Re: [Emc-users] Plasma
A few things I learned in hindsight... I should have made the Y axis rails extend beyond the end of the water table enough so the torch head could reach all of the water table. A little more Z travel would have been nice. My slats are not rigid enough to keep thin material from moving when cutting at high speeds so I have to clamp it down to a frame rail with a piece of scrap. I don't have a downdraft table but I assume you will have to move huge amounts of air to capture the dust from the plasma. Quite a bit of the dust flies up from the cut point so to be efficient the table will need to be completely enclosed to capture the dust. The amount of dust depends on the material condition as well. It seems to me that the more rust, crap, and dirt on the plate the more dust I see. A marking device like a spring loaded center punch with a pneumatic cylinder to push it down would be a nice addition if the plasma cut parts need any machining like drilling after cutting. That would save the second op a ton of time in not having to lay out holes. John On 6/27/2012 11:18 AM, Viesturs Lācis wrote: Hello, folks! I have 3 small things. First one is a question for any useful plasma-specific tips, when designing plasma cutting machine. I just got a contract for building one and I would appreciate a chance to learn from other people's mistakes rather than my own. Following things are on my to-do list: 1) use shielded cables for encoders AND for motor power; shield is grounded only on one end of cable, most probably the drive end; 2) connect the machine frame and all the moving constructions and everything possible to earth grounding; 3) route plasma cable separately from motor/encoder/signal/whatever cables wherever possible; I would appreciate, if plasma machine owners could share their experience and some problem areas they have encountered, when designing their machines. Second question - I would appreciate some advices for good and efficient downdraft table design. I have one brochure, where one concept is shown, but, guess what, it is not very detailed. So maybe there is some webpage with useful information on this matter. And last one - I would like to share a video of Anthony's 5 axis plasma cutting machine. I think that he has built very nice machine and I find his design of the rotary head to be very interesting (well, take a look at other of his videos for some closeups). Actually it showed me a solution to the problem I encountered, when designed the head for the waterjet. I helped him out with 2 kinematics modules: With the first module the machine can take the angle of torch tilt, given in the g-code as A word, and keep the direction of the tilt perpendicular to the XY movement. I do not know about plasmas, but for waterjet this concept handles the kinematics for taper compensation. The second is usual 5 axis module, which compensates for torch length offset along x, y and z as the torch is rotated by rotary joints. Both kinematics modules will also adjust torch height along central line of the torch instead of just moving along Z, which is crucial for 5 axis cutting. The video shows the taper control module in action, running a testcode, consisting of 2 arcs. http://www.youtube.com/watch?v=myNtcNJBcTA -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Plasma
On Thu, Jun 28, 2012 at 1:30 PM, Viesturs Lācis viesturs.la...@gmail.comwrote: 2012/6/28 Yishin Li y...@araisrobo.com: Then we realized that we need an isolated pulse/encoder interface for such machine. Thanks! Could You, please, explain a little more, what does it exactly do? We were using Mesa's 7i34 as the pulse/encoder interface to servo drivers. It was okay in one workshop with Hypertherm 45A plasma cutter. But, it failed in another factory with 300A plasma cutter and large EMI noise around that field. Our USB/FPGA link was full of CRC error messages, and we couldn't understand why. We had all digital and analog I/O isolated. Finally, we found the noise was coming from the pulse/encoder interface. We then developed AR02 in replace of 7i34, and it solves the EMI noise problem in that factory. You may refer to http://en.araisrobo.com/linuxcnc for the functional block of our control system. Yishin -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Jitter reduction tip
Hello, I have learned much lurking on this list. Thanks everyone. I have a pair of dell machines that _horribly_ failed the max jitter test initally. Now they rank with the best in the comparison table. The difference? Turning off the serial and parallel ports in the BIOS. This works for my application because mesa's 5i25 eliminates the need for them (thanks Peter!). I am merely a customer, not a representative. Just an heads up for anyone stuck with hardware dead ends. -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Status of Linux-emc and 3d printing?
Ed; The fundamental problem with a RepStrap made from a typical milling machine is speed: my rather customized Thing-O-Matic prints reasonably well at 30 mm/s and makes rapid motions at 250 mm/s. Interesting comment - my KX1 config is not with me, but as it has a Gecko G540 and runs 48v turned down a bit, it can move faster than some. I have seen at least a dozen Thing-o-matics and the older cupcakes running (plus a bunch of high priced 3d printers) and I don't remember being that impressed with their x/y speeds, but I was not focused on details like that, then. I think I'll just order a Reprap kit, and leave my Linux-CNC stuff to one side for now, and learn the rep rap route for now. Thanks; John A. Stewart. -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Status of Linux-emc and 3d printing?
I regularly run my Thing-O-Matic at 120 mm/sec while feeding (I can do 160 but the quality suffers), and travel at up to 200 mm/sec. Most older ToM's and cupcakes ran at 30 mm/sec, since the earlier firmware did not use acceleration, leading to missed steps at higher speeds. On Thu, Jun 28, 2012 at 7:50 AM, John Stewart alex.stew...@crc.ca wrote: Ed; The fundamental problem with a RepStrap made from a typical milling machine is speed: my rather customized Thing-O-Matic prints reasonably well at 30 mm/s and makes rapid motions at 250 mm/s. Interesting comment - my KX1 config is not with me, but as it has a Gecko G540 and runs 48v turned down a bit, it can move faster than some. I have seen at least a dozen Thing-o-matics and the older cupcakes running (plus a bunch of high priced 3d printers) and I don't remember being that impressed with their x/y speeds, but I was not focused on details like that, then. I think I'll just order a Reprap kit, and leave my Linux-CNC stuff to one side for now, and learn the rep rap route for now. Thanks; John A. Stewart. -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Status of Linux-emc and 3d printing?
On Thu, 2012-06-28 at 10:50 -0400, John Stewart wrote: I don't remember being that impressed with their x/y speeds They tend to produce better results below 30 mm/s, mostly because the stock firmware doesn't use any acceleration limiting at all, and I've seen some down around 10 mm/s near my Sherline's limit. Using firmware that applies acceleration limiting helps with the non-printing moves, but the plywood-and-acrylic frame isn't rigid enough to print accurately much above 40 mm/s. The dreadfully heavy custom build platform in my TOM requires a rather low acceleration, but even the stock platform isn't a real featherweight... -- Ed http://softsolder.com -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Status of Linux-emc and 3d printing?
On Wed, 2012-06-27 at 21:20 -0400, Stephen Dubovsky wrote: his X3 sized mill does 300ipm That certainly puts it in the running! What are the acceleration rates on the dedicated machines? Given my heavy custom build platform and 12 V stepper supplies, the accelerations aren't all that spectacular: X = 15 k mm/s^2 and Y = 5 k mm/s^2. The Z axis uses the stock motor, which isn't well suited for microstepping drive, and runs at 1000 mm/s^2. My Sherline runs X and Y at a sleepy 5 in/s^2 = 125 mm/s^2 and Z at 3 in/s^2 = 75 mm/s^2... -- Ed http://softsolder.com -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] (no subject)
http://englisheasy4u.com/pokpre.html -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Plasma
I don't have a downdraft table but I assume you will have to move huge amounts of air to capture the dust from the plasma. Quite a bit of the dust flies up from the cut point so to be efficient the table will need to be completely enclosed to capture the dust. The amount of dust depends on the material condition as well. It seems to me that the more rust, crap, and dirt on the plate the more dust I see. I recall reading someones build blog where they immersrsed the metal roughly 50 mm or so below the water. The plasma would hold the water back during operation and the intimate water contact kept the dust to a complete minimum. I cannot recall who did that though Brian -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Plasma
On Jun 28, 2012, at 10:02 PM, BRIAN GLACKIN wrote: I don't have a downdraft table but I assume you will have to move huge amounts of air to capture the dust from the plasma. Quite a bit of the dust flies up from the cut point so to be efficient the table will need to be completely enclosed to capture the dust. The amount of dust depends on the material condition as well. It seems to me that the more rust, crap, and dirt on the plate the more dust I see. I recall reading someones build blog where they immersrsed the metal roughly 50 mm or so below the water. The plasma would hold the water back during operation and the intimate water contact kept the dust to a complete minimum. I cannot recall who did that though I have tried submerged cutting on our plasma table (http://wiki.linuxcnc.org/cgi-bin/wiki.pl?GantryPlasmaMachine). It works, but with our Hypertherm 45 the cuts are not the best. I think the molten metal cools too quickly and adheres to the under side of the cut. We get more dross that needs to be chipped/ground away. It isn't unmanageable, but it isn't as good as a cut done (just) above the water. It does indeed keep the dust down, even more than simply having the water table alone but it is a compromise with cut quality in my (limited) experience. I have heard that there are torches designed to cut underwater so perhaps it is a matter of what model torch you have. A more powerful (than the Powermax 45) torch might have no problem underwater, not sure. In general the water table keeps the dust to a minimum. There is still a little that is blasted off the top surface but I would say 95% of the dust is captured in the water table. The thing we are finding is that the dripping water/rust preventer which drips off when people handle parts after cutting is also a mess causer in terms of the floor and surfaces immediately around the plasma machine. There is also a fine steam vapor that fills the room if we are cutting continuously. 10 minutes of cutting you won't see it, 30 minutes and it is quite prevalent. Ultimately I would like to have a mist extractor hanging over the table. We have Green Cut rust preventer in the water and though it is supposedly non-toxic I don't like the idea of breathing it. Even straight water (vapor) will have particles of whatever is on the surface of the metal in it, so a mist extractor would be nice. Tom -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Plasma
ps: I have no experience with downdraft tables, and perhaps they are the cat's meow, but I am skeptical that they could work as well as a water table. The amount of force with which the dust is created seems like it would too great to be carried away by a downdraft. But, this is just conjecture. -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Plasma
On 06/28/2012 07:02 PM, BRIAN GLACKIN wrote: I recall reading someones build blog where they immersrsed the metal roughly 50 mm or so below the water. The plasma would hold the water back during operation and the intimate water contact kept the dust to a complete minimum. I cannot recall who did that though Brian Sounds much like the approach for an underwater (diving/salvage) acetelene torch. Certainly with high carbon steel you would get quenching/hardening along the cut. Dave -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
