If you have ever aligned or need to align the beam in a laser cutter, you have probably made hundreds of dots trying to get the thing trued up. After many dots and feeling hopeless, I came up with an aid to help speed the alignment process. Here is a video from ThunderLaser making it look easy. I am going to present two designs and hopefully one of them can help you out. This is a bit of chicken and egg project as you need a working laser cutter in order to pull it off.
The result of this ible is to add a visible laser in line with your work laser. The resulting laser will act as a general point of reference for when you are adjusting your mirror screws. There is no substitute for your actual laser so don't get too dependent on the visible laser. It will let you know just how far things are moving as you make adjustments.
Step 1: Materials
This project should be pretty easy to source parts and materials. I was able to use scrap wood, and spare parts for the rest.
- Some 5mm plywood
- 3v Laser Diode - like these
- Wood Glue
- Some wire
- A switch (optional)
- Tin Foil
- Sand Paper (150grit)
- 2 paper clips
- 2-3 small screws
- 2 AA batteries
Step 2: To Cap or Not to Cap
Initially I set out to make a permanent attachment for my laser. My design had a hinge so you could flip the visible laser in and out of place. The simple screw hinge added a little more inaccuracy than was acceptable. As mentioned in the intro, there is no substitute for the actual laser. I wound up using a simpler less permanent option, a cap. Both designs are available for download, feel free to see which suits your needs.
Step 3: Assembly
Before you go cut out your parts make sure you have the right dimensions. The design is meant for my machine and the laser diodes specified on the materials step. The tip of my machine is 29mm O.D. and the laser diode I used was 6mm O.D. If your machine and diodes fit these measurements the DXF files will work fine. Otherwise you will need to make adjustments to fit your needs.
Once you cut out the parts, you will have a handful of rectangles and circles.
Start by gluing the big hollow circles together. They will go over the tip of your laser. When gluing the parts together it is imperative that everything lines up perfectly. If your parts fall out of line, your resulting laser holder will be askew. Be sure to wipe off any excess glue, especially on the inside of the circle.
Next is to glue to two diode holder pieces together. These are the pieces with the circle in the middle and the groove cut to the side.
The last step is to add the solid piece. If you are building the cap version, this piece goes between the diode holder and the big hollow pieces. If you chose the flip version, glue this to the diode holder and screw it to the big hollow pieces. In addition the flip version had a flip stop that should be glued to the big hollow pieces as well.
If you have glue anywhere, or the cap doesn't fit over your laser, you can use the sandpaper to make things right.
Step 4: Add Power
The battery holder was a pleasant surprise. I thought were a few AA battery holders in my shop but after looking high and low, I couldn't find one. Within reason I will be making more custom battery holders as they fit my project needs.
The battery holder is made from two hollow rectangles.
- Glue the two rectangles together.
- Screw two small paperclips into the holes.
- Fold the small end of the paper clip down over the inside of the rectangle.
- Push the remainder of the paperclip up out of the way.
- Cut the long ends leaving yourself 1/4" terminal to solder to.
- Wrap a fair amount of foil over the opposite end of the rectangle.
- Put your batteries in opposing directions and test your have connectivity.
Everything should fit pretty tight. You may need to move the connection terminals so they hit the right spots on the batteries.
The wiring for this one is pretty simple. You are either going to wire the battery directly to the laser diode, or you are going to add a switch.
Step 5: Installation and Use
If things went well, you should be able to carefully fit the visible laser holder over the tip of your laser.
The visible laser will rarely line up exactly with your work laser so use it as a reference. If you mark your tape with the work laser you might find the visible laser is 1/2" to one side or the other. As you twist your mirror screws watch the visible laser and gauge its distance to help you get tuned up.