Marking Plastics

[Darren Wilson]

Hello All,
I've had my fiber laser now for about a month. Been able to find some good info on marking metals and pretty happy with the results so far. What I'm struggling with is the plastics. I was given one basic setting form the laser mfg, Maxphotonics and it works with some materials but definitely not all. See attached photos.
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These are both Screwdrivers from same mfg, the handles are the same material just one is orange the other red. From the photos it is hard to see but the red looks nice and dark, while the mark on the orange one is grey and faint. Marks were made with 20w Fiber/f=160 lens and parameters as follows:
Speed:2000, Power:25, Freq: 60kHz, Pulse Width:50
Fill: Double Line w/.01 @ 90/180
Is this normal? I could see an issue if one was a black handle and the other red, but from red to orange?
Not quite sure how to go about tweaking the settings to get a darker mark, any help would be greatly appreciated.
Daz

[Kev Williams]

First of all, 'pulse width', do you have a MOPA?

Second, your line angles of 90/180 are the same angle, only difference is one will start from end X and move to end Y, the other will start at Y and move to X - what may help is a 90/0 or 45/135 which results in right-angle cross hatching...

Third, you can probably move the .01 hatch spacing to .03, however, with plastics who knows, you may even need to tighten it up!

And finally, speed and frequency-- the balance between these two is the most important. I just barely finished up a batch of I-pads. These things I found, are touchy- My dialed-in settings were 1800 speed, 35 power (30w) and 52 frequency-- This was as good as it got, and 52khz was THEE optimal frequency- 48khz resulted in burning thru the top layer of whatever these things are, and into the second layer, which engraved blotchy- 50khz was very good, but under a loupe I was noticing small spots of burn thru. 55khz resulted in barely getting thru the anodizing resulting in a light gray. Very consistent, but gray. I zeroed in on 52khz as the brightest white with no evidence of burn thru...

I could have moved speed and power settings, but just moving the freq just +/- 3khz resulted in drastic differences. If anything, lower power and a bit faster may have given me more freq leeway.

I've also found copper to have a very narrow sweet spot with fiber marking. Plexiglass too..

My point is simply, when you're close (and you are), try tweaking the freq in 2khz increments. With luck, you'll find the number that makes all the difference! :)

[Darren Wilson]

Hi Kev,
Yes, it is a MOPA and been very difficult to find info on setting Pulse Width, aside from some SPI documentation which has preset waveforms with some reference to PW. My unit is adjustable from 4ns to 260ns with rep Freq, 20-1000kHz
I was given a few basic settings for metals and black oxide on clear anodized (ipad, etc.) but very difficult to find much on hatching and other parameters.

I did some more some tweaking last night and ended up with a bit better and bit worse mark, but still haven't found the "sweet spot" for this Orange Plastic ( I think it's acetate) All of the Red handled S/D came out great, just a bit of foaming and nice dark mark. I found going over the orange a few times (3-4) helped out but still kind of grey. Will try again using smaller frequency increments as suggested, I was jumping 10kHz. Will also try 90/0 and 45/130 to see if there is any change, although 180 and 0 should be same looking at compass and I can see the marking happening at perpendicular.

Thanks for your suggestions
Daz

[Rodne Gold]

Not all plastics work well .. you have to suck it and see some times, as you have discovered :)

[Darren Wilson]

Hello Rodne,

So I am learning! I found a .pdf with quite a few basic settings, from TYKMA. Great place to start, but not sure where to place the pulse width. I'm starting to wonder if I should have started with a Q-switched model, and then moved on to MOPA.

These laser sure do make a great looking mark when settings are dialed in...
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[Kev Williams]

I just found a great PDF from Datalogic that explains a LOT about fiber lasers (theirs, of course) ;)

--I've downloaded it, heres the linky:

https://www.datalogic.com/upload/ia/prodlit/reference%20guide/RG-LaserMarking-ENA4.pdf

I haven't read thru the whole thing, but I DID find what I was looking for on page 16, highlighted in red: A pulse width 'starting point' based on Q-switched fibers :D
(hope this helps!)



FIBER LASER
Fiber lasers are not new in Industrial Laser Marking, CW fiber sources have been used for high speed marking of integrated circuits (IC) since
1998. In recent years, fiber lasers have tremendously progressed in terms of flexibility and overall performance enabling the ‘Fiber Revolution’ in
the laser market.
With a monolithic, solid state, fiber-to-fiber design which eliminates mirrors and optics to align or adjust, fiber lasers have technological
advantages that dramatically improve reliability and repeatability of laser processes.
Fiber lasers also offer integration and operational advantages:

• Fiber lasers are compact and deliver their energy through an flexible optical fiber
• Fiber lasers are scalable and more efficient than any other laser technology, with wall-plug efficiencies greater than 30%
• Fiber lasers offer higher and stable beam quality and excellent pulse-to-pulse stability ensuring the best repeatability over time, especially for
critical marking processes
• Q-Switched Fiber lasers offer a long pulse-width (typ 100 nsec) that make these sources the first choice for marking metal in the automotive

industry
• MULTIWAVE M.O.P.A. fiber laser technology offers the capability to select the emission pulsewidth from 4 ns to 250 ns ensuring superb
marking performances in term of process optimization and repeatability.

[Darren Wilson]

Hello Kev,
Thanks mate, will have a read..
djw

[Kev Williams]

was just thinking of some trivia--
light will travel around the earth 7.5 times in 1 second-

in 4 nanoseconds, light travels about 46 inches...

I find it pretty amazing that we can switch something on and off that fast.. :D

[John Stevenson]

was just thinking of some trivia--
light will travel around the earth 7.5 times in 1 second-

in 4 nanoseconds, light travels about 46 inches...

I find it pretty amazing that we can switch something on and off that fast.. :D

Unless you have Lucas electrics fitted to your motorcycle.

I have found you can run over the main beam in excess of 68 mph.

[Lyle Cheredaryk]

Lucas, The Prince of Darkness. Horrible excuse for motorcycle electrics. But plenty of fun to work on.

[Neville Stewart]

And the age old reason why the English drink warm beer, Lucas fridges :/)

[John Stevenson]

Actually we drink proper beer at the right temperature.
It's only when you make that Bid that is made with rice instead of hops that they need to freeze it to hide the rice taste.

[Charles Hawkins]

Being an avid motorcyclist with several Brits under me at times past (1967 Norton Atlas 750 and 1968 BSA Thunderbolt 650) i am in possession of a 1996 Royal Enfield 500 Bullet that I look forward to riding this spring! And yes, the addition of rice hull to make beer is worse than Mr. Lucas' remarkably dim and unreliable lights. The Prince of Darkness is an apt descriptor, as well. I like beer with flavor, not just alcohol!The Canadians had the right idea when they regulated their beer to 5 ingredients.
Hope you get that fiber laser figured out Darren!!


Actually we drink proper beer at the right temperature.
It's only when you make that Bid that is made with rice instead of hops that they need to freeze it to hide the rice taste.

http://forums.mtbr.com/beer-forum/bud-made-43%25-rice-771986.html

[Mike Null]

Being from St. Louis, where that awful stuff is made, I share your disdain for that beverage. I have always contended that it --well, that's best left unsaid.

We did wander a bit off topic here.

[Darren Wilson]

A little off topic but entertaining...
Very familiar with the Lucas, Off, Dim, Intermittent function!