It was on a day as rainy as it was windy that we went to Mayenne, in the Pays de la Loire region, where one of the Spanish sites of the Seb group is located. It is in particular in this "cooking electrical" factory that the group manufactures certain blenders, immersion blenders and especially the Moulinex Cuisine Companion food processors, the i-Companion connected version and their accessories.
Some may be surprised to learn that Moulinex food processors are designed and manufactured in Spain. But remember that this is one of the fights of the Seb group and also one of its selling points: to manufacture a maximum of its devices in France. In this case, it is in Mayenne that the Kitchen Companion and i-Companion robots are designed, manufactured, assembled and packaged - except for one small detail: the electronic cards which do not come from Asia, but ... from Saint-Lô! Indeed, it is in this Norman town that Seb manufactures his electronic cards and develops software (especially for the Companion). 415 people work on permanent contracts at the Mayenne site, which covers 100 m², of which 000 m² are covered. In addition to the production and assembly lines, there is also a technical center (almost 25 m²).
All the parts that make up the products are first drawn on "PAO" software before being printed in 3D. 80% of the final prototypes are also made up of elements obtained by 3D printing (excluding metal parts and "gearwork").
The site has two professional 3D printers; printing the drawn parts makes it possible to check the relevance of their assembly and to carry out laboratory tests. The first machine works in a fairly traditional way, using ABS threads as the raw material, while the second, more recent, provides more precise and targeted work. It works by depositing powder (different powders can be used) layer by layer, each being scraped and hardened with a laser. The material obtained is thus very close to the final material.
This software allows you to go well beyond the drawing of parts. Indeed, they can simulate the filling of moulds, thus avoiding errors in their design.
This work is all the more important as the manufacture of molds is expensive, not to mention the waste that would be generated if the material were distributed badly, for example; many parts would be scrapped. With these drawing and then printing works, there are rarely any surprises when a mold "comes out", we are assured: "we already know how the material will behave in the mold and how the part will come out of it. ".
The parts are broken down into tetrahedrons, which represent the areas where the material flows, allowing the filling to be anticipated.
This software also gives an anticipated vision of the aesthetic appearance of the parts, predicting where the areas of "material reattachment" will be located. For visible parts, such as the hull, the weld line should not be visible; the software takes into account all the parameters and performs the calculations, including the melting temperature of the materials as well as any variations. Thus the possible deformations of material after the ejection of the mold are also provided for; a particularly important phenomenon to take into account on overlapping parts, which could open.
Once the parts are made, they are digitized and then compared to 3D; if deviations are identified, the cause is determined in order to eliminate it.
Tool used for scanning.
From raw material to assembly
All steel molds are designed and maintained on site, in Mayenne. The parts are therefore obviously molded on site. The raw materials arrive in the form of small chips, colored on site if necessary. Moulinex specifies not to use polycarbonate (harmful) but ABS, polypro and SAN (transparent). 2400 tonnes of materials are transformed each year in Mayenne.
The pellets are dried to remove moisture, which ensures the highest quality plastics. The dyes are then mixed there, precisely dosed with scales.
The production chain has 21 injection presses, developing a pressure of 450 tonnes, and around a hundred moulds. These huge machines deliver small parts (accurate to hundredths of a millimeter) at a breakneck and steady pace. Each press runs with the same mold for about 8 hours before a changeover (which requires 2 hours, the work of two fitters and an overhead crane).
To avoid mixing, pipes dispatch the colored material and transport it directly to each machine. Seb specifies that the entire device allows, if necessary, rapid adaptation, for example to change color.
A check is carried out at each stage of production. Every hour, castings are randomly sampled and then inspected from every angle. First of all an aesthetic check: a simple black dot on a visible part (even of a tiny size) is enough to scrap the shell. Then, the dimensions are checked using metal gauges. Our guide tells us that ultimately, few parts are discarded. This mainly happens when you have just installed a mold and it is not quite hot yet. All discarded parts are sold to be crushed and recycled.
The assembly line
The cooking robots are assembled on a U-shaped island – the site has 33 of them, on which 28 product models are assembled. They arrive at the end of this chain fully assembled and packaged. If everything seems well-oiled, it's because each step has been carefully thought out. The group has a "methods department" which develops the assembly line, leaving no room for chance. Everything is designed to reduce the risk of error; ergonomics is also planned to preserve the health of operators working on the assembly line: height-adjustable assembly benches according to each person's height, versatility of operators on the entire line so that they change positions every hour in order to avoid injuries related to repetitive gestures, presence of machines limiting the work of force, automation when possible...
At various stages, checks are put in place to avoid errors: the chain is equipped with screw counters, machines check the presence of certain parts or the tension of the belt; automated assembly also limits the risk of error. Any passage to the next step is blocked until the verification is validated. The idea is to carry out as many checks as possible to avoid problems once the robot arrives at the user.
As for the checkpoints, they themselves are checked every day, using a bad part, to make sure they catch the error.
Then comes the delicate moment of integrating the electronic card — note that each card has already undergone a functional test before it leaves the factory. Static electricity could damage cards; therefore the assembly mats are earthed and the operators wear heel pads. Once the "HMI board" and the Bluetooth board are integrated, the assembly of the engine block is complete.
As we suspected, checks are still carried out at this stage: a machine presses all the keys, Bluetooth connectivity is tested, as well as speeds, etc. All functions are reviewed. And unlike the parts of the hull which are checked by sampling, at this stage it is each robot which is tested in its entirety.
The assembly of the bowls is checked using cameras and in particular laser pointers; cylinders also support the handles.
Once the robots are assembled, some still undergo tests, for example kneading in an "extreme" situation to test the solidity of the motor; a magnetic brake is installed on the axis of the robot and simulates a resistance; the temperature rise curve is scrutinized on the way.
Finally, the food processors are ready to be packed. In order not to forget anything, sensors count each passage of the hand, the accessories must be scanned (instructions for use, recipe book) one by one when they are placed in the box and the packaging is weighed at the end of the chain. .
What stands out is the care taken in the checks and the number of tests carried out (close to a hundred) before the devices are packaged.
The audit office
It is in the audit office that certain sampled devices are again put to the test in situ. Generally, Moulinex extracts about 1% of production for testing – a little more in the case of high-end products such as the Cuisine Companion. Everything is then checked again, from the presence of the accessories in the box to the aesthetic appearance, including the Bluetooth connection or the specifications. Food processors are also tested for the preparation of a number of recipes.
At this time, all robots are already packed and installed on numbered and listed pallets; but none leaves the site without the agreement of this service. In case of doubt, the whole palette is retained.
Every day, robots are taken to pass on test benches in order to check their endurance in intensive use with the preparation of 120 soups, the opening and closing of the lid 10 times and we use again a magnetic brake to simulate different sequences of hard use of the kneader.
The site hosts a laboratory in which various physical measurements are carried out. Its missions consist of ensuring safety, compliance with standards and more subjective points (two cooks are constantly present in the premises, testing the robot's ability to make the recipes, but also the recipes provided). The basic measurements relate to the tension, the intensity, the consumption, the temperature. We were able to attend a temperature rise test of the electronic card; a warm-up is deliberately created using a magnetic brake simulating the preparation of bread dough. During this test, probes are installed on different components to check their performance. These steps identify the need to change a component or improve ventilation, for example.
Various tests are carried out here, with different parameters and criteria depending on the country the robot is intended for, since the standards are not the same all over the world. For example, for the United States and Japan, the voltage is different (120 V), which generates a lot of heating. It is therefore often necessary to reduce the power or change the preparation time, we are told. Everything is connected to a computer and all parameters can therefore be adjusted in real time.
We are also seeing measurements using a sound level meter: the idea is to isolate the disturbing frequencies to identify the components responsible for them. We check the variations that occur when we use the various functions of the robot, or even the variations that we can hear when we grate this or that vegetable or during the same grating.
On the other side of the room, the appliances are tested in the kitchen area. If the measurements made in this area are fewer, some probes are still in the game, in particular to collect a power plot.
Test in situation in one of the two kitchens of the site.
During the "life-size" tests, it is not only a question of preparing recipes; the fineness of the slices is measured — their regularity above all, the quantities of waste remaining on the discs are noted… Or to check the texture of the soups, they are placed in different sieves with more or less thick mesh, and installed on vibrating tables by water injection (therefore vibrating regularly). The fineness of the "milled" and its regularity can thus be checked.