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  1. P

    Managing liquid nitrogen flow for fiber laser

    I now have the system set up with my high-pressure N2 gas "pusher" tank. What an improvement! I now have my liquid cylinder headspace at a consistent 300psi, which is giving me a consistent supply of liquid into the evaporator, which in turn is giving me a consistent supply of 200psi gas to the...
  2. P

    Managing liquid nitrogen flow for fiber laser

    Sounds like a good plan. Using an up-to-pressure liquid cylinder to push the in-use liquid cylinder is a smart improvement over only using a high-pressure gas cylinder to do the pushing. I'm just waiting for some regulators and custom hoses to arrive and I'll be up and running with this setup...
  3. P

    Managing liquid nitrogen flow for fiber laser

    Yes - I spoke with the liquid cylinder Manufacturer and they say that will work and will help matters. However there will still be a bit of a roller-coaster effect from any liquid that is in the hose and in the vaporizer. When you pause consumption of the gas, that liquid is going to continue...
  4. P

    Managing liquid nitrogen flow for fiber laser

    Well you have a good idea for just blowing nitrogen at the start of the cycle so that I can get to a reliable situation prior to running the part. I can do that easily. However, the pressure-build enable situation that you described is not an actual thing. The pressure builder circuit is a...
  5. P

    Managing liquid nitrogen flow for fiber laser

    We have the 500psi version. The liquid cylinder's max pressure is not the problem.
  6. P

    Managing liquid nitrogen flow for fiber laser

    Thanks, but this doesn't solve the problem, because the only way to fill that accumulator tank is to be pushing liquid out of the liquid cylinder, and that requires turning on the pressure builder circuit, so we're still at the same point.
  7. P

    Managing liquid nitrogen flow for fiber laser

    Yes, I could see the benefit in having an accumulator tank between the vaporizer and the machine. Possibly no fancy valves or controls needed, other than an in-only / one-way check valve at the entrance to the accumulator tank. I could see how this could smooth out peaks and valleys of demand...
  8. P

    Managing liquid nitrogen flow for fiber laser

    I have a fiber laser that uses significant flow rates of nitrogen (as much as 2,550 CFH at 200 psi). We are using a liquid nitrogen cylinder, feeding liquid into an evaporator, which then feeds nitrogen gas to the machine. Here's a photo of our setup: I am finding that it managing the liquid...
  9. P

    Minimizing liquid nitrogen cylinder venting from laser

    One more question: My gas vendor says that I can manually vent the liquid cylinder down to around 200psi, and then it will take a while until it reaches the 350psi automatic relief vent pressure. He says this will reduce the overall venting loss. To me this sounds wrong: Wouldn't I just be...
  10. P

    Minimizing liquid nitrogen cylinder venting from laser

    Apparently the fiber lasers use a ridiculous amount of nitrogen. Its a 4KW machine, so not giant but not small. No leaks, it just really uses that much. With a 2.5mm nozzle orifice (which seems to be the one for most of the materials I cut), at 200psi, it uses 1,302 CFH. And a 3mm nozzle...
  11. P

    Minimizing liquid nitrogen cylinder venting from laser

    Thanks for the replies. I will look into an insulating blanket for the cylinder. The massive nitrogen needs of fiber lasers is something I was not expecting when I bought the machine. The 12-packs of high pressure cylinders are expensive and only last a few hours of use, and the liquid...
  12. P

    Minimizing liquid nitrogen cylinder venting from laser

    Have you noticed if the venting happens more in the summer compared to the winter? I am new to having it, so I don't know yet.
  13. P

    Minimizing liquid nitrogen cylinder venting from laser

    We are using liquid nitrogen cylinders to supply nitrogen assist gas for our fiber laser. It is normal for the liquid nitrogen to always be boiling off, so the cylinder vents to the atmosphere periodically to reduce the internal pressure. It is the peak of summer right now, so I was wondering...
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    Fanuc M198 - can you have multiple subprograms in one file?

    I am using M198 to call subprograms which are located on my Fanuc Data Server Board. I am doing this because the programs are too big to fit in the main memory. I have it set up so that within the I call the file name of the subprograms on the data server board. This works, however sometimes...
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    Coolant that can sit unused for weeks without going bad?

    I have a machine (a dedicated punch tool grinder) with flood coolant, which sometimes sits unused for weeks at a time. Currently we are using the same water-soluble coolant that we use on our CNC machines (Hocut 795B), but I find that it breaks down if let to sit for too long, and then we...
  16. P

    Machining long parts that are much longer than your X travel - sugggestions?

    Thanks guys! I like the ideas to clamp on some sort of stop to the part, and reference the stop. Now I'm saying to myself "why didn't I think of that?"!
  17. P

    Machining long parts that are much longer than your X travel - sugggestions?

    I need to do some machining on very long parts (approximately 9' long) which is much longer than the X travel on my CNC machines. I can run them on an open-sided bed mill so I can hang the parts off side of the machine. My X travel is around 40". I'm looking to achieve locational tolerances...
  18. P

    7075 handling after machining

    For aluminum parts that are to be anodized, we keep them submerged underwater (in a bucket) until we are ready to clean them properly. They are immediately dried after cleaning.
  19. P

    How to pause a long program to replace/re-measure a tool on Fanuc control?

    Hi pcasanova, on all of my machines, when I use optional stop it stops at each tool, even without a M0 or M1 in the code. Is this not the way most machines work? We currently do use optional stop for testing out new programs or for when a tool sounds like it is going to break, but we need a...
  20. P

    How to pause a long program to replace/re-measure a tool on Fanuc control?

    I am running some challenging parts with a cycle time of approximately 20 minutes. We have to stop the machine frequently to change / re-measure tools when they break (or when they sound like they're wearing and might break soon). When we do this, we end up re-running the program from the...

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