Study and Execution of a Specific Transducer as an Industrial Tool
The cooperative relationship between HBM and Cetim-Ctdec should be regarded as more than a customer-supplier relationship but a partnership. HBM has ramped up the development of hermetically sealed electronics and, in particular, has deployed its customized transducer department to match its strain gauges to the demands of the customer's spring element. This partnership has allowed Cetim-Ctdec to develop an industrial tool for optimizing the settings of turning machines with all the benefits imaginable in terms of productivity...
The Centre Technique du Décolletage (Ctdec) was created in 1962. As it name suggests it lends support to industries specializing in bar turning. It employs 55 individuals and is based in Cluses, Haute-Savoie, in the heart of the Arve valley where more than two-thirds of French companies engaged in bar turning are concentrated. Ctdec was merged with the Centre Technique des Industries Mécaniques in 2015 at the request of public authorities (the regulatory authority) and is now called Cetim-Ctdec.
This merger promotes the convergence of turning and machining jobs and allows the offering of support to industries over the full life cycle of products.
Cetim-Ctdec is engaged in diverse activities, particularly in the provision of consulting services and technical expertise in the field of materials (characterization, failure analysis, tests, etc.), production methods (machining, production organization and management) and metrology. It also carries out significant work in training (more than 1500 trainees per year) and information technology (databases, standards, technical documentation).
Cetim-Ctdec also works on large-scale projects involving a large portion of the profession as well as on projects addressing a problem presented individually by an industry.
Cetim-Ctdec relies on partnerships in its developments. HBM is one of those partners, having played a key role in the MAAT (machine automatique à auto-adaptation technologique/self-adaptive automated machine) project developed in recent years. Like many Cetim-Ctdec research projects, the MAAT project involved the development of an advanced technology allowing French (or European, since this project benefits from a European financial contribution) bar turning companies to improve their competitiveness in relation to competitors. The stakes are high since the bar turning industry constitutes around 600 companies in France, with a workforce of 14,000 people.
The idea here is to optimize the cutting conditions in machining, helping machinists to reduce setup times during production startup and, consequently, prevent drifts or even automatically correct the cutting condition parameters of machines in operation. Ctdec has supported the project and was backed by various experts in machine building, tools, lubricants, vibration and measurement. The developments made in this project should be usable in existing machines, old or new.
"The objective of the study was to be able to determine scientifically the speed and feed rate of tools in an optimal manner, taking into account lubricant consumption and the tool's service life. The project was started in 2007 and industrial production was launched in 2010 with the assistance of HBM", says Patrice Laurent, head of the Mechatronics Division and Group Activities at Cetim-Ctdec.
Several approaches were investigated in order to ascertain a cutting condition. The simplest approach is to measure the electrical power consumed at no load and during machining. This yields an image of the cutting pressure, that is, the tool pressure on the material. However, this method is unclear and is only applicable in case of chip removal and relatively large chips. There was a need, therefore, to shift towards a technique based on a transducer mounted on the tool. The idea of using a quartz transducer was quickly abandoned because, though this type of transducer has the required accuracy, it is also fragile and relatively costly, and hence ill-suited to industrial conditions.
"In the end we opted for the development of a new tool that directly measures the strain between the cutting tool and the material. Thanks to the sensitivity of this transducer we can study the cutting conditions for different operations, both during rough turning (when a lot of material is removed) and finishing of final dimensions. This is the key element in determining the ideal speeds and feed rates", explains Roger Busi, project leader and cutting expert.
Clearly, if one manages to increase the speed and feed rate, the work on the piece is done more quickly, allowing the production of more pieces during the day and hence the reduction of production costs. With this improvement in competitiveness, companies are better able to fight low labor cost competitors.
Exemplary Partnership with HBM
Ctdec has set up long-term cooperative arrangements with HBM on this project, spread out over four years. More than six months were devoted to product qualification, especially its performance in industrial premises and endurance. Ctdec initially worked with HBM on the transducer-related electronics and then this collaboration very quickly expanded to the transducer itself.
Ctdec was looking for rugged electronics (IP67). During the course of development HBM had a product that could meet this demand. As the opportunity arose, the manufacturer HBM then expedited the release of the product.
This involves a new MX411P module integrating the QuantumX family.
As for the transducer, Ctdec had already approved the technology of the metal foil strain gauge.
"In working with HBM on the development of sealed electronics we came into contact with HBM's customized transducer department and this has allowed us to make far greater progress in the development of the tool holder", says Patrice Laurent. In concrete terms, the collaboration involved the search for the right compromise between the spring element geometry and the bonded gauge
Ctdec and HBM both praise the exemplary nature of the partnership. Several models and mock-ups were built before the best compromise was found, with special attention paid to sealing (a lot of oil in the vicinity of the tool holder) and to mechanical protective devices (metal chip emissions). The wire outlets also received a great deal of attention so as to avoid wire breaks.
Now that the industrial production stage has been reached, HBM continues to this day to carry out the bonding of its gauges to the spring elements supplied by Ctdec, while Ctdec performs calibration and analysis.
"This partnership is based on a perfect balance between the two companies. This collaboration with Cetim-Ctdec has really allowed us to progress and to develop a new generation of transducers. In particular, we have made use of the numerous tests conducted by their technical center. This is focused development to which we also bring our long-term capability to supply transducers that exhibit very stable performance", emphasizes Bernard Vindret, HBM engineer and architect of the partnership with Cetim-Ctdec.
This development has led to an innovative product, the Cut Optimizer, placed on the market by Cetim-Ctedec. This product allows industries to determine the optimal area of operation of cutting tools based on the tool used, the material and the lubricant. It comes in the form of kits composed of a set of transducers, processing softwares and methodologies that can be used in production machines.
At the moment, this is primarily an adjustment tool used by turning industries (as well as those who work with them such as suppliers of cutting tools and lubricants). Industry can thus take a structured cutting approach through a global approach to machining (tool-material relationship) and quantify workshop practices. Once this data is recorded, the tool holder is withdrawn and replaced by the classic cutting tool. The production methods department uses this information to allow machine operators to carry out the optimum settings for each production variation.
The future plan is to be able to work in a closed loop with a permanently installed tool that carries out self-adaptive adjustments. Of course, once the first step is taken, a big market will open up for Cetim-Ctdec...and HBM!