Chinese laser purchase/Shenui/Laserworks tips and tricks thread

[Dave Sheldrake]

that I can satisfy

Quite true Rich, the problem is not everybody who reads these forums understands that their new laser has mirrors that move in at least two axis when adjusting the beam. How many new owners are more likely to jack the tube only to find they spend the rest of the week chasing a spot like a demented cat chasing a laser pointer

cheers

Dave

[Rich Harman]

Quite true Rich, the problem is not everybody who reads these forums understands that their new laser has mirrors that move in at least two axis when adjusting the beam. How many new owners are more likely to jack the tube only to find they spend the rest of the week chasing a spot like a demented cat chasing a laser pointer

I don't understand you Dave. You generally give very technical answers but in the case of post #140 you dumbed down your answer to accommodate what you believe some people may or may not understand? If you knew that the tube does not actually have to be "bang on" why contradict me in post #145?

If a new user does not understand that their mirrors adjust in two axis, I think they will have a great deal of trouble making a proper alignment.

Not sure what you mean by "jack the tube" - so long as the beam hits the center of their first mirror it won't contribute to their imitation of a demented feline. How much of the week are they going to be spending tweaking the tube thinking that it isn't exactly at a 90 degree angle and concluding that is the source of the trouble with getting the beam aligned?

I think it is better to be technically accurate, to with what a forums level of understanding may be, tell them to get the tube as close to 90 as practical, adjust it so that the beam is dead center in the first mirror, then leave the tube alone and move on. Don't stress about getting it perfect, it makes zero difference. If someone does not understand, I for one am happy to attempt to explain it better.

[Jerome Stanek]

On mine the mirror that shoots into the the final mirror above the lens was to low. I could get it to hit side to side but not up and down. It would hit low when close and high at the far side. I ended raising both the first mirror and that one to get it to hit in the same plane. so I think the mirrors are 3 axis not 2

[Dave Sheldrake]

You generally give very technical answers

Indeed but sadly much of the time they only really benefit people who understand them. Something Dan mentioned to me a while ago when I was trying to explain 90 degree Phase retarding mirrors made a lot of sense.

If a new user does not understand that their mirrors adjust in two axis

It's been my experience over the years that the majority of new users actually have very little understanding of what a laser machine is (mostly Chinese machine buyers due to their relatively low cost market entry point). New owner buys a machine and reads about jacking the tube up to remove bubbles (Jack as in like a car hoisting instrument) if they don't realise that moving one mirror axis also moves the other they are going to be back the following week after chasing spots around wondering why they can't get their laser to cut across the entire table. In response I could merrily go off on a 10 page description of the differences between the Transverse modes and how they can be affected by reflective angles or why TEM00 is unlikey or how they are going to get a multimode beam profile along with 500 meg of DWC images of real world beams etc etc I've just got to the stage where it's easier and just as effective to say "Don't move the tube, raise one side of the machine then adjust your beam on the mirrors"

I think it is better to be technically accurate

I'm currently the joint author of a book that's due for release that is indeed technically accurate but has taken more hours than I care to remember to work on and it made me realise (along with Dan's comments) that explaining to the nth degree exactly what Photon Saturation is or what Transverse Modes are in a DC tube is pointless. Those that do understand it already know it and those that don't likely have no desire to if it doesn't help them.

so I think the mirrors are 3 axis not 2

Radially explained they are likely hundreds of thousands of possible moves based on two axis that have effects into all possible axis of movement. Think of it like the two turrets on a rifle scope, you move one for windage and one for elevation, now imagine when you turn one a full turn it moves the other by an unknown amount. It's the reason gimbal mounts are great for mirrors, when you move one axis only that axis moves without affecting the other.

cheers

Dave

[Levi Chanowitz]

I am happy you are addressing what I think is my problem, My letters do not come out sharp, and I think it is because of the dot hitting different parts of the mirrors.

You are correct to say that most people will not understand what you are saying
However, I do not need to understand the theory, Just please tell me, does the tube need to be on the same plane (level) to the 3 mirrors and at 90 degrees to the y axis? how close is close enough. Please go easy with me, try to use words that are not more than 2 syllables and dont use words like "Photon, Saturation or Transverse Modes"

[Rodne Gold]

Your letters may not be sharp for other reasons , check backlash compensation.

[Levi Chanowitz]

the letters are not sharp at any part of the page and even when I engrave them in one direction only and even when I engrave on a slow speed

[George M. Perzel]

Levi;
Make sure your head is perpendicular to the table-use a good level and square. Also check that lens holder is tight and lens is not jiggling.
Good luck
Best Regards,
George
Laserarts

[Levi Chanowitz]

thanks. lens is tight, I need to check my head!!

[Joshua John Cruz]

Hi Levi,
I have the same problem before. I fixed it by adjusting the Z axis. And to avoid adjusting the Z axis when acrylics with different thickness, I cut out credit cards and stack it at the bottom of the blades (the one where you put the honeycomb). It is easy for me to change from 3 to 2 to 1.5mm acrylics without changing the Z axis. Hope this helps.

[Joshua John Cruz]

Still have no luck with getting the 2 dots on the same (close) spot. Adjusting the tube (of course with the 1st mirror dot at the center) did not help.

So what I did is adjust mirror #2 and 3, not near or far but at the middle and I am happy with the results.

But now I have a problem

The laser wont fire anymore for some reason.


Before this happened, I was able to cut several sheets, switched the laser key off, to change acrylic sheets, turned it on, pressed Laser button to check, then it wont fire anymore.


Any ideas what the problem might be?


Also, tried to reset the machine but I get no errors.

• no smoke
• no burnt marks on the laser tube wires
• it just wont fire

Please let me know if you need pictures of specific parts and I will post it here.


TIA!

[Jerome Stanek]

when you adjust the second first mirror to hit the second mirror where is it hitting whe close and where when far

[George M. Perzel]

Hi
What do you mean by "switched laser key off" ?
Best Regards,G
eorge
Laserarts

[Joshua John Cruz]

Hi
What do you mean by "switched laser key off" ?
Best Regards,G
eorge
Laserarts

Hi George,

What I mean is the one where you put the key to turn on the laser tube.
I turned this off (just to be safe), changed acrylics, turned it on again, then it suddenly wont fire anymore when sending the job.

[Dave Sheldrake]

Hi Josh,

Flow switch?
Door switch?
Trigger wire to the tube PSU?
Key switch now faulty?

It's unlikely to be a tube fault (there are other symptoms when a tube fails) but could be one of the above.

Leave the machine turned off at the mains for AT LEAST 6 hours.

Check every screw lock that holds a wire on both the mainboard and power supplies to ensure they are clamping the wires correctly.

Place a strong magnet (NdFeB if possible) on the door switch (if it has one) BE AWARE this will bypass the door safety lock, KEEP ANYTHING and EVERYTHING out of the machine working area when you test fire it.

Locate the water flow sensor in the machine (if it has one) tap it lightly a couple of times to ensure the flow bobble isn't sticking. (also check your water supply for signs of dirt or junk, this can make the flow switch block up and cease working)

If these don't work drop back and we can go into a few more things

Did I mention:

Leave the machine OFF for 6 hours first
Keep anything you don't want destroyed OUT of the working area of the machine.

cheers

Dave