blobs of slag on stainless 11gauge

[adekker]

I am cutting 11gauge ss on a bytronic bystar 4020, 2800watt.
I'm having some difficulty with holes and tight slots, I end up with small hard blobs of steel at the pierce / leadout points

I have an arc leadin and leadout with plenty of length.

I also end up with the blobs in corners (with rad, and withouth) and some on straight lines

here is a pic of the blobs and the parameters

https://picasaweb.google.com/andrewcdekker/11gaSsParameters?authkey=Gv1sRgCOOQpfvqgdbrTg#

 

[HenryRollins]

Just how long is your lead in and size of the rad?
Have you adjusted either your acceleration or braking factor?
It could be too much power, too tight of a rad in the lead in, dynamic factor too low. What is the focus on the head?

 

[adekker]

lead in - rad .1875, length .200

focus is at 6mm

I have played with the acceleration / braking factor - not much has changed,

I tried a straight lead in and the blobs are much smaller but still present.

 

[adekker]

The blobs are inconsistent. Sometimes a hole has it sometimes not without a change in parameters.

Check out the updated pictures from the link in my first post

 

[HenryRollins]

What thickness is that? It looks as if your focus may be too deep and you are cutting into the cutting grates.

 

[HenryRollins]

Never mind, 11 gage, your focus should be at 3mm to 3.5mm. What is the zero point on the lens?

 

[adekker]

To set the focus position I put a small cardboard shipping tag on the table, turned the focus all the way up till it topped out then brought it to 0. Then I brought my head down and took a pulse shots increasing the focus number (lowering the focus) by 15 every time.
The pulse size decreased then increased. I repeated the process when I found the smallest pulse hole by stepping the focus by a smaller #. I ended up with a focus position of 60, now this is with a nozzle height of .7mm

According to my manual .7mm above is equal to 7 ticks on the cutting head focus ring.

When I'm cutting 11 gauge stainless with a hk15 nozzle I have my focus set to 2 full revolutions, or 120
so 120 – 7 (.7mm nozzle height) – 53 (head focus position) = 60, which is equal to 6mm, The manual says one turn on the decimal scale corresponds to a variation in height of 6mm ie 1 unit corresponds to 2/10mm

 

[HenryRollins]

You are reading the Operator's Manual? That thing is useless for setting the focal zero. You need the procedure from the Basic Apps book, you can get that for free from the Applications Department at Bystronic in NY. 631-231-1212 and ask for Laser Applications.

 

[adekker]

Ok, thanks. Hopefully that will give a better description of the head, and what the numbers represent - higher number = lower focus, 1 tick = 1mm etc. because my manual is 15 years old and was translated from some European language

 

[msandoval]

I think you may want to play with your modulation which at 30% may be OK but I would certainly play with your laser basic power. I agree with Henry Rollins as well in double-checking your braking and acceleration factors and to also call the apps. department at Bystronic.

 

[krugtech]

You're in good hands and your getting some good advice. I just want to point out a common mistake when dialing in one of these machines- Don't stop adjusting as soon as it cuts good. Go a little more until it cuts bad again and then back off about 1/2 way. You don't want to be on the edge, you want to be in the middle of the road so if any little thing changes you'll still be cutting. When you're on the edge, production and consistency suffer.

Chris Krug

http://krugtech.com/