Recent 24 watt diode laser engraver seems to be putting out 14.5 watts on materials test

Community Laser Talk
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I received a 24 watt laser from Wizmaker which seemed to be well constructed, not the flimsy 2020 rail construction suitable for lighter weight laser modules.

Once set up I ran an immediate materials test on 2.7mm bass ply and did the same with my current 10 watt. My 10 watt produced a clean cut at 456 mm/min while the 24 watt maxed out at the same settings at 611 mm/min, approximately 1.4 times faster or 14.5 watts worth of cutting power. When I queried support, they stated that that is normal and that their 36 watt laser only doubles the cutting thickness of black acrylic. Since we are talking apples and oranges, their response was meaningless. In prior evaluations of 20 watt lasers they seemed to double the cutting speeds for the same results but I had never done an accurate side by side on the same panel.
I am returning the laser this morning but would like to know if itā€™s me or the laser. Bottom line is that I need the cutting power of 24 watts for a forthcoming project and the Wizzbang isnā€™t going to cut itā€¦pun intended!

To sum up I have assumed that doubling the power would allow doubling the cutting speed Ā± ā€¦is that correct?
Bob

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(Note that I am in the process of replacing all the Vslot wheels in the Kentok laser to the labels are a bit squigglyā€¦

UPDATE: Duh! If you look at the 24 watt materials test the 47.5% power cuts clean at 300 mm/min and the 100% power cuts clean at 611 mm/min. I ran a similar test on the 10 watt Kentoktool with 100 to 500 mm at 50% and 100% max and got exactly the same results. Double the power, double the speed. So it does look like Wizmaker is pedaling a 24watt machine that actually puts out 14.5 watts.

This is a well known Chinese expression, especially in Shenzhen: 呃得就呃. Translated it means, ā€œIf you can cheat, then cheatā€ I think the western equivalent expression in English is: ā€œThereā€™s a sucker born every minuteā€
Bob

2

Sounds pretty typical, unfortunately.

Many times the factory stated focus distance is not correct.

Iā€™d suggest a ramp test if you havenā€™t done one to check for the proper focusā€¦ before shipping it backā€¦

The lens/focus is what makes a laser workā€¦ so focus is critical.

Good luck

:smile_cat:

3

Thanks Jack!

No focus was perfect, I had already tested. The laser claims .06 x .06 and the frame is very robust as well. And again, the factory stated my finds were accurate. I am a former photography professor and architectural photographer, so I understand focus and depth of field.
Bob

4

If youā€™re sure focus is correct, I donā€™t have any further suggestionsā€¦

They look like a very nice machineā€¦ pretty fast alsoā€¦

Let us know the outcomeā€¦

Good luck

:smile_cat:

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Thanks. I was pleased with everything but the power. The module seems to be very similar to the Atomstack 24 watt which I had tested and seemed to perform as expected. I returned it because their air assist nozzle was defective and they refused to address it. Told me speak to Amazonā€¦so I didā€¦back it went. But the Wizmaker was a far better build.
BTW I am close to Orange Grove and I10ā€¦
Bob

6

No outcomeā€¦dropped it off at UPS this morning! I may revisit Wiz with their ā€œ36 wattā€ unit. Maybe I can eek 25 watts out of it. I have confirmed above that double the speed, double the power, so if an unknown laser cuts clean at 600 mm and a 10 watt at 300mm, same wood, etc then the unknown laser would be around 20 watts. Interesting discoveryā€¦
Bob

7

Then you will understand that optical focus is not the same as intensity focus and lases use Intensity focus not optical focus. You will understand Collimation that occurs with multiple diodes. which is why 20w is not double 10w ( 4 diodes Vs 2 )

1 Like
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Everything Iā€™ve read seems to indicate a 30w is approx twice as powerful(fast) as a 10W. Due to optical losses at the mirrors. You would have to see how the various module types are laid out to make any inference on how that translates to the even higher power machinesā€¦40-50Wā€¦ fewer diodes/sources would seem to favor better efficiency and throughput. ie, 2x 10W diodes with one mirror would be more effective than 4x 5W diodes with three mirrors.

More mirrors and diodes also adds diffraction and misalignment, so spot size grows and power density drops.

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I get that. Assuming the 6 watt they claim for each diode doesnā€™t account for the losses. Is it 6 watts after collimation or 6 watts at the source? Or is it 120 watts, as some lasers claim on Amazon?
I feel comfortable that if the only variables are speed and power then speed and power are directly proportional, On the other hand 4 collimated ā€œ6 wattā€ lasers may or may not produce 24 watts at the work surface. I have seen listing for lasers that state 20-24 watts for power output. But regardless of what this laser claims, based on real world cutting speeds, compared to a 2 year old 10 watt collimated laser, the output is 14.45 watts, a far cry from a claimed 24 watts. In retrospect, possibly one of the lasers wasnā€™t firing and I would have followed up with Wizmaker had they not informed me that my tests were accurate. They were, however, confusing cutting speed vs. power vs cutting depth which then has many more variables. They stated that it takes a 36 watt laser to double the cutting depth of a 12 watt laserā€¦but of course cutting thicker materials introduce a whole different set of variable which a Lightburn materials test does not.

I will revisit the Wizmaker or similar in October when I get caught up on other projects, but for now I feel comfortable that the laser was, infact, defective. Assuming 4 x ā€œ6 wattā€ lasers theoretically resulting in Ā±20 watts at the work surface but should only 3 be operational, that would explain the 14.45 watts Ā± at the work surface. Unfortunately Senzhen has gone on their 5 day fall break so I decided to end the process of resolving the issue and simply return the product. I will have to wait up to 5 weeks for a refund.
Thanks for all the input. I actually learned a few thingsā€¦
Bob

10

Yes everything I have seen and read says 6w at source, yes definitely sounds like you have 1 diode failed from your results.

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I just informed them that was my diagnosis of the problem. Seems that there are now a number of similar lasers availableā€¦spoiled for choiceā€¦
Go raibh maith agat
Bob

12

Can you explain thisā€¦ I thought I understood how a lens worksā€¦?

The part of the laser that makes it work is itā€™s focus. Generally we focus with a ramp test. This indicates proper focusā€¦ How optical focus is different eludes meā€¦

An example of this anomaly would be great and most welcome addition to help understand your position.

Surprisingly these are pretty powerful and have about a 5% lossā€¦

The module consists of 6 - 6W dpssl (diodes). If you notice they lose 1.8W through the mirrors/combiners. They seem to perform well ā€¦ Hopefully this one module wasnā€™t picked out because it had superior performance. :thinking:

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This is a ~150W unit, this of course is input power. Most everything is rated with input power. You light bulbs, stove, computer ā€¦etc do not relate to output of any kind.

People wiring stuff up, like your home, need to supply enough current for the device, irrelevant of what kind of output it has.

Co2 machines are difficult to deal with using input power, output is a more useful/meaningful metric. Most scientific lasers have, at least an output power rating.

Co2 lasers, because of light amplification, they need to be very precisely aligned during manufacture to extremely tight tolerances. Remember they are working with molten glass and mirrors. I understand the tolerances are in fractions of the wavelength.

Those that donā€™t pass inspection are not thrown out, but sold to vendors who buy them at lower cost, even though they are grade B type tubes. These commonly have a lower output that they shouldā€¦ The internet is one of the main places these are sold. A Reci tube is still a Reci tube even if it fails testing. These people sell them as new Reci tubes, which is technically correct, but far from truthful.

Although Iā€™m sure similar thing happens with these solid state machines during manufacturer. I doubt most of these can be corrected after they manufacture them.

Some donā€™t perform as specified, they get jarred or something happens during shipment enough to cause a misalignmentā€¦

Even with three 6W, there should be about a 5% loss from source to table. That 14.45W is almost 20% loss rateā€¦ from the 18W source. It would almost indicate a major misalignment?

Could be worse ā€¦ Chinese new yearā€¦ :crazy_face:

Good luck and have funā€¦

:smile_cat:

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Yeah, I was wondering too. Incoherent and coherent light do not take different paths thru lenses. Incoherent can get hot too. Ever fry an ant with a magnifying glass?

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I am a former photography professor so I know a bit about light, less about coherent light.When you fry an ant, you are using a spectrum of light, probably from infra red to UV, but we only see the visible spectrum, and use that to determine the focal point where the light and heat will be most concentrated. The magnifying glass, or a camera lens, is designed to have a refractive index centered around the visual spectrum, however light of different frequencies will focus at different points. This is why all proper optical lenses are coated to hell all frequencies achieve similar focal points. A cheap, uncoated, lens will display chromatic aberration where the blues and reds focus differently:
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Since we use coherent light in a very narrow spectrum, the light can still be focused but the refractive index of the lens needs to be compatible with the frequency of the laser. So your magnifying glass may have now affect on a laser if the glass is not compatible with the spectrum.
Thatā€™s my take on fired antsā€¦
Bob

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The only reasonable explanation is that only 3 lasers are firingā€¦

Bob

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Everything I have done refutes what you have readā€¦but the problem is sometime they are referring to cutting depth which is a crap shoot. I am simply stating that double the output power and you can double the cutting speed, all other variables being equal. I can well imagine it would take triple the power to cut through double the thicknessā€¦unless we are talking about a few millimeters, well withing the depth of field (focus) of the beam.
Bob

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I believe this helps explain intensity vs optical focusā€¦ I assume locating the waist at the workpiece surface would be optical focus.

Many maths and words

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I think when I burn a line on a ramp test, I can tell where the best distance for focus isā€¦

I donā€™t think I can do better than actually measuring it?

Iā€™m willing to make adjustmentsā€¦

:smile_cat:

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Iā€™m sorry, this makes no sense. Is this a coherent beam of light or something else? It certainly doesnā€™t apply to visible light optics where the focal point is always on the ā€œfilm planeā€ (sensor plane, retina, etc) Please elucidate!
Thanks,
Maybe this is from the Star Trek Tractor beam??

Bob

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Itā€™s from EO Edmund Optics: Laser Optics Resource Guide > Section 2.1 - Gaussian Beam Propagation.

Thereā€™s a ton of highly technical details there. Dig in, Professor. My math skills arenā€™t great, so most of itā€™s over my head.