From the idea to the product

Product definition, mould making, mass-production: a Lombard company extensively operates in the sector of technical polymers and liquid silicone

Piero Scardelli

Some pieces made of liquid silicone implemented by Duepi S.r.l. for the early childhood sector

Headquartered at Palazzolo sull’Oglio (BS), Duepi S.r.l. is an enterprise with over thirty-year expertise in the manufacturing of moulds for thermoplastic materials and liquid silicone, of plastic polymer moulding and, more recently, of liquid silicone, too. The company, which currently engages fifty workers and is managed by Elio Plebani, Andrea Libretti and Usvaldo Paris, can manufacture a broad product range for countless sectors, from early childhood to electric, food, medical and ventilation and so on, due to the staff’s know-how, forefront manufacturing technologies and extreme plant automation.

Starting from the piece study

Elio Plebani tells: «Duepi was born as mould manufacturer. Along the years, it was able to evolve, becoming a reality that not only designs and manufactures moulds but, through a forefront up-to-date moulding division, performs mass-production, too».

Andrea Libretti goes into detail: «Duepi offers an all-round service that, if demanded by customers, starts from the idea definition and reaches the product implementation. This is executed trying obtaining the best technical solution and pursuing the best cost-benefit ratio, always with the fruitful collaboration of customers themselves. In such phase, we avail ourselves of rapid prototyping technologies that allow showing a “preview” of the moulded product to the customer». This is followed by design development of the mould and of necessary equipment, afterwards the real mould construction starts inside the mechanical workshop. Finally, we proceed to the mass-production through press moulding.

Elio Plebani: «We are specialized in medium-small size parts and, due to the notable expertise in the field of technical polymers, we can process all kinds of materials, even the least common ones. Moreover, for some years we have been able to implement components made of SLR, the so-called “liquid silicone”».

All-round technology

Concerning the phase of component definition and mould development, technical office engineers avail themselves of forefront software such as Unigraphics NX by Siemens with Moldex package for filling analysis and VISI software by Vero Solutions; the latter includes also the CAM module for the programming of machine tools and EDM plants.

Speaking of machines, Elio Plebani specifies: «Concerning rapid prototyping, we are provided with a HP Multijet Fusion 4200, which we consider a feather in the cap of 3D printers. This tool allows us to print parts of nylon and other materials, so succeeding in implementing both the single prototype, wider samples and batches of some thousand parts. We believe 3D printing is an excellent solution, especially in case of small batches, alternative to the much more expensive manufacture of a mould».

Duepi relies on highly interesting technology also in toolshop ambit: among the most interesting machines, it is worth pointing out lathes and 3- and 5-axis machining centres by Kitamura, Deckel Maho, Nikkei and Digma, in addition to Ingersoll plunge EDM machines and wire EDM plants by Fanuc and Mitsbishi, all of them with numerical control and CAM station programming.

In moulding departments, finally, 34 presses are at work, 6 of which for liquid silicones, from 60 to 190 tons, and 28 presses for thermoplastic material injection, from 25 to 500 tons, equipped with robot for the collection and the deposition of the moulded component. «Presses are by brands like Engel, Battenfeld Wittmann, Haitian, Negri e Bossi, Arburg, Plastic Metal and Sandretto», Andrea Libretti specifies.

The gray room for the moulding of liquid silicone components

Specialists in liquid silicone

As briefly said, one of the added-values of Duepi activity is the production of moulds and components through SLR (“liquid silicone rubber”) moulding, material broadly used in challenging sectors like pharmaceutics or early childhood, for instance for the production of teats, breast pumps, nipple shields etc. For such ambits, components must be moulded in a “gray” room, that is to say at controlled atmosphere, as Andrea Libretti explains: «In 2015, Duepi set- up a room inside its factory in virtue of the acquisition of an outstanding customer in the sector, Artsana S.p.A.»

Liquid silicones are added liquid silicone rubbers consisting of two components: a catalyst and a cross-linking agent. These components are generally supplied ready-to-use and separated each other, to manage their stocking and handling at best and most of all to allow their mixing at the most opportune time. Elio Plebani adds: «The dosing phase, managed by a special system we have implemented outside the gray room, homogeneously mixes components and eventual additives needed to meet customers’ specific requirements, to assure excellent quality of the final product».

Some machining centres in the toolshop

Wire and plunge EDM in the mould making division

Once mixed components, the liquid silicone compound cures very quickly at high temperatures, which allows, with right thermal regulations, very short moulding cycles. Libretti further adds: «The moulding of the liquid silicone rubber is essentially a thermosetting process because SRL is a thermosetting polymer where a bicomponent compound is mixed and hot polymerized in the mould through a component called catalyst». This means the final moulded piece is in a “permanent” form and, when hardened, it cannot be melted any longer. Once moulded, parts can be removed manually or mechanically, in virtue of the notable material elasticity; moreover, they are almost completely burr-free. Plebani: «Implementing high-quality moulds, featuring high precision and excellent surface finishing, is anyway very important, especially when we manufacture components for the sectors of early childhood and the pharmaceutical industry».

Elio Plebani and Andrea Libretti, two of the three members of Duepi S.r.l., headquartered at Palazzolo sull’Oglio (BS), near a mould

Looking at the future

Duepi works to satisfy customers’ demands fully and, to hit the target, it assures professionalism, technical support and timely deliveries: it is a winning formula in time. However, it is not enough: they must always look at the future to be prompt and reactive versus often unexpected market logics. Andrea Libretti ends: «The target for next months is not only acquiring customers in maybe new sectors but also investing in forefront technologies and tools. We think, for instance, that 3D printing represents the future for us, mould makers, especially in this market phase that demands for smaller and smaller batches.

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