Does your beam do this?

[1n2]

Hi Guys

Can someone peek in the back of their machine and see if the beam does this----> http://www.youtube.com/watch?v=ogSNClK53A8
ie. "snakes" around by the output ?.....

Thanks

I can't say I had noticed it before

John

[Tech_Marco]

It happened when driving the laser in low current. It is very common to see it on bigger tube but in samll tube it seldom happen.
If you tune up the current higher, it shouldn't happen

Maroc

[1n2]

It happened when driving the laser in low current. It is very common to see it on bigger tube but in samll tube it seldom happen.
If you tune up the current higher, it shouldn't happen

Maroc

Thanks Marco I was cutting 3mm ply at the time around 38% so that seems to be around 11-12Ma.
Would that qualify as low?

I have had a new tube just before the power supply .
I now seem to have to engrave at 10-12 % (whereas before it was 22%) but cutting is around the same if anything I need to up the power just a little
I assume the difference is because the new power supply is "getting up to power" quicker *shrug*.

John

[Tech_Marco]

No! For small tube, even 5~6mA shouldn't do it
I think you should see our tube and you will be amazed to see how stable it is

"%" is not significant but the true current matter. Different power supply has different charastertics. % is for reference but not for true output.

Let me have my staff to run a demo and pust it on Youtube


Marco

[1n2]

No! For small tube, even 5~6mA shouldn't do it
I think you should see our tube and you will be amazed to see how stable it is

"%" is not significant but the true current matter. Different power supply has different charastertics. % is for reference but not for true output.

Let me have my staff to run a demo and pust it on Youtube


Marco

Thanks Marco
I appreciate that Ma is what matters

...Tomorrow, as a test, I shall remove the ammeter and make a direct Neutral for the tube and see if that changes things.
Also I will double check my earths/Grounds (though I am positive they are good!).
It may this instability that makes me feel that the beam is a bit "harsh" not stronger but coarser somehow.. the engraving seems to leave more ridges than it ever did although very low power and slow speeds seems to offset this a bit.

John

[Tech_Marco]

I found out that even though with low current like 3~5mA, the beam closed to the cathode would moved around. If I used a 60W to power a 700mm tube, it bouncing of beam happened quite a bit. However, if I used a 40W power supply(single HV transformer), the beam stayed still at 1~2.8mA. But it start to moved rapidly at 3~5mA. But once it hit somewhere 15mA or up, it was more stay there. The purple beam inside of the tube that most folks called it "plasma". It is electronics 'flow'. The color of purples is a reaction to the gas. If you see "yellow", it is not good.

The beam moved was due to the imperfectly of metal conductor on the cathode. Electronics always choosing 'short' route (resistance) to flow. But once current flow reached certain level, it will become stable because the electronic flow got situated.

http://www.youtube.com/watch?v=ABP9F3gemsc

I did test two tubes: 700mm and 830mm. So John, I think you're fine

Correct me if I were wrong.


Marco

[1n2]

Thank you for all your effort Marco you are a star.

Well I am going to order a honeycomb bed from you in a few mins.

Its a shame you are something like 5000 miles away because your prices are good but the shipping ,import duty (and the bit that REALLY hurts is the ££ they charge to open the package to inspect it so see how much tax to sting you on it) things start getting expensive

Keep up the good work!

John