Tips for engraving on both sides of a substrate?

[Keith Upton]

It looks like I might be trying to engrave on both sides of a substrate (Rowmark in this case) in the near future and was wondering if anyone had any tips for making sure the engravings line up on both sides of the substrate. The top side would have Icon A and the bottom Icon B for example. After engraving the bottom side, I'd want to cut the engravings out. These would be pretty small pieces (about 6-8mm in diameter), so some precision is in order.

[Henri Sallinen]

I'd make a jig that the pieces fit exactly in and align my engravable artwork according to the jig file.

[Keith Upton]

Henri,

thanks for the reply. So your suggestion is to cut them to size first and then engrave both sides? Seems like that could take forever to engrave a bunch of the almost .25" parts. I was hoping there would be a way to engrave and entire 12x24 sheet on both sides and then cut them out.

[Gary Hair]

Keith,
I have had a few projects like this and found the best way to ensure alignment is to start with a piece that is about 1" larger than you need. Draw a rectangle 1/2" smaller than the material and center it on the material. Using two layers, "side a" and "side b", place your graphics where they need to be. Tape the material in your laser. Vector cut the rectangle. Even though the kerf is very small, make sure you push the cutout firmly to 0,0 before you laser side a. Flip the material keeping the same corner at 0,0 and laser side b. You should be perfectly aligned. If you want to test it first use a piece of paper or cardboard and follow my suggestion.

Gary

[Kev Williams]

I build aluminum operator panels- these panels have blind studs pressed in the reverse side, which require a .050" boss machined to accept the stud. So all of the machining is done from the back side of the panel. However, the engraving is of course done on the front. Problem with laser alignment of the text after hole machining is, the top left 0,0 corner of the panel while machining is now the top RIGHT corner on the engraving side. If the panel is not EXACTLY the same size as is entered in the engraving program (and they never are), I can't simply line up the panel in the laser in the top-left corner of the machine.

The fix was to create a top right xx,0 position in the laser by adding a ruler stop on the right side of the table. Once the X,Y coordinates of the right stop is verified, I put a guideline(s) in my software at that location, and save the job as a "setup" job. I just mirror the panel, line the right side up to the guidelines and now all the engraving will line up perfectly to my holes, saves me a LOT of time in verifying text alignment!

This setup would work great for your job, you just need to add a top-right corner to do your second side. (you can put the right side anywhere, your software just needs to know where it is!)

Put the plate in the top left, run the front side pass, flip the plate over and put it in the new top right corner, and run the second pass. You'll need to experiment with a few pieces first to get the 2 sides to align perfectly. But once you do, all pieces after that will line up perfectly. And, you'll be able to run 2 pieces at a time!

(You just need to make sure the right stop won't move!)

[Jerome Stanek]

I would cut the back first and use a couple of the holes to register the part by making a jig with the holes in the correct place and use pins in the holes.

[Keith Upton]

Thanks for the input guys. Some of it I'm fallowing, some if it not so much. lol

It seems like the key here is to ensure that the 0,0 point on both sides is the same? If that is the case, could I not throw a 12x24 sheet on the laser, cut it to 11.5x23.5 (so it is always the exact same size), center my A side icons, engrave. Flip the 11.5x23.5 sheet and engrave the B side icons?

I think that is what Gary is saying correct?

Would I need to leave the outer half inch of material on the laser bed as a "jig", or could I just line up the newly cut sheet to the laser's fences since it has been cut to a standardized, known size?

[Gary Hair]

Keith - I would leave the outer 1/2 inch on the table to ensure you have it aligned perfectly. If the laser cuts the fixture then it will always match up, that's not the case with your guide rulers. Even though Kev's way would work, it is going to take some adjustment to get it right whereas my method takes no adjustment, it just works.

[Keith Upton]

Thanks Gary.

[Ross Moshinsky]

Engrave. Cut. Take out cut pieces. Flip the pieces over individually. Stick them back in the "jig".
I also like Gary's idea. A little wasteful in the material but very effective.

[Gary Hair]

Engrave. Cut. Take out cut pieces. Flip the pieces over individually. Stick them back in the "jig".
I also like Gary's idea. A little wasteful in the material but very effective.

Did you notice that the pieces are about 1/4" and he is talking about a 12x24 piece of material? On a piece that is 11x23 that would be 1024 pieces - the time to cut and flip the pieces would be more than offset by wasting 1/2" of material.

[Ross Moshinsky]

Did you notice that the pieces are about 1/4" and he is talking about a 12x24 piece of material? On a piece that is 11x23 that would be 1024 pieces - the time to cut and flip the pieces would be more than offset by wasting 1/2" of material.

Nope. Didn't read that carefully.

[Keith Upton]

Did you notice that the pieces are about 1/4" and he is talking about a 12x24 piece of material? On a piece that is 11x23 that would be 1024 pieces - the time to cut and flip the pieces would be more than offset by wasting 1/2" of material.

That's the reason I was looking for an engrave both first then cut method of doing it ;)

[John Bion]

I have Chinese machines which are not the easiest to place X Y co-ords on the table. My fix for this type of job is to first engrave one side, followed by either cutting a fine border/frame around the entire board or a marker square in each corner (border or marker squares either being masking taped or two-way taped down), I then flip the entire centre of the board fitting it back into its frame/markers and engrave and cut the individual items. I find this quick and simple (for my simple head and simple machines).
Kind Regards, John

[Keith Upton]

Thanks John, sound like what Gary advised I try.

[Andrew Holloway]

Did you notice that the pieces are about 1/4" and he is talking about a 12x24 piece of material? On a piece that is 11x23 that would be 1024 pieces - the time to cut and flip the pieces would be more than offset by wasting 1/2" of material.

And when you have 1024 pieces, the kerf width is going to add up quite quickly and you will end up with most of them not aligned.

[Keith Upton]

And when you have 1024 pieces, the kerf width is going to add up quite quickly and you will end up with most of them not aligned.

So long as I push the "inner sheet" back up tight against the upper left of the opening, I don't think kerf will be an issue then... the cut coming last and all??