Ortur Diode Laser Testing

[DougL]

I think you are in luck since I don’t see the bearing housing moving so it looks like it’s just the pressed on soft wheel part. I would take the thing off, find a hard flat surface and then try to straighten it on the bearing.

Maybe in F360:

1. make cm thick block with a slight recess for the bearing(notice it’s slightly proud of the rubber on both sides ). Maybe 1mm deep. Also create a 5mm hole through the center.
2. 3d print this and put the bearing/wheel in it and using the screw and nut tighten it so it moves the rubber flush with the bearing on one side.
3. now flip it over and do it again but now just move it so the bearing is slightly proud of the rubber on both sides.

Should be straight at this point.

[tim.peachey]

Thanks for the suggestion. Now I just need to order and receive a 3D printer to do this with.

Your suggestion is sound. Maybe I can make something using wood and my driller-miller, or even aluminum.

In the meantime, I’ve continued to characterize the behavior of the laser itself. I find that if I take focus slightly off of the sharp line, I get more of a dot burnt into the target. However the kerf is pretty wide at that point. Useful for many applications. As others have pointed out, distance from the lens is only a minor factor. I did a bunch of ramp testing and found that my best results were at about 20 or 30 mm. I also had better results for nice circles if I focused first to the sharp short line, then went off focus by twisting the lens about 20 or 30 degrees.

[DougL]

ya, you really just need something to put a 5mm hole in and then a 1mm shallow round recess. Just gotta be harder than rubber and perpendicular to the 5mm hole. I can print something if you’d like.

Regarding the laser spot, on my low power ramp test I get a .15mm line but at the higher power used to make the arial letter size test I saw a .45mm burn line width but I know I was not exactly on focus. I lowered my whole X axis by moving the nut from above the bearings on the Y axis carriage to above the mounting plate. I’d like to get the focus to the floor since at that point I can adjust up by most material thicknesses. I want to be able to etch something much larger that 160x150.

[tim.peachey]

It was a great idea, Doug. I used a bunch of washers of various sizes. I haven’t had time to test the results in detail yet, but hope to later today.

Meanwhile, I contacted Ortur and Justin agreed to send me 10 wheels. So if anyone else is in need of these wheels, please let me know. I must say I am pleased with Ortur support in this case.

[tim.peachey]

Good thing they are sending replacements. I discovered that the wheels are molded with a land in the center, and a bearing inserted on either side. There is a copper washer inside to keep the land from being over-compressed between the two bearings. In my case, the plastic wheels appear to have been deformed somehow, beyond simple repair.

[DougL]

Tim, if you want wheels faster it turns out the wheels are the same used on the Ender 3 so lots of people sell them on Amazon( Prime 2day options too ). $10…

https://www.amazon.com/Printer-Plastic-Bearing-Passive-Creality/dp/B07RRJ54LK/ref=sr_1_2

[tim.peachey]

Yes, I found those also and ordered them as a backup. Despite being “Prime”, they are scheduled to arrive Saturday, a week after the order

[DougL]

Ya, I learned the hard way to look very hard for where they are shipping from even on Amazon. Bugs me to no end when I find out my 2 day delivery will be 2days+2 weeks.

[DougL]

focusing

https://www.youtube.com/watch?v=AuhHsIySGlo

unfocused, 1/32nd of a turn to focused

[SDFWA]

To be clear, one “monkey hair” is equal to 1/32"?
Remarkable that so little change makes such a difference.
If you do perform this test then please share your results with us.

I’d be curious to know if the Ortur is similarly sensitive.

[DougL]

Well of course I had to try. Not sure yet though and could not get the lines under microscope.

[DougL]

Do the sharp dot focus on black paper, it makes the world of difference. My default focus was 180 degrees off!

[SDFWA]

Correct me if I’m wrong but I don’t see much change with rotation in either direction.

[DougL]

correct and I didn’t know what to make of it. CCW started to look darker but quickly went light at 3-ccw.
But look at the added line in the bottom row, right side. That was after the dot focus on black paper and it is darker than the rest.

A friend had just turned 60 and his wife posted a “Vintage Dude” round emblem and since she is putting together a kit CNC router I told her she’ll need to get a laser for it eventually. She wasn’t sold so I took the emblem and did 3 tests with Lightburn and the Ortur to get the power set so there was decent gray scale and the small test was readable. Well, I just etched that emblem and it burned the letters so much I could not read them. Focus is definitely sharper. Not as obvious with monkey hair adjustments though and I tried a monkey hair CW and CCW from the dot focus point and got inconclusive results. ie CW one monkey hair and surprisingly it didn’t etch the paper. weird. Redid the dot test, the adjustment was slightly different from before ~2 monkey hairs CCW and it burns a dark line like the line etched after the first dot focus adjustment.

Black paper and wearing the laser glasses is a must.

[SDFWA]

Black paper and wearing the laser glasses is a must.

Hmmm, I’ll give it a try when I get my Ortur back.

[Justin-Ortur]

Shared by a talented artist.
PS. I have got his permission to post his photos.
If you have any good photos, want to share with other Ortur users, feel free to send to ortur@ortur3dprinter.com

[DougL]

Setting up for some white tile coasters. Bought 2 types of paint and made a test file for the speeds and power. Also dither vs grayscale. Dither won and so did 25mm/s 80% power.

[SDFWA]

That’s a great array … what was your logic?
Why were the two paints a part of this?
What will you etch on the tiles?

[DougL]

Yes, testing the paint and determine the laser power and speed for the best contrast.

The left(SE) side has to be evaluated a bit more closely than the right. I’d first made a grayscale in Inkscape and saved the SVG and imported into Lightburn thinking it would recognize the grayscale. It did not and showed a hollow box. I exported the PNG from Inkscape and imported and it showed correctly so I just placed on the boxes already there. During the lasing it did the grayscale first and while I wasn’t watching it then rastered the boxes solid black. The result was double lasing and concealing what was previously done. BUT, I caught it before it could finish the re-burn of the 25mm/s-80% tests and you can see a thin strip of the first pass still there. But there’s enough data to indicate to me that the PP paint presents a higher contrast(darker black vs white) at 25mm/s 80% power.

I need to work on why the true grayscale burning method resulted in that very poor 3rd column output.
It is almost as if it just cuts off at a threshold value which is quite high.

Memorial Day weekend was always about the Indy 500 with my Dad so I’ve put together a image to try making a coaster with. Burning it now after generating gcode with Lightburn and sent to the laser cutter controlled with CNCjs off an rPi( in the garage since this stuff is stinky! ).

[ryjones]

Hi - I was puzzled by this as well. Go to move, fire (at whatever tiny percent, I think 0.25 is the lowest) then, with the laser on, hold shift and click “frame”. The laser stays on.