80w EFR Tube Engraving Quality and Beginner Questions

[Steven Taitinger]

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?

2
Do you guys normally run your min and max power percent the same in RDWorks? Why would you ever want the min less than the max? I noticed it doesn't draw nearly as much power when you have the min lower than the max.

3
When I try to use the scan setting to engrave a photo I get basically only two tone black or nothing. How do you get it so you have a range of grey like on every other photo engrave I have seen? My tube seemed to only kick in at about 16-18 percent and 20 percent already seemed fairly deep at 100mm/s speed. On the RayFine website it says my machine has a 100mm/s engraving speed. I tried it at 150mm/s and it did seem to work. What speed do you guys run engraves at? These settings were all with a 2in 50.8mm focal length lens.

IMG_20170606_222025.jpg

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?

Any help would be greatly appreciated! If anyone is in Edmonton area I would love to have a chat too.

Steve

[Kev Williams]

I'll address the MIN-MAX power issue:

If RDworks's MIN and MAX power work like my LaserSoft does (and I'm not sure it does but I think so)-- here goes-

A laser moves in 2 speeds when vector cutting, full speed and slow speed. Full speed occurs in long straightaways and larger arcs where the head can move smoothly AND quickly.

However, whenever the laser needs to change direction abruptly, such as at the four corners of a square, or when running complicated shapes, and even when it stops at one section to move to another, it has to slow down to minimize shock in the drive train, allowing the stepper motors to keep up without losing steps.

Ergo, your MAX power is the power applied at full speed, MIN power is the power applied at the slow speeds.

It's very easy to check the results by cutting a simple 4" square. First, cut a square at 80% power both MIN and MAX. You'll likely notice overburn at the corners...
Now, do the same job only change the MIN power to 60%. You should find the overburn is gone, and in fact 60% may not be enough power, and you may need to adjust. Also, if you have a meter, you can watch the power change on the needle...
--this is the fun with Chinese lasers, figuring all this stuff out! (Western machines, this stuff is mostly all automatic)

Note that this also relates to Min and Max acc speeds and such in the machine parameters settings, where you can make adjustments to the actual speed differences-- but that's another story

[Bert Kemp]

On my rabbit It asks for max power setting and another box for power setting on corners. I set them both the same and assume the machine adjusts speed on the corners to compensate for the power setting. My corner cuts look the same as my straightaway cuts.

[Steven Taitinger]

Thanks for the answers Kev and Bert. I feel confident now in knowing what to look for when adjusting the min power.

Any answers to the other question are welcome too

[John Lifer]

I'll chime in and say that I never have used anything but the same settings for min/max. It is what Kev said, at turns it may help to reduce power. As to speed, I don't know what reason you are limiting to 100mm/s, Now others that have same model will probably chime in, but I've run mine up to 500mm/s with no ill affects. (x axis) If I remember, my y is set at 400 max, and x at 500. I normally stay in the range of 8mm/s for thick wood vector cutting, on up to 400 when doing raster engraving on a few items. Was doing glass bottle today at 300, just where it needed to be to work right. Very few vector cuts faster than 50mm/s as I haven't cut anything that WILL cut moving that fast.

Cone DOES NOT get hot. You are hitting it with the beam most likely. Adjust those mirrors! Yeah, no fun.

Air assist. If cutting, It is ON. I'm using the 50mm lens almost exclusively. the tube for it has a large opening for the air and I get a lot of airflow. the 38mm I have installed in my other tube has a very small orifice and would probably be fine in leaving on all the time. I DO need to put in a small valve at the nozzle to cut down flow. I cut off on a lot of engraving due to the depositing of the smoke and dust into already engraved areas.
Just have to watch to insure no FIRE!

I've done some halfway decent photos on plywood, but they are only decent. Go Watch the last 3 videos on rdworkslearninglab youtube. He plays with engraving and it is relevant to Chinese lasers.

[Kev Williams]

This pic is the first of a couple hundred of these, this was the first wood job I ever did on the Triumph-
woodcorner.jpg
Note the outline box, which I vectored to save time-- the corners are obviously overcooked -- this is when I asked myself "I wonder if lower the Min Power would help?"

-- It did!
woodcorner2.jpg
This was probably the 3rd tweak, much better!

[John Noell]

I use a Gast compressor, good for continuous running and relatively quiet. Those aquarium pumps are pretty useless. The air assist keeps flaming down, and can help with cutting thick acrylic. I ran it at 20psi with my Epilog but the orifice is bigger on my cone and the same compressor never gets to nearly the same pressure on my Longtai.

As for photos, the preparation is everything. search for Gold Method (from Rodney Gold) for some excellent tips on where to start. Photos can be very tricky and if the photo does not have a good range of contrasts to start with, you may never get a good looking engraving. Many people swear by PhotoGrav for prepping photos. I hear the expensive machines now often come with photo tools included.

[Steven Taitinger]

Thank you so much for the helpful answers. I am quite sure the RayFine website has a typo on the speed and will try faster engraves tonight + look at the other suggestions. I will post pictures back and say what changes made what difference.

Does anyone with an 80W EFR tube know what the min power percent or amperage is that you can use? I was expecting a bit lower than the 17 or 18% like what I am seeing.

[Brian Book]

Hi Steven ... I also have a Ray Fine EFR 80W .... and when I'm cutting 3mm Baltic Birch plywood I use 35% min and 40% max 10mm a sec and to engrave I use Min%20 and Max 25% at 175 mm a sec .... if I don't want the engraving as deep I will go higher on the speed .... also on my Machine I have a dial on the front to dial it down below 20% power .... but it will start at 20% .... also they gave me a measuring gauge for height of the nozzle of 10 mm .... when I ran my test my best is 6.5 mm height.... so you may want to check that as well .... I also don't use the Air Pump that came with my machine .... I have a 185W pump .... and if you ask me I get cleaner cuts because of it .... and I have a small valve to control the air for different applications.

Hope this helps

Brian

[Lyle Cheredaryk]

Steven,
Looks like I have the same machine you do. Only had it for a week now.
I have been running my air assist while cutting at about 18 p.s.i. off my shop compressor.
As for engrave speed. I have gotten some good results running at 300 mm/sec.
I also have the 80 watt EFR tube and have found it will not fire at 16% and is so very nice and fine at 17%.
I have been playing with making a sign for camp today. Using Baltic Birch and engraving at 250 mm/sec and 20% power. Comes out beautiful.

Lyle
20170606_212151.jpg

[Lyle Cheredaryk]

Steven
That was a first try on the sign. Burned the corners badly. Never considered the pattern and how busy it was there. No pictures of the next step yet.

Lyle

[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.

[Doug Fisher]

Does anyone with an 80W EFR tube know what the min power percent or amperage is that you can use? I was expecting a bit lower than the 17 or 18% like what I am seeing.

My EFR works well at 12% or higher. Going 11% or lower has not been reliable at times in the past. That means sometimes it cuts fine and sometimes it does not.

Remember that below 15% is probably in the range that Russ calls pre-ionization range so the beam performs different.

[Dave Sheldrake]

percentages are just hot air

Amperage is what matters, this stupid percentage thing flying round the internet that Russ promoted is causing tubes to get killed and people to think they have machine faults

"pre-ionisation range", that's actually meaningless, until the gas is ionised there is no beam, it's the nature of DC lasers, a pre-ionising charge is what keeps the gas semi excited so reducing ramp time to lase and is usually around 4mA on a DC tube and is available on EFR and RECI power supplies but very few laser builders implement it.

Many of the myths floating round are why I don't do much with laser support these days, it takes longer to explain why what folks have been told is wrong than it does to actually fix problems

[Steven Taitinger]

Doug, does 100% on your tube give 25mA?

My honeycomb table didn't fit and so I have been emailing Blanca to fix it and I asked about recommended engraving settings out of curiosity. She said for wood they normally do 20-40% power and 500-800mm/s! So I went and tried 20-30% and 600mm/s and it turned out pretty good.

I would be really interested in a complete list of settings for anyone that is getting multiple shades of brown on an actual photo engrave. See attached for my settings and results (considering my tube still isn't aligned perfectly). These were all with my 50.8mm focal length lens. Each of these dog photos were 1in wide by 2in tall. I didn't record all my settings perfectly but I tried to record the main things I was changing each time.

Does everyone doing photo engraves use Output direct? It seems to be the only setting that allows me to get close to multiple shades since it varies the power based on the grey scale. I think tomorrow night I will try some more scientific graphics to test. Exactly where the cutoff points are for the tube starting to fire. Once I know that then it shouldn't be too hard to edit every photo to have the white start at around that shade of grey.

Edit
Shoot, it looks like the forum automatically downsizes photos. Try original here where you can actually read most of the settings. https://drive.google.com/open?id=0Bx...3JUX2xEbmgtajg

IMG_20170608_080307.jpg