totally blacked out dark areas)
-if it is so fast you lose accuracy (lines curved, borders skipped entirely etc)


https://drive.google.com/open?id=1sk...bKe-Y1Rh6-ys3g

Thanks for helping me get this far. I spent about 4 nights not making any progress in quality (aside from learning) until I started using this method. And now in one night of testing I know more useful information about my laser than in the last 4-5 combined.

Note that this method of detail is only required for photo quality engraves. Engraving vector fills you can go way faster and larger scan intervals and still get the same quality. Also, Output Direct is a total waste of time for engraves if you want photo quality. It makes everything blurry even at slow speeds. I haven't tried that for a large photo with low dpi and low speed yet though...

Thanks again for all your help and if Russ reads this thanks so much for your last series of videos on scan settings!

[Daniel Norman]

I wanted to comment briefly as I found this post very helpful and have many on the same questions. My machine arrived in April and work and family demands have not allowed me to do much more than basic testing until now. I am on holidays now and have a week alone to do some testing. Thank you Steven for asking and everyone for their input.
Cheers, Dan