Best way to register engraving on the reverse side of a piece

Hi,

I have tried a number of attempts to get the back side of a piece engraved and perfectly registered, but to this date, not successful. I wind up have to set the origin and frame it a number of times by eye. Not very effective. I set up a square and place the work piece into the inside corner of the square and secure. Then I burn the front image, not so crucial where I start on a blank piece of stock. After the face is burned, I take the entire work piece out, dislodge the piece I engraved and place it back in the cutout area , reverse side up. I have another file with logo on it that I need to get registered just right.

I have looked at a number of videos, but either they are not explaining well enough or I just do not understand the way they are presenting it. I am pretty sure that I am not using the proper job origin either.

Any help will be appreciated.

Thank you,

Jim

It sounds like you have a means of reliably placing the work piece back onto the same location of the laser bed. If so, then the next part might be easy.

Are you using Absolute Coords as your Start from mode? If so, identify the position coordinates of the design used on the front side. Then in the second design, relocate the design so that it’s on the same position as the front side design. Then you should be able to burn. Suggest you frame and such beforehand to confirm that it works.

berainlb,

Thank you for the quick response. Yes, I do have a pretty consistent way to replace the cut out piece back in the opening. I usually use User Origin and did so on the last attempt. I will try Absolute Coordinates when I get a chance and try to figure out the coordinates for the front side as a reference.

Jim

This could work with user origin as well… as long as it doesn’t change between designs. It would probably be a little harder to reproduce between job runs as compared to absolute coords if you needed to do this over time, unless you always preserve the same user origin.

" I burn the front image, not so crucial where I start on a blank piece of stock."

If your workpiece is located to the corner of a square and flipped, the front (and rear) image would have to be dead centre to the blank stock to line up properly.
You could mark the centres of the stock on each side and use ‘centre’ job origin, start from ‘current position’ after you have moved the laser to the mark.

Alan,

Thank you. I will try again tomorrow. This should be a piece-of-cake, but I just cannot get it right yet.

Jim

Hi,

Just cannot get the laser to my set coordinates. I obviously am very close but do not understand this enough and need much more detailed instruction. Absolute coordinates has not been useful.

Jim

Can you elaborate what this means? What are your steps and what’s happening?

Absolute Coords should allow the design to be burned at a repeatable location on your bed. Is this not happening?

I see you have a ruida controller and I guess a CO2 laser.
I don’t have this so I can only advise for a diode.

The comments on Absolute coords are valid, but as you are flipping a workpiece over, the starting image may not return to the expected position for the reverse.
I think this may be your issue.

This would be my ‘workflow’ I accept there will be smarter solutions.
(This is if your laser has a position marker spot - it may not - a diode has a visible low power test fire dot)

Find a point on both sides of the stock material that correspond and mark it, if it’s square then I’d draw a line corners to corners.


Move the laser to the marked position on the workpiece.
Burn the image one one side with the job origin in the middle, Start from ‘Current position’
Turn the job over
(keeping the orientation parallel, of course)
Repeat for the other image.

Hi berainlb,

I cannot seem to drive the laser head to the exact coordinates. Tried using the “balloon” tool, tried plugging in the X and Y values and hitting go. Just not working. I finally used current position and am doing one at a time.

Jim

Hi Alan,

I do have a CO2 laser and a Ruida controller. Played around with various methods. Finally used current position, marked the centers on both surfaces, used current position from the center origin and lined up the green square for laser head origin with the center of the selection. It is working, but I am doing one at a time and have to mark the center, which I wish I did not have to do.

Jim

You needn’t move anything manually. The laser should bring itself to the position on your bed that correlates to the location on your design. In other words, the workspace where your design is created is a virtual representation of your bed. Place the design where you want to burn. Repeat for the back side.

Can you take a screenshot of LightBurn and a photo of your bed with the workpiece situated?

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