Wednesday, 16 October 2013

Fast, for complex moulds

Mondialstampi needed to produce large, high quality moulds with complex profile shapes as quickly as possible; the answer was the Breton Flymill 1000 machining centre, and considering the mould improvements achieved, it was exactly the right choice. 
When we move around the home or the garden we rarely pay much attention to the objects around us because we see them every day and know them well. If we did stop to look at them closely we'd soon realize that most of them are made of plastic. The same conclusion would be reached also if we were to examine our cars, both inside and out.   What's fascinating about this is the complexity of some of these parts: wafer thin in sophisticated shapes. A lot of work goes into the design of parts like these, not just the design of the part itself but in particular the mould into which the plastic will be injected

For Mondialstampi  a company that has become highly successful in the industry since its incorporation in Vicenza in 1990, solving problems in the plastic injection-moulding process is their daily bread.

For your home and car
“Our company is entirely dedicated to the production of injection moulds,” says Mondialstampi owner Giorgio Cortese. “We specialize in medium-large moulds mainly for household goods, such as under-bed storage units, boxes and other storage units of various shapes and sizes. We also produce moulds for automotive parts, such as bumpers, wings and interior trim, and last but not least, we make moulds for various garden articles such as outdoor storage cupboards, plant containers, composters and ornamental objects. In collaboration with third parties we also touch on many other minor sectors, but the three I have mentioned are the primary drivers of our business.”                  
“We've always worked very intensively in Italy, although market conditions have led us increasingly to look towards exports,” continues Diego Bertollo, Head of Mondialstampi's Engineering Department “Today, our production is roughly half and half: 50% for the domestic market, and the rest for export, mainly to other EU countries. We also export to Russia, Canada, and South America and, on a smaller scale, to several other countries.”
Today the company has a workforce of around 50, of whom 10 in the Engineering Department, where mould design activities are conducted using CAD/CAM systems. We have 20 technicians in the workshop and another 15 people engaged in mould assembly and testing procedures.

A well-defined structure
The Engineering Department has a very delicate job: the moulds are produced in a co-engineering process together with the customer since this approach has proven to be the optimal way to produce any given component, but it means we must also adapt each and every solution to comply with the technology and plant available to the customer.                               
Once the 3D model of the part has been created, meetings are held to eliminate any possible misunderstandings between the mould designer and the customer in terms of the solutions to adopt. When the project has been approved, the 3D model is used to produce the actual mould. First, the guidelines of the mould are defined, and then the engineering department uses CAD software to produce the definitive 3D model. The next stage involves the transition to CAM, the implemented features of which mean it can automatically recognize a large number of the work processes defined in CAD. 
“At this point the production department takes over, but first the steel ordered by the engineering department for the mould is checked before it goes into production,” explains Cortese. “The initial roughing operations are now performed on some of the machine tools at our disposal. As the production cycle proceeds, the plates are moved to the finishing machines to create angled holes and for other special machining processes.”
Once machining chips have been removed, the plates are transferred to the assembly area, where operators check conformity of the parts before proceeding with assembly. “To aid our personnel and minimize the risk of errors we've equipped the various assembly areas with CAD stations,” explains Bertollo. “Thanks to this solution, our personnel can actually see how the various parts fit together, leaving no room for doubt.” Once finished, the mould is tested in a mould testing press to check for any problems and see if any minor corrections are needed. Final testing is performed in the presence of the client, and if all requirements are met, the go-ahead for production can be given.
There's no dedicated unit in charge of quality control, which is instead performed directly on the machine using probes that can detect even the smallest imperfection so that the part can be reworked without having to remove it from the machine. Mould quality is therefore guaranteed by the two Breton machining centres installed in our factory, which are used for mould finishing operations.
Reliability pays
“In the household articles industry in particular we work with very thin parts where even one-hundredth of a millimetre can make a difference”,  continues Bertollo – “We need machining centres that can guarantee the highest quality and that’s why we chose the Breton Flymill 1000.”
“Producing large, complex moulds, reducing milling times, improving surface quality and increasing working life.  These were the requirements we wanted to address by purchasing a new 5-axes machining centre,” says Cortese. “Ten years ago we bought a Breton Matrix 800, and we've never had any problems with the plant or the after-sales service. That's why we decided to look at the possibility of purchasing another Breton machine.”
The company finally opted for a Flymill 1000, a 5-axes machining centre that differs from the Matrix in its working range, structure and spindle power: longitudinal travel of the new machine in fact is up to 8 meters and it is equipped with a 5-axes head with Direct Drive motors. In any case, both solutions were designed specifically to meet the requirements of high-speed machining in the mould  making industry, so they are the natural choice for these applications. 
In particular, the Matrix is a travelling cross beam gantry type machining centre with a fully enclosed structure and drive assemblies located at the top of the machine, making it extremely safe for operators and guaranteeing the highest level of reliability and precision during machining. The high quality and precision of the machining work are also a result of the thermal symmetry of the structure, while a thermal stabilization system for the Z axis ball nuts and bearings and axis drives keeps the temperature of these parts the same as the machine structure.
Both the Matrix and the Flymill are equipped as standard with a continuous rotation Direct Drive twist head with C axis continuous control, and the spindle can be used with a continuous power output of up to 40 kW at 18,000/28,000 rpm giving the machine considerable chip removal capacity. 
Mondialstampi actually purchased the Flymill with a more powerful head to use the new machining centre not only for finishing, like the Matrix, but also for prefinishing operations.
In addition, the new machine is much faster than the original one: 60 m/min for the X and Y axes and 100 rpm for the C axis compared to the 40 m/min and 19 rpm of the Matrix. This performance derives from the choice to equip the machine with guideways mounted on racks rather than on recirculating ball screws, giving the system a more rigid structure and allowing it to reach higher speeds.  
Furthermore, the Flymill is ideal for machining complex profiles thanks to the generous working range of the A axis, which is from –105° to +120° thus making it possible to machine difficult undercuts without having to reposition the workpiece.
“Both units are extremely high-tech solutions and that's why they're entrusted to highly specialized technicians dedicated exclusively to running the machine”. Cortese concludes – “Our aim is to exploit the Flymill to its maximum potential in order to transform our investment into a technological advantage that will help us consolidate our market position.”
For more INFO about Matrix  800 and Flymill 1000 write to
Thanks to Mondialstampi

Thanks to TM - Tecnologie Meccaniche, by Davide Davò. 
Sergio Prior


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