Tag Archives: laser cutting

How to Two-Sided Laser Etch or Laser Engrave

This is for all my Laser Cutting, and laser engraving friends out there who have shied away from laser etching two-sided designs. The secret is in two parts.

Why etch both sides?

As part of my other job at marginallyclever.com, I want to make beautiful boxes for my electronics. I want to put a part numbers and helpful maker tips on each piece, for reference… but I don’t want them to show on the outside of the box when it’s done – that would be ugly. I need to etch both the inside and outside of the box parts.

Another great example would be dog tags. On the front I want logos for my club or team logo, and on the back I want something custom for that member.

The Challenge

Flipping parts creates a registration challenge: When the material is flipped it might shift out of place. The first part of the secret is to make a jig that will hold the material in the right place before and after flipping.

The second part of the secret is to make sure the jig has only one line of symmetry. A jig with two lines of symmetry is a mistake waiting to happen – You might flip your parts the wrong way and create a waste of effort.

The method

  1. Fix your material in the laser cutter.
  2. Draw a symmetrical shape around the pieces that has only one axis of symmetry. The goal is a shape that can only fit in it’s outline one of two possible ways.
  3. Etch the back of your work.
  4. Cut only the symmetrical outline.  The material is now in two pieces, A (inside the outline) and B (outside the outline).
  5. Carefully lift and flip A.  B is still fixed in place and will make sure that the part is well aligned.
  6. Etch the front of your work.
  7. Cut the front of your work.
  8. Clean up and remove as usual.

The software setup

How do you set all this up in the laser cutter software? Well everyone’s laser is different (Seriously? Just give me a printer driver)

My laser control software has a horizontal and vertical flip command, as well as a way to cut only certain colors in the file. This way I can use one color for each step and enable them one at a time. Much easier than trying to store each step in a separate file where I can visually check they are still ligned up correctly.

Even more precise

I want to know why you need to be more precise! Comment below, I’m very curious.

After the etch cut on the back of the work, cut two dots inside A and outside the work. After the flip, check that your laser’s red dot is still on the center of each dot. Adjust the work and check the dots again, repeating until satisfied. Proceed with the front etch and continue as before.

Final thoughts

I hope that was useful to you and you are now +1 laser skills. Please comment below with your laser cutter tricks so I can learn from you.