[fdm_guy]

Hi everyone!

Recently I have purchased a 1290 Laser from China, the transaction was quite a pleasant experience and machine arrived configured as promised, without serious issues.

The configuration is as following:
1290 Laser
Reci W6 tube (130-150w)
Ruida RDLC320 Controller board
CW-5200 Chiller
550w Standard air blower
Small membrane air pump

I spent two days with the beastie and was able to collect some experience, in general I liked the way the machine works and software is quite OK as well (LaserWorks). I have tried to cut 3 kinds of plywood: 12mm (2/5") outdoor birch, 10mm (2/5") laser grade birch and 6mm (1/4") indoor populus. As I expected, outdoor plywood is a no go. It is terribly hard to cut and is a dirty job.

Cutting 6mm populus is like butter, while 10mm laser grade ply gave me most interesting results:

It seems as if using more power actually makes the machine less effective. The best result I was able to achieve with 10mm laser grade plywood was at 10mm/s and 25% power. Any increase in power above 25% resulted in worser / incomplete cut. From 35% and up it did not even penetrate the back side of the board. Speeding up the machine did not help either.

I am quite sure this is not a power issue, I can clearly see power increase on the burned image if I engrave test images picture with 20% to 100% power.

Does powerful beam cause more smoke which in turn diffuses the laser? And if yes, will replacing the cheap air assist pump on something more powerful be of much help? If so, what would be the right choice? Will something like this do: Mini air compressor - airbrush makeup china,airbrush compressor,airbrush compressor china,airbrush makeup,airbrush china,mini air compressor china,airbrush,air compressor-Fenghua Bida Machinery Manufacture Co. Ltd. ?

And another question: When I got the machine, I cleaned the lenses and noticed a rather well visible darkened spot on the reflecting mirrors, I assume this is where laser beam is reflected, is this normal on a new machine (Which was tested on the factory)?

Thanks!

[Exsecratio]

Did you clean the mirrors when the machine was set up?

If not then it is likely protective oil burned onto the surface causing the dot.

Does powerful beam cause more smoke which in turn diffuses the laser?

That's part of it, the main cause is the invisible CO2 gas given off by the cutting action that works like a brick wall to laser beams.

cheers

Dave

[fdm_guy]

Did you clean the mirrors when the machine was set up?

If not then it is likely protective oil burned onto the surface causing the dot.

Yep, I did clean it before turning power on for the first time. So the dot / darkening is not a normal thing to have?

That's part of it, the main cause is the invisible CO2 gas given off by the cutting action that works like a brick wall to laser beams.

Hm, okay, it is kind of useless to have a 150W laser then? If 40W is about maximum you can really use productively?

[Exsecratio]

So the dot / darkening is not a normal thing to have?

On a mirror that's a year or more old then yes but on a new machine no.

it is kind of useless to have a 150W laser then? If 40W is about maximum you can really use productively?

Not really, big tubes pump lots of power and can overcome the effect to a certain degree. The down side is double the power doesn't get double the speed. High grade air assist will help and make a big difference. My baby 180 watt cuts about 1.75 times faster than a good 80 watt and the thicker the material gets power requirements go up in orders of magnitude.
A 40 watt will cut 6mm MDF, to cut 18mm at any kind of speed you need closer to 500 watts (or a 400 watt high grade like a GSI)

cheers

Dave

[gio.gee]

Hi Dave when you say

High grade air assist will help and make a big difference

Can you explain? how would one get a high grade air assist?

[Exsecratio]

Hi Gio,

You need something like a BIG compressor, the little things that come with the machines are air pumps not really compressors (they go to about 5psi) what you need is clean air (no oil in it) at around 15psi+ directed as close as possible to the actual cut from above. This works like an extension of the air cone and keeps CO2 gas as well as carbon build up out of the cut area (carbon and CO2 both block IR radiation) it also has the added benefit of introducing more oxygen into the cut (more air = more oxygen volume per total volume) This will aid in cutting thicker material at better speeds and give a much better surface finish with no staining.

A Clarke Silent series compressor (the 7/100) or one of the Titan models is good if you want performance at a decent budget (the clarke is £1,500) they also won't destroy your hearing or upset the neighbours

OPLaser support forum ? View topic - Titan 5004 "Silent" compressor

cheers

Dave

[gio.gee]

cheers Dave

I have used compressed air before, how would you keep the air flowing as normally you have a gun or a trigger that needs to be pressed for the air to come out.

How does the Tesco Thermos dry the air (as per OPL thread)

Only ask as i want to make my laser more efficient

[Exsecratio]

The air is supplied to the laser full time, a simple rotary valve can be used to turn it on and off or you can modify the piping to use the card function that turns the air on when the cutting action is running.

How does the Tesco Thermos dry the air (as per OPL thread)

OPLaser support forum ? View topic - Water in airline (With Solution)

Air dryer still use the same thing on all my machines, works like a dream and costs next to nothing

cheers

Dave

[fdm_guy]

Hi Dave,

Thank you very much for advises, I am now looking at compressor with 220+L/MIN, 50+L tank and I also plan to install a solenoid valve so controller will enable air when needed. This should reduce noise and load on compressor.

Do you know how one could improve a 'cheap' Chinese laser head to direct air properly? Is it possible to buy just a nose cone or does one need to replace entire head?

Also, my laser does not seem to fire up at power < 15%, is that a tube or power supply thing?

[Exsecratio]

Just the cone needs replacing it's quite normal for DC tubes not to fire under 15% power, it needs a minimum power to maintain the arc in the tube and below 15% it's just not enough.

Have a look round the forums I posted links to, there are a few posts about making extended cones for lasers

cheers

Dave

[ozstockman]

to cut 18mm at any kind of speed you need closer to 500 watts (or a 400 watt high grade like a GSI)

Unless it is related to plywood only it is not entirely true. 280W in two GSI tubes is more than enough to cut through 18mm thick MDF.
Actually it is quite fast about 400mm/m at 90% of power. Not straight cut with a 3" lens though but it is not too bad and it is acceptable by my customers.
Air pressure is about 55 psi with up to 70 psi recommended by my laser manufacturer.

Plywood is a different story, in most cases even the one made of softwood may need more power or less speed to get through it. Mostly because there are knots in hidden plies which cannot be seen and avoided.

[Exsecratio]

At speed Oz

cheers

Dave