incomplete small hole cutting problem

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bagul
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incomplete small hole cutting problem

Post by bagul »

hello. i'm new member to this group and also new to cnc plasma cutting. Wow! so many things to learn. i've been having trouble cutting a complete hole (small holes that has to be cut center pierce). been trying all (at least of what little i know) but could not correct it (tried speed and arc of delay). so far still the same result. out of wits here :oops: ha!ha!. maybe somebody can help me out. picture of sample cut is 1/8"(dirty, ) steel plate. small hole is 1/4" dia. set speed is 40 inch/min. 40 amps. arc off delay is .3sec...thank you.

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robertspark
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Re: incomplete small hole cutting problem

Post by robertspark »

can you post the gcode please
bagul
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Re: incomplete small hole cutting problem

Post by bagul »

sorry for the late reply (have to attend an unexpected farm maintenance). i also notice it does not cut complete circle on outside cut with straight lead. though it not that noticeable. heres the g code.
%
G21
G91
G00X14.01Y20.01
G42
M07
G01X2.96Y-0.50
G02X0.00Y0.00I-2.96J0.50
M08
G40
G00X9.04Y0.50
G42
M07
G01X-2.53Y-1.61
G02X0.00Y0.00I2.53J1.61
M08
G40
G00X-17.61Y-12.53
G42
M07
G01X3.53Y3.53
G03X0.00Y0.00I10.61J10.61
G01X0.00Y-01.00
M08
G40
M02
robertspark
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Re: incomplete small hole cutting problem

Post by robertspark »

ok, couple of things....

what motion controller are you using??? mach3, linuxcnc... etc etc...

I notice you are using g42 (tool offset compensation....)
but I cannot see what you are offsetting the tool by..... normally (dependant upon machine) you have to tell the machine how much the offset is with a "D" parameter (tool diameter)... or a "P" parameter (tool pitch.... half diameter.... IE the actual offset)

looking at your gcode I don't see that being set.... it may be possible that the machine is offsetting by a default "T" number.... say T1.... Tool #1 will have a set diameter... and this could be used and it just offsets according to the set Tool number presently programmed


next one.... you are using m07 to fire the torch and m08 to turn it off...... m7 and m8 are normally coolant controls.... where m7 is most coolant, and m8 is flood coolant and m9 turns them off (both or if either one is on)
https://smithy.com/cnc-reference-info/c ... rol/page/3

with plasma we tend to use m3/m5 .... because me with plasma if your controller allows for a plasma setting will also monitor the arc ok signal.... no arc ok.... no motion....

sorry need to understand a bit more about your setup.... but your problem is probably the tool offset compensation.... if you edit the gcode and remove the g42 statements it should run fine
robertspark
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Re: incomplete small hole cutting problem

Post by robertspark »

sorry forgot to post a link about cutter compensation

https://machmotion.com/blog/what-is-cutter-compensation
bagul
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Re: incomplete small hole cutting problem

Post by bagul »

thanks very much. think i'm way off my league by the answers your giving me...haha. will have to chew and digest evrything you'r telling me. i think its a must to understand g code. my setup is a chinese huawei (cheap) portable flame/plasma online. much like the cross bow which i like (but could not afford ). comes with a fastcam software and a starfire system. hope thats helpfull. here's a link to the machine https://www.alibaba.com/product-detail/ ... vIiVCe&s=p
bagul
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Re: incomplete small hole cutting problem

Post by bagul »

i did the program in cad, output it in dxf file. using fastcam i save it as cam file and use fastnest to output the g code of the .cam file. so the g code was generated by fastnest. then i use a usb to tranfer the file to the cnc machine. in short, i have no idea how a g code works. ha ah!
bagul
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Re: incomplete small hole cutting problem

Post by bagul »

will to remove g42 and test tomorrow.
" with plasma we tend to use m3/m5 .... because me with plasma if your controller allows for a plasma setting will also monitor the arc ok signal.... no arc ok.... no motion...." i think the machine while using coolant control m7 and m8, monitors arc ok because it does not move when cutting arc is not generate. ??? starfire likewise have a arc detect setting (0/1). maybe the coolant parameters setting are controling the on- off time of the plasma torch ???
robertspark
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Re: incomplete small hole cutting problem

Post by robertspark »

have you got a link to a user manual?

I've done a few Google searches but come up with nothing
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WyoGreen
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Re: incomplete small hole cutting problem

Post by WyoGreen »

Bagul,
I know nothing about your software or equipment, but my first thought when looking at your pictures was that you are using an Arc lead-in and lead-out. You might try using no lead-out, and perhaps a little over-cut if available in your software. Sometimes a Tangent lead-in instead of an Arc also helps.
Steve
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robertspark
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Re: incomplete small hole cutting problem

Post by robertspark »

the closest I can get to your machine is the steel tailor series of machines..... they all seem to use the same or similar software...

https://www.google.com/url?sa=t&source= ... 6581531306

have you set the kerf width correctly?
bagul
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Re: incomplete small hole cutting problem

Post by bagul »

"You might try using no lead-out, and perhaps a little over-cut if available in your software." yes lead in lead out is straight. set to center pierce on small holes. tangent lead in/out works but on small holes maybe there would be a lot of splater and either the tip crashes on it or it raises the torch. i will try no lead, though i think it will not cut a clean circle coz of piercing is on the hole edge. "overcut" do you mean everlap? yes i think that will work but cant seem to find the setting for it in fastcam program.
bagul
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Re: incomplete small hole cutting problem

Post by bagul »

"have you set the kerf width correctly?"
yes, i think i have (or at least fastcam did) dimention of the cut part are correct.
bagul
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Re: incomplete small hole cutting problem

Post by bagul »

"the closest I can get to your machine is the steel tailor series of machines..... they all seem to use the same or similar software..." yes quit similar. the setup...
robertspark
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Re: incomplete small hole cutting problem

Post by robertspark »

sorry I have no other ideas for you, good luck
bagul
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Re: incomplete small hole cutting problem

Post by bagul »

thank you.... learned a lot though.
bagul
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Re: incomplete small hole cutting problem

Post by bagul »

think i found a solution. internal exit parameters set to CONTINUES. set the lenght to 1/8". haven't tried it yet though. will update results.

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Dfabltd
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Re: incomplete small hole cutting problem

Post by Dfabltd »

Did you find a solution
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