English
Italiano
Deutsch
Following what is described above regarding the first phase of the recovery operation for the Noto Antenna, azimuth axis, on 16 November 2011, the site was temporarily suspended, pending the completion of the expansive mortar curing, meanwhile the construction activities of new mechanical components and revision of some Antenna details were taking place in the Oggiono workshops according to the schedule agreed with the heads of INAF and, in detail, as follows.
The construction of the Radio Telescope rail consisting of 12 circular gear teeth sectors at 30° each, was brought to a successful conclusion at the Galbiati Group workshops in Oggiono; the calendaring of the gear teeth sectors, after the arrival of the semi-finished materials from the United States, was carried out carefully and with sufficient precision to obtain a final roundness with a max. 2 mm error (Versus 5 mm max acceptable).
The subsequent mechanical machine milling of the lower levels (Support at the base plates) and higher (For supporting the wheels of the 4 wheel boxes) as well as those of milling at 45° junctions between the heads of each sector with an adjacent one have been carried out on a numerically controlled milling machine of the latest generation, the final geometric control has confirmed a parallelism between planes and precision of the “rope” in the order of hundredths of a millimetre, well beyond expectations.
As envisaged by the Specifications in the Tender, at the Galbiati Group assembly department, this was carried out by a preliminary assembly of the whole rail (See photo) of more than 18 meters in diameter and, through modern means by LASER TRACKER controls, we proceeded with the verification of the whole geometry of the “antenna “azimuth track” system, the results obtained were more than satisfactory for both Galbiati Group as for the INAF technical experts who were present at the controls of the radio telescope.
New axes of rotation and alloy steel wheels for the radio telescope were created, hinged conically, and performed with machine tools with numerical controls and perfectly controlled within expected tolerances.
The gearboxes removed from the antenna, were removed to check the state of wear of all rotating parts (Gears and bearings), the condition of all steel components and seals; observed all rotating and static parts which were more than acceptable (Given the length of service of over 30 years), all the material of the radio telescope was reassembled, rotation was controlled, properly repainted, an activity not particularly requested in the contract that could not have been simply avoided by a professional business such as Galbiati Group, known for quality and reliability.
In fact, after about 4 weeks, the expansive mortar has reached the degree of curing required with the help of the climate characterized by an almost constant rainfall, somewhat unusual in Sicily. Afterwards, site activities by A.POINT in charge of the installation and alignment of the 12 gear teeth sectors, continued to form the whole circumference, the replacement of the new wheel boxes in the radio telescope under the alidade and the removal of temporary supports that supported the entire antenna during the entire time spent for the curing of the mortar, the replacement of gearboxes and their alignment, in parallel with the above steps, a series of intermediate geometric controls and, of course, all final checks with the drafting of the relevant reports of the radio telescope materials.
Also in this second phase of Galbiati Group operations in collaboration with A. POINT, we enjoyed the active collaboration of the INAF technical experts sharing the common goal of obtaining a positive and totally perfect end result.
