What a difference alignment makes . . . .

[PhillyDee]

Decided to check alignments despite not having any major problems. Beam was a bit off to the head mirror, but when checking the alignment to the cone, found that the laser part itself was more of a D shape than a spot.

Possible cause:
Overtravel on the Y- direction causes belts to slip. This would have twisted the X axis. This was straightened out and helped keep the laser in the same place all over the bed.

Tweaked the mirrors at the bottom left to align the beam more central to the aperture.

After cutting one of my standard jobs, discovered that there was a lot of splash back of the cutting beam from the table and honeycomb bed. Engraving was also quite a bit deeper.
For the record, was cutting at 75% power (40W tube) and 11mm/s

turned down the power,and got as low as 55%, and increased cutting speed upto 16mm/s.

So an overall decrease in the power requirements, means longer tube life, less heat to get rid of from the watercooling, and a speed increase of more than 30%.

Result!

Now a couple of more questions.

1. How do you find the optimal cone point of the focused beam? Trial and error?
The beam itself on acrylic is 0.3mm wide, might not seem a lot, but Im sure it can be tighter!

[Spooky]

Beam should be sub 0.1mm Phil at the focal point. Even though the len's have a stated focal length it's rarely exactly that,it's a good start point though and then it usually within 0.5mm up or down from that.Kerf should end up at between 0.1 and 0.13 if the focal distance is bang on. A cut of 0.3 with a deep cutting ability usually means too close so I'd drop the table a bit.(if it was the other way cutting ability would be worse) the amount of taper top to bottom is also a good indicator of focus

Dead right though, alignment is everything, 80% of posted problems with lasers comes back to alignment

best wishes

Dave

[Mike]

The hardest thing with a new mahcine is knowing what is the best you should be able to achieve and how to achieve it.
I am getting there slowly too, my alignment is pretty good at the moment, extra air has helped too.. need to get a chiller now

[PhillyDee]

Likewise with the chiller. I have been asking HPC for a week and a half and am still no further forward! Might try and source one elsewhere, I need one desperatly!

[Spooky]

I have a 300 sat here Phil, under an hours use if thats any good? 6 litre capacity (like all the models) holds 18 degrees easily on smaler tubes like 40's and 60's @ 75 power on a 50% duty cycle.

best wishes

Dave