Laser power

[cseybert]

I am trying to determine whether or not the laser tube is bad. How many amps/ohms should be indicated on a test meter in order to determine if the tube is bad or the power supply is bad?

[Tech_Marco]

I don't think anyone know if you don't provide more info about your power supply or tube.
You didnt tell power wattage, laser tube power, length... this is all basic info we need

Marco

[cseybert]

I've had this laser for 4 years (haven't replaced the tube before). Here are the specifications:

Laser is a SenFend SF640
Processing area 600mm*400mm
Laser power: 50W or 60W (we have 60W)
Laser type: Co2 glass laser tube (the tube measures 49" cap to cap, so I believe the length is 1200mm)
Laser cut 5.5
Dimension: 1060mm*1000mm*730mm
Engraving speed 1-6000mm/min
Cutting speed 1-1000mm/min
Cutting thickness 0-20 Plexiglas (others determined by materials)
Gross power 1000W
Driving mode: DC0.8A 24V stepper motor
Cooling mode:Circulation water cooling
Working voltage: AC220V/50HZ or 110V/60HZ or depend on customer (it is AC220V, but we are
operating it utilizing a step down converter)
Operating temperature 0-45℃

[Tech_Marco]

Can you double chech the dimension of the tube. Need to know the total length and the diameter . The info you're providing doesnt sound right. Fyi, a 60w tube should have 1200mm length and 60mm in diameter. A 50w tube should have 1000mm long, 55mm diameter

By the way, what is problem do you have?

[cseybert]

Looks like it is approximately 7 inches in diameter.

The laser is not firing. When I hit the laser button, there should be a "fire"...there is not. Also, the gauge does not indicate a power surge as it normally would when the laser is firing.

The laser will "run" a test pattern, but there is no fire.

We have never changed the tube and we purchased it new approximately 4 years ago.

[Tech_Marco]

Most likely the tube is gone. In general, a normal laser tube last 1500hrs to 2000hrs within 2 yrs. Four year is an outstanding for that matter. Im going to try a small setup to test whether a laser power supply still working or not. I will post the info once I tested it

Marco

[cseybert]

Tube is approximately 7 inches in diameter.

The red dot, exhaust fan, axis table, and arm is all working....the laser just isn't firing. The manual indicates that it is probably the tube.

[Tech_Marco]

7inch (175mm) in diameter??!!! Are you sure about that?
I never seem any tube bigger than 3.5" (90mm) in diameter.
If you can, post some pictures and I love to see it

Marco

[Tech_Marco]

Make a cheap cheap setup to test if the Laser Power output anything. Note, it must be in 'closed-loop' setup which means that a laser tube must be connected. Don't test the laser power supply without a load - laser tube connected!

Once you press a "Test" button (if any), or you fire the laser, the LED should light up. The LED I used is a regular 1.5V and I coiled up the wire about 5 rounds with LED poitive leg to the HV cable and the negative leg connecting to the case (ground). Note that the LED light up brigher if coils are stretch out than tighten up.


Marco

[cseybert]

I apologize - I was not at the shop and had someone measure the tube....I think they measured the length around the tube. I believe the diameter is 3 inches.

We will be running the test today.

Thank you

[cseybert]

Though the simulated test was not successful, we were able to determine that the laser tube is still functioning by depressing the red test button on the laser power supply box. When the red test button is depressed, the laser fires and the power gage show a strong amp - so the tube is still working. The software running the laser is working as an uploaded file is calculated and the laser arm will "run" the pattern, but the laser will not fire.

[Raman Narayan]

It could be either there is a loose wiring/firware issue from the laser controller to the power supply
pwm input, or the power supply pwm input could be faulty.
You could connect a simple led with a resistor(1k) to the pwm output going to the
powersupply(disconnect from power supply, and give to the resistor in series to
anode of led, cathode of led to the gnd). Just run a test file see if the LED keeps blinking.
If it does, the power supply pwm input is most likely faulty. It is definitely not a good
idea to open the power supply, since it could be fatal, if anything goes wrong.

-Raman