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Nano-Hexapod Struts mounting - Test Bench


This report is also available as a pdf.


Mounting Bench

A mounting bench is used to greatly simply the mounting of the struts as well as ensuring the correct strut length and coaxiality of the flexible joint's interfaces. This is very important in order to not loose any stroke when the struts will be mounted on the nano-hexapod.

A CAD view of the mounting bench is shown in Figure fig:strut_mounting_bench_first_concept.

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The main part of the bench is here to ensure both the correct strut length and strut coaxiality as shown in Figure fig:strut_mounting_step_0.

/tdehaeze/test-bench-strut-mounting/media/branch/master/figs/strut_mounting_step_0.jpg

The tight tolerances of this element has been verified as shown in Figure fig:strut_mounting_bench_first_concept and were found to comply with the requirements.

/tdehaeze/test-bench-strut-mounting/media/branch/master/figs/check_dimensions_bench.jpg

The flexible joints are rigidly fixed to cylindrical tools shown in Figure fig:cylindrical_mounting_part which are then mounted on the mounting tool shown in Figure fig:strut_mounting_step_0. This cylindrical tool is here to protect the flexible joints when tightening the screws and therefore applying large torque.

/tdehaeze/test-bench-strut-mounting/media/branch/master/figs/cylindrical_mounting_part.jpg

Mounting Procedure

The mounting procedure is as follows:

  1. Screw flexible joints inside the cylindrical interface element shown in Figure fig:cylindrical_mounting_part (Figure fig:strut_mounting_step_1)
  2. Fix the two interface elements. One of the two should be clamped, the other one should have its axial rotation free. Visually align the clamped one horizontally. (Figure fig:strut_mounting_step_2)
  3. Put cylindrical washers, APA and interface pieces on top of the flexible joints (Figure fig:strut_mounting_step_3)
  4. Put the 4 screws just in contact such that everything is correctly positioned and such that the "free" flexible joint is correctly oriented
  5. Put the 8 lateral screws in contact
  6. Tighten the 4 screws to fix the APA on the two flexible joints (using a torque screwdriver)
  7. Remove the 4 laterals screws
  8. (optional) Put the APA horizontally and fix the encoder and align it to maximize the contrast (Figure fig:strut_mounting_step_4)

/tdehaeze/test-bench-strut-mounting/media/branch/master/figs/strut_mounting_step_1.jpg

/tdehaeze/test-bench-strut-mounting/media/branch/master/figs/strut_mounting_step_2.jpg

/tdehaeze/test-bench-strut-mounting/media/branch/master/figs/strut_mounting_step_3.jpg

/tdehaeze/test-bench-strut-mounting/media/branch/master/figs/strut_mounting_step_4.jpg

Mounted Struts

After removing the strut from the mounting bench, we obtain a strut with ensured coaxiality between the two flexible joint's interfaces (Figure fig:mounted_strut).

/tdehaeze/test-bench-strut-mounting/media/branch/master/figs/mounted_strut.jpg