In these definitions, the term "drive data" always refers to speed, acceleration and jerk limitation.
2. Gear unit
Gear unit load (M gear max.) [Nm] …refers to the maximum permissible mechanical torque at a spindle speed of 1 min-1.
Feed torque (M feed) [Nm] …refers to the diminishable torque at a speed of 1 min-1, which corresponds to the maximum permissible gear unit load. Depending on the motor and/or the duty cycle used, however, it can be correspondingly lower.
to 0 Nm for EA and M rotary tables as well as dividing / indexing axes of the T rotary tables (standard load always centric)
and, for T rotary tables, to the maximum torque that has an effect on the tilting axis by the dead load of the dividing / indexing axis as well as cubic standard load. Please refer to the respective parameter list, catalog values.
For T rotary tables, the eccentric load usual* is identical to the gear unit load with sls. For an EA rotary table, this torque corresponds to the value resulting from the max. eccentric load when applying a rotoFIX Alu with a standard load. Please refer to the respective parameter list, usual values. The eccentric load max. load* corresponds to the max. mechanical torque which can still be transferred with the gear unit at a minimum speed of approx. 10 min-1 without any damage. Please refer to the respective parameter list, max. load values.
* For definitions, see "Geometry / integration", p. 85.
Change in the center of gravity if used without and with load. The larger the red center (of gravity, the higher the gear unit load in the tilting axis. The blue arrow indicates the direction of the change in the position of the center of gravity when comparing "without load" and "with load".
pL standard spindle load (sls = sl standard), p. 76/77 [kg]
…refers to the pL spindle load defined as a standard, derived from practice, with approximately 90 % of all applications being covered. All drive data and parameter lists are based on the cubic pL standard load. All masses that move within the volume (workpiece incl. device) and are clamped coaxially to the rotary axis can be moved by applying standard drive data. For pL standard spindle loads arranged eccentrically, it might be necessary to reduce the drive data.
Standard moment of inertia (J standard), p. 76/77 [kgm2] …refers to the moment of inertia resulting from the defined pL standard load and its shape provided that the load is clamped coaxially to the rotary axis. The usual J relation between load and motor generally corresponds to 1:1 or less (e.g. 0.5:1).
Max. permissible moment of inertia (J max) [kgm2] …refers to the maximum permissible moment of inertia of the drive system. However, it must be noted that the J relation between load and motor may not exceed 10:1 for the positioning mode or 1:1 for the interpolation mode. In the parameter lists provided by pL LEHMANN, the limit value of 10:1 is never exceeded.
3. Gear unit accuracies
5 warm-up cycles
5 measurement cycles
15 measuring points (24°)
Heidenhain ROD 800 measuring and test equipment with K15 coupling
Unloaded rotary table as an individual module – room temperature of approx. 22°C
Explanation of the indexing accuracy Pa ±: Explanation of the different parameters according to VDI/DGQ 3441:
Indexing accuracy (Pa ±) [arc sec] …refers to the sum of the maximum positive and negative deviations between the ACTUAL position and the TARGET position of all angular positions over 360° measured in the same direction of rotation, specified as ±-value. This corresponds to the position deviation Pa according to VDI/DGQ 3441, but accumulated (example: TG ± 15" corresponds to Pa 30") and:
ohne Berücksichtigung der Umkehrspanne
without taking the radial and axial concentricity error of the spindle into account
Repeat accuracy (Ps max) [arc sec] ...refers to the maximum deviation within the results of the repeatedly measured angular positions, approached from the same direction. This corresponds to the position variation range Ps max according to VDI/DGQ 3441, i.e.:
without taking the backlash range into account
Positioning accuracy (P) [arc sec] ...refers to the largest possible deviation between the TARGET position and the ACTUAL position with a change in the direction of rotation. This corresponds to the positioning uncertainty P according to VDI/DGQ, i.e.:
without taking the radial and axial concentricity error of the spindle into account
Backlash on reversal (U gear) [arc sec] ...refers to the maximum mechanical gear backlash with a change in the direction of rotation within a specified number of angular positions that have been measured several times.
does not correspond to a measurement parameter according to VDI/DGQ 3441
the elasticity of all parts connected in the drive train is NOT taken into account
Backlash range (U mit*) [arc sec] ...refers to the mean backlash range incl. elasticity, backlash or overshoot of all parts connected in the drive train with a change in the direction of rotation within a specified number of angular positions that have been measured several times. This corresponds to the backlash range U mit according to VDI/DGQ 3441. The mean value is calculated based on all measured values.
* For compensation and definition of backlash, see "Geometry / integration, 6.4".
Duty cycle (Einschaltdauer, ED) [%] …refers to the operating time of the movement per time unit according to the DIN/VDE 0520 standard. The pL rotary tables are designed for intermittent operation (positioning mode) S3 at ED 20%, but with a backlash time of 1 minute. If these conditions are to be exceeded through use, the drive data must be reduced accordingly.
Spindle speed (n spi) [min-1] …always refers to the max. possible speed on the spindle
complying with the duty cycle (Einschaltdauer, ED)
with the corresponding motor
with the cubic pL standard spindle load
Cycle time 90° / 180° (t 90° / t 180°) [sec] …refers to the time required for the entire dividing process / indexing of a 90°/180° movement
Dividing / indexing process, STANDARD pL = unclamping and clamping, monitored with a pressure sensor. During clamping, the clamped signal is output as soon as 100 bar has been reached. Thus, the machine can already move before full clamping pressure is applied. If full clamping pressure has not been reached after 2 sec, the clamped signal is taken away again. Everything is controlled by the blackBOX.
Dividing / indexing process, OPTIMIZED = like standard, but the clamped signal is only requested prior to the feed movement. This process requires an adaptation of the respective machine PLC and is not included in the pL scope of delivery.
5. Spindle bearing
Axial force (F axial) [N] ..refers to the maximum permissible axial load onto the spindle. It includes workpiece, devices, machining forces and forces resulting from rotational and tilting movements.
Pull-out torque (M tilt) [Nm] ..refers to the maximum permissible tilting load onto the spindle, measured from the spindle face. It includes workpiece, devices, machining forces and torques resulting from rotational and tilting movements.
Transport load (sl max) [kg] …refers to the entire, maximum permissible load starting from the spindle nose and performs a rotational movement together with the spindle (device and workpiece). This load is not the same load as the pL standard spindle load.
Radial and axial concentricity (ro con/ax) [mm] …refers to the maximum deviation resulting over 360° measured in axial (axial concentricity) or radial (radial concentricity) direction. In each case measured on the maximum possible diameter of the spindle nose.
Clamping torque (M clamp) [Nm] …refers to the maximum permissible torque load on the spindle nose with the clamping active. The pL clamping is extremely rigid. Depending on the load, there is also still a setting behavior in addition to the usual elasticity. We distinguish between three phases that are completed from zero load to maximum load. The setting behavior manifests itself as remaining torsion following unloading as described below:
Phase 1 "normal" (approx. 1/3 to 1/2 of the permissible clamping torque) up to approx. 0.0015 mm*
Phase 2 "increased" (approx. 2/3 of the permissible clamping torque) up to approx. 0.005…0.01 mm*
Phase 3 "maximal" (up to 100% of the permissible clamping torque) up to approx. 0.035 mm*
* With one-sided load, related to the spindle outer Ø of the respective rotary table. The indexing and repeat accuracy is not impaired after repositioning.
7. Tightness (according to EN 60529)
…refers to the tightness with respect to protection against contact, protection against foreign matter and protection against water:
IP 65: protection against contact, no ingress of dust, protection against the ingress of water jets IP 66: like IP 65, but protection against the ingress of powerful water jets IP 67(standard at pL): like IP 66, but protection against the ingress of water when temporarily immersed in water IP 68 (optional bei pL): like IP 67, but protection against the ingress of water when continuously immersed in water
8. Geometry and integration
Tilting drift (sd 200) …refers to the deviation of the perpendicularity between the dividing / indexing axis and the tilting axis over a specified tilting range. pL LEHMANN always measures 3 points: -90° (horizontal), -45° and 0° (vertical), always related to the position of the dividing / indexing axis and on a radius from the tilting axis center of 200 mm.
Offset values (offset) …refers to the deviation from any theoretical target values in order to be able to align the rotary table on the machine more easily and put it in operation more quickly.
pitch error (pe) …refers to the effective target-actual deviation over a specified angle of rotation ("pitch error") from the axis error compensation on the CNC machine. For rotary tables, this typically occurs when eccentrically arranged loads such as clamping yokes, tilting axes etc. are moved.
backlash (bl) …refers to the mechanical and electronic backlash range (gear unit, angular position measuring system, positioning controller…) for the loose backlash compensation on the CNC machine.
usual …refers to the practice-oriented drive values for pL standard spindle loads that should usually be set (pL recommendation) in order to still provide for certain reserves to include deviations from practical applications and allow for simpler controller balancing.
catalog …refers to the maximum catalog drive values that can be reached for pL standard spindle loads. To reach these values, more stringent requirements must be met by both the commissioning operator and the material. Depending on the application, they must be reduced (empirically).
max. load …refers to the maximum drive values that can be reached for the maximum permissible spindle loads at a speed of approx. 10 min-1.