OMTech Laser Lessons Learned: How to Replace a Laser Tube

I hate that I'm writing this blog post, but I'm writing it in hopes that someone else doesn't make the mistake that I made. Insert facepalm and embarrassed emojis.

Where I went wrong

A month ago I decided to empty and clean out my water chiller. You should do this every 30-60 days or so, but I took a little longer. It didn't hurt a thing. What I did after I replaced the water is what cost me a new laser tube a month later.

When I was hooking up the chiller to the machine, I connected the chiller inlet to the machine inlet without even thinking about it. I then connected the chiller outlet to the machine outlet. Huge mistake. I had it all connected the right way when I first set up my laser but for some reason, I didn't think much about it this time. I can't even tell you if I did this on purpose or on accident. I would like to think it was an accident.

What this mistake did to my laser

Over the last month, I started to notice that my laser wasn't cutting through as much and needed more power to cut. I just thought it was the wood or the focus. I even went as far as to check my alignment, level the bed of the machine, and clean my mirrors. Everything was perfect. But, little did I know, my laser wasn't getting the 18º C water that was trying to get to the machine from my chiller because my outlet from the chiller was just being pushed by the outlet of the machine so the same water was just dancing around the laser tube without ever getting cold. It all finally crashed and burned when I started looking more into the laser and I touched the head of the laser for it to break right off and show me the lens of the laser completely charred. The laser was still trying to get through the lens, and it was firing, but it wasn't firing at its full potential. Here's what it looked like:

Close-up of the lens char and burn from the laser tube not receiving cold water.

Glass end of laser tube broken off to reveal the burned lens.

At this point, you wouldn't have wanted to hear the noises coming out of me. I was so upset.

But, you live and you learn and this experience definitely taught me a lesson – to always confirm things are set up the way they are supposed to be before moving on and playing with a laser.

What I did next

After I stopped having a panic attack, I checked OMTech's website for a new laser tube. They didn't have the 60W CO2 laser tube that I needed in stock, so I went to OMTech's Amazon store and checked out my options. I could get the laser tube in 24 hours (which I needed because I still had Etsy orders to complete and fast). Ultimately, I chose this laser tube after confirming it was the same length and diameter of my laser tube. From what I was reading online, this is very important, otherwise you have to order new clamps for the tube if the diameter is larger (or smaller) than what you have.

So, if you've gotten this far in the article, you're probably wondering how to replace your tube. You may have made the mistake I did, or you may just have a failing laser tube. If you think your laser is failing, here are a few signs to look out for, according to OMTech.

• Your laser engraving machine pauses or resets for no reason.

• The laser beam quality is weaker than normal, or the color of the glow changes.

• Materials that normally cut easily suddenly don’t cut.

These signs indicate it's time to replace your laser tube and if you're looking for steps on how to do that, I'm here to help.

How to remove an old laser tube from the machine and install a new laser tube

1. OMTech has a helpful video on their YouTube channel. Check it out here.

2. You're going to need 440 electrical tape, wire strippers and an allen wrench that fits the bolts holding your tube into the mounts.

3. The first step is to clear the water from your inlet and outlet tubes. I put a bucket under mine and let it all drip out. You'll still have some in the laser tube when you take it out, so keep that in mind.

4. Start by cutting any zip ties that attach the water tubes to your tube. Slowly remove those tubes and be prepared for any water to come out.

5. Next, you want to detach the black and red wires. I am saving the mounts for last so that nothing goes wrong while you do the wires. You don't need a tube going rogue and flipping around while you try to get the wires off.

6. On my 60W 2028AF CO2 laser, the black wires were connected with electrical tape. This was easy to disconnect. The red wire was a little more difficult. It was molded onto the connection so I had to just cut the wire and then strip some of the red off to use for the new connection.

7. This is when I started to unscrew the mounts. Grab your allen wrench and hold the bottom bolt in place to loosen these screws. Take note of how far away your laser head is from the first mirror so that you can mimic this placement with the new laser tube. I measured the distance to help save myself some trouble when installing the new tube. Once all of the bolts are off and the top of the mounts are off, lift up your tube and get ready for the new one.

8. I made sure to wipe everything down and make sure the water tubes had enough slack for the new installation.

9. I placed the new tube onto the mounts and positioned the laser head close to where the last one was sitting according to my measurement I did in step 7.

10. I connected the black wire to the screw on the laser head of the tube and then eventually covered with black electrical tape.

11. I connected the red wire to the end of the laser tube and covered with the white cap. (photos at the bottom of this list)

12. The tube I ordered came with a cap for the left end of the laser where the wiring connects from the power supply to the laser tube itself. Once you connect the wiring of the power supply to the laser tube, go ahead and pop that cap on the end to cover the connection and you're ready to go.

13. It's best to make sure your mirrors are aligned. OMTech has a great article about this and they also have some great videos. Check it all out here.

    
    

I really hope this article was helpful. If you have any questions about OMTech Lasers, how they work, what they can do, etc. please reach out! I'm happy to chat about it with you and help you along the way. Happy Laser Engraving!