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Thread: The OT thread V1

  1. #2361
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    With the caveat I couldn't care less about this but really want this to be over forever:

    Per ISO-15926:

    Poppet valve: A disc globe valve that is a disc globe valve where the operating mechanism is a non-rotating linear** action.

    Disc globe valve:
    A globe valve that has a disc type plug closure member. [emphasis mine]

    Globe valve: A valve that is a valve where the closure member is a disc or piston operating with linear motion normal to the flat or shaped seat. [emphasis mine]

    Valve seat: A physical object that is the part of a valve against which the closure member bears to provide shut-off and throughout which process fluids flows.

    Valve: An artefact class that contains classes of artefacts intended to be used to control, i.e. permit, obstruct or regulate a fluid stream.



    ** From Wikipedia: The word poppet shares etymology with "puppet": it is from the Middle English popet ("youth" or "doll"), from Middle French poupette, which is a diminutive of poupée. The use of the word poppet to describe a valve comes from the same word applied to marionettes, which – like the poppet valve – move bodily in response to remote motion transmitted linearly. [emphasis mine]


    I'd say John was entirely right, but in the spirit of rules-lawyering, a face seat could be actuated by sliding, which would not constitute a poppet (nor spool) valve - as the linear motion normal to the valve surface wouldn't be present. However, your claim that a poppet valve constitutes a multitude of components is, per my reading of the ISO spec incorrect.
    "So you've done this before?"
    "Oh, hell no. But I think it's gonna work."

  2. #2362
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    "So you've done this before?"
    "Oh, hell no. But I think it's gonna work."

  3. #2363
    Insider PBSteve's Avatar
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    Oh come on, you've killed my fun
    Ever so many citizens of this republic think they ought to believe that the Universe is a monarchy, and therefore they are always at odds with the republic. -Alan Watts

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  4. #2364
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    Spool valves have operators too, ya know.

    WHY WON'T YOU THINK OF THE OPERATORS.
    Finding operators that think is the problem.

    (Plant humor...)
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  5. #2365
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    Quote Originally Posted by new ion? View Post
    I thought so too. It's less a 'tool change' than a CNC machine, but I figured that it'd be possible to at least take some of the concepts from CNC over to this. I may have been wrong.

    As I was just taking a cursory glance into the mechanics of it all (I'm not set up in the slightest to work on something like this... yet...) I'm kind of just brainstorming.

    Kind of makes sense how the guy is doing it though - yes you have issues with Z axis offsets, (nozzle height differences) but that can be done with a microswitch or something. As for the X/Y offsets, I'd have to look into it further but I feel like the tool heads could be set up in such a way so that they centre within error of the plastic shrinkage... he's looking into using a camera to detect X/Y errors with image recognition. Not saying he's wrong, but I am saying there's got to be a better way than that, if it's necessary at all.
    I'd think some kind of self-centering mechanism with pre programmed offsets, like they do with traditional CNC cutters, would be the easiest... I agree image recognition seems like overkill and expensive.
    Ever so many citizens of this republic think they ought to believe that the Universe is a monarchy, and therefore they are always at odds with the republic. -Alan Watts

    I work for the company building the Paragon

  6. #2366
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    Quote Originally Posted by PBSteve View Post
    Oh come on, you've killed my fun
    Global warming isn't anthropogenic if it's even real

    you're welcome
    "So you've done this before?"
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  7. #2367
    i agree with lurker's definitions, how the valve opens, if it is a pre-load closed valve that then is pushed open by contact .... that makes it a poppet. whether the valve is a face seal, or a radial seal i don't think is important, nor do i think the method of pre-load is important. but the key to a poppet valve, to me, is that its knocked open by something hitting it or pushing it.
    social conservatism: the mortal fear that someone, somewhere, might be having fun.

  8. #2368
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    Quote Originally Posted by Lurker27 View Post
    Global warming isn't anthropogenic if it's even real

    you're welcome
    Well now you've killed my day

    Way to go

    Quote Originally Posted by cockerpunk View Post
    i agree with lurker's definitions, how the valve opens, if it is a pre-load closed valve that then is pushed open by contact .... that makes it a poppet. whether the valve is a face seal, or a radial seal i don't think is important, nor do i think the method of pre-load is important. but the key to a poppet valve, to me, is that its knocked open by something hitting it or pushing it.
    BAHAHAHA

    See what Gordon did there? He just read everything you said and responded with a big old "FUCK YOU, RYAN."
    Last edited by PBSteve; 10-04-2017 at 04:02 PM.
    Ever so many citizens of this republic think they ought to believe that the Universe is a monarchy, and therefore they are always at odds with the republic. -Alan Watts

    I work for the company building the Paragon

  9. #2369
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    Quote Originally Posted by PBSteve View Post
    I'd think some kind of self-centering mechanism with pre programmed offsets, like they do with traditional CNC cutters, would be the easiest... I agree image recognition seems like overkill and expensive.
    And this is exactly what I'm thinking. He's using straight rods to hold the tool. Why not tapered to provide the x/y centering, and use a magnet to keep it held on?

    And then do the same thing of a touch sensor for Z offsets...

    I really need to build a CoreXY machine.

  10. #2370
    I agree it's a silly discussion and in the bigger picture it means absolutely nothing of engineering relevance, but it does seem to mean something to the market place.

    A gun is not just a valve. It's more than that and in most/many cases it is multiple valves of different types.

    The bigger factor is the design concepts and evolution, and why we touched on this subject again.

    I do however think it very short sighted to define a mechanism based just on the point at which it releases the firing gas. Why is that the determining factor? I believe the bigger picture of the mechanism that makes it function to be how you define something but even that has draw backs.

    I made up the PCP (Pressure Controlled Poppet) description when trying to explain how the Mini worked to a sales guy. It's very clear that the motion of a spool is what makes the gun function. The fact it has a face seal allows people to argue that it's a poppet gun but it really has no importance in the functionality/operation of the gun. Obviously you can use a face seal as it does, or make a o-ring seal inside the bolt guide bore. Would that simple change convert the gun from being a poppet to a spool valve? I think it a travesty if your answer is yes.

    The sales and marketing guys grabbed onto the fact it was a "poppet" gun because at that time Poppets guns were perceived as being more air efficient and reliable and they thought that would sell better. So it stuck. They could call it either depending on what attributes they were using to sell it to someone and whichever it is really doesn't change the way it operates significantly.

    Likewise with most of Mike's guns. I just spoke to him on the way back from the anodizers. He believes they are spool valve guns... When building the Faction with him (I think there was a thread here somewhere on it) we went through a huge number of iterations of the stem that released the gas. Some using face sealing o-rings like his earlier guns that you guys are more familiar with and some with spool style tips that pulled out of the bolt's bore. Just changing that interaction never changed the fact that the gun was a spool operated system. You could change the face seals on his earlier guns to be bore seals and they would work almost identically. That doesn't change the type of gun it is or the overall way the system functions.

    Thinking that just one seal in a whole system defines the system... seems to be an injustice to the system.

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