Need Troubleshooting assistance - PLEASE HELP

[WarpedMindGames]

I recently ran into an issue with my water pump going south. I replaced my pump, but I believe I ran the laser for an hour or two without water actually cycling through the tube or my temp sensor reading higher than 75 F. At no point did my tube have air inside it, and during the life cycle of this tube I've never gone above 16mA during operation.

Problem 1) for about the last week when cutting out a 3mm acrylic object, the laser beam would take about 30 seconds or so to "warm up" to cut. I mean there would be no cut line mark on the edge I'm cutting for this time, then suddenly I'd have a very small line that would grow to the cut line and then the cutting would be ok.

Problem 2) When aligning my mirrors after replacing my water pump and removing air from the laser tube, I noticed that the laser beam that struck my acrylic target was not a complete circle. The impression it left was a donut shape, the center not showing a laser strike.

Problem 3) See the comparative pics below. The first pic is what I am actually engraving, the second pic is what started happening about the time I found out the water pump had died. This also has continued after replacing the pump with a new higher L/Min pump and after the optics alignments.

I don't know what has happened, I'm hoping the tube that I bought a few months ago hasn't fried.

I have a replacement tube and a Laser PSU on order, thinking the issue is with one of these two items. Someone fill me in on what has happened, and if I am able to correct the issue without using the parts I've bought, or if these aren't the problem and what the issue really is.

Thanks in advance,

My setup:
Franken K40
DPS AWC608 Upgraded
"custom DIY honeycomb/steel bed
35W tube AC 110v
20-40-60 PSU
Water cooled 160GPH pump running distilled water/RV Antifreeze 10/1 ratio
Scientific Digital Thermometer with alarm set at 80 F
Water reservoir is 5gal painters bucket with rubber seal. I've cut the holes for tubing and cords out of the top and added a pop-off valve. I've also caulked all the areas where tubing and the pump cord comes out, and where the lead for the thermometer goes in. I have this "sealed reservoir" placed in storage tub with a pump and regular water which creates a circulating water bath.

[Techgraphix]

Problem 3) See the comparative pics below. .

I don't see any pictures but from what you described, your tube is gone..
Put a piece of paper in front of the lasertube, press laser and see what you get.. To get the mark (instead of a hole) you might reduce the power

If it is an odd shape or a "donut", some parts inside the tube are not in place..

Kees

[WarpedMindGames]

That's what I figured. I'll add photo

[laserdude]

I believe I ran the laser for an hour or two without water actually cycling through the tube.

You destroyed the tube by doing this! You should add one of these! http://www.lightobject.com/Water-flow-p ... -P815.aspx

[WarpedMindGames]

I bought one, a new 45W tube, and the mod housing. All are arriving between now and next Tuesday. I'm taking a grinder to my machine this weekend to do some "modding" of my own. I'm going to cut my exhaust vent larger, cut my water inlet and outlet tubes larger, and I'm thinking about cutting out some of the metal strip between the first mirror and the gantry, I still need to protect the tube from the back end of the K40 laser head mount, so I can't cut the strip completely out.

Thanks for all the advice. This will NOT happen to me again. I will not allow myself to cheapen out on a 10$ part that tells me the 50$ part isn't working correctly and destroying the 200$ part on my machine. I'm still new to this hobby, so I'm learning the hard way too often. I need to read these forums much more often.

Thanks again all.

[Tech_Marco]

Get a water sensor to protect the laser tube!

http://www.lightobject.com/Water-flow-p ... -P815.aspx
or
http://www.lightobject.com/Water-flow-O ... -P680.aspx

Just hook two wires from the water sensor to the "WP" & "Gnd" on the laser power supply. When no water is flowing, the sensor(a switch) is in Open circuit stage. When water is flowing, the switch is closed circuit and shorted the WP & Gnd , that will enable to the LPSU.


Marco