cutting circles in 3/8" with a pm65

[DibbleDesignFab]

alright here is a small 2.5" circle that i have cut this is the best i have been able to produce after hours of cutting circles and trying different suggestion to reduce the amount of edge angularity, it still worse when i try to cut a 5/8" hole in the 3/8" plate, i started with brand new consumables, i have 70psi of air which is whats recommended with a 25ft lead, my setting are by the book, i went 60% of the hypertherm setting so i am running at 65amp 25ipm, .7 seconds pierce delay, .06" cut height, .15" pierce height and i cant seem to get rid of the edge angularity.

[robertspark]

https://www.hypertherm.com/Download?fil ... &zip=False

Step 4, is the torch square in both planes?

The top photo shows that it looks like a rhombus where the two opposite sides are slanting the opposite way.

You may need to check the squareness of the torch to the material when the material is on the table because if your table is anything like mine, the stats are covered in dross and lumps etc.

Step 5 may also be worth considering maybe changing the torch cut height (UP?) for a square'r cut.


Are the consumables genuine??? I see that you state they are new, but are they genuine..... it may be possible that the hole in the end of the nozzle is not square..... loosen the retaining cap and rotate the nozzle without moving the torch and try again.... does the angularity (rhombus) move to the opposite side?

[acourtjester]

I found to check torch cut problems is to cut squares with the side in the X and Y direction. This will show if the torch is cutting off perpendicular, also the plasma stream is like a candle flame but inverted. If the torch height is off you will have a taper in the cut in the top to bottom direction check both edges of the cut.

[DibbleDesignFab]

https://www.hypertherm.com/Download?fil ... &zip=False

Step 4, is the torch square in both planes?

The top photo shows that it looks like a rhombus where the two opposite sides are slanting the opposite way.

You may need to check the squareness of the torch to the material when the material is on the table because if your table is anything like mine, the stats are covered in dross and lumps etc.

Step 5 may also be worth considering maybe changing the torch cut height (UP?) for a square'r cut.


Are the consumables genuine??? I see that you state they are new, but are they genuine..... it may be possible that the hole in the end of the nozzle is not square..... loosen the retaining cap and rotate the nozzle without moving the torch and try again.... does the angularity (rhombus) move to the opposite side?

yes i checked both sides of the torch to the plate to make sure they are square, and it is,

i have adjusted the cut up before to try and see if that was the issue and it only made it have a more positive cut angle meaning more was missing from the top then bottom

and yes i am using genuine hypertherm consumables

[yseguy]

Have you changed the swirl ring recently? Ive heard it can cause similar issues

[Thor]

Are the circles the good parts or are the holes? I see leadin/out on the circles so assuming they are the drops, so thats where the taper should be then. What direction are you cutting cw or ccw. if the holes are the good part then it should be ccw.

Its very hard to get it perfect especially the thicker you go, triple check torch angle and play with volts a little to change the ht to move the taper around a bit.

[jimcolt]

When you have wildly varying angularity like you have pictured then you have a damaged nozzle and/ or shield. Shields and nozzles can be damaged on the very first pierce if pierce height is too low or pierce delay is too short. You also should be cutting at the correct cut height (which is .06", adjust arc voltage to be sure you are achieving .06" during steady state cutting). You also are cutting way too slow.....book spec for 65 amp shielded consumables on 3/8" material is 45 ipm, you say you are cutting at 25. Post closeup and focused pictures of the nozzle orifice and the inside of the shield and I can probably help solve your issue. Note that some cnc machines use a different start point for pierce delay timing.....watch the pierce carefully, the torch should stay at pierce height and with no x or y movement until the molten metal sparks are exiting out the bottom of the material. If motion starts before the material is fully pierced the nozzle will get damaged and you will get results as shown in your picture. Increase the pierce delay time as needed. Again...pictures of the nozzle orifice (the one that cut the pictured parts) as well as the inside of the shield will help me help you. Jim Colt

[Brand X]

drop down to 45 amp consumables, and compare the two..

[DibbleDesignFab]

When you have wildly varying angularity like you have pictured then you have a damaged nozzle and/ or shield. Shields and nozzles can be damaged on the very first pierce if pierce height is too low or pierce delay is too short. You also should be cutting at the correct cut height (which is .06", adjust arc voltage to be sure you are achieving .06" during steady state cutting). You also are cutting way too slow.....book spec for 65 amp shielded consumables on 3/8" material is 45 ipm, you say you are cutting at 25. Post closeup and focused pictures of the nozzle orifice and the inside of the shield and I can probably help solve your issue. Note that some cnc machines use a different start point for pierce delay timing.....watch the pierce carefully, the torch should stay at pierce height and with no x or y movement until the molten metal sparks are exiting out the bottom of the material. If motion starts before the material is fully pierced the nozzle will get damaged and you will get results as shown in your picture. Increase the pierce delay time as needed. Again...pictures of the nozzle orifice (the one that cut the pictured parts) as well as the inside of the shield will help me help you. Jim Colt

this has been awhile ago i dont even have that piece anymore, but i am still fighting hole quality,and the reason i am cutting down to 25ipm is that 60% of the recommendeded. , i can cut and run some new pieces if that would help you determine what my issue is and i will double check what you already have said