Laser cuts stronger at 20% than 99%

Community Laser Talk
21

I have the exact same tube :crazy_face:

They usually specify both maximum and maximum working current. Maximum current is the don’t exceed this. The maximum working current is the where it’s designed to run for the user.

If you run 80% of that, it’s 16mA, and I run that as a general maximum. I push it up to 18mA if I want to cut something heavy like 1/4" (>6mm) acrylic. Note this bump is only to 90% of the working current or where it is designed to work.

If I felt the need, I won’t have a problem running 20mA, that is my maximum setting of the lps.

If I needed this kind of power very often, I’d have purchased a longer, more powerful tube.

It should be insulated, this is clearly not. Once hv punches a hole through something, the damage is done and the insulation can no longer be trusted … hv will reach out and touch something if given the chance… and it’s more than likely it will reach out and touch you…

@bernd.dk suggestion will work fine… I have used these HV connectors from Amazon a number of times. At least Amazon says this is what I ordered. Measure the size of your hv wire… There’s at least two sizes…

My hv meter uses a pair of them in the anode circuit in the electronics cabinet and another set for the tube connection up stream, they are easy to use…

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Another option is a high voltage tape that bonds to itself and blocks a high voltage potential… These are specifically formulated types of tape, not usually found locally. This particular tape is rated at 69kV. I’ve seen this used successfully for these types of issues.

For your application I’d try the tape… ensure you read and understand how to use it properly.

Trust me, you don’t want a surprising and intimate relationship with your lps.

I’ve followed this chart for tube current for a couple of years and it’s always seems to be accurate … So, I’d suspect @bernd.dk is under utilizing his tube … :thinking:

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:smiley_cat:

22

Hi Jack, nice explanation/documentation.
By the way, I have also finally figured out how PWM works, long story :star_struck:

I also have the table you show, but as I said, I made a test series and it showed that after the approx. 18 mA it was the end of the increase in penetration depth. So the 16 mA suits me very well. We also discussed last year whether my tube was 100% ok or not, I really don’t know, but I still cut 16mm acrylic quite nicely with this tube.

23

Don’t say that around the airport… :crazy_face:

All biological creatures does what makes them feel comfortable. If that works for you and does what you want there is no need to change it… moving you to somewhat of a less comfortable state.

IMHO, I see it recur, you buy something and don’t want to damage it, so you don’t really use it fully or at all. Like the kid who buys skates afraid they’ll get scraped or damaged, so he never uses them.

We are so afraid of burning out a tube from too much current we fail to use the tube effectively as it was designed. Tubes and light bulbs are consumables… Can you imagine what it would be like if we looked at light bulbs the same way… keep them turned off and at low levels so we don’t have to buy another one too soon…

Most of the time, I engrave… running power < 20%.

For the < 5% of the time I cut material > 6mm acrylic I have no issue running the manufacturers stated working current of 20mA. That’s what the manufacturer stated as a working current and therefore safe for my tube and my comfort range. My 44W tube was running at nearly your comfortable maximum and doing a good job.

I think we are generally under utilizing these machines in an effort save them (money)… I’ve spent so much more on other parts.

After a year and a half into the experience I have to cough up about $200 for a new grade A tube… less than it costs me a year to maintain my Lightburn license on all my devices…

I also think the temperature during storage has more effect than we think on the tubes gas mixture. I know my machine, when off, sat in the 115 F ambient temperature in Arizona… I know that wasn’t good for it…

I still feel the colder the tube, the lower percentage it will reliably lase… seem backwards …

I have to keep things in perspective…

:smiley_cat:

24

Thanks again for everyone’s tips!

I snipped out the bad part and used a high voltage connected salvaged from the old power supple, and then i put everything in a silicone tube, so seems pretty well insulated now!

Also in terms of the debate for what to set the mA to, cloudray wrote back to me and said:
" after confirmation with the technician,if you aim for to have the machine running at in general,you can set the power as 17mA."

25

I have the same tube and they told me max 20mA working. :face_with_spiral_eyes:

Their numbers makes the upper limit 85% (17/20), I think that’s excessive.

Guess we know what that’s worth… :crazy_face:

Fortunately you get to pick.

When the specifications say maximum working current, I take it as stated.

:smiley_cat: