Large holes with plasma

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1/8"x3" FB, black.One set of holes 2.625", another 2.875".Pic 1. Setup.Pic 2. Template. Greased with antispatter greas.Pic 3. Practicing.Pic 4. The sets.Pic 5. One hole.Although perfectly works for me, yet makes it clear - CNC table is the way to go.... Attached Images
Reply:WOW, I can't believe that you can't get any better results then that using a template.What amperage? machine? old tip?I start in the center then work out to the edge when cutting a circle.Tim Beeker.
Reply:Something is not right. You should be able to get better results.Bad consumables?Small machine?Low air pressure?Miller 330 A/BP Bernard SS coolerMiller cst 250Miller Big Blue 251DCentury 210 Mig (first welder I bought)Hypertherm PowerMax 800Victor torch setRu Fong 31 MilAtlas lathe
Reply:Thank you, guys, for reply.Although I was particulary hurt by "WOW" Current is 35A. Pressure 70psi.Nozzle, yes, needs to be replaced (I actually cleaned it with file). But I have only 3 spares. And I ordered some more (Chinese from ebay) but will take probably a month to arrive...
Reply:I can get better results free-handed when I cut circles or any other shape its all in the wrists, and not clinching down on the gun, but you have something wrong, looks like lack of amps to me
Reply:I do this all the time for smaller holes.  There is something not quite going right for you. Does your straight cut come out OK?  Maybe a little dross stuck to the tip?I agree with tnjind... start inside the circle, then move out to the template.   From the looks of the third picture, you're not working smooth & steady. (practice)The best things in life all come on a stick!
Reply:Hole saw setEd Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:About amps - I can go very high. My breaker would allow up to 50A. But the machine is 80A. So, if I have to - I will go all way to 80A.With 35A - I just break through 1/8" and can move really fast. About 10ipm or more.Straight cuts seems to me OK. But may be excessive slug... The plates also were cut off with plasma.Can somebody post pictures of 1/8" so I can see where to go?
Reply:The tip is like this Attached Images
Reply:Nomad, I'd agree that you should be able to get much better results with a template.I've cut lots of holes just the same way and have nice smoooth edges just like a straight cut. Make sure the tip to work distance is appropriate for your machine, ( template thickness ), and if the tip is smoked... well you know what to do.You may want to make the cut in two motions so you can pull each half toward you. Better speed control with the torch.
Reply:You need a drag tip or hold a little gap. That template probably makes it real tuff to hold a decent gap.
Reply:Who says there isn't a difference in plasma cutters.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Originally Posted by daddy Better speed control with the torch.
Reply:Originally Posted by SandyYou need a drag tip or hold a little gap. That template probably makes it real tuff to hold a decent gap.
Reply:Originally Posted by NomandNozzle, yes, needs to be replaced (I actually cleaned it with file). But I have only 3 spares. And I ordered some more (Chinese from ebay) but will take probably a month to arrive...
Reply:Originally Posted by SundownIIIWho says there isn't a difference in plasma cutters.
Reply:Originally Posted by DesertRider33This is one very good reason to go with a name-brand machine from Hypertherm, Thermal Dynamics, Miller or even Lincoln.  Walk into any welding supply shop with money in-hand and walk out 10 minutes later with new tips in-hand.
Reply:That tip isn't really meant for plasma drag cutting. You should maintain a gap of 1/8" from torch tip to metal, psi about 60-65. For the most part it appears the metal was clean but its best to be assure you removed any oil/grease film (use clean rag with acetone), Make sure your grounding clamp is on Clean metal and firmly clamped. Make sure your torch cuts all the way through the metal before starting your torch cut along your guide. Maintain a slight angle with your torch so as you cut you are blowing the dross away from the cutting areaRealise when you use a guide you will see some dross spray back from use of the guideSpray-back dross on the torch tip will also affect your performance. As you move along the cut if you notice a buildup on your tip stop and clean off the buildup or consider changing tipsI could could on with advice but without being there to witness your settings, torch tip and distance to metal, distance you move along as cutting, etc etc it hard to fully explain.Best advice is to keep practicingCo-Own CNC shop:Miller :1251 plasma cutter, MaxStar 700 TIG/Stick, & XMT 456 Multiprocess Welder.&  2 Hypertherm HPR260's Plasma CutterSorry I had a bad stroke but now I am back.
Reply:Originally Posted by DesertRider33This is one very good reason to go with a name-brand machine from Hypertherm, Thermal Dynamics, Miller or even Lincoln.  Walk into any welding supply shop with money in-hand and walk out 10 minutes later with new tips in-hand.
Reply:Originally Posted by specterYou should maintain a gap of 1/8" from torch tip to metal, psi about 60-65.
Reply:Originally Posted by NomandYep, the gap was maintained. Pressure 70psi. But what about 35A is it OK, not enough, too much? For 1/8" FB...And how does the tip look like - is it too bad or still operational?
Reply:Nomand,Not knowing what kind of import machine this is, I am aware of the torch.  The torch is an exceptionally smooth cutting torch, if it is from the right source and manufacturer.  There are now two versions of the P80.    But,  they both cut very well. The new version has longer life electrodes, though there is nothing wrong with the average life of the current one at the price of the consumables.  Everyone is willing to blast a machine without considering other factors.  You admit to clean cuts on other straight line cuts, so the torch and the unit must be okay.  It seems that technique is what is required to make a clean cut.  Seeing the areas where the cut goes off course tells me that is part of the problem.  Using a template takes practice.  And yes,   a standoff may help. You may also consider a smaller nozzle size.  They are available in multiple sizes for different amperage ranges. I believe you can get a .9 mm or 1 mm nozzle for this torch to improve your cut.  This is the SAME as other US mfgr's practice to improve cut quality.  I don't know which you bought from ebay, but you have to be careful as the testing we have done with Everlast shows A LOT of difference in life span.I agree, that standoff is your key here.  A light easy hand will make a better cut that a gorilla death grip.  The torch is capable of making as smooth a cut as any other torch on the market.  The consumable, though worn, is still serviceable.  When you see elongation or deep pitting of the orifice, then it is time to change.   More pressure on some of the import units does not make them cut any better, in fact, it could make them cut worse, just as I suspect, every manufacturer has their own PSI "sweet spot".  Try going down to about 60 psi even 55 or so. Just as some people see a bad weld, people blame the machine, when they all know that the best machine is capable of producing the worst weld in the right hands.  Not all NIKE Air Jordans made everyone a superstar basketball player either, even before they went off shore!Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:I disagree with the brand name machines comments, at one time I thought the exact same thing, but A LOT of it is skill.  I'm slowly getting the skills to figure out what pressures/amps the machine should be on and here are some cuts that were made on some relatively thin plate with a giant tech ct520d.  I have the same issues he does with circles though they come out looking like trash and need a bunch of grinding.  Erniethese cuts were made dragging and leaving the powdercoat on, not eve cutting raw steel. Attached ImagesThis cat does it doggie styleMiller Bobcat 225Miller Matic S52ACT520D TIG/Arc/Plasma
Reply:Originally Posted by TopSpin80I disagree with the brand name machines comments, at one time I thought the exact same thing, but A LOT of it is skill.  I'm slowly getting the skills to figure out what pressures/amps the machine should be on and here are some cuts that were made on some relatively thin plate with a giant tech ct520d.  I have the same issues he does with circles though they come out looking like trash and need a bunch of grinding.  Erniethese cuts were made dragging and leaving the powdercoat on, not eve cutting raw steel.
Reply:And I have never blamed the machine - although it is chinesse - I absolutely love it.Of course, I had unusual headike to set it up - some bitches did not cut all the threads - but works like Swiss clock.I only ask for 5 years of trouble free operations. And I simply buy a new one. For $1130 Cnd - 80A - all I've  ever needed...I think that my problem is steady motion. With this consumable I did abot 50' of staight cuts. And only those 4 holes and 10 or so on practice.Therefore I am absolutely positive that in my case the table would be the answer. Although - theese holes suit me very well...Thanks you guys all for the comments - very helpful.This is 1/8" plate, 4" diameter hole, aprox 20 amps at 50psi .....drag cut around a template. Cutting holes is a PITA, but with practice it becomes much easier. Attached ImagesLast edited by BruceTS; 01-10-2010 at 04:56 PM.Synchowave 180SD  Bernard 3500SS water coolerMillermatic 200Parker Plasma Tec 40dvOperating Engineers Local 12
Reply:Originally Posted by BruceTSThis is 1/8" plate, 4" diameter hole, aprox 20 amps at 50psi .....drag cut around a template. Cutting holes is a PITA, but with practice it becomes much easier.
Reply:There is a difference in template cutting between plasma systems. The original pictures here show a non-shielded nozzle that was used to drag cut, using a template. Drag cutting at over 35 to 40 amps....with the nozzle contacting the plate produces a phenomenon called "double arcing".....this is an arc from the electrode to the copper nozzle body (inside the torch) then a second arc that jumps from the front of the nozzle to the plate. When the nozzle arcs to the plate at power levels over about 35 amps it causes "stiction".....which makes the torch stick to the plate.....and when this occurs the motion gets rough and causes an ugly cut. A good cut requires accurate nozzle to work distance and smooth, fluidic motion. Further, using a non shielded nozzle at over 35 amps for drag cutting causes instant nozzle damage. The nozzle orifice must be perfectly round with no crater...in order to shape the plasma arc. The very first contact with the plate with a non shielded nozzle at over 35 amps will ruin a nozzle. A shielded front end on a plasma torch has an electrically isolated copper shield in front of the nozzle....the shield is spaced properly from the nozzle so that when it is dragging on the plate the nozzle to work distance is correct. No double arc occurs because the shiled hold sthe nozzle off the plate.....the nozzle orifice last much longer, there is no stiction....and the operator has a much easier job providing the correct standoff and smooth motion. Hypertherm shilded front ends are designed for template cutting.It is also important to use the correct nozzle when template cutting holes by hand....typically the smallest nozzle produced by your torch manufacturer for the particular thickness you are cutting...allows you to cut slow, and provides the best quality. Using a 60 amp nozzle with the power turned down to 30 amps produces a low energy density arc (a soft arc) that will cut well. Using a nozzle designed for 30 Amps (small orifice) at 30 amps will work best.Here is a picture of hole quality on 1/4" plate with a Hypertherm Powermax45......on a cnc! I don't have any hand/template pics!Jim Attached Images