View Full Version : Can we talk a bit more about job alignment on a Trotec?

Raphael Weil
11-03-2016, 9:29 AM
I've been able to master most of what I need on my speedy 300, but job alignment is still something I find surprisingly slow for my purposes. I work almost exclusively with rectangular hardwood as a medium, and the level of detail on what I do is so precise that it's very important that my pieces be aligned to probably less than 1/32 of an inch.

As I've mentioned previously, what I loved so much about the FSL is the outline mode the laser would provide. You could run the outline mode with the laser open, and nudge your piece so that the laser dot basically followed the perimeter of your medium till you got it bang on. In my case my design is always the same size as my medium, so if my wood is 8" by 15.5", so is my design. The Trotec's outline mode is basically useless. You can't run it with the door open, and it doesn't trace the perimeter of the piece, it traces content. The last bit of advice I got for alignment on the speedy 300 was creating jigs. But honestly to have to create a jig for every piece seems absurd after having spent that kind of money on the laser. The other thing worth pointing out is the nudging can be in one of many spacial directions. My pieces aren't always perfectly square (but I get them darn close), so sometimes I may want to pull a corner down ever so slightly, and see if the wood is lining up just right.

So how do you vets do it? The hack I did was create an invisible box around my perimeter in my design so that the outline function follows it. But that adds a ton of time to my engraving as the head needs to travel the whole piece. Any other ideas? I've contemplated created a digital design of just the perimeter box for alignment, and then engraving the other file when I'm happy.

I try to align for something like this:

Brown exterieur is the edge of the wood, the slim dark lines are the fine detail of my frame effect that need to be very precise. Red dot top left you know.


Thanks in advance!

Ross Moshinsky
11-03-2016, 10:01 AM
Few options/suggestions:

1. Spend some time and make sure your rulers/guides are right on the money. If your ruler is a little off your engraving will be off.

2. Very accurately measure your material size. We typically measure to the 1/32" and can go down to 1/64" if it's required. The more accurate you measure, the better off you are.

3. Center center. Find the center point of the actual piece. Mark it. Bring the red dot to that point. Align the artwork to the center. You may need to draw a box around your artwork for this to work properly. We do it in red and then disable the red function. We do this with crystal and glass awards all the time. It's the only way to get consistent results IMO.

4. For multiples, don't go edge to edge. Products aren't perfectly made. Assume there is error. So we put about 1/2" between products. Have the laser mark the edge on blue tape. Then line it up that way. It takes a few extra minutes but it comes out damn close to center.

5. Lower your margin of error. I do a job where I'm engraving a logo on a narrow piece of wood. It's made is china and very inconsistent. I can't make a jig because of this. I was having a heck of a time getting it center every time because if I was off by 1/32" or even less, it looked like I was off by a mile. I tweaked my method of aligning a bit but the biggest thing I did was make the logo 80 or 90% smaller. Now if I'm off a bit, it's far less noticeable.

6. Run the job on blue tape at low resolution and high speed. It's something I picked up on here and use it almost daily. I'd rather spend 5 minutes double checking my work than throw out a $30 item because the alignment was slightly off.

Raphael Weil
11-03-2016, 10:37 AM
Appreciate the advice. I do think that the perimeter box design method I suggested where it's just a box the same dimensions as my piece, minute per minute, is still faster than what you're suggesting. It's good to know that someone with the experience level you have hasn't found faster. Means what I'm looking for probably doesn't exist. Wonder if I can suggest to my rep to get them to improve the outline function. It's such a tiny amount of code.

Gary Hair
11-03-2016, 11:24 AM
Wouldn't the easiest solution be to cut the wood more accurately? If you have a few sizes you use all the time it would be very easy to make a sled that would allow you to cut them exactly the same size and never have to deal with alignment again!

Raphael Weil
11-03-2016, 11:43 AM
Yeah I get as close as possible. Depending on how the wood comes to me though there are variations, or I may end up with odd lot pieces here or there. So for the most part I do what you suggest, but in practice I still like checking that each one is perfect, specially given how rare the wood can be.

Tony Lenkic
11-03-2016, 12:14 PM

Would it be helpful if you pulled guide lines and for placement of your image than drag the artwork to the guidelines.
What exactly is your outline? If you have a plate size of 12" x 12" set in graphic program than your outline will be the same in job control 12" x 12" and you can place it anywhere on the table.

Kev Williams
11-03-2016, 12:28 PM
Is the machine cutting square? Lets assume it is...

I live & die by "home position". My rulers are on the left and top. Problem is, they're just screwed down pieces of aluminum, and some of the heavy stuff that goes in my laser can move them. But for the most part, they're close, and they're square to the machine. In addition, I have a Romark L shape ruler to create a zero point at the top-right corner, it fits dead against the right side of the machine's box and the top ruler. The machine cut it, so it I can rest assured it's square to the machine!

Most jobs are okay 'as is', but for critical alignments, I run a simple test. I put some material in one of the corners, then draw a small box, size not important, just 1/2" or so box. I park the top edge of the box side at exactly 1" down and the left side exactly 1" from left. Then I engrave it, then measure where the engraving actually is with caliper micrometers. The result is rarely "dead on", but now I have a correction factor. If the box actually engraved 1.004" down and 1.021" from left, then I simply move the engraving .004" up and .021" to the left. Now the engraving will be EXACTLY where it's supposed to be.

In your case, it would be a good idea to test engrave 4 corners, ideally, around the size of your project. Just be aware that measurements MUST be taken ONLY from the left and top edges of the test piece. This could be tricky without some good measuring tools. I have a set of Kanon 24" vernier calipers, very very handy--- Just checked online, this place on ebay sells 24" calipers for cheap, but even so they'll be a far sight more accurate than any other way to measure that distance... http://www.ebay.com/itm/like/300691637698?lpid=82&chn=ps&ul_noapp=true

Glen Monaghan
11-03-2016, 1:19 PM
My fences/rulers are my first-line aid as I register non-jigged items to those. I engrave some box lids that vary slightly in size and squareness so, for those, I register the nominal artwork to the fences/rulers and then visually position and align each lid within the nominal space. If you can't easily visualize that space, you could either create a jig with the max allowed, or slightly oversized, cutout and then visually position and align pieces within that cutout. Or similarly, put down some tape and lightly run a line around the nominal space, then visually position and align pieces on top of that.

For a custom knife that I engrave, the exact shape varies slightly from production run to production run, and the manually sculpted handle scales are enough different from knife to knife that the engraving can look noticeably misaligned if I don't check and adjust the engraving for each. For those, I resort to creating a bounding box around the engraving as the last thing I do when preparing the artwork. To engrave, I select and run (vector) just that bounding box with red dot on, observe how the bounding box looks on the scale and nudge the piece around as needed, probably averaging 20 seconds each. Then I select the actual engraving and raster it. A bit of a nuisance but better than messing up a custom knife with shoddy looking alignment.

Gary Hair
11-03-2016, 1:52 PM
Just a thought - if this is your main product, or one that generates a fairly significant amount of revenue, then you may want to consider a galvo co2 instead of gantry. The two big benefits for you would be speed, galvo would be a huge speed increase over gantry, and the ability to "paint" the engraving on the part interactively before engraving. It's pretty seldom that I put something in my fiber without using this feature and it would be nice to have on a co2!

Raphael Weil
11-03-2016, 2:05 PM
Thanks for the suggestions guys, I'll try some of them out. Appreciate it!

Brian Leavitt
11-03-2016, 4:53 PM
I run 99.6% of the items I engrave using the top guide and my lasered ruler for positioning. For oddly shaped things I lay some masking down on the table and run the outline on the masking, lining the final piece up with my lasered outline.

This one is for a boomerang. I have a customer who is getting 50 of them engraved so this will allow for quick alignment of each piece. Normally I don't peel up the excess masking until the job is done, but this shape has to stay on the table for a couple of months so I peeled the excess up to get it out of the way.

Chuck Thomas
11-03-2016, 11:31 PM
If you don't want to use the rulers and the machine home position, and would rather have the wood more centered in the machine, try using spacers. Make a jig that resembles a carpenter square, only thicker, with varying sizes. Place them on your grid table and bump it to your tables rulers, then simply put your wood on the table and bump into the spacer. This should align two sides parallel the X and Y axis. And it'll also give you a repeatable anchor point for your jobs. I've had to do similar when the objects I was marking had rounded edges and slipped right over the low profile rulers attached to the table.

Seann Fordham
11-04-2016, 4:17 AM
If I were to line up something that requires precision / very fine engraving like watch backs with not alot of room for error because you have to sometimes arc the engraving around the manufacturers own engraving, I would use markers.

A watch might be a bit hard to explain, so I'll give an example of a square item. Set up the exact measurements in the graphics program, place the item so its square in the machine and then with the laser, put a marker (f8) in the top left corner and another marker in the lower right corner of the item, and then place the graphics so the corners of the graphics line up perfectly with the 2 markers (may have to adjust the x/y axis manually in the top left corner to get it close to 100% accurate as the artwork will snap to the closest marker.

I've found this works really well, I've never had to do an outline / test run on any piece of jewellery in ages using this method, because the markers just give you a visual indication of where the job is in the machine.

Mayo Pardo
11-05-2016, 4:00 AM
I would create a rectangle the same size as your wood. Make it any color other than red or black. No fill - just the hairline in the size of your wood.
In job control make the color of that rectangle "for positioning" instead of for engraving or for cutting.
Make your design within the rectangular outline exactly where you want it.
Position the wood on your laser bed at the top and left rulers.
Move your red dot pointer to the top left of the wood or the bottom left of the wood.
After you open the job in job control, designate the starting point wherever you positioned the red dot.
You can also designate to start from the bottom and go up or from the top and go down if you're engraving.
If you prefer to start from the center of the wood, you can place a bit of masking tape or transfer tape in the approx. center of the wood
then mark the center point. Position your red dot on the mark you made, then carefully remove the tape and try not to shift the wood.
Then don't forget to tell job control the position is the center.

Raphael Weil
11-05-2016, 7:01 AM
Interesting idea Mayo. I think I won't be able to do exactly that since I work in relief mode, but there's something there for sure. And I for sure always engrave bottom up. I'd be curious to know why anyone wouldn't, my work is consistently better as a result.

Kev Williams
11-05-2016, 11:49 AM
Here's a job I did last night, 20 SS disks that need a scale and PN laser etched. Normally I do these one at a time but I'm really busy now and need to multitask, so I made up a quickie temporary jig arrangement to do 10 at a time. (running 10 takes nearly 30 minutes, plenty of time to run other jobs in between :) )

The way I do this is completely foolproof, the engraving simply can't be in the wrong place because only one setup is used for everything,,,

This is the the 10 piece layout in Corel...

I've spoken many times about my 2" shims, here the table is loaded with them.
Also, on the right is my upper-right corner 'zero point' square I spoke about. Not using here, just showing it. As I mentioned, the laser cut it so whatever I park there, the machine will cut or mark perfectly aligned.

So I'm essentially starting 4" from left and 10" from the top...

So what I did was put down some tape where the holes in the parts are, then taped some scrap Rowmark down.
Then I cut the hole centers. Note that I did some test cuts beforehand to make sure the hole centers fit right...

After the cut, I remove the excess plastic & tape.

My parts fit perfect, and the engraving is absolutely dead to rights.

-- in this case I used the hole centers, because they're notched and the engraving must be referenced to the notch. If the hole was just a hole, I could've just created holes the size of the parts in scrap plastic (or cardboard) and just dropped the part in, same results. Cutting holes in cardboard is how I align engraving to watch backs, I measure the crystal (if doing a whole watch) or the back itself, I park or tape down the cardboard, put that circle as measured somewhere convenient, cut the hole, and then align the engraving within the circle that cut the hole. This like 10x faster than 'randomly' parking the watch, and figuring out where it is!

Back to my right-corner zero scale-- all anyone has to before a critical alignment job is to tape down an as-long-as-possible x 3/4" or so wide piece of scrap plastic against the top and left rulers then have the machine cut them at .500" from top and left. Once done, run a test as I describe above to verify actual zero, since the cut may remove 3 or 4 thousandths of an inch...

Once your project is ready to engrave, the new corner you created will be dead-on aligned to the machine, and the zero coordinates (now +.500/-.500") will be dead to rights. And all you've lost is 1/2" of table space...