The different models of washing machine marketed since the post-war period until today propose the same concept solution. The students in mechanical engineering of Milan Polytechnics, in the ambit of the courses of the last year of the master degree, have dealt with the theme and revised this product, succeeding in developing interesting innovative proposals, from the detail design up to the cost estimate. Let us discover the results.
The education of engineers with outstanding skills of problem analysis and at the same time able to develop the design of a product, from its concept definition phase up to the engineering and the evaluation of the technological feasibility of what proposed, together with its economic evaluation, is an important target of engineering schools. However, the multiplicity of the aspects implied by an approach of this type complicates the definition of general ways of proceeding, which are not linked with the specificity of what is being engineered.
In other words, the traditional education of the engineer is more focused on the aspects connected with the analytical part of the design instead of on the synthesis aspects of the project. Actually, in time a gap has aroused between the world of the scientific research, which has developed from the German and North American schools of the engineering design, and the contents of the engineer’s education.
The overcoming of this dichotomy, in education, is enabled by initiatives that go beyond the single teaching and make students able to face the various aspects linked with the concept of the design itself, up to the development of subsystems and components, taking into account all the aspects inherent to manufacturing technologies and available materials.
This means defining a series of actions that, even if with different fulfilments, are accomplished during the design activity and lead first to the systematic development of innovative concepts worth exploring and afterwards to the detail design and up to the evaluation of costs and the engineering.
In university ambit, this means defining didactic projects matching the knowledge of different ambits, targeting them to the development of a new product.
This is the goal of the proposal of integrated project of courses, delivered in series (I and II semester) at the II year of the Course of Master Degree in Mechanical Engineering, study programme “Advanced Mechanical Design”, of Milan Polytechnics, “Methods and Tools for Systematic Innovation” (Prof. Gaetano Cascini) and “Advanced Methods for Mechanical Design” (Prof. Mario Guagliano).
The project was carried out with the support and the collaboration of Elettrotecnica Rold company, with headquarters at Nerviano, and in particular with the engineers of its new Research and Innovation laboratory R-Lab. Elettrotecnica Rold is world leader in the sector of the components for household appliances and in 2016 it established R-Lab, a laboratory where a team of researchers works in collaboration with universities, sector companies and experts in new technologies and in new materials, to develop innovative solutions in various ambits, such as the Appliances one.
The design issue was the development of new engineering solutions for a washing machine, distant from the conventional solution we all know and able to grant new functions, like small overall dimensions and the absence of rotating parts.
In the first part of the design, students worked at the patent research and, according to the systematic innovation methods, they developed the design concept.
In the second part of the design, the concept was developed and engineered, defining its implementation and assembly modalities, designing the components (or choosing them in the catalogue, if necessary), executing the necessary structural, reliability and economic assessments, up to the base list and the overall and constructive designs.
The experience ended with a workshop organized at the headquarters of R-Lab at Cerro Maggiore, where the seven teams who undertook the work shared the achieved results.
INFLATABLE WASHING MACHINE
Team WEAST – Riccardo Candeo, Niccolò Beretta, Luca Colombo, Kizhakke Parambil, Sarvothama Radhakrishna Pai) The “inflatable washing machine” is an idea stemmed from the need of developing a device able to reduce its overall dimensions when not used, however maintaining the functions of a common washing machine. The structure is organized as in a washing machine with vertical drum. All components are arranged in the basement, which is made of stiff plastic material and houses the dampers for the drum, too. The latter consists of an inflatable wall that can collapse when the washing machine is not running, while it remains rigid while washing. The control interface for the user is positioned on the drum top, as well as the door for the garment introduction. The structure integrates various solutions purposely studied to grant an experience strictly resembling a conventional washing machine, starting from the special design of the drum walls (equipped with bending flanges with a different behaviour in the washing and in the spin-drying cycle) and from the suspension system, up to including the fixed assembly system and the use of flexible heaters. All that is contained in a low weight, thanks to the large use of plastics in the structure.
JET WASHING MACHINE
Swirl Dynamics Team – Juan Alberto Sabogal Linares, Luca Trentini, Marco Giuseppe Agrò To improve the functions of current washing machines- WM, to succeed in it in innovative manner and to overcome the paradigm of the washing machine that exploits the rotational force of the drum, we have developed the “Jet Washing Machine-JWM”. Considering the main weak points surveyed in current washing machines (for instance: noise, vibrations, weight …), the operation principle based on water jets, hence “jet”, proved to be a winning element, due to its flexibility and the possibility of eliminating the problems previously met. The absence of a rotating drum has allowed the elimination of the electric motor, besides the elimination of the big and heavy cement blocks and of the expensive spring-damper pairs. The washing effect has been obtained through the alternate action of two different cycles: – Flushing: maximization of the interaction among clothes and generation of motion inside the fixed drum. – Spraying: direct impact of water jets on garments for a direct washing (hydro-massage water+soap). The linen drying is performed similarly, accomplishing the same washing procedure, but in this case the work fluid is not water but hot dry air. JWM has been essentially developed in conformity with the guidelines dictated by the theory of the Design for Assembly, where have been designed some hybrid elements that perform a double function both in the water circuit (washing) and in the air circuit (drying). The remaining elements have been taken from the washing machines already available on the market or from other household appliances. In this way, it is possible to implement a household appliance that matches optimally elements of absolute novelty and elements already consolidated in common washing machines, in order to accomplish a mass production at low costs and featuring high reliability. The final result consists in a machine able not only to wash but also to dry the clothes, manufactured and sold at the same cost as today’s washing machines, eco-friendly and also ready to be used in houses and flats, since it does not take up additional space.
WASHING MACHINE POWERED BY A GAS TURBINE
(Team MCML – Mirko Maero, Ans-Al-Rashid, Luca De Bernardi) The initial target of the design was the implementation of a washing machine able to operate without 220V current. The project is suitable for uses in zones not provided with electric energy, such as alpine huts. The development has led to the realization of an idea that completely eliminates the need of electric connection and drastically reduces the electric energy circulation thanks to the use of a gas cycle (Joule Brayton cycle). Such solution allows having a single energy input (thermal) and 2 outputs under the form of mechanical energy (to move the drum) and thermal (to heat the water that will intervene in the washing). The thermo-dynamic cycle is of closed type: the work fluid used is helium. The energy input is supplied by the combustion of kerosene: the flame transfers heat to the operation fluid through a heat exchanger (transfer by radiation and conduction). The fluid expansion occurs in a “miniature” turbine, flanged on the same shaft of the compressor, it too of small sizes. The turbine- compressor shaft transfers power to the drum through a belt transmission. After the expansion in the turbine, a heat exchanger cools the helium to warm up the water that will be used for washing. The washing machine will have the shapes of one today commonly available on the market: the cycle components have been introduced by exploiting the free spaces in a household appliance today on sale. The main hindrances of this prototype will reside in the practical implementation, especially owing to the small sizes of the turbine.
ACCORDION-LIKE WASHING MACHINE
(Team The Future Gadget Lab – Andrea Linzaghi, Andrea Locatelli, Ramprasath Sundararaj) Target of the design is the development of a washing machine able to reduce its sizes (ground area taken up) during the standby. This washing machine reaches this goal through an operation resembling the one of an accordion, which allows the system to open, to carry out the washing phase and finally to close, limiting the space taken up in standby phase. The operation principle strictly resembles the one of a current washing machine. The washing machine is composed by three stiff sections, which provide structural support to the system: they are composed by an external frame, connected, by means of springs and dampers, with an inner structure containing an internal ring, with which is connected the drum (Kevlar), bearing (races made of “Delrin” polymeric material, in particular, and steel balls), in its turn connected with a plastic material structure that, by means of the said springs and dampers, grants the connection to the outer frame. The electric motor is positioned in the rear section, it transfers the torque to the rear drum through the inner ring of the rear bearing that, being of polymeric material, can be produced with the suitable geometry for acting as a pulley. The torque transmission from the rear section to the central and frontal ones occurs by means of nylon wires that are embedded inside the Kevlar composing the drum. The use of bearings is fundamental: the inner race rotates together with the drum, thus granting the normal operation of the washing machine while the outer race allows the connection with the external structure of the system, which acts as structural support. The opening and closing of the system (sliding of the central and frontal sections) is ruled by a kinematic gear, controlled by linear actuators. The drum support (useful for the water containment) and the external shelter (connected with the outer frame), are made of rubber, so that they can deform, being then compatible with the accordion-like operation of the system.
TELESCOPIC WASHING MACHINE
(Team The Thinkers – Nicolas Carbone, Matteo Donati, Sara Ström) The “Telescopic Washing Machine” is an innovative washing machine able to decrease its volume when the latter is not required, i.e. when it is in standby. That reduction is assured by a fundamental characteristic of the washing machine from which it takes the name: the use of deformable materials (rubber) and of cylinders able to slide one inside the other allows the machine to be “telescopic”. From the macroscopic point of view, it is possible to divide the systems into parts: we can recognize the assembly of the drum, in frontal position; the power unit, positioned exactly under the drum and composed by a direct drive electric motor; the vibration damping system, integrated between drum and protection panels, where also various hydraulic and electric connections are opportunely placed. Finally, the rear section houses the opening and closing system of the machine, which allows compressing and extending it, in addition to a useful touchscreen to let the user interact with the machine and the apposite drawers for the insertion of detergents. If we analyse the opening and closing system, the latter is composed by a pinion-rack mechanism (the first integral with the outer cylinder of the telescopic part and the second integral instead with the frame), and the motion of the pinion is granted by an electric gearmotor. Thanks to the implementation of techniques of “Design for X”, where particular attention has been paid to the aspects of manufacturing, assembly and disassembly, impact on the environment and machine reliability, it was possible to design a machine compliant with all above mentioned items, meanwhile granting also a limited impact on the environment thanks to the high recyclability of the materials composing it.
AN INNOVATIVE MAGNETIC DOOR LOCK SYSTEM
(Team Force – Michele Piccoli, Santhosh Kumar Gopi Subramanian, Padmanabha Kanchi) The entrusted issue consisted in replacing the hook equipping the current closing systems of washing machines, which use 220V solenoids, with an alternative device able to operate at low voltage. A complex demand, since there is the need of both supplying a suitable closing force and of permitting a simple shift from the closure state to the locking one of the door itself. To attain this target, the design turned to the use of permanent magnets and in the specific case of a particular typology of magnets, called Polymagnets. These magnets, instead of presenting a single pole per surface, show a multitude of points, each with a distinct north/south orientation. A specific design of magnets allows achieving a specific behaviour between the two elements. In our concept we have used a subsection of polymagnets, called align polymagnets. These have the shape of metal disks that, once aligned, feature a different attraction force depending on their mutual relative rotation (0° closure-low force, 20° locking-high force). An electric 12-volt motor sets in rotation a worm screw/gear system that, hinged to the magnet, allows the passage from the closure state to the door-locking one and vice versa.
THE FOLDABLE WASHING MACHINE
(Team Swirl Dynamics – Alice Colombo, Marco C. Fumagalli, Filippo Gallina) The design aims at renewing the concept of washing machine reinventing its operation principle. Taking into account the requisite, today increasingly felt, of the volume reduction in standby, we have developed a washing machine that exploits a different principle of operation and washing, as well as of the system in its whole. The laundry, introduced through an apposite opening, is hit by pressurized water jets with high flow rate, able to perform an energetic washing and a continuous recirculation of the linen inside a particular not-rotating fixed drum, then without problems of vibrations and noise. Finally, a system of levers, managed by a pair of actuators, squeezes the laundry, eliminating most of the water. The washing machine, then, closes, taking up only 12 centimetres in depth from the wall to which it is fixed. Thanks to an attentive and meticulous engineering, the team managed to pass from the concept to a real industrial product, competing with the current models in terms of functions and costs. We have opted for a “shell and frame” structural approach, using aluminium structural works and PVC panels, bpvc, epdm rubber for the bellows, essential to insulate and to allow the door rotation. The simple assembly, determined by the particular shape of the structural works and by the fixing method, leads to hypothesize even a kit version to be produced and customized.
(Team BePatent Group- Tommaso Marzi, Mauro Filippo Molla, Danilo Moretti) The present washing machine can wash dirty laundry by using a 100 W motor powered in direct current at 12 V. The low-power and low-voltage operation of the household appliance is enabled by a completely new architecture of the washing machine, differing from the conventional one: the drum is replaced by a vertical conveyor belt that raises the clothes on one side and drops them on the other side. The conveyor belt raises the clothes by means of draining blades that are opened in ascent phase and closed by gravity in descent phase, thanks to the geometry of the constraint between blades and conveyor belt. With a slow and continuous motion, the system can transfer mechanical energy to the clothes, necessary for an effective washing of garments, absorbing limited electric energy. Consequently, the system can work at low voltage without dangerously increasing the current intensity. The integration of the electric motor into the handling system needs a dedicated transmission with reduction ratio of 182. The transmission is composed by an epicyclic reduction gear (i=91) and by a belt transmission (i=2). To overcome the lack of the spin-drying phase, the washing machine has been equipped with a new drying system that exploits a series of infrared panels and fans to heat clothes and to force the evaporation of the water contained in fabrics. Considering the really limited base area of this new concept of washing machine (400×780 mm) and the possibility of notably increasing the loading capacity by simply rising the height, the present solution can arouse lively interest in industrial ambit.