My omtech Polar has a digital read out on machine that shows a number with “mA” (assuming correlated to power) the slower I go the lower that number, regardless of my “min max” power settings. I cant get it above 20 on the read out. Its been awhile since ive used mine.
I feel at one point I turned something on or off that gave me more manual control to that. I cant get through 1/4 birch with multiple passes. (Gets close). Tried many different feeds/speeds power.
I think you are confused about the readings.
mA reading is power required to do what the machine is performing currently. When you slow the machine it requires less power to do whatever task you have applied.
I am going to assume you are using 1/4" Baltic Birch. It is difficult to cut through because of the glue used and how the material is manufactured.
Not familiar with the Polar. Do you have a supposed output of 40W? You will likely need slow speed such as single digit with 80% power. I have a 60W OMTECH.
I cut 1/4" with speed of 7 and power of no more than 50%. High power settings (80%-90%) will shorten the life of your CO2 Tube.
Be aware my answers here are assuming you have a CO2 laser.
Others on the forum can probably help you more than I.
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TY Ferg. mA and lasering is still a little foreign to me. It is a 50w CO2 yes. So I do understand slowing it down requires less power. I’m curious if there is a way to manually control that. Example I slow it down a little but force the same power?
You can actually change your speed and power in the Cuts/Layers window.
Such as: speed = 10mm/sec and power 50%
Does that help you?
Just for clarity, the mA reading is only measuring current through the laser tube, not the full machine electrical current. The c02 tubes are designed to work with usually a max mA. Slowing down your speed should have zero effect on the current going through the laser tube.
It is correct, but power density is increased. Same power but longer time on the same spot…slightly roughly explained 
This isn’t entirely true.
This is probably true depending on settings, speeds and type of operation you’re doing.
It should/can vary if you are doing vectors and using min/max power settings. The Ruida will adjust current levels based on current head speed. Slower head speed, lower current.
If you use min/max power settings with a Ruida, you’ll get minimum power anytime you’re at or below the Ruida start speed.
If you are using a scan operation there is no use for minimum power as the overscan ensure the machines head is up to speed when it needs to lase.
20mA is the maximum you should run through a 40W tube, so it’s likely that it’s limited in some way.
This is an old thread… isn’t it?
Yeah, that’s my bad. Didn’t look at the date. Tell me about this head speed setting? I use lightburn and use the same power setting for max and min. I have a digital meter on my laser tube power supply and an analog meter on the machine itself. I adjust power and speed in lightburn depending on what im working on. The head speed has no effect on the power setting. What is this setting that adjusts power with head speed and when would it be useful?
If you have both minimum and maximum set to the same power level you won’t see a change.
The minimum power setting is used when doing vectors and the head speed changes where it has to slow down, change direction and get back up to speed. The Ruida will adjust power based on the current head speed to try to ensure the same type of cut/engraving results.
If your speed goes to or below the Ruida start speed, it will only produce minimum power.
When doing a scanning operation, the Ruida uses overscan to ensure the head is up to speed before it moves over the area where it must lase, so only maximum power is used. You can enable overscan in the preview… it shows up as red…
A higher acceleration value reduces overscan and can decrease job time. On the left is 40,000mm/s^2 compared to 6,000mm/s^2. Notice the job time difference between the two.
I came up with this graphic… I believe it to be correct with start speed. The red is the power line.
Make sense?