nut of er32 collets ( lathe live tools ) getting loose @ rpms > 2000

[deadlykitten]

hello i have a lathe setup with few milling tools ( shank o6 ) , inside live holders with er32 collets

2200 - 3500 rpm

i noticed that some nuts are getting loose, and i believe that it is because of the high acc/decc of the M axis ( which is more aggresive than a mill spindle ); also the effort is not constant during cutting, there are light vibrations, but nothing strange

is not the 1st time i notice this, but it is the 1st setup which will use such rpms for a long-period time

did somebody else encounter such a thing ? kindly


ps : no torque key, just me even so, i guess i'm doing it right ... or am i ?

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[deadlykitten]

nut has bearing ( thus increased weight ), material is 40hrc, tool wear appears sooner, etc

also, after the nut makes contact with the screw, it requires more than 30 degrees to tight it ( the bearing leads to increased angle ); on another threaded assembly, after the nut_without_bearing & screw make contact, tightening occurs in less than 1mm ( perhaps other tolerances, etc )

i writed a soubroutine, that allows stepped acceleration and deceleration ( if you wish, pls check this link for a video of what it delivers : https://we.tl/vsR9q2uC7m )

i noticed that i can use less steps when accelerating, because the holder inertia is lower then the M spindle, while, when breaking, the opposite occurs; thus if i acc and decc at same rate, then decelartion will be bumpier, because the axle of the liveholder will kick into the M spindle; also, at the live holders with 2 axles, this phenomen is greater, because there is a small play between those 2 axles

    M110 
    safe position
    T
    NOEX V1 = 2200        ( rpm )

  ( * )


    CALL OMACC LV01 = V1 LV02 = 100 LV03 = 1000 ( it will go : 0 1000 1100 1200 ... 2000 2100 rpm )
    SB=V1 G00 M63                               ( final rpm is executed here, toghether with rapid+M63 )
    G04 F0.3
    CALL OMDEC LV01 = V1 LV02 = 100 LV03 = 1000 ( it will go rpm : 2100 2000 ... 1100 1000 )
    G136 M12                                    ( stop is executed here )

available syntaxes for both OMACC and OMDEC :
... CALL OM**C LV01 = rpm LV02 = rpm_step LV03 = threshold_rpm
...... or
... CALL OM**C LV01 = rpm ( if LV02 & LV03 are missing, then the soubroutine will load default values )

kindly

---

the soubroutine :

OMACC ( acceleration for M axis )
      ( LV01 = rpm LV02 = rpm_step LV03 = rpm_threshold )
      ( LV02 & LV03 may not be specified )


  IF   LV02     NJUMP1
     ( NFALSE ) NOEX LV02 =  450  ( defaults loaded )
       NJUMP1   NOEX


  IF   LV03     NJUMP2
     ( NFALSE ) NOEX LV03 = 1000  ( defaults loaded )
       NJUMP2   NOEX


  NOEX LV04 = 0                   ( create variable )


  CALL OMHLP


  SB = LV03 M13


        NOEX LV00 =        0
  NHERE NOEX LV00 = LV00 + 1
        SB = LV03 + LV04 * LV00   M13
  IF [ LV00 LT LV02 - 1 ] NHERE


RTS ( . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . )


OMDEC ( decceleration ... )


  IF   LV02     NJUMP1
     ( NFALSE ) NOEX LV02 =  450  ( defaults loaded )
       NJUMP1   NOEX


  IF   LV03     NJUMP2
     ( NFALSE ) NOEX LV03 = 1000  ( defaults loaded )
       NJUMP2   NOEX


  NOEX LV04 = 0                   ( create variable )


  CALL OMHLP


        NOEX LV00 =        0
  NHERE NOEX LV00 = LV00 + 1
        SB = LV01 - LV04 * LV00
  IF [ LV00 LT LV02    ] NHERE


RTS ( . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . )


OMHLP


  IF [ LV01 GT LV03 ] NJUMP
       NLOOP M0
       GOTO  NLOOP
       NJUMP NOEX


  NOEX LV02 = [ LV01 - LV03 ] / LV02 ( nr of steps : real                 )
  NOEX LV02 = DROUND [ LV02 ]        ( ... ... ... : real with 3 decimals )
  NOEX LV02 = FUP    [ LV02 ]        ( ... ... ... : integer              )
  NOEX LV04 = [ LV01 - LV03 ] / LV02


RTS ( . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . )