ADH” SYSTEMCHARACTERISTICS OF THE MATERIALS”
:Spheres
Carbon steel F-1140 in accordance with UNE-36011 (similar to AISI 1040 or 1045 and to steel CK-40 in accordance with DIN norms.

:Tube
Normally, tubes made in threes with longitudinal welding are used.

The qualities usually used are A-37 and A-42 and to a lesser extent, A-52, in accordance with UNE – 36080. These are approximately equivalent, in terms of other regulations, to the qualities ST 3373-2. RST 42.2 AND ST 52-3, in accordance with DIN 17100.

Conical caps:
Normally, these are obtained by forging weldable steel F-1120, in accordance with UNE 36011 (Approximate equivalences: AISI 1035 or CK s/DIN)

Occasionally, they can be obtained by bar mechanization, using the same material. In any case, the welding drill and the bevel are mechanized to achieve the precise dimensional tolerance points.

Screws:
These are obtained from steel F-1250, in accordance with UNE 36012 (equivalent to 34 Cr Mo 4 in accordance with DIN 17200, or to AISI 4340). In order to guarantee greater endurance of the material, and without affecting its capacity, tempering toughens the screws.

ADH” SYSTEM”

MANUFACTURING PROCESS

The manufacturing process of the spatial networks made with the ORTZ system is as follows:

Many components, normally materials such as the tube, the forged conical caps, the screw parts and the forged spheres are obtained from specialised manufacturers.

The LDEIAKO manufacturing process entails the following basic operations:

a) Bar manufacture 

– Mechanization of the conical caps.
– Assembly of the ends of the bars.
– Cutting of the tube.
– Welding of the tubes to the conical caps.
– Painting of the bars with kiln polymerisation  (subcontracted operation)
– Marking and classification for sending to site.

b) Sphere manufacture

 – Mechanization: hole drilling and threading.
– Preparation of surface and painting.
– Classification and preparation for sending to site.

It is worth pointing out a feature particular to the bar manufacture which concerns the welding process.  This is carried out after previous positioning of the ends on the welding bench.  The separation between the end screws is defined by this positioning and by the accumulation of the dimensions of the elements in between:  screws, conical caps and tube.  This system avoids the accumulation of dimensional errors of these elements and allows very narrow tolerance margins in the obtaining of the bars which are practically the result of the dispersion of the welding process.

This process is carried out in automatic equipment in an atmosphere of protective gas.  This equipment has a numerically controlled positioned which automatically determines the real length of the bar and the sequence of which is established by the computer printouts.

This manufacturing system allows the attainment of a dimensional tolerance of 0.3mm in the length of the bars. As for the mechanization of the threaded holes of the spheres, this is done on a machine which has been specially conceived for this purpose.  It is a C.N. machine which can be programmed manually but normally works within a CAD CAM system. It receives the coded information either directly from the computer or from floppy disks which store the information to be introduced into the machine’s C.N. system.

The operative only feeds in the unworked parts and loads the C.N. programmes.  The machine successively carries out the necessary operations:  drilling, countersinking and threading of the holes, successively positioning the part for each hole and automatically carrying out the change of tools.

The definitive production system does not work controlled by the operatives.  The direct information on the manufacturing parmeters is not transmitted to the workshop by means of constructive plans but is transferred with computer back up (disks or cable) in codes that are directly interpretable by the production units.