Friday, December 31, 2010

New Years - LASER Fire

As some of you know, we have a 35 watt laser engraver that we use to create artwork, build prototypes, and sometimes make a few extra dollars doing wedding glasses and such. The primary rule of the laser is to NEVER leave it unattended when it is in cutting mode.

Engraving mode could have some problems, but the laser is firing tiny blasts of power to create a pattern on the surface of the material. When in cutting mode however, it is usually running at full power burning it's way completely through the material. On a lightweight material it can overheat and catch fire... usually you can just blow it out. But what if the machine was being run with nobody around to watch over it?

Bad things happen.

This is what I found when I came home from working in Connecticut. (I also had a bad case of kidney stones while there... so it's been a rough month.)

This is what the laser looked like when I opened the top... full of ashes, badly burned interior, and the optical head would not move more than an inch [25mm] in either direction. (Normally it moves 24 inches [600mm] in the X-Axis.)

You can click on any image to get a larger view.

I knew that the unit sustained high temperatures and that the X-Axis gantry contained not only the lens assembly to focus the laser on the target, but the electronics and optical encoder system that allows the precise positioning of the unit. I was hoping that the optical encoder was intact as it is an expensive part due to the accuracy needed to produce it.

After opening up the gantry cover I saw what I was really up against. The cooling hose had completely melted and had to be cut away... this gave me an idea into just how much heat had been generated... it was not a small fire in there.

The optical encoder which is pivotal in the overall accuracy of the machine was melted in a couple of spots... one bad area will throw off the entire machine so it needed to be completely replaced.

The ribbon cable which carries the power and position signals to the processor sustained major damage and also needed to be replaced, but the socket it plugs into was intact. If the rest of the lens assembly was in good shape it wouldn't be too expensive, but would take a good deal of labor. (I have the skills needed.)

When I examined the auto-focus switch, a plunger assembly on the bottom of the lens housing, that's when I started to get a bad feeling. It was frozen in place which meant that the unit probably melted in place. I would need to pull the lens assembly off for shipment to Epilog Laser for repair or replacement.

After looking closely at the lower lens, I saw that it had sustained heat in the fire too... and if it has any materials fused to it, the assembly will need to be torn down and the lens replaced. That is likely expensive and will also mean that I will need to do a complete alignment on the machine.

I'm still hopeful that they won't need to run a calibration on the machine... if they do I have two choices... fly a tech here or ship the machine to Golden, Colorado. The best price I can find right now is $300 shipping each way.

So for the moment it looks like this is the shopping list for the replacement parts... but I won't know until Epilog reopens in January and I speak with the tech there. I'll send him (or her) this blog so they can evaluate it better.

I also have images posted on Photobucket so they can take a closer look.

Replacement Parts List

* X-Axis Belt Assembly
* Top Cover
* Cooling Hose
* Optical Encoder Strip
* Ribbon cable Assembly
* Plunger switch
* Lower Lens (possibly)
* Optical Encoder Sensor (Possibly)

Stay tuned for more information as I find out.

Wednesday, December 8, 2010

A hot time in Kyle Texas

Well last night I got an interesting phone call from Eve. She was cutting foam board on the laser to make Christmas ornaments. That was fine... but with foam board you need to cut it to fit inside the machine... if you don't, and it sticks out... when the parts are cut out the board in the machine now weighs less than the board sticking out of the machine. This means that unless the foam board is taped down, or propped up, it can tip up and hit the lens assembly which could cause damage.

Whenever doing a vector cut (cutting through a material) there is more power being delivered to the material than during raster marking. As a result, you want to pay particular attention to the material being cut at that time. (I had a piece of walnut catch fire and had to blow it out once.)

Eve set up a job in the machine with foam board and had the material sticking out of the machine, she started the cut, then went back to her office to finish up a drawing she was working on. The machine cut out the parts, and now that the foam board in the machine was lighter than the part sticking out, it tipped up and jammed into the optics of the machine. That wasn't very good... but because she wasn't in the room... when it caught fire, she didn't know about it until the fire alarms started going off.

By the time she got in there the main drive belt melted and burned, the top cover deformed and charred, and the entire assembly was filled with soot. I'm still in Connecticut for another week... so I don't know if the upper optical encoder is toast or if it was protected by the cover, and I don't know if the laser fused the soot to the optical glass as the beam was still at 100% power the whole time.

I'll know more when I can disassemble it and take a closer look. For now however, the laser is definitely out of service. I'm just glad the upper door didn't ignite or it could have been much worse. (Remember, there was an air compressor and a vent system pulling air through it too.)

If the optics didn't get toasted, I should have to replace the belt, replace the lid, and clean the machine, then do a calibration on it. If the optics are messed up then it gets more complicated and we will need to drive it to Colorado to be repaired. (I priced shipping the unit... $288.00 each way.) Eve is okay... that's important, and the house didn't get damaged aside from being a bit smoky so I'm thankful for that.

I'll keep you posted.

Saturday, December 4, 2010

Connecticut - The Starbucks Run

Eve likes to collect the Starbucks mugs... and since I was pretty much just sitting around the hotel this weekend, I decided to do something special for her and get the Boston mug. I mad a few calls... I'm glad I did... not everyplace has them. Then I found a Starbucks just under two hours from here that had not only the new series, but the older, hard to find version too. It was time for a road trip.

After I made the video and posted it... I ran across this next video. I usually post only my stuff here... but this was pretty good... and it made me laugh... so it was worth it.

Usually I can stay fairly positive while away... but this week... I just feel like being at home, doing stuff around the house, and being with Eve. I have two more weeks to go before I get home... then only for a day or so and I'm off to Canada. It has been quite a month or so.