cant get my second hand laser to cut

[geebee]

Hi all
just bought a second hand 90120 with a 150w 10,000 hours tube upgrade
the seller showed me it cutting 3mm mdf at 35 speed at 95% power
now i have it home best i can get it to cut is 18 speed at 95%
and to me the cut looks like a wide and an over burnt cut
ive played about with the alignment of the mirrors, ive changed the first mirror for a new one and changed the focal lens
i think what the problem is, when im checking the alignment with a single fire of the laser im not getting what i think should be (tell me if im wrong ) a single dot of around 2mm wide but im getting what looks more like a circle about 4 to 5mm wide, sometimes with an un-burnt part in the center, as though something is out of focus and this is same on all mirrors even if i cover the first mirror in front of the tube,

any advice would be really great thanks in advance Graham

[Tom]

Welcome Graham

The dot size of the laser between the mirrors will be 4mm to 8mm depending on tube make
But it should be a solid burn mark.
The charring on the mdf will depend on mdf make and if you are in focus

Tom

[Daven]

But it should be a solid burn mark.
Tom

Not sure about that - I set the power on the panel low when aligning and you get a similar pattern. Remember the final lens focuses the beam so I'm wondering if it is a power issue?

On the panel menu check in the laser settings option and see if the power option is set to 99 or 100% (not the top layer option). Use laser quality MDF/Ply and make sure you have the focus height correct.

Cheers
Dave

[geebee]

hi guys thanks for comenting

i already have a 6090 with a 60w tube and im using the same wood on that fine
on the 6090 im cutting 3mm mdf at 20 speed at 80% so this one is cutting better then the new 150w
this one had an alignment cleat dot of around 2mm, is this because its only a 60w tube ?

one the digital panel on the machine it says 100% power (dont think any settings could have changed while in transit ? )
what do you mean by (not the top layer option) ?
im using the focal guides that came with the machine

thanks Graham

[Daven]

There are two power settings on the panel.
First is the top menu :-
File
Speed
Power
Pieces

If you press 'Menu' - select Laser Set and enter there is a 'Power Set' - this is the one to check as it remains at the last entry.
Sounds more like an alignment or focus issue though - have you tried a ramp test? Put a bit of tape of the output nozzle and see if the beam is exiting central (do it all four corners of the bed

Best
Dave

[Tom]

Hi
At least you know the mdf is ok
As Daven says do a ramp test to find your optimum focus
Did you get all the air out of the tube
Big tubes can be quite sensitive to movement

Tom

[Spooky]

150 watt should manage 45 to 50mm per second at 80% power

Spot size on the 150 between mirrors is 7 - 12mm or so but the final spot on the work will be smaller (the bigger the input beam the smaller the final spot)

A ring shaped spot isn't at all unusual, it depends on the beam mode as to what shape you get

[geebee]

hi guys
still no luck
ive checked the power setting ad its at 100%
i cant see any air bubbles in the tube
i have a wooden square that came with the machine to set the focal depth correctly
ive put a piece of tape on the end of the laser and it seems to be firing through the center ok
think ive run out of things to check
think its time to get HPC in to do a service and a check over ?

[Diysurgeon]

Hi

I would be interested in how you resolve this problem. I have exactly the same issue from an identical machine I also bought second hand. I collected it last Wednesday. It worked fine when demonstrated.

[Tom]

Oh dear