Cut Quality ?

[Largemouthlou]

Jim and gang, this is with a 1250 hypertherm and 40 amp fine cut. CnCNC dragon cut dthc electronics and Mach 3,
Jim, Bob Ballard says Hi..
Well finally making some progress, have the motors tuned to make a 5 X 5 square. The first little sample I cut did okay, then got worse from ther, I wrote a tap file for a 5" X 5" square using the mild steel settings in the manual. .08 cut and .167 for pierce. and the square only gets cut in the corners wher the machine slows down. The material ia 1/16 aluminum.

Just trying to figure out if it is my machine speed, bad air, or settings. I only have a motorguard filter on it right now..

Here is the tap file and some pics
N0000 (filename square 5X5.tap)
N0010 (post processor: Mach3 plasma.scpost)
N0020 (date: 7/29/2011)
N0030 G20 (units: Inches)
N0040 G53 G90 G91.1 G40
N0050 F1
N0060 S500
N0070 (part: square 5 X 5)
N0080 (operation: outside offset, layer 1, T1: Plasma, 0.06 kerf)
N0090 M06 T1 F500.0 (Plasma, 0.06 inch Kerf)
N100 G00 Z0.5000
N0110 X1.1271 Y3869
N120 Z0.05
N0130 M03
N0140 G04 P1
N0150 G01 Z0.0800 F10.0
N0160 G02X0,9671 Y5.2269 I-0. 1600 J0.0000 F500
N0170 G01 X0. 1969
N0180 G03 X0. 1669 Y5. 1969 I0.0000 J-0.0300
N0190 G01 Y0.1969
N0200 G03 X0.1969Y0.1667 I0.0300 J0.0000
N0210 G01 X5.1969
N0220 G03 X5.2269 Y0.1969 I0.0000 J0.0300
N0230 G01 Y5.1969
N0240 G03 X5.1969 Y5.2269 I-0.0300 J0.0000
N0250 G01 X0.9671
N0260 G02 X0.8071 Y5.3869 I0.0000 J0.1600
N0270 M05 M30
N0280 G04 P0.3
N0290 G00 Z0.5000
No300 M05 M30



The few things that did cut all the way out looked like this (heavy dross onthe bottom)

[jimcolt]

You will notice in your manual that there are no cut charts for aluminum with the Fine Cut parts. That is because our process engineers did not design these parts for cutting aluminum......however I have had great success...here is what to do:

You must use the deflector shield part number 220404....in fact, this is the one that you should use for all Fine Cut cutting jobs. With this deflector.....you should sparay some mig welding anti spatter spray on the front of the torch after the consumables are installed.

Because this deflector extends past the nozzle....you have to reset the cut height to .06". Adjust arc voltage once cutting so that the torch to work distance is .06"...any higher and you may not cut through the sheet.

We will guess a bit on cut speed....since there are no cut charts from Hypertherm. Start at 90 ipm....adjust voltage so that height is .06" (1/16") your pierce height should be .120", and your pierce delay time should be about .4 seconds....or enough so the that arc penetrates the plate before moving. If there is dross on the bottom of the cut...increase the speed by 10ipm and test again.....eventually, by increasing speed and maintaining height....you will get just a fine hairy fuzz on the bottom of the aluminum sheet.....this will be the optimum cut specs.

Keep in mind that you must periodically wipe the aluminum spatter off the front of the torch...and be sure your pierce height and cut heights are maintained.

A better way to cut aluminum (my opinion) is to use the 40 amp shielded consumables and follow the specs exactly as stated on the cut chart under "40 amp mechanized shielded consumables" in the Hypertherm operators manual. Be sure you are using the exact consumable part numbers suggested...especially the 120930 shield. Use the optimum (not maximum) travel speeds.

PS....Bob Ballard is a long time friend....and also works for Hypertherm.


Jim Colt Hypertherm

[Largemouthlou]

Thanks Jim, I will ck the consumables and start playing with the heights..

Bob came to the shop one day and explained a few things to me as well, I will be giving him a ring also and seeing how his schedule is.. I told Bob that I talked to you a few times on line he said to say hello

Just looked at the manual and I'm using the standard fine cut shield (120979) I believe. I also see the 220404 deflector, next to it there is a separate retaining cap (2200061) there is a note for this retaining ring, it says ** "Use an ohmic sensing cap when a compatible torch height controller is installed" Does this pertain to the DTHC chip board I installed in the 1250??

I will get the proper consumables and try again.

[jimcolt]

The Candcnc torch height control system....to my current knowledge....does not use the Ohmic plate contact method of initial height sensing.....so you do not need the ohmic cap on your machine. The 404 shield will improve FineCut performance and life....


Jim

[cjdauthier]

Lou, I am cutting 1/8 aluminum with my powermax85 with fine cut consumables...I had similar problems to start with on it as well...more heat, more speed.....I know that sounds stupid, but its what I had to do...I basically had to use the settings for the regular consumables, not the fine cut, and just fine tune...I want to say if I remember correctly that I am cutting on about 65 amps, running about 125 ipm on that thickness aluminum...too much dross, speed it up....kerf too wide, cut your amps back a hair....its really about the only way to do it with fine cut consumables....it just takes alot more juice than it does to cut steel of the same thickness...

[Dawgonhawg]

I need this info. I will be cutting aluminumn some day.

[Largemouthlou]

Sorry been away for a while again.. Thanks for the info CJ. I hope to spend a little time with the machine tomorrow