Stainless cutting issues :(

[Darklin918]

Greetings all! I am having an issue dialing in a good stainless cut (see attached somewhat blurry pic)
Specs:
Bystar 4400W
8ga 304 Stainless
5.0" head w/ HK20 nozzle.
Focal: -1.9, N2 gas @ 17bar pressure, 65 feed speed, 3400W power, not sure what all other parameters I should post. Been fighting this for a while and decided to ask for help. I really appreciate your time.

 

[Foostrap]

What thickness is that? Maybe this is too thick for the 5" lens. Do you have a bigger focal length on your machine (like 7.5")?

Looks like the nozzle is too small, or focal point too high.
Lack of N2 gas pressure can also cause that burr, but 17 bar should be plenty (unless you are not actually getting 17 bar at the head)

 

[lasermate]

Have you heard of the Mate Black Magic Lens? This is the perfect lens for cutting stainless and aluminum. Look on Ophir website for the info. Good Luck.

 

[SGAFFNEY]

With the 5" lens your focal point location will be critical and have a very narrow window where the cut will be acceptable. While you can cut the 8 ga with the 5" lens it will just make life harder. I would move to the 7.5" and look at lower focal point. -1.9 is not low enough in my opinion. When cutting that thickness of SS with N2 I always use the maximum power I have available. Why are you only using 3400 watts? If I were working on this I would:

1. Max out power.
2. Lower focal point. (-3 range)
3. Increase feed rate. With 4400 watts available I would think you could at least 100 ipm feed rate.

Hopefully someone with more experience with Bystronic lasers will confirm this and provide further guidance. Good Luck!

 

[Darklin918]

Hey all, thank you for your feedback! The reason I was only at 3400 power is that was what the preloaded parameters had, and everything I had read so far pointed to focal position and feed speed, not power so much. I'm still very new at laser operation (only been pushing buttons on this for about 4 weeks now)
I ended up changing from the .160 parameters to the .187 parameters, which called for a 7.5" head, same nozzle, and my first cut using the preloaded params was as beautiful as I could have wished.
Again thank you for the feedback!

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