New 50w Fiber Laser

[Tim Bateson]

Not wanting to hijack someone's thread, I started a new one to continue the conversation.

TIM-- trade ya my 30 for your 50...

I'm curious as to why you think 50w is overkill, I've been tempted to get a 60w or higher machine, and very glad I didn't get a 20...

What lens you get with that? A 110mm at 50w would produce a very small and powerful beam spot; might be doing more cutting than engraving, or put another way, more melting than 'chewing' and vaporizing. Even a 160 lens (what I have) might be prone to melting with 50w, but I have NO problem with 30w...

You might try de-focusing a bit, to fatten the beam spot, that'll cool it down and may help with the overkill.

Another idea to try-- with my 30w my settings for deep engraving are 100 power 300 speed 30 freq. with 45/135 hatches at .03, and a 0 hatch at .04 with 800/80/80 as a 'cleanup' pass. Here's the thing, if you look at the beam overlap at 300 speed and 30 freq, it looks like this:
Attachment 367158

Now, double the speed to 600 and the freq to 60, and --
Attachment 367159

--the beam overlap is identical, which means the actual engraving/ablating process should be identical, but with less power density due to the increased engraving speed-- but you have nearly double the power! So, I'm thinking you should experiment with higher speed and frequency, maybe you'll be pleasantly surprised! -- or not..? I do know there IS something to this because when attempting to engrave pure copper, I found a very narrow speed/freq setting that worked, and doubling those settings, also worked. Nearly any other settings wouldn't mark the copper a bit.

speaking of focusing, how are you focusing? Red lights or-? About 2 months ago I decided to run a focus-line test, basically 6" worth of 4" long lines spaced 1mm apart, ran at zero power on anodized aluminum while moving the table up & down to find the sweet spot. When I found it, I took a piece of 1/4" thick Cintra, cut a 1/2" wide piece of it and cut it to fit perfectly between the aluminum I was engraving and the bottom edge of the lens housing. That was one of the best 'upgrades' I've done, and haven't used the red lights for focusing since. Last night for example, I engraved dutch oven lids, and with the focus stick, I could move it around and physically and visually find the 'average' focus distance between the low and high spots in the arc of the lid. With the light you have one spot to focus on and everywhere else is just a guess...

[Tim Bateson]

I am still trying to find the right settings. You seen in another thread that I still am trying to figure out EzCad2 as well. Deep engraving is the first thing I'm working on as that was one of the driving reasons for buying it. I am still trying to develop a good set of parameters. Not much online in the way of a 50w to help. Haven't even attempted to Mark anything or use the rotary.

I got both an f160 (150mm) & an f254 (180mm) lens. So far have only used the standard f160. They give you an aluminum stick for each to set the focus. Are these dead on... again haven't yet done the testing to see if they are perfectly sized.

These are an M&P 45 slide - engraved much deeper than I had intended, but turned out good, and a test piece of aluminum - engraved deeper than my gantry style fiber could ever dream of engraving..

[John Lifer]

Just don't use 100% power

When I started playing with my baby 20w, I got a piece of aluminum tread plate (had several pieces I'd saved from a project) along with a chunk of 2" x 1/8" cold rolled steel flat I had laying around and just went to town trying to see how long it took and settings. I'd bet that 50w makes REAL short work of engraving. Could blow thru an aluminum lower quickly. They are way softer than the plate, and cut quick even with the 20W Just enjoy not taking hours!

[Tim Bateson]

The mistake I made was to use some settings I found online... later I found out they were for a 20w. I should have gotten over to the Metal Supermarket this week & picked up some different types of metals for testing. Maybe next week.

[Kev Williams]

Appears (to me) in your skull engraving that you're indeed melting down the aluminum! Could be partly because the f160 lens you're using is actually a 115mm lens, not 150mm
--the lens f number is the working diameter of the lens, the mm# is the size of a square that will fit inside that diameter-- and that square represents the machines working area. You CAN engrave beyond the boundaries in many places, but the entire circular boundary isn't accessible due to the limits of the mirrors.

so anyway, assuming the lens you're using is indeed an f160, you've really got some firepower going on! If it's not much trouble to change the machine settings (I don't suppose it is but I've never done it) I'd put that 180 lens on and take 'er for a spin-- I'm betting you'll be doing more engraving and less melting and sparks-throwing!

[Michael Henriksen]

Exactly how deep is the engraving in the third picture and how long did it take to do?

[John Lifer]

I didn't see that either Kev, if it is a F160, mine is only marked up as 100x100mm, and my f210 is a 150x150. And I can tell the difference in the two on the 20W machine.

[Tim Bateson]

Exactly how deep is the engraving in the third picture and how long did it take to do?

This is about .04 deep & took just over 10 minutes.

[Tim Bateson]

I didn't see that either Kev, if it is a F160, mine is only marked up as 100x100mm, and my f210 is a 150x150. And I can tell the difference in the two on the 20W machine.

Are you using the F-theta lens?

[Michael Henriksen]

This is about .04 deep & took just over 10 minutes.

That's about 1mm in my part of the World. Not bad at all. Have you tried cutting thin mild sheet steel with it?

[Kev Williams]

I'm no lens guru, but I'm assuming that all the published numbers from different lens mfr's are rounded up or down to suit their preference based on their lenses actual grind size..

I just drew this up in Corel, these are numbers based on EXACTLY 160, 210 and 254mm dimensions...
flens.jpg

there may be some other math formula involved with lens focal numbers I don't know about, but the square in a circle is pretty close..

[Kev Williams]

since I've never really tried to engrave as deep as you did that aluminum sample, I was curious --wondered what this machine would do do in twice the time with 60% of your power and using a 'colder' 150mm lens...
mhafb2.jpgmhafb3.jpg
This measures just under .030" deep, and took 22 minutes-- the entire logo is the size of a nickel. Hatch was .040 'fast hatch', auto rotated, did exactly 100 passes...

With my lesser power and longer lens the aluminum isn't melting down much at all-- I think if you change your lens and get your settings dialed in you should be able to match that in about 12 minutes...

[John Lifer]

Yep, Tim, theta lens. I'd almost bet they are almost all the same. There seem to be two mounting systems. Mine has ring that screws on lens, then into head.

[Tim Bateson]

I'm no lens guru, but I'm assuming that all the published numbers from different lens mfr's are rounded up or down to suit their preference based on their lenses actual grind size....

All I have to go on is what the sales guy told me. The lens themselves say "F-theta lens 1064nm f=160mm" & "F-theta lens 1064nm f=254mm".

[Kev Williams]

Interesting-- so, what's your table's current workspace in EZcad? - top of the screen, click the wrench next to the hatch H button, then hit workspace- It can be anything the user enters, I'm just curious if it's set for 150 or 100-ish..

How long your focus stick may be a clue, mine is almost exactly 9-3/4" long- if your lens is a 150 yours should be pretty close to the same length. If you have a 100-ish lens its stick will be quite a bit shorter--

Red light test-- my table is set for 150mm, and if I draw a 150mm square and red light it onto a piece of 8x8 aluminum, measuring the red light with a regular ruler I get just over 5-7/8", and 150mm=5.9" so pretty much dead on- if I expand the box to 210mm, which is 8.27", the biggest the box will draw is just a hair over 6-9/32", roughly 6.3", or almost exactly 160mm... measure the box diagonally and it comes to 226.27mm.

A 100mm lens is going to max out a red light box at around 4.7", maybe less.

My lens is also an F-theta, 1064nm f210 ...

I'm thinking your sales guy simply misspoke on the lens numbers...