From aluminium to steel with zero problems with Breton MATRIX vertical machining centre

Demo Technology chose the Matrix 1000 Dynamic CNC machining centre with 5 continuously interpolated axes to produce finished steel and aluminium dies for the automotive industry. Stiffness and flexibility are the winning features of Breton's solution.

(by Davide Davò and Andrea Pagani for June issue of Tecnologie Meccaniche)

People who work in the automotive industry are used to a frenetic pace of production, shrinking delivery times and constant project changes before final approval. These factors are all too familiar not only to the world's car makers but also throughout their supply chain among so-called tier 1 companies. To make their products, suppliers in turn rely on another tier of vendors, the tier 2 companies, which must work within even tighter schedules for obvious reasons, offering the utmost rapidity and flexibility in meeting the broadest possible range of requests. This situation is well known to Demo Technology, a company based in northern Italy in Pionca di Vigonza (Padua) having several decades of experience in the production of metal dies for the automotive industry. Demo Technology has recently purchased one of Breton's Matrix 1000 Dynamic machining centres to streamline its production of aluminium and steel dies, thus further increasing the company's production flexibility.

Castings and dies

«Our company was incorporated in 1974 under the name Demo Meccanica – explains Demo Technology owner Gherardo Demo. From 1974 to 1985 we operated in the foundry sector as patternmakers, initially making wooden patterns and then progressing to metal patterns. In 1985 we purchased our first 5 axis CNC machine tool - a major investment that gave us a competitive advantage. In 1990 we extended our operations to the tooling industry, producing dies for gravity casting, low pressure casting and pressure die casting. We have been specialised in the production of dies for wheels for around ten years, although this sector suffered a sharp decline in the early noughties, obliging us to approach a different group of customers, while remaining in the automotive industry».

In 2010 the company demerged into two entities working independently, although remaining in close contact: Demo Technology and Demo Modeltech, the former specialised in the toolmaking industry and the latter in patternmaking. Demo Technology today produces tooling for lots of industrial processes (injection moulding, pressure die casting, etc.) for customers operating in the automotive sector. Remaining in the automotive industry, the firm also produces gauges and jigs for checking components such as doors and bumpers.

«In recent years we've invested heavily in machinery and in the engineering department – explains Demo – With regard to plant, we currently have five 3-axis CNC machine tools and six 5-axis CNC machining centres, half of which with continuously interpolated axes, which allow us to produce small series of medium and large size parts».

The acquisition of the very latest technological solutions is a necessary by-product of market evolution, resulting in demand for parts with increasingly complex shapes and hence dies with geometrical features that are ever harder to machine. Evolutionary changes have also affected the methods used by customers to send us the specifications of the components they need.

Gherardo Demo continues:  «Around ten years ago our customers stopped supplying drawings of parts and replaced them with the mathematical characterisations. This led to the need to procure CNC machine tools and, above all, to ensure our engineering department was capable of handling the incoming data and processing them with computerised design and simulation tools. In this process our customers supply the geometrical characteristics of the part and specify the working life required of the tool. It's then down to us to design the tool in such a way that it is optimised for the production of 30,000 parts or to guarantee one million production cycles».

Multiple criticalities, one solution

Geometrical complexity is therefore one of the technological criticalities that the Veneto based company is faced with, plus the need for extreme precision of machining work and impeccable surface quality of the finished die.

«Each sector has its own problems – notes Demo – With regard to the production of jigs and gauges, for example, we need to guarantee tolerances in the region of tenths of a millimetre on parts of up to 1500 mm in length and with complex morphology such as doors, bumpers and chassis members. Conversely, with regard to dies, one parameter of primary importance is the aesthetic appearance of the part so that in addition to guaranteeing compliance with tolerances and surface roughness specifications  the surface must also be completely uniform and free of machining marks left by the mill, or, as in past times, by the operator performing manual polishing operations. That's why in recent years we've invested in increasingly high performance plants, capable of precision machining work and able to finish parts without removing them from the machine».

These criticalities are further compounded by the frenetic nature of automotive industry activities, which call for speed and mental and productive flexibility to provide an ultra-quick response to requests for a range of extremely diverse products.

«The 5-axis CNC machines in our factory allowed us to work on aluminium dies with optimal results – continues Demo – The production of steel dies has been similarly successful, but we realised that our existing machine tools were working close to limit conditions, especially in the case of series of 20 or 30 parts. That's why we started to seek a more robust solution in a process that terminated with our recent purchase of a Matrix 1000 Dynamic machining centre with 5 continuously interpolated axes, made by Breton».

Bigger and more robust

The Padua-based company had already purchased a Matrix 800 in 2001 and, having confirmed the validity of the solution in terms of precision, productivity, finished part quality and reliability, they decided to contact Breton again to choose a new plant.

«We opted for the Matrix 1000 Dynamic mainly due to its ruggedness – explains Demo – To excel in our sector we have to be proactive in responding to our customers' needs, and that means that we need machines that can handle aluminium finishing or heavy chip removal on steel without problems. Our existing Matrix 800 handles both tasks correctly, but thanks to its enhanced rigidity the Matrix 1000 Dynamic model is ideal for removing large volumes of chips when working with steel, while assuring precision in the region of hundredths of a millimetre».

The machine's ruggedness is the result of the Metalquartz frame employed by Breton. The machine's shoulders are composed of a sandwich structure made of stabilised arc welded steel, with ribbing embedded in a quartz composite material with a polymeric matrix. In addition to imparting a high level of structural rigidity, this technology offers excellent vibration damping, which translates into a superior surface finish and longer working life for the milling tools. In addition to the qualities listed above, the machine features generously sized recirculating roller guideways that further increase its structural solidity while simultaneously supporting maximum rapid traverse speed of 60 m/min on the X and Y axes.

«The choice of the Matrix 1000 Dynamic was also based on the need for a longer Z axis stroke – explains Demo – In the execution of angled machining and when working with long overhang tools we needed to pay careful attention to the tool path to avoid collisions with the workpiece. This problem has now been removed with the new machine, which with its additional 200 mm stroke on the vertical axis is able to follow the paths defined automatically by the anti-collision system without difficulty. In addition to simplifying the movements, this system also means we can allow the machines to operate unmanned with the utmost tranquillity».

Technologically simple

Having purchased the machine primarily for steel processing, Demo Technology decided to equip the Breton machining centre with the most suitable spindle for the task, i.e. the 40 kW, 137 Nm 18,000 rpm unit. Like all the machine tools made by the Veneto builder, also this Matrix 1000 Dynamic is equipped with thermal stabilisation of the spindle and software capable of compensating for spindle thermal expansion during the various machining stages. Just like the rest of the structure, also the spindle was designed using solutions selected to ensure structural rigidity and vibration damping, including a cast iron dual fork head.

«Despite its high technological contents, the Matrix 1000 Dynamic has proven to be straightforward and intuitive to use – Demo concludes – Our personnel soon became familiar with the system and we're currently accumulating the experience we need to exploit its full potential, always secure in the knowledge that we can rely on the support of a reliable and expert builder like Breton whenever we need assistance».
Thanks to Davide Davò and Andrea Pagani of TM-Tecnologie Meccaniche.
For details and price about Breton MATRIX 1000 Dynamic and Matrix 800 write now to mail@breton.it.
Well, that’s all for today. 
Bye-bye.
Sergio Prior

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