This note describes one of the tools used during Process-1 of the integration of the Detection Units (DUs) in the KM3NeT experiment. In particular, the device is designed to seal the Break-out-box (BOB). The BOB is a box interface between a Digital Optical Module (DOM) and the electro-optical cable (VEOC) for power and optical connection of each optical module (DOM) to the DU. The original manual version of the tool developed by NIKHEF was then automatized by INFN-LNS in order to guarantee a reproducible operation in the recursive process of the DU integration and two samples have been realized for the integration sites at LNS and Genova respectively

Cacopardo, Giorgio

Claudio Pizzorno

Cresta, Massimiliano

Lo Cicero, Andrea

Ottonello, Giacomo

Ottonello, Stefano

Parodi, Franco

Pollovio, Palmiro

Tavilla, Giuseppe

Trovato, Andrea

English

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 1     ISTITUTO NAZIONALE DI FISICA NUCLEARE  Sezione di Genova e Laboratori Nazionali del Sud _________________________________________________________________________________	  INFN-20-014/GE     31 august 2020 	INFN INTERNAL NOTES  The new “Welding Machine” for the DUs integration in the KM3NeT experiment: Mechanical and Pneumatic parts  Giorgio Cacopardo1, Palmiro Pollovio2, Claudio Pizzorno2 , Andrea Trovato2 , Andrea Lo Cicero2 , Giuseppe Tavilla2 , Franco Parodi2 , Giacomo Ottonello2, Stefano Ottonello2, Massimiliano Cresta2 1) INFN, Laboratori Nazionali del Sud, Via Santa Sofia, 62, 95123 Catania, Italy 2)INFN, Sezione di Genova, Via Dodecaneso, 33, 16146, Genova, Italy      Abstract 	This note describes one of the tools used during Process-1 of the integration of the Detection Units (DUs) in the KM3NeT experiment.  In particular, the device is designed to seal the Break-out-box (BOB). The BOB is a box interface between a Digital Optical Module (DOM) and the electro-optical cable (VEOC) for power and optical connection of each optical module (DOM) to the DU. The original manual version of the tool developed by NIKHEF was then automatized by INFN-LNS in order to guarantee a reproducible operation in the recursive process of the DU integration and two samples have been realized for the integration sites at LNS and Genova respectively.  .                   Published by Ufficio Biblioteca e Divulgazione Scientifica Laboratori Nazionali di Frascati  2  			INDEX Sezione di Genova e Laboratori Nazionali del Sud ....................................................................... 1 Abstract .......................................................................................................................................... 1 Introduction .................................................................................................................................... 3 Machinery Directive Rules and guidelines .................................................................................... 4 Chapter1 Mechanics .................................................................................................................... 5 1.1 General layout ..................................................................................................................... 5 1.2 Mechanical workings .......................................................................................................... 6 Chapter 2 Pneumatic ..................................................................................................................... 7 2.1 General layout ..................................................................................................................... 7 2.2 Pneumatic scheme ............................................................................................................... 7  ........................................................................................................................................................ 7 Chapter3 Technical construction dossier ..................................................................................... 7 Improvements ............................................................................................................................... 16 References .................................................................................................................................... 16  	 Table of figure: Figure 1: km3 experiment……………………………………………………………………………..3 Figure 2: general layout……………………………………………………………………………….5 Figure 3: global view …………………………………………………………………………………6 Figure 4: scheme………………………………………………………………………………………7 Figure 5: improvements……………………………………………………………………...............16              Introduction  Figure 1: Km3 experiment The KM3NeT experiment [1] for the detection of high energy cosmic neutrinos is being built in two sites of the Mediterranean Sea, Capo Passero in Sicily ARCA) and Toulon in the French coast (ORCA). The full detection system includes 3 building blocks of DUs [2], each block of 115 DUs. Each DU accommodates 18 DOMs [3], kept vertical by a top buoy and connected to the DU base via the VEOC. The DOMs are produced in various integration sites of the KM3NeT collaboration while the VEOCs are provided by the Dutch MCAP company specialized in cable and glass fibers assemblies.   The schematic of cable, filled with oil to be in equi-pressure during operation at the sea bottom is reported in fig.1  Every 9m in ORCA or 36m in ARCA, the VEOC has a breakout box (BOB) made in black Simona polymer to allow connection to the corresponding DOM. The box has two separated compartments. The first is already sealed and includes a 375/12V DC-DC converter. Here the two conductors and one fiber of the VEOC are addressed to the second compartment which is open and oil free to allow the connection to the DOM via the splicing of the optic fiber and the clamp of the electrical wires. This operation is described in detail in the Integration procedure manual on Google Drive. As a result, the DOM is electrically and optically connected to the VEOC but in order to guarantee water tightness and equi-pressure during operation, the second compartment of the box must be finally sealed and oil filled. In each DU this operation must to be repeated 18 times, one for each DOM, and hundreds of times when all the DUs of the building blocks of the detector are considered. The automation of this process via the so called “automated welding machine” (AWM) can then of great impact during the DU integration process not only with respect to time optimization but also to improve the reliability of the process. The design of the AWM was developed by one of us (G.Cacopardo) while the realization  4 of all the mechanical structure was performed both at INFN-LNS and INFN-Genova. In this note we focus on the general description and requirements of the machine while details on the mechanical structure, the electronic components and the software will be given in separate reports.   The qualification of the device based on the check of the welding procedure repeated in a relevant number of spare BPBs is also discussed.   Machinery Directive Rules and guidelines The AWM is not realized to be market to outside companies: it will be used during the DU integration process 1 by trained people, only inside the INFN laboratories.  However, the design is compliant to the EU's Machinery Directive which defines the essential health and safety requirements for a wide range of products, including machinery  conformity with respect to the essential health and safety requirements (in Italian RES, Requisiti Essenziali di Sicurezza).  This is accomplished by  • a detailed   risk analysis which includes the application of technical standards already during the design phase, the implementation of safety devices and guards, highlighting, in the instruction manual, the residual risks that cannot be eliminated, • the technical documentation file to collect all the documents produced during the design phase, the construction and the test of the machine, • the operation and maintenance manual • a manufacturer plate for identification The AWM was designed following the guideline of the technical code DVS 2207-1 that applies to the welding of pipes, fittings and tapping tees made from PE-HD including types PE 63, PE 80 and PE 100.  In this approach the quality of welded joints depends on the qualification of the welder as well as on compliance with the welding standards. The welded joint can be tested by means of non-destructive methods: in our application this is accomplished using pressurized air inside the welded volume and checking for leaks. Within the framework of the quality assurance it is recommended to produce and test samples of joints before and during welding. This was done various times on spare BOBs as described in next chapter            5    	Chapter 1 Mechanics 1.1 General layout  The mechanics, designed by G. Cacopardo, is mainly made of aluminum, the sides, through 4 columns, are bolted to the base and on them are mounted the linear guides that allow the sliding of the heating plate and the upper cup. The actuator of the upper cup and the heating plate are also anchored to the sides via two crosspieces and a plate. The lower cup actuator with the relative guides are instead mounted directly on the base which also houses all the other pneumatic elements (pressure regulator, solenoid valves, vacuum generators etc.).  Figure 2: general layout 1. Upper and lower cups 2. Pneumatic actuators 3. 2-way solenoid valves 4. Solenoid valve 5. Pressure regulator 6. Base 7. Linear guides 8. Heating plate 9. Sides Figure 2: General layout  6 1.2 Mechanical workings   The processes for the construction of the mechanical structure of the Automatic Welding Machine were entirely carried out in the mechanical workshop of the Genova Section with the commitment of all the technicians involved in the service. The construction of the components required the use of lathes and milling machines. The simplest pieces were made using traditional machines, while the pieces with more complex shapes required the use of numerical control machines.  In particular, the base and the sides, due to their shape and size, were machined on the DECKEL FP 42 NC 3-axis CNC milling machine which can allows contouring, drilling and series milling. The programming of this milling machine was carried out on the machine using the ISO language and a simple graphic interface. Instead the two “cups” that house the BOB and the relative cap were processed on the Mikron UCP 800 Duro 5-axis CNC machining center, the machining program was created using the Hypermill CAD / CAM software.  Figure 3: global view    					 7 Chapter 2 Pneumatic 	2.1 General layout  The pneumatic system consists of an electronic "pressure regulator" which varies the pressure in the circuit of the actuators from the network pressure (7/8 bar), according to the phase of the welding cycle and the necessary force. A solenoid valve (EV) is mounted downstream of the "Pressure regulator", which must be powered in order to move the actuators. Subsequently, 3 type 5/3 solenoid valves (EV1, EV2, EV3) are mounted which control the relative actuators. All 3 actuators of the same series and have the same diameter (20mm), they moves the heating plate, the upper cup and the lower cup; their range varies according to the connected user (heating plate> upper glass> lower glass). Finally connected upstream of the "Pressure regulator" there are 2 vacuum generators that exploit the Venturi effect to hold the elements to be welded in position on the cups (upper and lower); they operate at the mains pressure and are controlled by two 3/2 solenoid valves. The pneumatic elements are connected together using 6x4 mm plastic tubes and joined with quick couplings. Valves are present on the actuator inputs which, by acting on the air flow, can modify the speed of movement.  2.2 Pneumatic scheme 		Figure 4: scheme  8 Chapter3 Technical construction dossier  Pressure regulator   9  Solenoid valve  2-way solenoid valves   10 Type 3/2 Type 5/3    11   Actuators  5mm travel          12  50mm travel             13   200mm travel     14   Vacuum generator       15  Flow regulator         16 	Improvements  This version of Welding Machine is a prototype, so some future improvements are possible: -  The stroke of “upper cup” system will have to be longer and adjustable to allow for different BOB sizes. - To improve the safety of the machine, a mobile screen may be installed in the bob area to prevent the operator from inserting his hands during the automatic processing cycle. - The “lower cup” will be implemented with an aluminum arch for better centering of the BOB.   		                      Figure 5: improvements   REFERENCES  [1] arXiv:1601.07459 [astro-ph.IM]. [2] Adrián-Martínez, S., Ageron, M., Aharonian, F. et al. Eur. Phys. J. C (2016) 76: 54. [3] EPJ Web of Conferences 116, 01002 (2016). [4] I. Sgura. VEOC to DOMs and base container integration procedure, internal note KM3NeT_INT_2016_004. 

The new "Welding Machine" for the DUs integration in the KM3NeT experiment: Mechanical and Pneumatic parts

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The new "Welding Machine" for the DUs integration in the KM3NeT experiment: Mechanical and Pneumatic parts

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