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Stuck with the basics....- Metal Deforms when Cutting

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pony
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Stuck with the basics....- Metal Deforms when Cutting

Postby pony » Sat Feb 26, 2011 4:01 pm

I added some support slats today, and set about cutting my first piece that wasn't just a test cut.
I clamped the material all around the edges.

Whenever I start to cut the metal deforms when it gets hot and ends up raising off the bed, I raised the torch to prevent it shorting out, but some pieces buckle up very high as shown in the picture. This is 14 gauge hot rolled.

What am I doing wrong? :oops:
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pony
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Re: Stuck with the basics....

Postby pony » Sat Feb 26, 2011 7:23 pm

leatherhands wrote:Some warpage is normal with 14g but let us know the amperage and cut speed used. You may be able to reduce the amount of warpage with less amperage, and an appropriate cut speed.

Do you have auto height control? It's a very important feature to have. If not then you will need to use something to help hold the material down when it is warping, a shortened broom stick or something will work well.


I wish I had torch height control but it wasn't an option on my table. It has a 4th axis for wood routing but there is no way to get it to work as a torch height control.

I took your advice and I turned down the power, and also tried cutting a much less complex piece. I think it was dwelling in the same area too long and hence the warping. The reduced current made a big difference.
I managed to get a fairly successful cut just now and I'm calling it a day for today, quitting while I am ahead:
Image

Thank you for your help, I was getting frustrated.
I designed the couple and horse artwork for this (I posted it to the forums a while back if anyone wants it), but the wife isn't in to 'western' scenes, as we both ride English. Tough luck, she got this sign for one of the gates :lol:
Last edited by pony on Sat Feb 26, 2011 7:27 pm, edited 1 time in total.

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Re: Stuck with the basics....

Postby pony » Sat Feb 26, 2011 7:26 pm

leatherhands wrote:....If not then you will need to use something to help hold the material down when it is warping, a shortened broom stick or something will work well.


Just to clarify, you mean 'follow' the torch around the table and hold down areas as appropriate, right?

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Re: Stuck with the basics....

Postby Scratch » Sun Feb 27, 2011 8:18 am

I know you don't have auto torch height control, but do you have manual torch height control? Like with a pendant or buttons that are in a handheld box connected to the control box with a wire?

I'm embarrassed to say it but I also don't have ATHC. I use my pendant with the up and down button and watch the torch go all around the steel with shade 10 goggles on. I bring the head up and down manually.

You're gonna get some warpage with steel that thin and if you cut thin parts, the warpage will be higher. I wouldn't hold the steel down with a stick as it cuts, you might get it stuck against a part, and the head will come along and move the entire sheet.... then you're screwed.

If yours didn't come with a manual pendant Z control, call and get one.
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Re: Stuck with the basics....

Postby jimcolt » Sun Feb 27, 2011 9:40 am

I expect virtually no warpage on 14 ga steel. The trick is to use the smallest nozzle orifice available for your torch (I use the Hypertherm Fine Cut consumables) and cut as fast as possible, maintaining the torch manufacturers recommended height within .010". I do have torch height control, and I consider it necessary for the best cut quality and longest consumable life. Here is a pic of my torch setup on a PlasmaCam machine...the torch is a Powermax85, it is mounted on a new magnetic breakaway...nice design. The pic of the horse is of my wife riding one of her horses in an English 3 phase event....the drawing was done from a photo, cut on 14 gauge steel.

The things that cause warpage:

1. Too much power
2. Nozzle orifice too large
3. Cut speed too slow
4. Torch too high off plate.

Jim Colt

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pony
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Re: Stuck with the basics....

Postby pony » Sun Feb 27, 2011 9:46 am

My table is aimed more at the hobbyist market. The Z axis is a different head I swap out that holds a router. It is only attached when routing. The Z axis at the moment is raised and lowered by hand :oops:

This is probably a 'how long is a piece of string' type question, but what gauge (if any) do you need to get to to have warpage becomes almost non-issue? I don't mind cutting thicker material if that is the solution. I bought 14 gauge, 11 gauge, 3/6", and 1/4" to practice on.

I think the mistake I was making in my first attempt was too much heat, and too intricate details. The Torchmate software doesn't seem to be too smart. It seems to convert the DXF to G-Code and just run with it as is. I couldn't find the ability to rearrange the cut order for example.

Torchmate make a ATHC unit, I don't know if its compatible with my small table. It costs $2,400 though :o

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Re: Stuck with the basics....

Postby pony » Sun Feb 27, 2011 9:51 am

Jim,
Some good things for me to try there. I cannot get fine cut for my Thermal Dynamics A60, not that I can find.
I did have too much power, and probably still do. I need to investigate the cut speed more, the software has a 'faster' and 'slower' option, but I'm sure it has more granular control if I read the manual. My torch is too high off the plate, it freaked me out when it started dragging a warped sheet around the table and grinding :oops: so I lifted the head up a little, then the material warped more so I raised it again, then it warped more so I raised it again; each raise it height required more juice, can you see where I went with this one. Probably as high as a 1/4 inch and 60 amps :roll: . I thought it affected cut quality (and for my test pieces I wasn't too worried about this), I did not know I was perpetuating my own misery by creating corrugated sheets out of perfectly good flat metal :lol:

I was approaching this as getting it cutting out shapes properly first, then fine tuning the quality later. It seems you need all pieces in place for this to work, if you miss one then all the rest go too.


jimcolt wrote:1. Too much power
2. Nozzle orifice too large
3. Cut speed too slow
4. Torch too high off plate.

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Re: Stuck with the basics....

Postby Dennis » Sun Feb 27, 2011 10:15 am

pony wrote:Jim,
Some good things for me to try there. I cannot get fine cut for my Thermal Dynamics A60, not that I can find.


jimcolt wrote:1. Too much power
2. Nozzle orifice too large
3. Cut speed too slow
4. Torch too high off plate.


If you use 30amp Nozzle and set your A60 to about 30 amps ,you will cut better..Cut speed between 90 and 130 ipm ...You will have to find the happy spot as far as speed goes. :D

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Re: Stuck with the basics....

Postby pony » Sun Feb 27, 2011 11:32 am

I think automatic torch height control is a must when working with anything bigger than a foot across. I've just been experimenting with the advice given and my piece of 14 gauge metal buckles ever so slightly, but enough to drag the tip. They don't make enough clamps to keep it flat.

EDIT:
I was able to overcome a lot of the warping by working with a smaller source piece of metal. Trying to cut a 4 inch x 10 inch piece out of a 4foot by 4 foot sheet on a 2 foot by 4 foot table wasn't such a great idea. I had hoped to cut pieces from a large piece until the large piece was spent. It looks like without ATHC I will need to use my metal nibblers to cut pieces slightly larger than the intended output and cut from these instead.

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Re: Stuck with the basics....

Postby fitzy » Sun Feb 27, 2011 1:17 pm

I have a tm3 5x10 table with unfortunatly no hieght control. I cut 16 gauge and thicker all day long with the hand crank you will have to babysit it quite a bit but it can be done if you watch your gap and keep your hand on the crank you move up and down as the material moves. I have seen up to 3/8 thick move3 while cutting although not as dramatic. soon I hope to upgrade and get a thc but for now I'll do with what I have hope this helps
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Re: Stuck with the basics....

Postby jimcolt » Sun Feb 27, 2011 1:54 pm

I realize that on entry level machines the torch height control cost seems high. Just keep in mind that on industrial cnc plasmas.....all of them that are sold have a height control system! Without a THC is almost like a car with no brakes....you could drive it but you have to be very careful and stand by the controls all the time. (I plowed my steep driveway for a couple of years with a chevy truck with no brakes....but I had snowbanks and trees to help me stop!).

Over time, the THC system will more than pay for itself with better cut quality, longer consumable life, and also allows you to walk away from the machine and do something else while it is cutting.

Jim Colt

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Re: Stuck with the basics....

Postby Dennis » Sun Feb 27, 2011 2:02 pm

WOW ! I am suprised how many poeple don't have a height control system on there tables.. I know most table manufactures charge extra.. I think it should come standard on all tables. Just bump up the price and don't make it an option.. The manufactures would probably save a lot of support time, as well as alot of negative comments on there equipment.

Not trying to piss any one off here , just a thought.. :lol:

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Re: Stuck with the basics....

Postby pony » Sun Feb 27, 2011 2:24 pm

jimcolt wrote:Without a THC is almost like a car with no brakes....


Thanks for the analogy Jim. I guess I'll be spending some more money next week.


Dennis wrote:WOW ! I am suprised how many poeple don't have a height control system on there tables.. I know most table manufactures charge extra.. I think it should come standard on all tables.....l:


My entry level $3,000 table would be a $5,500 table with ATHC. They hooked me with the low low price, then slowly revealed all the 'extras' I would need :lol: I've already upgraded my Japanese plasma cutter to a Thermal Dynamics with machine torch, so I suppose ATHC will be next. I wondering what I will need next, other than a lot more money that I had budgeted for....

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Re: Stuck with the basics....

Postby eggauto » Sun Feb 27, 2011 3:07 pm

Don't forget a good air dryer, ventilation system, powder coating system etc etc:)

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Re: Stuck with the basics....

Postby Dennis » Sun Feb 27, 2011 4:04 pm

eggauto wrote:Don't forget a good air dryer, ventilation system, powder coating system etc etc:)

:lol:

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Re: Stuck with the basics....

Postby Scratch » Sun Feb 27, 2011 4:29 pm

Dennis wrote:WOW ! I am suprised how many poeple don't have a height control system on there tables....


I actualy am too. I've always thought I was one of maybe 2 people in our solar system that didn't have ATHC on their table. I didn't know what that other guys excuse was, but I actually think I have a valid excuse...


I'm an idiot.
I think I'm the oldest 10 year old boy on the forum...

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Re: Stuck with the basics....

Postby plain ol Bill » Sun Feb 27, 2011 5:06 pm

I noticed the machine torch in Jim Colt's pics he put up. Who stole the rest of your torch Jim :o Is that the new mini? First pics I have seen of it.
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Re: Stuck with the basics....

Postby parrotlady » Sun Feb 27, 2011 11:30 pm

I posted a 2 page reply and then at the last sentance I accidently deleted it!! arghhh! I will repost a quicker version...

I have a torchmate too, and I am by no means an expert at it, as I only now have it working satisfactorily after almost a year... Here is my experience... I have cut much lighter material (16,18, 20g) and actually had my height control OFF alot of the time... It comes with its own problems I find... Anyway, I have had very minimal warpage.. I dont do what anyone tells mem because for some reason it doesnt work. I keep the amps at 25 for these materials.. I dont use a fine cut tip (although I would like to but it wont work for me). My speeds are around 100 - 110ipm with VERY inricate designs. I often pause the machine after every cut to let it cool down. I also stalk torchmate on a regular basis.. They know me by first name ;)

Here is a suggestion that might work until you feel like forking over the dough for height control... Our local sheet metal shop doesnt have height control either.. they have a lockformer table. What they have is a thing that looks like a pancake on wheels.. it is about 5 inches in diameter and it is attached to the torchhead. It always keeps the torch 1/8" away and follows it around on wheels. It keeps the metal flat as it goes minimizing warpage and has the added feature of blocking the arc so you can stare at it. the only disadvantage is that it can crash into tip ups. I imagine you could just buy that part? It is an older table so they must be available. The software and name of the company is Vulcan.. I am sure I could find the number if you want.

As for frustration... the reason it has taken me this long to get it up and running is because I regularily shut the door after going through all my curse words and simply leave before something gets hurt :x Hang in there.. it'll come.

April

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Re: Stuck with the basics....

Postby cncer » Mon Feb 28, 2011 1:12 am

i cut alot of 14g cold roll. and don't get too much warpage running 125ipm and 40 amps with a hypertherm 1000 with finecut consumbles. it was really bad with the 60 amp consumables. i have ATHC from torchmate but havent really figured it out yet. I don't know how to shut it off while cornering so it doesn't drive itself into the material.

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Re: Stuck with the basics....

Postby parrotlady » Mon Feb 28, 2011 11:43 am

i have ATHC from torchmate but havent really figured it out yet. I don't know how to shut it off while cornering so it doesn't drive itself into the material[/quote]

I never have done anything different for cornering? It switches in and out of auto on corners all by itself. You can actually watch it go down to the 1/8th height and then raise a bit again once it gets past the corner... You should call torchmate and get that figured out :)

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Re: Stuck with the basics....

Postby pony » Mon Feb 28, 2011 2:03 pm

I just ordered the ATHC from Torchmate. I've done some researching today and it looks like ATHC is a must.

Jim, I'm getting some brakes on my pickup :lol:

April , thank you all for your advice, and words of encouragement ;)

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Re: Stuck with the basics....

Postby jimcolt » Mon Feb 28, 2011 7:43 pm

Yeah Bill, the The Powermax85 mini torch is in the pictures, cute huh?

And April.....the Lockformer machine is designed for cutting ductwork (HVAC machine) at high speeds with low accuracy. The height control you refer to is known as a "plate rider", basically has about 5 roller balls that push down on the plate and hold the torch at a fixed height. Unfortunately when you start cutting materials thicker than 3/16"....you need to set a separate pierce and cut height in order to get decent consumable life and cut quality....can't do that with a plate rider.....so it is limited to just gauge thickness materials.

One of these days I'll put a piece of corrugated roofing on my PlasmaCam machine and show you guys how height control is supposed to work! The torch will not touch the material, and it will maintain .060" standoff while cutting this material. You cannot buy a PlasmaCam without the height control.......just like you cannot buy industrial plasma machiens without height control.

Jim Colt



plain ol Bill wrote:I noticed the machine torch in Jim Colt's pics he put up. Who stole the rest of your torch Jim :o Is that the new mini? First pics I have seen of it.

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Re: Stuck with the basics....

Postby Team Tracker » Mon Feb 28, 2011 8:09 pm

Cool torch Jim, I remember we had modified some Pmax380 hand torches into machine style and machined up short torch bodies for them for a couple trade show machines. They looked really cool.

jimcolt wrote:One of these days I'll put a piece of corrugated roofing on my PlasmaCam machine and show you guys how height control is supposed to work!


We have a great video showing the effectivness of an automatic torch height control in a situation like Jim was describing above. Play the 3rd video from the top of the playlist named "THC-Auto Torch Height Control" at this url

http://www.trackercnc.com/video/

This video was done 4 years ago on an older model, not our new ProTable or Nitro.

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Re: Stuck with the basics....

Postby pony » Mon Feb 28, 2011 10:42 pm

Reid T wrote:.....We have a great video showing the effectivness of an automatic torch heigh......


That video was the final piece that convinced me to buy a ATHC unit today. I watched it on TouTube here : http://www.youtube.com/watch?v=txGP-Qbii2E

This other video has more dramatic examples:
http://www.youtube.com/watch?v=DoHJ_rVx ... re=related

I don't own a Tracker machine, so my apologies it didn't get your company the sale in this instance. It was very helpful in my decision though. Thank you for sharing.

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Re: Stuck with the basics....

Postby jimcolt » Tue Mar 01, 2011 7:43 pm

Those are great videos.....that is the way height control is supposed to work with plasma torches. Cannot possibly do that with manual control of height!

Jim Colt


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