Installation at MPIA

  1. Mount shaft and nodes?
  • Clean inner part of nodes and shaft properly
  • Don't fix bolts fully, it must be possible to rotate the nodes.
  • Take care that it is prepared in the right orientation for the buffer of the horizontal beam.
#! Image(img_0239.jpg, 25%) Image(img_0242.jpg, 25%) (Pictures show SX configuration)
  1. Mount beams?
  • Attach inclined beam with bolt not fully fixed.

#! Image(img_0250.jpg, 25%)
  • Attach horizontal beam with bolts not fully fixed.
#! Image(img_0253.jpg, 25%) Image(img_0254.jpg, 25%)
  • Attach T-gusset/Dummy gusset with bolt not fully fixed.
#! Image(img_0328.jpg, 25%)
  • Adjust the arm and fix bolts.
#! Image(img_0322.jpg,25%) Image(img_0320.jpg,25%) Image(img_0327.jpg,25%) Image(img_0329.jpg,25%) Image(img_0330.jpg,25%)
  1. Mount strut?
#! Image(img_0376.jpg,25%) Image(img_0403.jpg,25%)
  1. Mount motor?
  • Attache motor to upper mount with 46Nm per screw.
#! Image(img_0339.jpg,25%) Image_of_screws
  1. Install upper mount with traverse and counter balance
  • screwing scheme

2 6 3 7

4 5 1

#! Image(img_0354.jpg,25%)
  1. Mount shaft with beams to motor
  • Attach shaft to motor with 160Nm per screw. Strain gauge was only able to do 100Nm controlled.
  • Take care: The threads are going into the gear box and liquid will spill out if no screws are in and stored vertically.
  1. Install lower mount with bearing already assembled
  • The bearing is conical and has to be mounted the right way if not it will not fit.

#! Image(img_0435.jpg,25%) Image(img_0438.jpg,25%) Image(img_0441.jpg,25%) Image(img_0412.jpg,25%)

  1. [Optional] Measure the axis direction to the lower mount surface
  1. The dial indicator will be screwed on the axis
  2. The encoder mount surface is the reference

  • Attach the absolute encoder

  1. Measure the axis direction to the lower mount surface
  2. The dial indicator will be screwed on the axis
  3. The encoder mount surface is the reference

Electronic Parts

  1. Cabinet
  2. 2x Mounts
  3. Motor electronic
  4. Thermostat box
  5. 2x Inc. encoder cable
  6. 2x Motor cable
  7. 2x Abs. encoder cable
  8. Cable for analog driving
  9. Telescope simulator
  10. Swing arm simulator

Parts for one swing arm

  1. Upper mount + 9x M30 (delivered)
  2. Lower mount + 16x M16 (delivered)
  3. Bearing (delivered)
  4. Bearing caps (done)
  5. Absolute encoder (done)
  6. Shaft (delivered)
  7. Upper node (delivered)
  8. Lower node (delivered)
  9. Motor + Gear (delivered)
  10. Inclined beam (delivered)
  11. Strut + connectors (delivered)
  12. Bracket for strut (done)
  13. Horizontal beam (delivered)
  14. Beam fixing angle (done')
  15. 2x T-gusset axle + 4x nuts (delivered)
  16. T-gusset (delivered)
  17. 2x digital dial gauge holder (done)
  18. 2x digital dial gauge (delivered, for Nr. 2 delivery in August)
  19. Mechanical dial gauge holder (done)
  20. Mechanical dial gauge (delivered)
  21. CalUnit holder (delivered)
  22. Magnet and position switch platform (delivered)
  23. Cable trail switches (done)
  24. Fiber connector plate (done)
  25. [Optional] CalUnit (open)
  26. T-gusset dummy [done]
  27. Beam fixing angle [done]
  28. Support barrel for lower mount [done]
  29. CalUnit dummy [done]
  30. Laser tracker nest plate [done, Nr. 2 open]
  31. Drilling template [done]

Assembly Log

  1. Screws and nuts missing but ordered.
    • in progress
    • delivered - M30 nuts missing, M16x55 are M16x60 some number mismatch to our favor. - Wednesday 30.03.2011
    • 10 M30 nuts with less strength.
      • Closed - Monday 04.04.2010
  2. Bracket to be prepared.
    • in progress
      • Closed - Thursday 07.04.2010
  3. Some difficulties with the lower bearing discovered.
    • Cap modification -
      • Closed - Wednesday 06.04.2010
  4. Tectyl for final steel preparation.
    • Open
  5. Clock, role of plastic, telephone asked to Technischer Dienst
    • plastic arrived, clock and phones are ordered.
    • phone is installed but only one can be added to Montagehalle basis - Friday 01.04.2011
      • Closed
  6. Special tool to unmount bearing in lower mount is needed
    • Closed - Thursday 07.04.2010
  7. Mounting lower bearing in line with upper
    • lower bearing 1 deg or up to 2.5 deg not in line possible
    • 1deg x 3600" x 4.82 urad/" x 2000mm = 34.7 mm
      • Closed - Wednesday 30.03.2011
  8. Additional threads for hooks on upper mount.
    • Closed - Monday 04.04.2011
  9. Modification on bridge to attach the swing arm horizontally
    • Closed - Tuesday 05.04.2011
  10. Gear grease was leaking and needs some treatment
    • Check changing period of grease.
      • live time
    • Check if with putting threads in leaking is stopped.
      • yes
    • Document amount of grease lost.
      • ~4cl
    • Get information about grease and what is lost.
      • so far ok
      • Closed


  • Harbor
  • Laser tracker tests
  • Laser tracker tests
  • Take of Absolute encoder
  • Switch #1 with #2 on test stand
  • Pinning and assembly of T-Gusset #2
  • Finish and test position switch and magnet #1 #2
  • Fiber connector terminal installation #1 #2
  • Cabling #2
  • Functional tests DX
  • Software tests with DX until 10:30
  • Take of #2
  • Change drilling template position
  • Final wrap up
  • Setting up for lifting
  • 13:00 Packing
  • Contingency
  • Shipping

01.07.2011 Gaessler

  • Installation of beam angle
  • Switch cabling

30.06.2011 Gaessler

  • Swing arm #1 SX was taken off and Swing arm #2 DX was installed.

29.06.2011 Gaessler

  • Laser tracker tests have been performed
  • The T-Gusset could be adjusted within 2 iterations moving of 1mm in all three directions and 5' tip and tilt.
  • The accuracy was within 0.3mm and 1'.

31.05.2011-28.06.2011 Gaessler

  • Drilling template designed and manufactured
  • Position switch bracket designed and manufactured
  • Endstop adjustments
  • Positioning devices for T-Gusset designed and manufactured
  • Cabling
  • Second arm assembled without T-Gusset
  • Second arm cabling
  • Habor design
  • Preparation of laser tracker measurements
  • CalUnit holder assemled
  • Fiber installation in arm #1
  • SX and DX parallel movements tests

30.05.2011 W. Gaessler

  • Positioning devices for T-Gusset
    • 2 dail gauge are ordered
    • holder to be designed
    • threads to be drilled into gusset
  • Drilling template
    • material arrived
    • material will be delivered to company this week
    • drilling next week
    • STEP file for conformation to Bob
  • Position switch bracket
    • design by today
    • check with workshop

08.04-26.05.2011 W.Gaessler

Further improvement, installation and verification of the swing arm
  • functionality tests
  • repeatability tests
  • vibration tests
  • alignment tests
  • installation of arm to the upper mount
  • installation of lower mount and bearing
  • installation of position switches
  • installation of gusset with fixation angle
  • installation of bearing cap
  • installation of end stop

Thursday 07.04.2011 W. Gaessler

  • Planning
    • Finish bracket parts and key for bearing
    • detach the single axis
    • Mount test of the bearing
    • Attach the strut
    • Attach the arm to the gear
    • Attach the bearing and lower mount

Wednesday 06.04.2011 W. Gaessler

  • Built bracket and missing parts
  • Rotated the motor and measured the movement of the axis at the lower mount level
    • 0.5mm = 47.8" = 0.013deg corresponds to 0.02 planarity on the gear junction.
  • Built key for lower bearing

Tuesday 05.04.2011 W. Gaessler

  • Motor attached to the upper mount
  • Motor gear is leaking oil. Lost of about 0.05ml
    • Contacted Harmonic drive.
    • The threads are open. The grease is very fluid as it is supposed to work down to -15 C.
    • Closing the threads with screws should fix the problem.
    • The gear was filled with 360g of grease.
    • Issues:
      • Check changing period of grease.
      • Check if with putting threads in leaking is stopped.
      • Document amount of grease lost.
      • Get information about grease and what is lost.
  • Fixed motor with upper mount (46Nm per screw)
  • Attached upper mount and motor with bridge to test stand
  • Attached single axis to motor with 160Nm? per screw (up to 300Nm possible)

Monday 04.04.2011 W. Gaessler

  • Installation of additional threads on the SX upper mount.
  • Balancing test for lifting at telescope and at MPIA
    • Issue: For vertical mount at MPIA the bridge will not be balanced in the right way. Some additional crane fixation on the bridge will be built.
  • Preparation of bridge modification
  • Preparation for motor installation on upper mount
  • Motor electronic tests

Friday 01.04.2011 W. Gaessler

  • Beams were bolted together.
  • Dummy gusset was re-worked for vertical beam. 1mm has been taken off and completely flattened.
  • Check of how to mount the motor.
  • Upper mount will get additional threads for attaching hooks to lift it vertically.

Thursday 31.93.2011 W. Gaessler

  • Acceptance of motor electronic and software at AAC.

Wednesday 30.03.2011 W. Gaessler

  • Arrival of bolts.


  • Dummy Gusset should be finished during Thursday
  • Bolts?
  • Bracket?
  • Friday: final assembly beams
  • Bearing cap should be fixed by Monday
  • Depending on arrival of M30 nuts the arm can be mounted on Tuesday

Tuesday 29.03.2011 W. Gaessler

  • Inclined beam was put into place.
  • Horizontal beam was put into place.
  • Arrival of second arm.


  1. Screws will not arrive today.
  2. Special tool to unmount lower bearing is needed.

Monday 28.03.2011 W. Gaessler

!!Take care, which side the shaft is placed, as the buffer is asymetric !!
  • Shaft and nodes have been mounted.
  • Reinraumschleuse prepared for mounting.
  • Interface lower mount checked with both. OK


  1. Screws and nuts missing but ordered.
  2. Bracket to be prepared.
  3. Some difficulties with the lower bearing discovered.
Topic revision: r2 - 07 Aug 2018, AndrewColson
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