Advanced Technologies for Machining Large Sheet Metal

Colgar was founded by Luigi and Mario Colombo and Attilio Garoldi in 1945, at S. Pietro all’Olmo (Milan), asa mechanical workshop. As time passed, the company started to develop its own products in the sheet metalprocessing field: cutters, electric, mechanical and hydraulic shears, and mechanical, hydraulic,synchronized and automated folding presses.

Situated in the industrious heartland of North-East Italy, Siderurgica Gabrielli of Cittadella(Padua) is certainly one of the most representativ eexamples of those enlightened entrepreneurs whohave based the growth of their company on theirability to follow the road of technologicalinnovation and always being proactive withclients.Founded in the postwar period by AngeloGabrielli, Siderurgica Gabrielli is today part ofthe Gabrielli group and is a service centre forsheet metal processing, subdivided into twodivisions: the coils division that is specialized inshearing, flattening and hot coil cutting processes,and the large sheet metal division that isspecialized in the pre-processing of quarto plate.

SUCCESSFUL DESIGN INTUITIONS

One of the overriding requirements was thenecessity of optimizing the structural rigidityrequired of the parts and of the whole, withweights that were not excessively penalizingfrom the viewpoint of handling and processingparts. “This aspect – commented Sergio Colombo,Colgar design manager – has involved acomplete revision of the structural design forthe PIS 200.71/101 with respect to ourprevious esperiences and therefore weconsidered it necessary to set up a design group with the participation of the MilanPolytechnic’s Department of Mechanics andthe Mechanical Engineering Department ofthe University of Rome - Tor Vergata”.

From the initial considerations, the need emerged toconstruct large individual elements, with therequired manufacturing and couplingprecision, to allow the transportation and insitu assembly of the elements . A press wastherefore conceived with the lower table resting o n the shoulders with the lattercomposed of mu ltiple sheet-metal layers ofvarying thickness.

EXCEEDING THE HIGHEST EXPECTATIONS

To make the crossbeam and rammer, Colgar’sdesigners followed known design andconstruction procedures, with the innovationof using multilayer structures, or ratherstructures of variable thickness.

“It is wellknown – Colombo continues – that thecrossbeam and rammer are the mostimportant structural elements and must havethe greatest possible rigidity. Upon checkingthe deformation values of the new machine’scrossbeam and rammer, it was found thatthese parts have the greatest rigidity of all ofthose previously constructed by us. Lastly, Iwould like to point out that the framework ofthis machine was cut in-house by SiderurgicaGabrielli and consigned to a nearby supplierfor mechanical finishing. The componentswere bench checked at Colgar, with mountingof components on the framework in-situ. Noproblems whatsoever were encounteredduring inspection testing at customerpremises”.

Just as the structures are important,it is also well known that the hydraulic systemdriving the cylinders that move the rammerrepresent the heart of synchronized presses .As this is a special machine, the hydraulicsystem and the cylinders required aparticularly refined design effort by Colgar.This latest generation, high-performancehydraulic system is composed of a control unitand two pumps with separate, variable flowrates, one for each cylinder. The cylinders arecomposed of single steel blocks derived fromforgings and perform the functions of boththrust and connection between the two half-shoulders. The CNC unit controls the two axesof the cylinders. The machine is equipped witha manual compensation system for compensating flexure via a series of wedges,the position of which can be determined by avisual indicator. The press was found to be sorigid that for various folded parts it was noteven necessary to adjust the compensationwedges to achieve fold angles completelywithin the requested tolerances.

ONSITE INSTALLATION AND COMMISIONNING

SUNFLUID and COLGAR engineers are committed to on-site machine installation and commissioning

Engineering Support
1 representative from customer office will be send to COLGAR, Milan for machine operation training and factory visits.

For more information, go to www.colgar.it

* We reserve the right to improve & alter the above specifications without prior notice.

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