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View Full Version : fiber rotary-- cruel joke, erwhut?



Kev Williams
07-10-2016, 8:17 PM
This about the 2nd most frustrating thing to understand next to.... I won't say it ;)

I've watched the video, engraving the rabbits on a 1" dia piece of ss pipe, and I get the jist of it, the laser engraves a bit, rotary moves, laser continues, etc... There's a thread going about the difficulty in the getting the pieces of graphics to line up. Yet the rabbits they did from the quick look you get, appeared to line up nicely. They also did a video with text-- enter the text, turn it sideways so it engraves around, simple...do a letter, rotate next letter, rotate... easy enough-- it seems. All these guys seem to have done is enter the diameter and go...

So my problem? I have a small aluminum vial I was attempting to engrave. It's 14.3mm in dia (.562"). I'm using a 1/2" drill bit as a test subject. I'm engraving a bunch of names- I did the names in Corel, fitted it to the vial, then saved it as a DXF which I imported. Put the names in, hatch filled, went to 'rotary engrave', put in the 14.3 diameter, drew the red box which had a cross thru it. When I hit start, the thing started engraving the chuck, which was at least 3/8" to the left of the red line boundaries! But, it DID engrave the drill bit in some places, even somewhat correctly.

After that, it got worse. After attempting some adjustments just for fun, pressing start would rotate the chuck about half-way around, then it engraved the full set of names, in 2 vertical-not horizontal- sections, without ever moving the chuck! I ended up putting the table next to the empty chuck with a piece of silver rowmark on it. Changed some other numbers in the software, then ran it. The chuck would rotate, then engrave the right 1/3 of the the graphic from top to bottom- which measures 29mm btw... then the chuck acutally moved, then it engraved the middle third, chuck moved again, and did the last third..

but- the 3 3rds didn't line up, they were all pretty much in the same vertical plane as the last 3rd-- the others didn't move left. And- it's acting like the diameter is more like 14.3 INCHES, since the laser is covering 29 vertical mm on a 14mm part before moving the chuck...

OK, duh, the light just came on in my head-- it was engraving in 'axis swap', putting the names AROUND the cylinder instead of ACROSS it..

OK--I looked for ANY version of 'axis swap'--- FOUND IT! Just a single X or Y choice... OK! Don't remember changing it, but I could have--

So now I'm cookin-- So I start engraving drill bits. YAY, it's doing it right!

Only the sections aren't EVEN lining up. OK, try the split lines--

YES! The names all came out nicely! And readable! And.....

in the wrong order? The names start from the bottom and work up. The engraving's not flipped or mirrored in any way-- so how did it take a stack names- which are DXF graphics- and engrave them from the bottom up, and while engraving from top to bottom...? FWIW the "invert" box is NOT checked...

As you can probably tell I've been typing on this for a couple of hours now... :D

Bert Kemp
07-10-2016, 8:46 PM
Kev go take the boat out on the water take the wife a few beers and relax the rest of ;)the evening come back to work tomorrow and all will be well with the world

Gary Hair
07-10-2016, 8:50 PM
Kev go take the boat out on the water take the rotary and dump it in the water, come back to work tomorrow and all will be well with the world

There, I fixed it for you...

Kev Williams
07-10-2016, 9:12 PM
Wish I COULD put a boat on our lake- but they're pumping it all into the Great Salt Lake. The harbor is only about 28" deep right now... :(

I'll get this thing figgered out...

Rodne Gold
07-11-2016, 2:16 AM
I think we should put all fiber/yag/galvo laser threads in a sticky
I havent attempted to use my rotary..too scared.. will ask Yarde to do a teamview with me today
Kev, what did you do in software to get it working...
?

Rangarajan Saravana kumar
07-11-2016, 2:33 AM
I wish to have my rotary for fiber laser to get it used as almost 4 yrs over with that.. Bit scary

regards

Kev Williams
07-12-2016, 10:40 PM
Kev, what did you do in software to get it working...
?

!!!!!!!!!!!!!!!!!!!! I hate computers....

I had half a novel of instructions all typed out on what I've figured out with this thing, was almost done, hit something with my left hand, and POOF. 2 hours of typing and pics gone. And no 'restore autosaved content'....???

ARRRHHGGHHH!!!

I'll do this again, but I HAVE to do some work or I'll be up till 3am tonight....

I think a couple of pics will post, won't make much sense but notice "TURBO" actually worked...

Rodne Gold
07-13-2016, 1:44 AM
Im getting a team view on setting up the rotary in the next few hours..will report back

Jesse Wheeler
07-13-2016, 2:24 AM
!!!!!!!!!!!!!!!!!!!! I hate computers....

I had half a novel of instructions all typed out on what I've figured out with this thing, was almost done, hit something with my left hand, and POOF. 2 hours of typing and pics gone. And no 'restore autosaved content'....???

ARRRHHGGHHH!!!

I'll do this again, but I HAVE to do some work or I'll be up till 3am tonight....

I think a couple of pics will post, won't make much sense but notice "TURBO" actually worked...

Ah that's the worst! Thanks for persevering.

Looking forward to seeing what you've come up with, I'm still having issues with my rotary.

Kev Williams
07-13-2016, 3:00 PM
I'm still pi**ed off at that.

2 important settings, diameter and lens focus length setting. With a C02 diameter don't mean squat other than to get the correct height-to-width ratio of what you're engraving, because the rotary turns per each line per inch. Since the rotary could never keep up with the fiber, it has to engrave in sections, and for each section to line up correctly, diameter input is critical! And lens focal length is also critical, because YOU choose how big of sections will engrave. It's critical because the software compensates for the 'downhill stretch' around the arc of your part, of whatever you're engraving. And to compensate correctly, the lens focus entered must match your lens. This is because the beam angle and path will be different between, for example, a 100mm lens and a 160mm lens (which is what I have, and is what was already entered). It's part of the pincushion effect. If the computer is compensating for a 100mm lens but you're using a 160, the sections won't line up correctly. There was a thread about 'not lining up' not long ago. Mine line up first try!

One more before I go back to work, the "invert" box... Mine must be CHECKED, or the engraves the sections in the reverse order! (like how my names did during my first tests)

Jesse Wheeler
07-14-2016, 1:49 AM
okay wait, so in the rotary parameters under "focal length" are you inputting the distance from the lens to the object or are you inputting the type of lens ie: 100, 110, 160 etc?

On my machine the "focal length" stamped on the machine is 273mm and I increase that distance to 281 to get a black "annealing" mark on stainless steel. I have been entering 280 into the "focal length" field in the rotary parameters. Are you saying I should be inputting my lens size(110)?

I have varied the "focal length" field a little bit hadn't really noticed a change between say 280 and 270. If it is supposed to be 110 that's a big difference.

This is an exciting turn of events, please post up any other details on how you were able to make it work.

Thanks!

Rodne Gold
07-14-2016, 3:29 AM
I had a team view and have sort of got the rotary stuff sorted.
What is vital is to calibrate the "pulses per round" setting

The way to do this is create a rectangle exactly the whole circumference of the object
IE lets say you have a 40mm tube , you need to create the rectangle whose length is 2piR
IE 2 x 3.14 x 20 = 125.6 mm long .. it can be 6mm high

Engrave this using rotarymark .. the left and right sides of the rectange MUST correspond..IE meet with no overlap
Of course it is vital that you enter the part diameter very accurately

What you then do is adjust the pulses per round to make this "meeting" happen.
you then have your corrected pulses per round figure.. this is the basis for all other rotary operations

In terms of the splits.. I have no idea of what "distance per" is , but the split size is obviously the area that can be engraved before the chuck moves to the next split
To avoid split lines , you can fiddle with the "part diameter" .. a bigger part diameter will reduce unengraved sections between splits .. and vice versa

I have tried different focal lengths ..doesnt seem to make much difference

I am fiddling around the whole day with the rotary.. so shall add anything that comes up

The chuck on ours is not a precision chuck.. but it works

You can really only do split marks on constant diameter tubes , tapering tubes or coffee mugs etc will create a problem as the part diameter is not constant over the engraving area

Jesse Wheeler
07-14-2016, 2:32 PM
Great Rodney, I'm going to check that out now.

Would you be able to post a shot of your rotary parameters?

Kev Williams
07-14-2016, 4:24 PM
Well, I got great results and never touched the 'pulses per round' ? The only thing I've used the param menu for is to change what seems to be the default "X" to "Y". There's an "invert" in there along with one in the main menu, not sure if they mean the same thing?

"Split size" is what you enter as the vertical engraving distance over the circumference before it rotates to the next section
Larger diameter objects of course, you can get away with larger distances. On that "TURBO" above, note that I stretched it like that on purpose, so it would cover more circumference.
The one in the left pic was done with a larger distance, and it was done in 3 sections...
The right one I shortened the 'distance per' and it did it in 5 sections. As you can see, both ways lined it up near perfect best I can tell.
There's a bit of wobble, but that's because I had the rotary stacked on a bunch of pieces of wood so I could get in focus, and it shook a little on the turns!

As for engraving tapered or weird shaped objects, what you do is enter the smallest diameter of the part, then the laser can't run off a smaller edge, and just use small section slices; something the size of a coffee cup, using a 1mm section should line up all sections nicely...

You can compensate for tapered objects-- like shot glasses-- if you know how to taper your engraving, the same but in the opposite direction. Casmate makes this easy ;)--There may be a way to do this in EZcad? Any, I do that with my LS900 rotary,
and get perfectly square squares on shot glasses...

As for split lines, they are best used for basic text, just place a split line between each line of text and let 'er rip.

There's boxes to check, "mark selected" and "mark by split line". Choose which one you want-- if you check both, it will mark by split lines...

"Distance Per" -- you can jog the rotary by pressing ctrl+ the arrow keys. The 'distance per', chosen from a drop down menu, is how far it will move based on the diameter entered. It's a good way to visually see how far it moves for a set distance. It wll also tell you what axis you're set for- if you have the rotary sideways to the machine so it will rotate up and down, that's the Y axis setting, and will move if you press the Ctrl-UP or DOWN keys-- if will only move with the LEFT or RIGHT keys, you're in X-axis mode...

All for now, gotta get some work done! ;)

Gary Hair
10-20-2016, 12:57 PM
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA GGGGGGGGGGGGGGGGGGGGGGHHHHHHHHHHHHHHHHHHHHHHHH!!!! !!!!!!!!!!!!!!!!

Whew, that feels better...

So, since I've had my fiber I have had no real success with the rotary. I have tried changing almost every setting and never got consistent results. The only thing consistent was that it was inconsistent... It has been extremely frustrating to see others get theirs to work and even when I did what I thought was the exact same things they were doing, still no success. Today, however, things changed. I tried Rodney's "pulses per round" test and noticed that even though I was changing the value in specific increments, the results were not even, three different times changing the value by 50 would yield three different results. On one test I noticed that it marked the same spot twice and I thought to myself, "self, that's odd". So I grabbed the chuck and turned it and, lo and behold, discovered the coupler was loose. Not falling off loose, but loose enough to not consistently turn the chuck. After I came down from the ceiling, a 20 footer in my shop, I grabbed an allen wrench and tightened the coupler. I put the settings back to what they were originally and ran the test again - it came out perfect! I imported in some text I was needing to mark on a few hundred powder coated parts, the job that really got me wanting to finally figure this rotary out, and guess what? it worked perfectly!

There were signs all along, and hindsight being 20/20, I now see that they all were pointing to something mechanical. My only excuse for not figuring this out sooner is that I never really took the time like I have in the last three days to get to the bottom of it. I was very fortunate that I had the Trotec to do anything on the rotary, but then again, maybe if I didn't have it I would have been forced to figure this out sooner...

I'm happy it's working, now back to your regularly scheduled programming.

Kev Williams
10-20-2016, 2:49 PM
That's good to know! I think of all this stuff as if they're Harley's-- there's always a loose screw somewhere!

And another thing, when these rotary's move, they move very abruptly. They start hard and stop hard. The chuck is pretty heavy its own self, and depending on how much weight is IN the chuck, the torque can move the whole rotary fixture if it's not clamped down (which is a bad habit of mine)...

And I found out another thing about these things the other day, that may (or not) help with rotary alignment issues-

Whatever size you tell your graphic to engrave, that's the exact size it will engrave in BOTH X and Y axis's, regardless of the part's actual diameter. This is much different than gantry rotating...

example: if you tell your gantry engraver you're engraving a 1" diameter part, but it's in fact 2" diameter, the Y height of what you're engraving will be twice as tall as it's supposed to be. Likewise, the reverse is true, telling the computer you're engraving a 2" part while engraving a 1" part , the Y height will be half what it should be. But in both (or any) case(s), the the X length will be correct.
This is because a gantry rotary moves in lines per inch the same as in 'flat' mode, and the computer compensates how far the line per inch spacing should be based on the circumference.

However, since a galvo don't do "lines per inch", there's no 'automatic' compensation for circumference. The machine engraves exactly what it 'sees'. So in order to engrave around a circumference, whatever you're engraving is done in horizontal "slices", and you have to chose how big each slice is. And you want the slices as small as possible, because engraving height stretches as it wraps down a radius.

The compensation that does exist is simply how far the rotary moves to engrave the next slice, and the machine needs to know the part's diameter. If you have it it slice in 3mm sections, it will engrave the 3mm slice, then move 3mm to do the next slice. The machine calculates how far 3mm is based on the diameter you've input into the software.

And therein lies the rub, because in my experience (so far), I've found the rotary seems to move farther than I've asked it to. The fix is to enter a larger diameter, which will shorten the move, closing the gap. And finally, to keep the seams less visible (or INvisible if possible), use and OPEN ENDED hatch fill with NO edge or contour engraving, this should help keep the engraving at the seams from overburning, resulting in less visible seams... hopefully!

When engraving using "textmark", the rotary works fantastic, because it moves the rotary automatically for each letter, no 'slice' guessing! The trick is to be sure the correct diameter of the part is entered. That's how I came to write this, as the other day I engraved a name around a 28mm diameter part. However, the entered diameter was the default 10mm-- the result was each letter was perfectly sized in both axis's, but the spacing between each letter was HUGE, like 3x the correct spacing, due to the diameter discrepancy...

All for now... ;)

Neville Stewart
10-24-2016, 3:21 AM
Couldn't sleep. Getting my rotary today. This is fascinating reading. Cant wait to pull my hair out as well. I shall be staying tuned, and BTW Gary. I'll be looking for loose screws first. Tx for that.

Jesse Wheeler
10-26-2016, 6:48 PM
The compensation that does exist is simply how far the rotary moves to engrave the next slice, and the machine needs to know the part's diameter. If you have it it slice in 3mm sections, it will engrave the 3mm slice, then move 3mm to do the next slice. The machine calculates how far 3mm is based on the diameter you've input into the software.

And therein lies the rub, because in my experience (so far), I've found the rotary seems to move farther than I've asked it to. The fix is to enter a larger diameter, which will shorten the move, closing the gap. And finally, to keep the seams less visible (or INvisible if possible), use and OPEN ENDED hatch fill with NO edge or contour engraving, this should help keep the engraving at the seams from overburning, resulting in less visible seams... hopefully!
All for now... ;)

I was having this problem with the splits not lining up and having to change the diameter of the item to adjust until I tried Rodney's suggestion to adjust "pulses per round" that is upthread. Once PPR was correct, the splits all lined up when I entered the correct diameter. I also use really small splits, .01mm seems to work.