Short bar loader questions
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  1. #1
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    Default Short bar loader questions

    Hi all,

    I have a new (used) lathe coming in to the shop soon that I would like to put a short bar loader on to load 4' bars. I have a LNS QuickLoad on another lathe that works great. The problem is that the new machine has a spindle that is only about 38" long. It is my understanding that you cannot use short bar loaders to load bars that are longer than the spindle length.

    So what are my options? Cutting the bars into four 3' chunks is not something I'd like to do. Has anyone had any success with making a spindle extension that will allow a 4' bar to be loaded into a shorter spindle? Any other way around this?

    Thanks!

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    No worries.

    The only bars that will bend at speed at 10" stick-out are very small, and when you make a spindle liner for it - just make the liner stick out a little further.
    Maybe 5"?


    My liners are maybe a foot longer on one machine that I have that has a short spindle assy.


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    Think Snow Eh!
    Ox

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    Thanks, Ox. I was hoping you would weigh in. So on your machine with the liners that are extra long, did you have to extend your coolant collector?

    And while we're on the subject of loaders, are there any models in particular I should be looking for? I'll be buying used, and so far in my search, I've seen SMW SpaceSaver, LNS Quick Load, LNS Quick Load Servo, LNS Eco Load, Iemca VIP 80, MTA Tracer, etc. Like I said, I have a LNS Quick Load (fully pneumatic, no servo) and am quite happy with it. I just wonder if I'd be missing out by buying the same thing again.

    Are the servo loaders that much better? What do you really gain?

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    My shortie loaders are LNS Quick Load Servo, so I could program them to index a specific amount and skip driving my turret to the stop position. (I use the flank of my parting tool.) But all my lathe work is odds and ends, and the convenience of one less machine to set up outweighs it.

    It'd save about 5 seconds per cycle, though, which in volume adds up. If you're doing big stuff it also makes sense, so you don't have a 150lb chunk of material whacking your turret.

    Otherwise I don't see a major advantage.

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    I have a SWM Spacesaver 2003 that we took off a lathe that worked fine, we just didn't use it enough to justify the floor space. t-000_0340.jpg
    img_20200109_074618973.jpg

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    Coma - I didn't follow your post much at all.
    ???




    WMPY - I only have the LNS Servo models as for short loaders. I have an old skewl FMB 12' that I wish was servo tho.
    And in all honesty, it's not really the servo that's the key here, but the encoder. I'm sure that a loader could be built with no servo and still have the encoder - as I am pretty sure that the 12' LNS models are to this day. But I've never used. (bought and sold 4, but never used)

    Extending the sheetmetal to catch the coolant is a good idea. Mine is mostly just a bucket underneath as I don't get a whole lot out during production, so I never bothered.
    I think it kind of depends on how close your liners get to your cut zone. If the coolant can get up into the inside of the liner - you're gunna have more come out the back end. If it's back 6" or so (bigger bars, or puller - I pull with the sub on this machine) and you don't get much coolant in the liner. But if you are pushing 1/2", your liner is going to need to be much closer, so ... yeah, I'd say that you would prolly want to add to your collector.

    I can only recommend the LNS as that is all that I have ran. I know nothing bad about the others.
    With that said - the LNS pendants don't tollerate the coolant so well (as does so many other plastic items) and a new pendant housing is many hundred dollars, so keep that in mind when searching. Also note that the Fanuc Beta CPU on the PLC is a known problem. Fanuc has quit building them new, but if you get a used one somewhere, LNS will program it for you.

    If you get a newer one (S3 and possibly an S2) they will have Mits PLC controls in them, and AFAIK they are better/cheaper/more available.

    But I've ran <1.5 mill parts through my oldest one in the last 22 years, so I've likely found most of the glitches by now?


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    Ox

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    I think you have two options. Either cut your bars to 3' like you said. However, you need to be careful cause if there is a big gap between the end of the bar feeder and the back of your spindle liner, the bar can "tip" as it gets loaded and it can jam up. We started running 4' bars and we use an extended liner so that the bar is supported outside the spindle. We got them from J.F. Berns. They also sell a "Coolant collector that attaches to the back of the actuator. This way there is no coolant leaks. We now have them on our two Miyanos and a Doosan.

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    Thanks for all the responses!

    I have seen those extended coolant catchers from JF Berns. Something like that might be the way to go.

    When using the servo bar feeders, I understand that you don't need to feed to a stop, but wouldn't it be safer to do so anyway? Or am I being too conservative?

    With a servo feeder, can you set it to alarm out if it doesn't feed out enough? And how accurate is that? Could it detect a feed out that is 0.010" short? Like if a chip got caught between the stock and the stop? That would be something worth having. I'm pretty sure my non-servo Quick Load has a encoder. That's how I set the end-o-bar length. But it isn't very accurate. It measures in whole millimeters.

    Anyone have any experience with 6' loaders like the LNS Quick Six? I started looking into these because they seemed like a good compromise between the short loaders and full bar loaders. The only drawback I have noticed so far is their size. Why does a loader that feeds 6' bars need to be 11' long?!

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    On edit - I want to say that the LNS S2 would still be Fanuc.
    You need to get to the S3 to get the Mits.
    And I think the S3 has been the current model for 15 yrs by now.
    Also - the S3 offers the lid with the big winder in it. I laughed when I seen it debute at The Tool Show back-in-the-day.
    I understood why they did that instantly as I imagine that their service guys went into shops constantly finding the lids all up so that we can see what the unit is dooing.

    I would only trust it to feed to a stop! (or pulled by the sub "and followed by the unit")
    There is at least one fella on here that says that he feeds w/o a stop tho.
    I feed to my trigon tho. The servo's will be slowing up as they approach the expected stop, and doo not normally damage stout inserts.
    You doo not need to lose a station for a stop.
    Unlike the old "dumb" feeders that hit the stop at full force.

    Yes - the Servo machines are super for alarming out if not fed out enough.
    THAT is the best feature of all if you are walking away from it - and "walking away from it" is the biggest reason that you bought a mag loader to begin with eh?
    If you blow a cut-off, it will know right away that it didn't feed out far enough. (if feeding to a stop)

    I would not expect it to detect .010. The servo mech may move the right amount, but the unit as a whole is not that rigid.
    I think about the only time that I have a "chip" issue is if the conveyor stalls on an overnight run and the whole thing is filled up.
    With that said - I overfeed. Doo to having a pull-back collet system (my pref) I will feed out to Z+.08 / +.100, but will yield more like .02-.05 face off.
    On machines with dead length - I will typically feed to .025.

    I believe that the amount of detected discrepancy is a line item parameter that you can set to your preference.

    No experience with 6'ers.


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    Think Snow Eh!
    Ox

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    To add to what Ox said, I agree that using a stop is the safest route. Also, our Miyano holders have threaded holes on the face of the holder and a stop plate. I saw that and thought it was a great idea. I even added that to our Doosan that uses the older pneumatic bar feeder. This is a great solution without having to sacrifice a tool spot. I just have a different offset for the stop.

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    wishin4snow- I have plates at the cut off position like you describe on most of my machines. It works pretty good.

    Ox- I normally only feed out with about 0.015" to face off in order to not waste material. Maybe I shouldn't be so stingy with the material.

    Does it matter what kind of collet closer you use when using a servo loader? I remember hearing something about only being able to use pull-back collet closers with servo loaders... Or maybe it was that you had to use push-to-close closers... Anyway, is that true? I don't see why you had to use one or the other. And do you have to use dead-length closers? Or are standard closers ok too?

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    My loaders don't care either way.

    They will push to the stop and hold at a thrust setting appropriate for the bar stock size until it sees the collet is closed. (slight dwell)
    In the case of a pull back collet, any amount that the collet pulls back - harder than the push thrust - will simply retract.
    Then once it's done it will pull back a predetermined distance. Possibly all the way - in particularly if you are feeding REALLY small stock and don't dare leave that tiny pusher up in your spindle during cycle. (another advantage of the servo units)

    I'm wondering if you are cornfusing a barfeeder built for a fixed headstock v/s a sliding headstock? (Swiss)
    THAT is a difference! One made for the slider will prolly be fine on a fixed, but prolly not the other way around.
    But here we are getting into 12' loaders, so - prolly not a concern - but still may be what you are thinking of.


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    Ox

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    I did some searching and got this off the MicroCentric website:

    "The CB-NDR is a new patented Dead Length design collet chuck to be used with servo stop bar loaders. The NDR chuck is actuated as the draw tube is pulled into the machine spindle. The collet is coupled to the chuck body and remains stationary as the tapered seat moves forward during clamping. This feature keeps the collet in a fixed Z axis position, and since the draw tube is moving into the spindle, the bar remains positioned against the servo stop."

    and also:

    "Pull to Close Dead Length design produces no pull back and will not push the bar off the servo stop"

    So I'm thinking that the above closer was designed for those that are not feeding to a stop and want a dead length collet. Typically, a dead length collet pushes to close, which could allow the draw tube to drag the bar away from the pusher while the collet is closing. But, as discussed above, feeding to a stop is the preferred way to go, so I guess it really doesn't matter what type of collet closer you have.

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