4x4'6" CNC plasma table build, Xalky...

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Originally Posted by xalky

The pierce delay is set to 0 seconds in sheetcam. The THC delay which is in Mach on the cut profiles is 2 seconds. Thc delay, i gather is how long it takes after beginning of pierce,that it takes the thc circuit to kick in, because during a pierce the voltage spikes quite a bit confusing the thc and sends it a torch down signal. If you wait till the torch is moving on a cut and the voltage has stabilized the THC functions the way its supposed to.

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Regardless where or what makes the delay it shouldn't be any longer than what the manual has, or at least close. I control the delay in sheet cam on my machine. If you are controlling the delay with Mach, sheetcam should be set at zero and Mach should have the correct pierce delay for a given plate thickness.

Typically the torch is set higher than cut height during the pierce. The torch comes down during the pierce and arch stabilization happens after the pierce during the lead in. I wouldn't think that it should be two seconds on any profile. Surely it won't be that across the board.....

You may have to edit the cut profiles to get the delay correct.... or you just have a better handle on it than I... Good posibility....

AJ

Pierce delay and thc delay are 2 different things. The. Pierce delay sets how long the torch stays put to make the pierce. Thc delay sets the delay time after the torch moves on from peirce to when the thc takes over cut height. They are not the same, I didn't know this till 2 days ago, even though tom had told me in a post a week ago, it didn't sink in till I actually started fiddling with it. Yours might be working perfectly with the cut profile settings, but mine did not. I suspect that it has something to do with the mechanical setup of my z axis, as tom told me, every machine is different, that the cut profiles are starting points. I guess that's why its so important to do a test run with thc off on every different material you encounter to get your own baseline settings for your particular machine. I'm starting to wrap my head around all the variables. But I'm having fun now that I'm actually cutting stuff.:)

Sent from my SPH-D700 using Tapatalk 2

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Originally Posted by xalky

Pierce delay and thc delay are 2 different things. The. Pierce delay sets how long the torch stays put to make the pierce. Thc delay sets the delay time after the torch moves on from pierce to when the THC takes over cut height.

I suspect that it has something to do with the mechanical setup of my z axis.

Sent from my SPH-D700 using Tapatalk 2

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I have different THC electronics than yours, that's why I don't have that setting.

So to put it another way....

The pierce delay, and the pierce happens, torch starts to move without THC control. During the THC handover delay, arch stabilization happens and then the THC takes over. The torch is moving druing the handover delay.

If you have a short lead in, the torch is cutting the part without THC control. When I cut 16g material at 130in per minute that's about 2inches per second.... 11g is 90in per minute, 1.5in per second.. So The two second THC delay seems a little to long to me...

I want to understand what you have and how it works. A buddy has same equipment and is in progress building a table.

Aj

Yes, you have the idea. you may very well be correct about the 2 second thc delay being too long, but i got it to work that way. Tom threw something else at me over at his support site, that I'm gonna play with today. If I said i knew what i was doing, I'd be mostly lying.:o
But I'm starting to get a handle on the different delays and why they're there.

Back in 1985, fresh out of engineering school, when I used to build and wire machines, this sort of thing would all be done with relay logic. We'd use adjustable time delay relays to do this sort of thing. PLCs were just coming out then. When i think in terms of that experience it helps me to visualize what the delays do. The nomenclature screwed me up in the beginning and so did the fact that some is done in sheetcam, and others in mach. I'll be messing with this a lot over the weekend, so i hope to get a better grip on it. There's no other way for me to learn this, except to get my hands dirty and experiment a little, that's the only way it sticks in my brain. I can read it 50 times in a book, but till i see it with my own eyes, and do it with my own hands, it,s just theory.

I'll report back.

I gotta say that I'm loving this Hypertherm pm85, it just works everytime, all the time. There is virtually no electronic interference to muck things up.

Thanks for following this thread AJ.

Marcel

Yeah baby! Here's a small sign i just cut out using the THC. It's getting easier :bounce

http://i1124.photobucket.com/albums/...7-07155818.jpg

And heres the video of it in action:

video-2012-07-07-16-08-01.mp4 video by xalky99 - Photobucket

The weather is getting cooler and I'm again looking at my plasma table that's on the verge of being finished. I ordered the hyt connect kit from cancnc and the serial port kit for the Hypertherm. They've both been sitting on the work bench for a couple of months. I have to finish wiring that up.

Tom is almost finished with his software and posts to get it all working together, so i'm pretty excited about getting all this working together.

On another note, I've reconsidered my plan to use a downdraft setup. In the video above, The downdraft was working well, but it's a bulky setup and the fiberglass filters on the negative air machine clog up very quickly. I don't see this as being very practical in my small 2 car garage at this time. So now, I'm planning on building a water tray for it. I read ajclays' thread on his water table retrofit which enlightened me quite a bit. I'm going basic, Filling it with a hose and draining it out with a ball valve with a hose attached to it. The under the table reservoir idea is great but not for my shop, i need to be able to wheel my table around in the shop when I'm not using it, all that water weight will just make it a bear to move.

So that's the progress report. I'll be posting more once i actually start working on it.

My busy season is passed and I'm again looking to start playing on my plasma table. I had to set this thing on the back burner for the summer. I just finished hooking up all the HY-t connect parts, so I'm ready to get this thing fired up and start making some parts.

I have a problem though... I forgot everything I learned. I have to get the new manuals and software for the bladerunner with Hy-t connect and start fresh at the beginning of the manual and work through it. I have a new post on Thoms support site for direction on which manuals and software to get so I can get my nose back in the game.

I'm also thinking about implementing a simple water table for the plasma. I haven't given it too much thought yet. My thoughts are that a water table would be better for conserving the heat in my garage during the winter months which is when i'll be doing most of my plasma table designs.

The table is running well now...finally.

I have the new DCC control on my bladerunner and it sure does take a lot of the guesswork out of setting up the toolsets in sheetcam.

It's looking good, and I'm looking forward to making some good parts very soon.

I'm trying to dial in the THC. Particularly the z axis velocity and acceleration settings. Right now I'm using 200 ipm and 35 ins/sec/sec. It seemed to work pretty well on a warped piece of 20 guage steel. I know the z cant be too fast or it will lose steps. I've had it as high as 400ipm and 45 in/sec/sec but that caused some fluttering. On the low end, i had set the z to 100 ipm and 20 in/sec/sec, and the THC seemed to not be able to keep up with the warpage. I'm cutting 20 guage at 350ipm as per the specs in the HT tool set.

Does anyone have any input on settings for the z axis?

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Originally Posted by xalky

The table is running well now...finally.

I have the new DCC control on my bladerunner and it sure does take a lot of the guesswork out of setting up the toolsets in sheetcam.

It's looking good, and I'm looking forward to making some good parts very soon.

I'm trying to dial in the THC. Particularly the z axis velocity and acceleration settings. Right now I'm using 200 ipm and 35 ins/sec/sec. It seemed to work pretty well on a warped piece of 20 guage steel. I know the z cant be too fast or it will lose steps. I've had it as high as 400ipm and 45 in/sec/sec but that caused some fluttering. On the low end, i had set the z to 100 ipm and 20 in/sec/sec, and the THC seemed to not be able to keep up with the warpage. I'm cutting 20 guage at 350ipm as per the specs in the HT tool set.

Does anyone have any input on settings for the z axis?

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There is a practical limit of how fast the Z can move under THC control. Because there are NO acceleration or deceleration curves set when the Z is under THC control (too many short moves ) MACH automatically lowers the Z velocity. That is set in MACH using the THC RATE and is in percent. Depending on the Z mechanics and motor you have that can be from a low of 10% to about 35%. It's actually playing with numbers because it is a percentage of the velocity in tuning so if you change that you basically change the equation. Lets say your THC RATE is at 30%. If you set the normal tuning velocity (motor tuning) to 100 IPM the actual Z velocity DURING THC moves is 30IPM. Set it to 200 motor tuning and you get 60IPM , etc. Your acceleration number is only used during normal Z moves, not during THC moves so changing that does nothing.

What you find is physically you can only push it so fast. A stepper tops out at about 600 RPM so if you exceed that too much you end up with lost steps. If you have servo it will spin much faster so you can get more speed out of it. Even then it is limited to the loop delay timing of MACH.

Set your velocity on Z to a number that you are comfortable with during a normal Z move (i.e. lifting the torch between cuts). Then use the THC rate to tune the Z "response". If you have a servo it will start to oscillate (rapid up and down while cutting) if you have steppers you get lost steps (Z ends up lower than the DRO shows) The higher the number the faster the response.

We have found that a number that results in about 60 IPM WHILE cutting is about all the system can handle with servos.

So.....to cut at 350 IPM the Z has to climb (real) fast on a slope. The more severe the slope the faster it has to climb.

I can give you the math that has to do with vector angles and the physics involved but if you tune the Z as high as it will go with the THC RATE it "is what it is"

I would see if you can get the Fine Cut consumables and lower the cut current and lower the feedrate down to about 250. you will have to play with the preset to hold the right arc gap.

We are pretty spoiled in our shop. We put all of the settings in the JOB file in SheetCAM and let'r rip.

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Originally Posted by Torchhead

There is a practical limit of how fast the Z can move under THC control. Because there are NO acceleration or deceleration curves set when the Z is under THC control (too many short moves ) MACH automatically lowers the Z velocity. That is set in MACH using the THC RATE and is in percent. Depending on the Z mechanics and motor you have that can be from a low of 10% to about 35%. It's actually playing with numbers because it is a percentage of the velocity in tuning so if you change that you basically change the equation. Lets say your THC RATE is at 30%. If you set the normal tuning velocity (motor tuning) to 100 IPM the actual Z velocity DURING THC moves is 30IPM. Set it to 200 motor tuning and you get 60IPM , etc. Your acceleration number is only used during normal Z moves, not during THC moves so changing that does nothing.

What you find is physically you can only push it so fast. A stepper tops out at about 600 RPM so if you exceed that too much you end up with lost steps. If you have servo it will spin much faster so you can get more speed out of it. Even then it is limited to the loop delay timing of MACH.

Set your velocity on Z to a number that you are comfortable with during a normal Z move (i.e. lifting the torch between cuts). Then use the THC rate to tune the Z "response". If you have a servo it will start to oscillate (rapid up and down while cutting) if you have steppers you get lost steps (Z ends up lower than the DRO shows) The higher the number the faster the response.

We have found that a number that results in about 60 IPM WHILE cutting is about all the system can handle with servos.

So.....to cut at 350 IPM the Z has to climb (real) fast on a slope. The more severe the slope the faster it has to climb.

I can give you the math that has to do with vector angles and the physics involved but if you tune the Z as high as it will go with the THC RATE it "is what it is"

I would see if you can get the Fine Cut consumables and lower the cut current and lower the feedrate down to about 250. you will have to play with the preset to hold the right arc gap.

We are pretty spoiled in our shop. We put all of the settings in the JOB file in SheetCAM and let'r rip.

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Thanks Tom; All the the velocity #s above were with the THC set at 20% in mach. So at 200ipm z speed I'm realyl only getting 40 ipm, ...got it.

I may not have what you have, but i think the Hy-t connect kit is the cats meow. It sure helped me out a lot. That plus having the toolsets for the PM85 pre-configured, so-to speak, in the new sheetcam was a huge boost for a novice like me. The "canned" toolsets helped out tremendously. It's a definite selling point for the Hy-t connect kit.

As i get a little more experience I'll change the toolsets to suit my table, but for now They're working out really well. Maybe not perfect, but a huge boost in accomplishment.

I am using the finecut consumables and i have plenty of spares. ;) Lord knows, I'll need them.

I got the picture on the THC z-speed. I'll twittle around with it a little more. 20 guage is probably the thinnest material I'll ever cut, which is why I started with that. I figured if i can dial that in acceptably the thicker materials won't be so bad. Plus 20 guage is cheaper to make scrap. :cheers:.

Marcel

This build is done. I'm still learning my software and getting to know my machine, fine tuning sheetcam settings etc... . I'm finally able to reliably produce some cool stuff.

Here's my first piece, traced from a jpg that i grabbed online. My 19 yr old son did most of the tracing, he's a graphics wiz. I coached him a little on what a plasma can and can't do and how to make the trace plasma friendly.

I got some patinas and played with them for the first time on this piece. I'm pretty happy with the way it came out :cheers:

http://i1124.photobucket.com/albums/...116_154057.jpg

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Originally Posted by Jarrod558

The pierce delay is set to 0 seconds in sheetcam.http://www.chauqui.info/7.jpg

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Is that a question or a statement?

My pierce delay varies in Sheetcam based on the thickness of the material. I use the Hypertherm cut charts to determine what my pierce delay should be.

Congrats on completing your machine Xalky! Learning the software itself is sure a challenge, and if you are anything like me I sure do miss building machines...

Great work on that plasma cutout for your son!

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Originally Posted by lukewarm

Congrats on completing your machine Xalky! Learning the software itself is sure a challenge, and if you are anything like me I sure do miss building machines...

Great work on that plasma cutout for your son!

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Yes, learning the software is a challenge. More of a challenge for me, than the build was actually. But I'm getting there with inkscape and sheetcam. I need to spend some more time on cad .
The good thing about having the plasma is that I can now cut parts for my next machine build on it.:D

Sent from my SPH-L710 using Tapatalk 2

Man, there's so much to know and learn to get these things running well. I've been spending some time today building toolsets for the FineCut consumables in sheetcam. It was well worth the effort. The cut charts in the Hypertherm manual work really well once i figured out what the hell i was doing. I cut some beautiful stuff with almost no dross and nice clean edges on 16Ga steel using the fine cut tips.

For anyone that's building a Machine using the CandCNC bladerunner kit and using a Hypertherm torch. I highly reccomend getting the DCC HyT connect kit for direct connection to the Hypertherm. You can set all your cut profiles in Sheetcam instead of setting them up in mach.

Plus many of the tools were already preconfigured for the 45/65/85 amp consumable tips. This might not seem like much help, but it was a huge help to me when trying to figure out how to setup the tool sets for the fine cut consumables. By referring to the cut charts and looking at the already configured tools, i was able to setup the FineCuts fairly easily.

http://i1124.photobucket.com/albums/...122_224523.jpg

Nice work Xalky! I just got done cutting a bunch of pieces using the fine cut and was really impressed with their quality, small kerf, and how fast you could cut with them! The feeds are pretty much on par with the 60 amp consumables but much better edge angularity (I found).

I notice you had issues with your lead in/out leaving a little crater behind. Were you ever able to fix this, or is it a non issue for you?

xalky,
how about a trade on the dxf... Take a look at this one since you like the man in the sun....

PM or post it if you like too....

AJ

There's no crater really, just a heat signature from the leadin. I made the lead ins a little too short. There are no lead outs. Most thin stuff doesn't need a lead out as the piece will drop out before the lead out even gets there, and could even cause a torch crash.

The torch marks sand right out with a flap disc, no biggie.

I'm learning all the time and experimenting with different lead ins. My machine is really running nice now. I just cut out a big eagle to hang on my house. I'll post a pic once it's finished and hung on the wall.

Oh okay, the picture must be deceiving then! Have you tried any thicker materials?

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Originally Posted by ajclay

xalky,
how about a trade on the dxf... Take a look at this one since you like the man in the sun....

PM or post it if you like too....

AJ

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I'm gonna make a clock with the one i cut out. I'll post the file shortly. I'm not sure if it's a dxf or a svg file. Can you use an svg? I'm pretty sure it was a jpg grab from online that I autotraced on inkscape and converted to svg. Sheetcam can import svg files directly and create tool paths from them. One of my favorite things to do is grab a jpg from online and trace it in inkscape to cutout. Inkscape has an awesome autotrace feature. I can then clean it up and tweak the lines,and nodes and scale it in Inkscape and export directly to sheetcam without having to convert to DXF. For artsy stuff, inkscape is the way to go.

Edit: It was an svg, i just converted it to dxf. Let me know if you can open it.

Sent from my SPH-L710 using Tapatalk 2