Mounting of multi-component sensors

The multi-component sensor consists of a hexapod framework, which is arranged between two plates without additional joints. The sensor is (as a rule) made of one piece of high-strength aluminum (3.1354) or high-strength, ferritic stainless steel (1.4542).

For the function of the sensor, it is crucial that the end faces are not locally deformed.

A local deformation is caused, for example, by a selective application of force Fz in the center of the sensor.

The force is applied flat on the circular ring between the inner centering collar and the outer diameter. The force is applied to the trapezoidal circular segments. The recesses between the segments are not loaded.

In addition to the introduction of force on the circular ring, flatness and rigidity of the connecting flange are important parameters. High-strength aluminum or tool steel 24CrMo4 or C60 tempered or high-strength stainless steel 1.4542 should be selected as material. Plastic flanges from the 3D printer are unsuitable!

An untightened screw can cause measurement errors of the order of 10% or more.

The tolerance for the flatness of the flanges is 0.02mm.

Table 1 gives guidelines for the thickness of the connection flanges and the recommended tightening torque. If the recommended tightening torque exceeds the rated torque of the sensor, then torque should not be passed through the sensor. Instead, it should be held against the flange directly.

The screws should have a minimum strength of 8.8. From 100Nm, screws 10.9 are recommended.

 

 

Sensor

Material thickness, tightening torque, screw-in depth t

F6D45

  • 20N/1Nm: 3.0 mm, M3, 1,3 Nm, t=5 mm

(counterhold directly on the bolted flange)

K6D27

  • 50N/1Nm: 3.0 mm, M2, 0,4 Nm, t=4 mm

K6D40

  • 50N/5Nm, 100N/5Nm: 5.0 mm, M5, 6 Nm, t=6 mm
  • 200N/5Nm, 500N/20Nm: 6.0 mm, M5, 6 Nm, t=6 mm

K6D80

  • 200N/20Nm ...1kN/50Nm: 8.0 mm, M8, 20 Nm, t=9 mm
  • 2kN/100Nm ...5kN/250Nm: 10.0 mm, M8, 30 Nm, t=9 mm

K6D68

  • 1k/20Nm ...2K/50Nm: 10.0 mm, M10, 40 Nm, t=12 mm
  • 5k/50Nm ...10K/500Nm: 12.0 mm, M10, 60 Nm, t=12 mm

K6D110

  • 1k/100Nm ... 8k/500Nm: 14.0 mm, M10, 50Nm, t=10 mm
  • 10k/750Nm: 14.0 mm, M10, 70 Nm, t=10 mm

K6D130

  • 1k/200Nm ... 5k/500Nm: 16.0 mm, M12, 80 Nm, t=14 mm
  • 15k/1.2kNm: 18.0 mm, M12, 120 Nm, t=14 mm

K6D150

  • 2kN/200Nm ... 10kN/1kNm: 20.0 mm, M12, 100 Nm, t=14 mm

K6D154

  • 50N/5Nm ... 100N/10Nm: 10.0 mm, M6, 10 Nm, t=8 mm
  • 200N/20Nm ... 500N/50Nm: 10.0 mm, M6, 14 Nm t=8mm

(To save mass, recesses of 6 triangles up to 1mm wall thickness are recommended (rib structure).

K6D175

  • 10kN/1kNm ...50kN/5kNm: 28.0 mm, M16, 250 Nm, t=24 mm

K6D225

  • 50kN/10kNm ... 200kN/20kNm: 40.0 mm, M20, 500Nm, t=23 mm

Symmetry of the flange

When designing the flange, care should be taken that local weak points do not cause unbalanced deformation of the surface of the force sensor.

Individual outbreaks, as shown in the picture opposite, should be avoided.

Negative example for the design of a mounting flange

Force- / Torque Introduction

When introducing forces and torques, it must be ensured that the flange plates of the K6D sensor do not deform. Particularly when introducing moments, the introduction should be central and symmetrical.

Negative example of moment insertion

Flatness of the flange plate

The illustration shows a local deformation of the flange plate due to an asymmetrical introduction of a moment.

Local Deformation of sensor surface due to unsymmetrical moment insertion

Symmetrical introduction

The figure shows a flange for the (largely) symmetrical introduction of torques for the K6D225 sensor.

Assembly rules for K6D Sensors

 

  • High rigidity of the flange plate,
  • Good symmetry in the load / force transmission via the flange plate,
  • Low deformation within the sensor mounting surface << 10 µm,
  • If these points cannot be achieved, it is recommended to calibrate the sensor with the accessories.
positive example of moment insertion

Mounting the flange

The assembly of all components from one side is often possible only by the design of a two-piece flange.

Example for K3D110:

Adapters for Comau SMART-5 NJ-60:

zb-k6d110_adaptation_000-a-.pdf

Flange for K6D80:

so051_001-a-.pdf

so051_002-a-.pdf

Centering

The multi-component force sensors have a centering collar. (Inside diameter 0 ... + 0.1mm oversize, 1 ... 3mm depth).

In addition, two pin holes are provided for clearance E7 / m6.

To secure the angular position, one of the following variants is recommended (depending on the manufacturing tolerances):

  • Use of the centering collar to secure the centering plus 1 centering pin to secure the angular position in a slot
  • Use of 2 centering pins: in an E7 hole to secure centering, and in a slot to secure the angular position
  • Use of 2 centering pins in two holes E7 to ensure centering and angular position ("double-fit")
  • Use of the centering collar and use of 2 centering pins in two holes E7 ("3-fold fit")

If double or triple fits are used, it is recommended to use centering pins DIN 7979 with female thread if they are to be dismounted ...

 

Materials

If possible, the flange should be made of the same material as the sensor: aluminum sensors with aluminum flange (about 23 μm/m/°C), steel sensors with steel flange (about 12 μm/m/°C). Otherwise, the temperature-related drift of the sensor can be adversely affected by the introduction of temperature-specific voltages.

Mounting position

The sensors can be mounted in any mounting position. As with any force sensor, care must be taken that the connection cable is assigned to the fixed shore (the non-moving flange). Otherwise, forces are applied to the sensor via the connection cable.