@Yuusuf_Sallahuddin_Y yes I will be abroad for another 2 weeks, with very poor connection (countryside). just trying to come daily to check on spam and free genuine post from spambox.
@StephaneBUISSON That’s cool. When you return I’ll discuss things with you in regards to creating sticky posts etc. for more of the regular topics (alignment, mirrors, lenses, air assist, etc). Take care & talk more when you’re back.
Can anyone tell me settings on my k40 laser cutter to cut 3 & 6mm MDF???
For 3mm About 12mm/sec and as much power as needed - it will be up there around 18ma or so probably. Slow down to maybe 6mm/sec if needed.
these lasers aren’t all the same, and alignment,air assist etc all make a big difference.
The K40 seem to have their own personalities, some tubes have odd shaped beams etc, so you DO have to play with it on some scrap to get a feel for it.
2 faster passes cut nicer than 1 slow one in my experience.
Reduce speed as required for 6mm. 6mm is tough for the k40 and may require multiple passes and re-setting the focal point after the 1st pass.
Keep it under 18ma on the meter or so for tube life (I run mine to 21ma, and it seems OK, but I may pay in the long run)
Oh, If you don’t have an air assist, watch for flare ups.
Have fun, Scott
Do I have to have air assist to cut MDF as I only have the basic k40 it is only new so it is just the standard laser cutter Will it catch fire without air assist
You can get by without it. But I’d say the an air assist setup is probably the biggest bang for your buck on upgrades.
I’ve heard of people using hair dryers in a pinch. For now, that may be a good option, just keep it back from the works and be careful. You will have to run the machine with the lid open. Unless you’re comfortable with that, don’t do it.
As I’ve mentioned before, the k40 is really a machine for experimenters who don’t mind tinkering and are used to working around machines without safety devices. You can pinch, laser or electrocute yourself if you don’t take precautions.
You’ll find the lens gets dirty quickly without some airflow past it. If it gets too dirty, it will burn on the ‘smoke’ and destroy the lens pretty quickly. The air assist does a few things positive. It protects the lens by recessing behind the nozzle, keeps smoke and fumes from depositing on the lens, and if you get the rectangular one from Saite cutter or Lightobject, gives you a larger lens and (the big one) adjustable focus without moving your workpiece. (within 1/2" or so range.)
There is some work involved, and you need a compressed air source, but they can be acquired pretty cheap.
Beyond that the fan that comes with the k40 is pretty anemic.
One freebie upgrade you can do is to simply remove the rectangular “tube” that the fan draws thru. Removal of the restriction increases the fans effectiveness quite a lot.
It’s held in place with 4 screws, just unscrew and it’s removeable. I don’t recall if you need to remove the framework to get it out or not. It’s been a long time since I removed mine.
Bottom line answer, keep something handy to blow out flames if they flare up and don’t go back out, (blow dryer probably great) don’t let them flare or you’ll damage the lens/head. The flames will be minor, but CAN propagate and burn your house down (worst case)
The air assist head, requires minor metal work (enlarge hole) to install, and an 18mm lens.
The lens to fit (USE 18mm dia, 50.8mm focal length, and the basic one works fine)
http://www.ebay.com/itm/HQ-ZnSe-GaAs-Focus-Focal-Lens-Si-Mo-K9-Reflective-Mirrors-CO2-Laser-Engraver-/261634544454
@Scott_Marshall yes you need to remove the frame (4 nuts & bolts and 2 wires) to remove the exhaust manifold.
@Scott_Marshall As Donna is wanting to cut MDF, I wouldn’t suggest removing the exhaust tubing, because MDF fumes are not really something you want to be breathing.
@Donna_Gray I am working through the process of a 3D printed air assist head (that goes around the lens) currently. I have just had one printed & picked it up yesterday, unfortunately I broke part of it (due to a flaw in my design) & cannot test it. But I am redesigning it. It runs off a simple air pump (like for fishtank). I am not 100% certain, but I feel like you were maybe in the Gold Coast/Brisbane region. If that is so, then when I get the next revision printed at 3dHubs (~$30 for the first print in the line & $20 for each print thereafter), I will be making a video to show it in action & if you’re interested we can organise getting another one printed for you.
Yes I live about an hour and a half away from Brisbane I am closer to the gold coast I come from the northern rivers area I don’t know much about machines as far as the mechanics of them so I am not able to do upgrades etc If it was a simple thing to setup I could maybe have a go at it Would the air assist stop charing of paper as well I tried the hairdryer but them it didn’t cut through I have to be truthful I did cut through the 3mm mdf but I didn’t know that a small flame was bad for your focal lense that is the only time it worked was when there was a small flame as the laser was cutting I feel like it is all getting a little hard now and I am very disappointed in outlaying the money as I am now finding I cant do much without upgrading things
@Donna_Gray You don’t really need to upgrade a lot. The only real upgrades I have done is replace the cutting bed (just to make things easier for the things I tend to work with) & added a makeshift air assist. I just used an aquarium pump & zip tied the hose to the lens mount so that the air focused roughly on the cutting position. The 3D printed one I am working on at the moment is to increase the precision of that (i.e. air will hit right at the laser beam target). Air assist won’t totally remove the charring, but it dramatically minimises the charring & also improves the ability to cut cleanly. As someone else mentioned, the laser vaporises the material, but as it causes heat, the material can burn, which is what causes the charring. I’m fairly certain it will happen always, but you can minimise it to be very small amount of charring (i.e. <0.5mm).
So, overall, only real upgrade you need will be to add an air-assist. As you are in the Northern Rivers area (& 1 1/2 hours from Brisbane) you should be reasonably close to me. I am in Nerang, so I gather you’re maybe 30-45 mins away from myself. I have spare air pumps (exactly the same as what I am using) that I picked up for next to nothing from an auction (they are actually Tanning Airbrush airpumps). Very basic pumps, but I would be happy to give you one for free (as I have about 10 of them). Are you up Gold Coast direction often? If so, we could arrange a pickup & once I get my air-assist head 3D printed again (have to revise the design as there are problems with the current design) I could show you it in action.
Might not have been clear on the exhaust. You remove the INTERNAL exhaust tubing. Once done, you re-connect to outside exhaust. I’d never suggest venting into a building.
If cutting anything that burns, Replace the Chinese exhaust tubing with aluminum flex tube (non-flammable) vented outdoors.
@Scott_Marshall Oh, I must have missed the INTERNAL bit. Glad to know you were not meaning to vent the MDF fumes straight into the room.