Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Ratpack on January 20, 2015, 02:04:25 PM
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Hi Guys, I am new to this, I need some help with my plasma can anyone help me? I would like to make cleaner cuts with my machine. Thanks you Ratpack
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OK but first you need to define cleaner cuts.
(;-0 TP
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Hello BR549 thanks for now. My cut on the X lines & Y lines are very nice ( smooth ) but when I cut angels to the left or right of a straight line or a curve it it very jagged. My calibration is good, check X travel asked 1" it travels 1" also Y travel same. Tried to slow fed rate down a bit better ( 45" per minute ) from (96 " )
Ratpak
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Is it just a rough cut OR a lot of slag. Do you have AHC (auto height control) ?
(;-) TP
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Not to bad on the slag but angel and curves are very jagged.
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I do not have a THC. I keep the torch about 1/8" to 3/16" off the material manual.
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That is too high for most plasma cutters. Here with a hypertherm I cut at .080 -.100 " off the top of the material. Cutting too high makes the arc wonder around when cutting causing a jagged cut most time.
Consult your plasma's MANUAL for the poper cutting heights and speeds.
(;-) TP
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I did, using a Thermal-dynamic 101 power source it recommends 1/8" and travel speed 225" per minute on 16 ga. mild steel, but it also says plus or minus 50% lot of good that is.
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I have just replied to your PM from the last day but I see you have also posted here on the forum.
TP is the best guy to help with plasma so I will leave you to it, however giving all details about your machine will help such as type of motors/drives and construction. The construction may be especially relevant as in your PM you mention that the machine shakes.
Hood
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Just a thought, is your machine configured to "exact stop"? If so, try "constant velocity". As I remember my CV is on but all the settings are off. Also sometimes it helps to have "line look ahead" set to 100 or more.
Mike
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Well, this is interesting, thanks in advance for helping me. I made this machine all frame is 4" X 4" X 1/4" tubing gantry same. The gantry runs on a rail system. Stepper motors ( Nema motors ) can not move or shake any thing by hand, using a vertical torch from Thermal Dynamic with a rack & pinon the X & Y travels with rack and pinon as well. Using a board from CN4. parreal port. X motor are set at 509.1702372 step per inch/ Velocity 93.6/ Acceleration/ step per 33.17149/ Y is set 526.7068/ Velocity 93.6 / Acceleration 33.171/ A is a slave for Y set as same as Y. Hope this is good for now.
Ratpack
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The real trick to plasma cutting is to keep the motion as constant velocity (feedrate). The plasma cutting function depends on this to cut smoothly. IF your accelleration is too slow MACH3 will slow dramatically in arcs and circles . THis slowdown effects the cut quality. SO the process ends up being a compromise on low end cutters that cannot achieve HIGH acceleration rates.
Testing and GOOD note keeping goes along way here as each type and size plate cut MAY require a different setting to cut cleanly. Finding the MAX acceleration that your machine can handle will help as well. MORE testing (;-).
Just a thought, (;-) TP
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Thank you BR549 I was thinking the same thing, because when I cut 3/8" or 1/2" plate it is not bad only on lighter gauges. So in hand acceleration is a key factor.I will lower this and do more test.
Ratpack
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You need to RAISE the acceleration to as fast as your machine can work without errors so it can react faster.
(;-) TP
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Thanks I will defiantly will try to raise it some time today and re calibrate avery thing all over before cutting a test pieces.
Ratpack