Star 5 over tension

Discussion in 'Stringing Techniques / Stringing Machines' started by dgdawg, Nov 22, 2009.

  1. dgdawg

    dgdawg Professional

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    This is a question for all you Star 5 owners/users.
    Do you seem to get a tighter string bed on completed string jobs? A couple customers, and my wife thought they're tension seemed slightly higher than before I got the Star. I've heard some talk about the Star tensioner "over shooting" the programed tension but I don't see that. The on screen read out never exceeds the programed tension unless the shift key is pushed.
    My thought is: the clamp bases have so little draw back that it effects the final string bed stiffness.
    Any comments/input would be appreciated. 8)
     
    Last edited: Nov 22, 2009
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  2. tennisstrngdude

    tennisstrngdude New User

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    It definitely overshoots and the string bed on completed jobs is higher than many machines.
     
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  3. Danstevens

    Danstevens Semi-Pro

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    Which machine did you use before the Star 5? Constant pull machines give a tighter feeling stringbed than lock-out models. Of course, the excellent clamps are another potential reason.

    tennisstrngdude, I've not heard of this problem/quirk with the Star 5 before. Could you elaborate on it a bit more?
     
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  4. SCSI

    SCSI Rookie

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    Got one, and had used Sensor for a few years also. Side by side, I couldn't tell any difference between the two. I would say the effect has a lot to do with how good (rigid) the clamps are on the these Babolat machines.
     
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  5. star 5 15

    star 5 15 Professional

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    coming from the wise you definately are going to feel more overshoot. It is not completely overshoot really. It is really the machine just being extremely sensitive to constant pull. You are not getting as good of constant pull with the wise. Yes the star 5 does have a bit more overshoot than other machines. But not enough for me to want to lower my tension coming from the star 4. The clamps are also a lot better. I wouldn't really call it a problem by anymeans and coming from the wise. It is just an adjustment that will have to be made. It simply provides better constant pull.
     
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  6. dgdawg

    dgdawg Professional

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    I don't subscribe to the "over shoot" theory. My digital calibrator doesn't over shoot the tension when checking it and I know that is accurate within .001 of a lb. I have to agree with star 5_15 in that it has more to do with better clamp bases and more accurate tensioner. tennisstngdude, do you string on a star?
     
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  7. abllee2198

    abllee2198 Rookie

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    Star 5 overshoot

    DGdawg: Sorry you don't believe it, but it's a proven fact and something you, as the stringer, will have to deal with.

    The Star 5 overshoots by 7-8 pounds on every pull. You need a peak reading force gauge to detect it. Get a $800 Shimpo Force gauge and you will see a consistent peak because the gauge makes and stores 1000 measurements per second.

    It does make a difference, especially when you compare it to Baiardo and Yonex machines which are dead on reference with near zero overshoot.

    This short peak overshoot results in a 4 point ERT difference in stringbed stiffness for the same reference tension.

    Albert
     
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  8. dgdawg

    dgdawg Professional

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    Fair enough Albert. I would think that a quality electronic calibrator would pick up 7 to 8lbs. So, this being the case, the Star 5 has an automatic pre-stretch? I wonder if it's possible to rent/borrow a Shimpo Force gauge from a machine shop? :shock:
     
    Last edited: Nov 22, 2009
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  9. dgdawg

    dgdawg Professional

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    So Albert-I'm told by Bab USA that the Star 5 and Sensor have basically the same electronics. Would this mean the Sensor also has the same over shoot? :confused:
     
    Last edited: Nov 22, 2009
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  10. abllee2198

    abllee2198 Rookie

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    Star 5 Overshoot

    DGDawg:

    You are absolutely correct. The Sensor does the same overshoot of reference. The one plus for the Sensor is its clamp bases have more drawback than the Star 5 bases, so the overall impact of the overshoot is less apparent.

    Regards,

    Albert
     
    #10
  11. Technatic

    Technatic Semi-Pro

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    Overshoot and pulling speed??

    Interesting item, because it is very difficult for electronic machines not to overshoot.
    My question is: Does the overshoot depend on the pulling speed?

    or do the Babolat machines also switch back to low speed when they get close to the adjusted tension??
     
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  12. abllee2198

    abllee2198 Rookie

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    Babolat Pull Speed

    Technatic:

    The Star 5 and Sensor DO NOT have user selectable speed. Only the Sensor Expert has user selectable speed.

    As the speed is not selectable, the amount of overshoot cannot be tied to speed setting.

    The Yonex or Baiardo have near zero overshoot at max speed. I never measured overshoot at lower speeds.

    Ideally a controller will pull at maximum speed until reaching 90% of reference tension before ramping down and creeping up to reference tension.

    Regards,

    Albert
     
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  13. drakulie

    drakulie Talk Tennis Guru

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    abllee, do you find any of the other Babolat machines having the same overshoot?? 5502? 3002? star 3? star 4?
     
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  14. abllee2198

    abllee2198 Rookie

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    Overshoot on older generation Babolat

    Drakulie:

    Sorry I cannot confirm overshoot on this older series Babolat machines. One problem is the load cell is particularly sensitive to electronic gauges and can best be calibrated with spring gauges.

    The Star 3 is a spring (internal reference) based machine and my guess is it does not overshoot reference because of its slow pulling speed.

    The 5502, 3002, and Star 4 are all based on same electronic loadcell and is difficult to measure with most electronic test gauges. I've tried testing my Star 4 and this results in oscillation of the tensionhead and leads to irregular measurements on both standard and peak reading measurements on the Shimpo Force Gauge.

    Regards,

    Albert
     
    #14
  15. drakulie

    drakulie Talk Tennis Guru

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    ^^You sir, are a gentleman and a scholar.

    Many thanks!!
     
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  16. Technatic

    Technatic Semi-Pro

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    The problem with electronic units is not that they overshoot on the first pull, they overshoot when they have to do a “constant pull stroke”.
    It is very difficult for such a complicated system to make exactly the travel that is needed to compensate for the loss in tension:
    The measuring system has a certain bandwidth and it tells the controller to pull because the tension is below the set tension.
    So the drive system has to be started and stopped over a very small distance.
    The higher the speed the more overshoot will occur.

    The overshoot will also depend on the type of string and the length, the longer the string and the more elongation the lower the overshoot, because the travel is bigger for a certain increase in tension.

    I have the Stringway EM450 which does exactly that, it switches back from the set speed to the lowest speed at about 85 % of the set tension, so the CP-stroke is always done on a very low speed.

    This is the reason that I think that there is no use in pulling at maximum speed with electronic units, to do it right you have to wait for some CP pulls anyway.
     
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