Hobby, 3D, Relief, CNC  

[ Új üzenetek · Tagok · Fórumszabályzat · Keresés · RSS ]
Oldal 30 / 51«1228293031325051»
A fórum moderátora: Amatőr, KisKZ, tweakie 
Fórum » Only in English » Technologies » Diode Lasers. (Using Diode Lasers with CNC Machines.)
Diode Lasers.
JJWMACHINECO Dátum/Date: Hétfő, 2013-04-08, 10:43 | Üzenet/Post # 581
komoly tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 443
Kitüntetések/Medals: 5
Hírnév/Fame: 2
Helyzet/Status: Offline
Welcome to the LD thread Yanxin.

I'm using a Anti Reflective (gold tint) 3 element lens and I'm able to focus it down to .007". That is the line size it engraves and how I know that is, I scanned an engraving and brought the picture into my cad program and measured it. That is why I use between a .007" to .008" step over.

If you read post #164 on page 9, it explains how I focus my lens. You may have your laser diode to far or to close to your material when you focused it. This may be causing the beam to be a rectangular shape.  Or even the wrong type of lens, or like Tweakie explained, a low quality one.

Here is the lens that came with the LD on my new build.

http://www.ebay.com/itm....9.l2649

It appears to be good quality so far, but I have not been able to do any good engravings with it yet because of the vibration of the other machine I first had it mounted on. However, it does appear to burn the same size line as my other machine because of the step over I used when testing it.

Now, to eliminate another issue that could cause problems. I was reading that you are using Bmp2Cnc. Try John's program PicEngrave Pro 4 to generate the code and see if there is a difference. I know when I started, I was using PhotoVcarve to laser engrave photos, I was really struggling to get good quality results.

There is definitely a difference how the two programs generate the code and John has mastered that for the diode laser engraving. Even his standard version works very, very good for this process. Dave, you want to jump in here to confirm this? I use the Z axis and encoder to control the lasers power so there was no editing involved, but you will have to change your drive letter to try out his demo version to see if it works better for you.

Here is a very fast text editor for you to use. http://www.contexteditor.org/

I would not recommend trying this with Notepad or Wordpad!!

Jeff


Extensivly Re-worked/Re-designed/Modified Servo K2CNC KG-3925 and the Mini Laser Engraver

Az üzenetet módosította/Modified by JJWMACHINECO - Hétfő, 2013-04-08, 11:04
 
Dave Dátum/Date: Hétfő, 2013-04-08, 12:16 | Üzenet/Post # 582
aktív tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 192
Kitüntetések/Medals: 1
Hírnév/Fame: 0
Helyzet/Status: Offline
Hi Yanxin, and welcome! I find that John's program does a really good job. I'm using the C-axis step and direction lines to control the digital to analog circuit that feeds the laser driver. I'll point out that even the smallest vibration can move the laser beam enough to blur the image. As far as I can tell at the focus mine looks like a single dot, but if projected on a distant wall it looks like 3 parallel lines.  
Dave
 
picengraver Dátum/Date: Hétfő, 2013-04-08, 13:06 | Üzenet/Post # 583
Fontos tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 528
Kitüntetések/Medals: 3
Hírnév/Fame: 2
Helyzet/Status: Offline
Hi Yanxin,
We're glad to have you join this group of laser diode pioneers.  It is a very exciting and dynamic group of enthusiasts.

Using Google Chrome with its auto translate can help you navigate all the forums here.

I think most of us on this English section are using the 445 diode.  I seem to be the only one with the line problem, and my lines I know are related to the cheap lead screws I used.  Looking at an image with a strong magnifying glass confirms this.  Rotating the diode did not help, and engraving in a vertical direction didn't either.  I am building a new machine and will use belt drives to see if they will eliminate the problem.  If so, it will confirm my opinion. 

Please send me a brief email when you read this to: picengraveATverizon.net .

Again, welcome,
John


I paint with a blue light beam.
 
yywind Dátum/Date: Hétfő, 2013-04-08, 21:40 | Üzenet/Post # 584
nézelődő tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 7
Kitüntetések/Medals: 0
Hírnév/Fame: 0
Helyzet/Status: Offline
Hi Tweakie, finally I am here, sorry stayed too long in your mach3 thread tongue . Laser engraving is a new world to me, with current trouble/experience I am having I already understand how much work you guys have put into this and shared all with us, many thanks to you all!

Jeff, many thanks for the information, I'll definitely try John's PEP and the lens you are using, I am also using a similar type of lens, 3 elements with yellow coating, maybe the focusing distance will make a difference. The distance between my lens and burning surface is about 5-6 cm, maybe too close, what's the distance in your setup?

Dave, thanks for you information and your DAC circuit, it works great. Yes, I will try John's PEP, I am trying to gain some knowledge at this stage.

John, thanks for inviting me here. I am still experimenting with the diode regarding different angles, distance and different lens later, plywood responses better with different angles but MDF is a little frustrating, can only say it's getting better, at the same time my Y axis need to be fixed too, need to change to a higher quality lead screw. I'll try your PEP soon.(email sent)


Az üzenetet módosította/Modified by yywind - Hétfő, 2013-04-08, 22:00
 
JJWMACHINECO Dátum/Date: Hétfő, 2013-04-08, 22:19 | Üzenet/Post # 585
komoly tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 443
Kitüntetések/Medals: 5
Hírnév/Fame: 2
Helyzet/Status: Offline
Hi YanXin,

Below is the quote where I explained to Dave how I focused my lens. You are about 1.00" closer to your material then what my setup is. Dave may be able to tell you if it worked for him, or how he ended up focusing his. Sounds like you have the correct lens though. Most likely it's a gold tint, not yellow.

Jeff

Idézet JJWMACHINECO

Dave,

the laser focal point takes 2 different steps or adjustments. One is the distance off your stock and the other is the focusing lens distance from the laser diode. To initially set it on mine was to bottom the Z axis all the way down and then I gave it a distance of .100" up as a starting point. Since my Z axis is 2-1 ratio, that was a .200" MDI move up. At that point since you have the same laser I do, that is exactly 3.00" off the table to the nose of the laser diode host. Not the heat sink. My piece of anodized aluminum is .75" thick (same thickness as my Birch ply) I moved up .75" actual distance or 1.5" MDI because of the 2-1 ratio. I rotated the focusing lens until the beam was the smallest on the black anodized aluminum.

Measuring the end of the focusing lens from the nose of the diode host, it's exactly .312". If your anywhere near 4.25" off your stock to the laser lens, then your way off based on my calibration method of focusing the lens. Try setting yours by making the nose of the diode host 3.00" off the table and make the focus lens stick out the host .312" and see what you get. The lens part that sticks out does not have any threads part way up. Maybe your lens is in upside down also. Of course you will have to move up the thickness of your stock from there to engrave.


Extensivly Re-worked/Re-designed/Modified Servo K2CNC KG-3925 and the Mini Laser Engraver

Az üzenetet módosította/Modified by JJWMACHINECO - Hétfő, 2013-04-08, 22:39
 
Dave Dátum/Date: Kedd, 2013-04-09, 03:53 | Üzenet/Post # 586
aktív tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 192
Kitüntetések/Medals: 1
Hírnév/Fame: 0
Helyzet/Status: Offline
I did some testing of the focus on my laser today. Shining the laser on the wall gives a rectangular pattern, and I wanted to see if turning the lens had any effect on the rectangle's orientation. It doesn't. My lens is also coated in a yellowish color, and appears to have at least two elements. My process for determining the focus is bit different from Jeff's, as I have trouble telling how small the beam is when it's focused. I set the laser housing so the beam is horizontal, and blow some smoke across the beam and measure from the front of the housing to the narrowest part of the beam cone. I used a small machinist square positioned to where the beam is narrowest, and measured the distance between the square and the laser housing with calipers.
 
To me, it looks about the same thickness whether the focus distance is 1 inch or 4 inches. The only difference I can see is that the angle of the cone is different. Seems to me that another way to do this would be to project the beam onto a distant target beyond the focal point, while intercepting the beam with a knife edge at the focus. At the focal point, the amount of movement of the knife edge perpendicular to the beam should be the least as it cuts off the beam quickly and entirely. I.E at the focus, you shouldn't be able to tell which side of the projected beam image on the wall gets cut off first. A similar method is used for testing telescope mirrors at their center of curvature. 
(  http://en.wikipedia.org/wiki/Foucault_knife-edge_test  )  Don't look into the laser beam if you do this, just look at the rectangular shaped beam as it's projected on the wall! I find it easier to do the smoke test wacko
Dave
 
JJWMACHINECO Dátum/Date: Kedd, 2013-04-09, 13:47 | Üzenet/Post # 587
komoly tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 443
Kitüntetések/Medals: 5
Hírnév/Fame: 2
Helyzet/Status: Offline
Hi Dave,

You have the same laser as I do and the seller claimed the lens was a 3 element glass AR coated which he said the coating was gold in color. It does look yellow'ish, but that is what he claimed. Also the new lenses I have the seller (different seller) claims the coating is gold too.

Interpretation of color doesn't matter, it sounds like Yanxin has the correct one as long it's not blue.

I'm curious, what kind of smoke works best for this focusing process?  smok

Jeff


Extensivly Re-worked/Re-designed/Modified Servo K2CNC KG-3925 and the Mini Laser Engraver
 
yywind Dátum/Date: Kedd, 2013-04-09, 15:05 | Üzenet/Post # 588
nézelődő tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 7
Kitüntetések/Medals: 0
Hírnév/Fame: 0
Helyzet/Status: Offline
Hi Jeff,

I ordered the lens you mentioned, should get it in a couple days, hope that makes some difference. And thanks for the focusing techniques you and Dave mentioned.

Yanxin
 
Bodini Dátum/Date: Kedd, 2013-04-09, 15:07 | Üzenet/Post # 589
nézelődő tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 3
Kitüntetések/Medals: 0
Hírnév/Fame: 0
Helyzet/Status: Offline
I waited too long to buy a diode driver board from that dude in the Netherlands (badpip).  I sent him a message but no reply.  I read elsewhere that he assembles them himself, so I suppose he will build a batch and relist on Ebay.  Guess I'll have to order one of those chinese box things, although I hate to give them any more American money than I have to.  I suppose on the day that the chinese driver gets delivered, badpip will repost. ;-)
 
Dave Dátum/Date: Kedd, 2013-04-09, 15:46 | Üzenet/Post # 590
aktív tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 192
Kitüntetések/Medals: 1
Hírnév/Fame: 0
Helyzet/Status: Offline
Hi Jeff,
AR coatings for lenses for visible light are generally magnesium flouride evaporated/deposited in a vacuum. The stuff is clear, the color comes from reflections from the front and rear surfaces interfering with each other. different colors of reflected light are related to the thickness of the coating that's 1/4 wavelength thick for a particular color of light.
I'm thinking about one of those FAP lasers but not sure they'd work the way we're trying to use them. Looks like a wavelength of 808nm from what I've read so far. An array of diodes feeding a fiber optic cable....  or maybe one of these:
http://en.wikipedia.org/wiki/National_Ignition_Facility  wacko
 
Dave
 
JJWMACHINECO Dátum/Date: Kedd, 2013-04-09, 16:47 | Üzenet/Post # 591
komoly tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 443
Kitüntetések/Medals: 5
Hírnév/Fame: 2
Helyzet/Status: Offline
That's interesting Dave,

I'm just referencing what color tint I see on the lens. All that other info and the process to coat the lens will just overload my small hard drive, so I just sent it to the Recycle Bin.  biggrin

Yanxin,

Like I said, it sounds like you had the correct lens, but it doesn't hurt to have spares.

Darn Nick,

that's a shame. Yanxin built his own laser driver and maybe he can post that info here for you to consider.

Jeff 



Extensivly Re-worked/Re-designed/Modified Servo K2CNC KG-3925 and the Mini Laser Engraver
 
picengraver Dátum/Date: Kedd, 2013-04-09, 18:02 | Üzenet/Post # 592
Fontos tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 528
Kitüntetések/Medals: 3
Hírnév/Fame: 2
Helyzet/Status: Offline
Yanxin,
Be sure when your lenses arrive that they are indeed gold tinted.  The seller is very reputable, but he did send both Jeff and me the wrong lenses.  He answered right away when we contacted him and is sending the right ones to me; Jeff already got his replacements.

Dave,
I think Peter is using 808.  Perhaps he will confirm. 

Maybe you could just use one of these biggrin :



ABC OTUS News - Navy's New Laser Weapon Blasts Bad Guys From Air, Sea (ABC News)

Nick,
I heard/read somewhere that the Denmark seller is in school full time, and he has not answered our friend Dan either from a couple of weeks ago.  Dan has another circuit he is going to build; maybe he will post about it here if he reads this.  It's always good to have options.

John


I paint with a blue light beam.
 
JJWMACHINECO Dátum/Date: Kedd, 2013-04-09, 18:34 | Üzenet/Post # 593
komoly tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 443
Kitüntetések/Medals: 5
Hírnév/Fame: 2
Helyzet/Status: Offline
John,

I want one of those. I could engrave 8bit shaded photos on the moon with that one.  laugh

Jeff

Hozzáadva (2013-04-09, 18:34)
---------------------------------------------
How about this 50kw one.

http://www.tgdaily.com/securit....zerland


Extensivly Re-worked/Re-designed/Modified Servo K2CNC KG-3925 and the Mini Laser Engraver
 
yywind Dátum/Date: Kedd, 2013-04-09, 21:37 | Üzenet/Post # 594
nézelődő tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 7
Kitüntetések/Medals: 0
Hírnév/Fame: 0
Helyzet/Status: Offline
My driver is based on Die4Drive(v1.2, free for personal use), I believe it's similar to FlexMod, Flexmod has floating ground(I may remember wrong, may not be useful for most of us) and maybe use different op amp, MOSFET and has more protections, wider supply voltages and power. It's possible to replace the MOSFET in the Die4Drive driver with a better one(such as NTP30N06L) to get more power(+3w). I replaced the sense resister with 0.33ohm(Flexmod is using 0.2ohm I believe), I am getting 1.65A max output current for my M140 LD. The power supply is +5v, the voltage I get max between LD is 4.65v, more than enough for M140, be aware that some LDs require higher forward voltage, so it may not work for all types of LDs. However, I accidentally supplied the voltage up up to +9v for several minutes and did not cause any problems. cry See below for the schematics and my ugly driver(I use four diodes and one 1ohm 5W resistor for testing, it's close to 445nm 2w LD).

BTW, I got PEP from John(many thanks), I am playing around with it. In the next couple of days, I'll probably convert/fix my Y axis first before doing anything further.

Yanxin
Csatolások/Attachments: Die4DriveRev1-2.pdf(16Kb) · 5974855.jpg(27Kb) · 5099904.jpg(36Kb)


Az üzenetet módosította/Modified by yywind - Kedd, 2013-04-09, 21:57
 
Dave Dátum/Date: Szerda, 2013-04-10, 03:42 | Üzenet/Post # 595
aktív tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 192
Kitüntetések/Medals: 1
Hírnév/Fame: 0
Helyzet/Status: Offline
Hi Jeff, sorry, didn't mean to fill up your hard drive. Feel free to put it wherever it fits biggrin
 
Dave
 
yywind Dátum/Date: Szerda, 2013-04-10, 03:52 | Üzenet/Post # 596
nézelődő tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 7
Kitüntetések/Medals: 0
Hírnév/Fame: 0
Helyzet/Status: Offline
I actually got some time this afternoon and fixed the Y axis, burned a small picture(2"x3") and the picture came out absolutely beautiful, no more dark lines! I am happy. Picture on the left is before the fix, on the right is after the fix. It's time to burn bigger ones to see what happens. Oops, running out of wood supplies. wacko

John, I looked your pictures at Page 14, looks like we have the same problem with thin lines, hope the new lens will help, what lens are you using?

Yanxin

Csatolások/Attachments: 6717732.jpg(55Kb)


Az üzenetet módosította/Modified by yywind - Szerda, 2013-04-10, 04:11
 
picengraver Dátum/Date: Szerda, 2013-04-10, 12:07 | Üzenet/Post # 597
Fontos tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 528
Kitüntetések/Medals: 3
Hírnév/Fame: 2
Helyzet/Status: Offline
Congratulations Yanxin,
Looks like we have you hooked real good now. smile  

I'm using a G2 (?) lens, which is a more expensive, single element lens.  It seems to focus to a smaller line than Jeff reports, because at 0.007 inch line spacings I can still see the individual lines with a magnifying glass.  The replacements I have coming are the three element ones, same as Jeff as others are using.  I'm trying hard to catch up to Jeff, but really not expecting to be able to do so. sad

I am pretty sure that my machine's lead screws are the cause of my line problem.  When I change engraving angles, the lines change also.  The new lens will help me determine the cause for certain.

i am also building a new, belt driven machine.  I started the frame last week, but yesterday I ordered a new X/Y assembly designed for a CO2 laser.  
http://www.lightobject.com/Lite-40....15.aspx
It has a working size of 16 x 24 inches, and a speed specification of +1100 ipm/500mm/s (way too fast for an LD, of course).  I have to wait for it to arrive before I can work up a final design.  Hopefully, this will be a platform that will help me further improve PicEngrave with some new features I have in mind.  I also want to do larger portraits.

Regards,
John



I paint with a blue light beam.
 
tweakie Dátum/Date: Szerda, 2013-04-10, 12:16 | Üzenet/Post # 598
alapvető tag
Csoport/Group: Adminisztrátorok
Üzenetek/Posts: 978
Kitüntetések/Medals: 6
Hírnév/Fame: 5
Helyzet/Status: Offline
Nice CNC frame John - Looks like a CO2 tube is certainly on the horizon. yes

Tweakie.


Success consists of going from failure to failure without loss of enthusiasm.
 
JJWMACHINECO Dátum/Date: Szerda, 2013-04-10, 13:10 | Üzenet/Post # 599
komoly tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 443
Kitüntetések/Medals: 5
Hírnév/Fame: 2
Helyzet/Status: Offline
Hi Yanxin,

Looks like your on your way to laser engraving success. To give you an idea on the settings I use with PEP to analog laser an image on wood. Since my laser will burn a .007" line, I use .008" pixel resolution. When editing the file in PEP, I multiply one of the axis dimensions the desired size I want to engrave by 1.25 and input that number into the corresponding axis. I used Gamma to adjust the image to the desired brightness/contrast. Then I have been sharpening the image between 5-20. I go to the lower end for animals with allot of hair, and to the higher setting for people/buildings/landscapes. Drew is not that hairy, so try between 16-20.  biggrin

With the laser power that I have, between 45-50IPM works the best for Birch Ply. You will have to play with the feedrates based on your laser diodes power, the type of wood and how dark/light your image is. Accel/CV settings are important also and you will have to play with those settings too.

John,

You have done some laser engravings that has blown mine out of the water. I have a different setup then you do and I believe it's the ballscrews that has made a difference on most of them. I have not been able to get as good results as you have on artist canvas and maybe it's the lens I'm using. My TTL ones came out good, but the analog and VFR ones suck.  facepalm

Darn, I wish those CNC frames were available when I bought my mini router. That is considerably more travel/speed and allot better price.

Jeff


Extensivly Re-worked/Re-designed/Modified Servo K2CNC KG-3925 and the Mini Laser Engraver
 
yywind Dátum/Date: Péntek, 2013-04-12, 22:33 | Üzenet/Post # 600
nézelődő tag
Csoport/Group: Felhasználók
Üzenetek/Posts: 7
Kitüntetések/Medals: 0
Hírnév/Fame: 0
Helyzet/Status: Offline
John & Jeff, thanks for the information. And, John, the frame looks great and also good price for such a large working area.
My Y axis is way too heavy because X is laying on top of Y and whole thing is made by MDF, both X and Y move freely with tips of fingers when machine is not powered on. The two ball bearings at each end of the threaded rods are not very high quality, the center of the bearings moves a little bit when pushed harder, so when this big chunk of stuff moves/stops, I can imagine what will happen. Everything of the machine is hand-made, even the anti-backlash lead screws, for what I have achieved with this machine so far, it exceeded my expectations tongue . I can still see light darker lines in some area, but it's fine for me at the moment. I Just need a lighter and more accurate machine dedicated for laser.

Hozzáadva (2013-04-12, 22:33)
---------------------------------------------
I accidentally destroyed my diode by connecting a defective digital ammeter to it sad , it's not totally died but outputting much less power and the power is no longer proportional to the current. This time I'll get another module from the ebay seller Jeff mentioned, I'll be out of town for the next two months,  probably John's new machine will be ready once I am back.

Az üzenetet módosította/Modified by yywind - Szerda, 2013-04-10, 14:57
 
Fórum » Only in English » Technologies » Diode Lasers. (Using Diode Lasers with CNC Machines.)
Oldal 30 / 51«1228293031325051»
Keresés:

Copyright HobbyCnCArt © 2017