Patent Publication Number: US-11376706-B2

Title: Assembly and method for loading parts to be treated in a single-side or double-side treatment machine

Description:
RELATED APPLICATIONS 
     This application is a national phase application of International Application No. PCT/IB2019/054170, filed on May 21, 2019, which claims the benefit of Swiss Patent Application No. CH00691/18, filed on May 31, 2018. The entire contents of these applications are hereby incorporated by reference. 
     TECHNICAL FIELD 
     The present invention relates to the field of single-side or double-side treatment machines. More specifically, the present invention relates to the step of loading these single-side or double-side treatment machines. 
     Single-side or double-side treatment machines can be used to perform different operations for treating the flat surface of a part, metal or otherwise, aiming in particular to adjust the flatness, surface finish and/or dimensions of the part. These techniques include:
         polishing, namely decreasing the roughness of a surface,   lapping, namely finishing a part by abrasion so that it has a smooth, polished surface, and so that it has a precise shape,   grinding, namely the removal of material carried out by a large number of grains of abrasive, sometimes aggregated, which act as a cutting tool,   resurfacing, namely a machining operation carried out using fine abrasives, which is used to take a part or portion of a part to a precise dimension within a close tolerance and to obtain an excellent surface finish that will provide a low coefficient of friction,   thickness adjustment, etc.       

     The invention therefore relates particularly, but not exclusively, to grinding or resurfacing, lapping and polishing machines. 
     The invention therefore relates to the treatment of parts, particularly but in a non-limiting manner the treatment of metal parts, particularly parts made from steel (stainless or otherwise), copper alloys, titanium, aluminum alloys, tungsten carbides, precious metals, glass, crystals, ceramics, composites, synthetic materials, natural materials, etc. 
     PRIOR ART 
     Most of the time, parts are loaded directly on the treatment machine, by placing the part holder (forming a tool in the form of a plate) on the lower plate of the machine, then placing the parts in the openings (cells) of the part holder so that the lower side of the parts is resting on the lower plate of the machine. It will be understood that this loading technique takes a significant amount of time during a full cycle of the treatment machine, which includes the following steps: loading-treatment-unloading. 
     A solution already exists for loading the parts off the treatment machine: all of the part holders (planet gears) intended to be positioned on the lower plate of the machine (for example a lower polishing disk) are placed on a rigid, smooth support (for example a loading pallet), and the parts are then placed in the openings of the part holders (individually or several parts per opening). Next, the support is positioned next to the lower plate of the machine and finally, each part holder loaded with its parts to be treated is slid from the support onto the plate. This method requires adaptations on the treatment machine (loading shelf, rail, etc.) and the aforementioned sliding operation is not very convenient to implement, especially in the case of thin parts, where there is a risk of the part holder bending during loading and the loss of parts, partial adhesion of the parts to the plate, etc. This solution saves time but therefore has a considerable number of drawbacks. 
     JP2000135672 describes a technique for filling the windows of the part holder with a rotating loader mounted above the part holder and including vertical recesses for storing the parts, these recesses being distributed so that they are positioned opposite the windows. Such a technique requires sufficient space in the machine above the part holder and is not suited to all part and part holder geometries. In addition, the geometry of a loader in particular is only suited to a given part and part holder pair. 
     JP2012076191 describes a technique for filling the windows of the part holder with a specific part holder, made up of two stacked plates, attached by a pivot in the center thereof, and having the same geometry and distribution of openings for accommodating the parts. In a first loading position, the relative angular position of the plates is selected so that the openings in the upper plate do not coincide with the openings in the lower plate so that a surface portion of the lower plate closes each opening in the upper plate. In this way, the parts placed in the openings in the upper plate are retained by the portion of the lower plate. The part holder is placed in this configuration in the treatment machine and the plates are then rotated so that the relative angular position thereof makes the openings in the upper plate and the lower plate coincide. In this way, the parts drop onto the lower plate of the treatment machine. This solution has the particular drawback of using an articulated part holder that can hinder the satisfactory operation of certain treatment machines. In addition, due to the presence of two stacked plates, this solution cannot be used for thin parts to be treated. 
     BRIEF SUMMARY OF THE INVENTION 
     One aim of the present invention is to propose a system and a method for loading parts in a machine for treating parts free from the limitations of the known techniques. 
     In particular, a solution is sought that reduces the time taken to load the parts into the machine. 
     A further aim of the invention is to provide a solution that is easy to implement and does not modify the pre-existing tools and installations. Finally, a solution is sought that does not detract from the quality of the treatment performed by the treatment machine. 
     According to the invention, these aims are achieved particularly by means of an assembly for loading parts to be treated in a single-side or double-side treatment machine comprising:
         a part holder in the form of a plate for holding at least one part to be treated, comprising a second side and a first side, said first side being flat, and said part holder defining at least one through-hole forming a cell for accommodating at least one part to be treated, and   a film mounted on the first side of the part holder opposite said through-hole and making it possible to hold said part to be treated in said opening at least during the loading step, said film being suitable for being destroyed during the treatment by the treatment machine.       

     It will be understood that this solution lies in the use of a temporary supporting film, used to hold the parts placed in the windows in the part holder during loading. Said film is suitable for being destroyed by dissolving or by friction. 
     At the start of the treatment, the lower plate and/or the upper plate is/are set in motion. If the film is in contact with the plate, this generates friction between the film and the plate of the machine in contact with the film, which makes it possible to wear and destroy the film, the component(s) of which are naturally discharged from the treatment machine. During the rest of the treatment, the film has thus been eliminated and the parts are in direct contact with the work plate (lower plate or upper plate) depending on the customary treatment procedures. 
     The loading time, and therefore the downtime of the treatment operations, is thus greatly reduced. The loading time is reduced to the time taken to load the part holders in the machine, as the parts are already loaded in the part holder. The applicant company has tested that this solution makes it possible, in some cases, to reduce the time taken to load the machine sixfold, going for example from six seconds to approximately one second. 
     This solution further has in particular the great advantage over the prior art of not modifying the tools, namely the part holder, already used, or having to adapt the single-side or double-side treatment machine. 
     The invention also relates to a method for loading parts to be treated in a single-side or double-side treatment machine that includes at least one lower plate intended to come into contact with the lower side of said parts, comprising the following steps:
         providing a part holder in the form of a plate, comprising a second side and a first side, said first side being flat, and said part holder defining at least one through-hole forming a cell for accommodating one or more part(s) to be treated,   mounting a film on the first side of the part holder opposite said through-hole, by which the film remains affixed to the part holder, said film being suitable for being destroyed during the treatment by the treatment machine,   placing the parts to be treated in said opening or openings, on said film (each part is placed against the film, in contact with the film), by which a loading assembly loaded with parts is formed, and   mounting said loading assembly loaded with parts directly on the lower plate of the treatment machine.       

     It will be understood from the above that as the solution according to the present invention makes it possible to place the parts on the part holder outside the treatment machine, a stand-alone (self-supporting) loading assembly loaded with parts is formed outside the treatment machine that must then simply be placed in the treatment machine according to the same procedure as an empty part holder, without having to devote further time to filling the part holder with parts. 
     It is therefore a particularly simple, cost-effective and easy-to-implement solution. 
     The present invention also relates to a method for treating parts in a single-side or double-side machine, comprising the loading method as described in the present document, in which, during the step of mounting said loading assembly loaded with parts directly on the lower plate of the treatment machine, the first side of the part holder is placed on the lower plate so that the film is in contact with the lower plate, and further comprising the step of treatment of said parts with said treatment machine, by which, during the starting of the treatment, the film is eliminated and the parts directly come into contact with the lower plate during the end of the treatment. 
     It will be understood from the above that the present solution does not result in the adaptation of the step of treating the part, and in particular in an additional step to remove or eliminate the film, which generally deteriorates during the treatment step as set out in greater detail below. In particular, it is for example the friction between the film of the loading assembly and the plate of the treatment machine in contact with this film that allows the natural and automatic removal. In the case of a treatment machine/method that uses a liquid abrasive suspension, a film that is soluble in said liquid can also be selected. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Non-limiting embodiments of the invention are set out in the description, which is illustrated by the attached figures, in which: 
         FIG. 1  ( FIGS. 1A, 1B and 1C ) illustrates the formation of the loading assembly according to a first embodiment, 
         FIG. 2A  shows a cross-section of the loading assembly and  FIGS. 2B to 2E  illustrate the steps for implementing a loading method and the treatment method according to the invention in a double-side machine, 
         FIG. 3A  shows a cross-section of the loading assembly and  FIGS. 3B to 3E  illustrate the steps for implementing a loading method and the treatment method according to the invention in a double-side machine using a liquid abrasive suspension, 
         FIG. 4A  shows a cross-section of the loading assembly and  FIGS. 4B to 4D  illustrate the steps for implementing a loading method and the treatment method according to the invention in a single-side machine, 
         FIG. 5A  shows a cross-section of the loading assembly and  FIGS. 5B to 5D  illustrate the steps for implementing a loading method and the treatment method according to the invention in a single-side machine using a liquid abrasive suspension, 
         FIG. 6  shows a variant of the initial position of the loading assembly loaded with parts, with a view to implementing the loading method, 
         FIG. 7  shows a variant of mounting the loading assembly loaded with parts on the lower plate of a single-side or double-side machine, 
         FIG. 8  shows a variant of mounting the loading assembly loaded with parts between the plates of a double-side machine, 
         FIG. 9  illustrates a loading assembly according to a second embodiment, and 
         FIG. 10  illustrates a loading assembly according to a third embodiment. 
     
    
    
     EXAMPLE EMBODIMENT(S) OF THE INVENTION 
     Reference is made to  FIGS. 1A to 1C , which illustrate a first embodiment of the loading assembly  10  according to the invention.  FIG. 1A  is a perspective illustration of the mounting of a film  20  on a part holder  12  shown in a vertical position: the film  20  is affixed to the first side  12   a  of the part holder  12  (lower side or upper side during the treatment). It will be remembered that generally, the part holder forms a plate for holding the parts in position during the treatment thereof in a single-side or double-side treatment machine, and defines to this end at least one window in the form of a through-hole known as a “cell”. The part holder illustrated is in the form of a disk with a central opening  13  in the center of the part holder  12  and openings  14  distributed around this central opening, in this case eight openings  14  placed every 45°. 
     Thus, in this non-limiting example, the part holder  12  has a circular outline and a center. Such a part holder is for example a planet gear comprising a toothed outline (not show), so as to mesh with corresponding teeth of the system for driving the part holder(s) of the lower plate of the treatment machine. According to the invention, at least the first side  12   a  is flat, in order to facilitate the placing and holding of the film  20  on this first side  12   a . In addition, in many cases, the first side  12   a  of the part holder  12  will be placed flat on the upper side, which is also flat, of the lower plate  40  of the treatment machine. In most cases, the second side  12   b  (often intended to be facing away from the lower plate, and facing towards and placed against the upper plate for double-sided treatment) and the first side  12   a  of the part holder are parallel to each other. In the example illustrated in the figures, the part holder  12  also includes cells  14  distributed evenly about the center, but other arrangements of the cells  14  on the part holder  12  can be envisaged, as well as other shapes of the outline of the part holder, and the central opening  13  is not systematically present. 
     The film  20  can be formed in advance and affixed to the first side  12   a  of the part holder  12  or it can be formed directly on the first side  12   a  of the part holder  12 . 
     In the case illustrated in  FIGS. 1A, 1B, 1C and 6 , the film  20  is formed in advance, then affixed ( FIG. 1A ) to the first side  12   a  of the part holder  12  and hold against this first side  12   a  ( FIG. 1B ). Depending on the respective materials used for the part holder  12  and the film  20 , different methods can be used for this adhesion and holding of the film  20  fixed on the first side  12   a  of the part holder  12 , for example adhesive bonding, welding, or static electricity, molecular adhesion, capillarity, etc. 
     In a preferred embodiment, the film  20  is made from a water-soluble material, and in this case simply moistening the first side  12   a  of the part holder  12  and/or the side of the film  20  intended to be placed on the first side  12   a  of the part holder  12  with water allows sufficient adhesion and the subsequent holding of the film  20 , on contact between the film  20  and the first side  12   a  of the part holder  12 . 
     In a preferred embodiment, the film is soluble, preferably water-soluble or oil-soluble. An example of a water-soluble film is a film made from polyvinyl acetate (PVA) or polyvinyl alcohol (PVAL), or another water-soluble resin, or a mixture of these water-soluble materials. 
     In the case illustrated in  FIGS. 1A, 1B and 1C , the part holder  12  includes a plurality of cells  14  and the film  20  covers all of the cells  14  in the loading assembly  10 . As a variant of this loading assembly  10 , according to  FIG. 9 , the part holder  12  includes a plurality of cells  14  and separate films cover the cells  14 . In the example illustrated in  FIG. 9 , a limited film  21  covers two cells  14  and two individual films  22  and  23  each entirely cover a different cell  14 , in order to form a loading assembly  10 . 
     In these examples, the films  20 ,  21 ,  22  and  23  are continuous, namely solid. In other possible examples not illustrated, these films  20 ,  21 ,  22  and  23  are perforated, or discontinuous, provided that they make it possible, once fixed to the first side  12   a  of the part holder  12 , to support the weight of the part  30  accommodated in the cell  14  of the part holder  12 , which the presence of the film  20  makes it possible to hold during the different handling operations prior to treatment in the machine. It can be an open net structure, with openings, woven or otherwise. 
     In the case of the loading assembly  10 ″ illustrated in  FIG. 10 , the film is formed directly on the first side  12   a  of the part holder  12 : to this end, the spraying of a liquid solution onto the first side  12   a  of the part holder  12 , followed by drying, these operations optionally being repeated several times, results in the formation of a perforated film  20 ″ in the form of interlaced filaments or a net of filaments. The aforementioned water-soluble materials can be used, together with other solutions, water-based or otherwise: for example, in a non-limiting manner, a solution of sugar, salt, milk, organic matter (garlic, etc.), that makes it possible to form such a film after drying, can be used. 
       FIGS. 2 to 5  show the steps of loading methods and treatment methods according to the invention. For these methods, a loading assembly or assemblies  10 ,  10 ′ or  10 ″ as described above is/are used. 
       FIGS. 2A to 2E  represent the situation of a double-side machine with dry destruction of the film  20  during the start of the treatment. For the loading method, the loading assembly  10  (film  20  mounted on the first side of the part holder  12 ) is supplied ( FIG. 2A ). Then, as shown in  FIG. 2B , the parts  30  are arranged in the cells  14 .  FIG. 2B  shows one part  30  per cell  14 , but it can be envisaged that two or more parts  30  be positioned per cell  14 . A loading assembly  10  loaded with parts is thus obtained, which can be stored and kept on standby until the time of loading and treatment in the machine. 
     These parts  30  are arranged on the film  20 , which forms a support for the parts: the part holder  12  can therefore be taken or grasped without losing the parts  30 . According to a first option corresponding to  FIGS. 2 to 5 , the parts  30  have been placed on the film  20  situated underneath the first side  12   a  of the part holder, which in this case forms a lower side of the part holder  12 . The storage and handling of the part holders loaded with parts  30  must maintain this position with the film  20  underneath, and the parts can move in the cell  14  by sliding on the film. According to a second option, corresponding to  FIGS. 6 to 8 , one side of the part  30  is fixed to the film  20 , for example by adhesive bonding, and there is no risk of the parts falling out during handling. If a water-soluble film is used, one fixing solution consists of moistening one side of the part, which will “stick” to the film  20 . In this case, the parts  30  are (temporarily) fixed to the part holder  12  by means of the film  20  and, in this case, the part holder assembly with film and parts can be loaded on the machine, with the film  20  arranged on the top or on the bottom of this assembly. 
     In the case of  FIG. 2 , next, the loading assembly  10  (the part holder  12  covered with the film  20 ) loaded with parts  30  ( FIG. 2B ) is arranged directly on the lower plate  40  of a double-side treatment machine ( FIG. 2C ). In this configuration, the parts  30  still rest on the film  20 , in turn resting on the upper side of the lower plate  40  of the machine. The loading method is finished; it can be completed to perform a full treatment method. 
     To this end, as can be seen in  FIG. 2D , the upper plate  50  is lowered onto the part holder(s)  12  in order to close the treatment machine. The treatment then starts by the setting in motion of the lower plate  40  or the upper plate  50  or both the lower  40  and upper  50  plates relative to the base of the machine (not shown). Such movement is represented by the arrows  41  (lower plate) and  52  (upper plate), and remains in the plane of the plate in question. This movement can tier example be an alternating back-and-forth straight translational movement, or a rotating movement of the plate, or a combination of these movements. This movement of the plate or plates  40  and  50  is optionally accompanied by the movement of the parts  30  in their cells  14 : either the part holders  12  (and therefore the parts  30 ) are immobile relative to the plate  40  (or  50 ), or the part holders  12  (and therefore the parts  30 ) are mobile relative to the plate  40  (or  50 ). 
     There are two phases during this treatment: in a first phase corresponding to the start of the treatment, the friction of the lower plate  40  against the film  20  arranged on it breaks down the film  20 , which is transformed into particles, in principle non-abrasive, that are naturally discharged from the machine during the subsequent treatment. This is in particular friction between the lower plate  40  and the film  20  without any other addition of material or lubricant, in particular dry friction (unless the film produces lubricating particles when it breaks down). It must be noted that during this first phase, there is the normal contact between the lower side of the upper plate  50  and the upper side of the parts  30 . After the film has been eliminated (see  FIG. 2E ), the treatment continues according to a second phase, still under the influence of the aforementioned movement, and the parts  30  now in contact through their lower side directly against the upper side of the lower plate  40 , undergo the planned treatment on the machine, due to the two plates  40  and  50 . 
     During these two phases of the treatment step, the speeds of the movements of the plates  40  and  50  and the pressure thereof, and all of the other machine parameters, are adjusted as required. 
     The unloading of the parts from the treatment machine is not illustrated, but is carried out as in the prior art. By way of example, once the treatment machine has been opened by raising the upper plate  50 , the part holder(s)  12  is/are removed by hand and the treated parts are slid off the lower plate  40  into a storage container, for example pending another operation on these parts (another treatment operation in the sense of the present invention, or another machining, cutting, mounting, etc. operation). 
     In  FIGS. 2C to 2E , the lower plate  40  is shown as coinciding with the size of the part holder, but in reality and in most cases, it is possible for several part holders  12  to rest simultaneously on a treatment machine lower plate. 
     Reference is now made to  FIGS. 3A to 3E : in this case, the situation is represented of a double-side machine with destruction of the film  20  by dissolving during the start of the treatment, via a liquid in the form of an abrasive suspension (water-based or oil-based). It is a double-side machine with liquid treatment of the parts. In this case,  FIGS. 3A to 3D  correspond respectively to similar situations to those described above with reference to  FIGS. 2A to 2D . Next, as illustrated in FIG.  3 E, the treatment is started, with the addition of a liquid  61  between the plates  40  and  50  (work space), particularly in the form of an abrasive suspension, which can in particular be hydrophilic or hydrophobic. By way of non-limiting example, a nozzle  61  is used to supply the liquid. 
     There are two phases during this treatment illustrated in  FIG. 3E : in a first phase corresponding to the start of the treatment, the presence of the liquid  61  allows the dissolving of the film  20 , which is transformed into particles, in principle non-abrasive, that are naturally discharged from the machine with the liquid during the subsequent treatment. It must be noted that during this first phase, there is the normal contact between the lower side of the upper plate  50  and the upper side of the parts  30 . After the film has been eliminated (see  FIG. 3E ), the treatment continues according to a second phase, still under the influence of the aforementioned movement and the liquid  61 , and the parts  30  now in contact through their lower side directly against the upper side of the lower plate  40 , undergo the planned treatment on the machine, due to the two plates  40  and  50 . 
     In the situations described with reference to  FIGS. 2 and 3 , the treatment machine is a double-side machine and includes a lower plate  40  and an upper plate  50  intended to come into contact respectively with the lower side and the upper side of said parts  30 , at least one of said plates being mobile in the plane thereof, and the method according to the invention further includes the following step:
         bringing the upper plate  50  into contact with said parts  30  after the mounting of the loading assembly.       

     Reference is now made to  FIGS. 4A to 4D and 5A to 5D , which represent the situation of a single-side machine, and the steps of the loading method and the treatment method with this machine. 
     In the case of the loading and treatment methods illustrated in  FIGS. 4A to 4D , as in the case of  FIGS. 2A to 2E , no liquid is used for the treatment; the film  20  is destroyed dry during the start of the treatment. In this case,  FIGS. 4A to 4C  correspond respectively to similar situations to those described above with reference to  FIGS. 2A to 2C , in  FIG. 4C , the loading of the loading assembly  10  loaded with parts  30  is finished: the parts  30  are still resting on the film  20 , in turn resting on the upper side of the lower plate  40  of the machine. In this case, as it is a single-side treatment machine, an upper plate is not used, Next, as illustrated in  FIG. 4D , the treatment is started by setting the lower plate  40  in motion relative to the base of the machine (not shown). Such movement is represented by the arrow  41 , and remains in the plane of the lower plate  40 . This movement can fir example be an alternating back-and-forth straight translational movement, or a rotating movement of the plate, or a combination of these movements. This movement of the plate or plates  40  and  50  is optionally accompanied by a movement of the part holders  12  in their cell  14 . 
     There are two phases during this treatment: in a first phase corresponding to the start of the treatment, the friction of the lower plate  40  against the film  20  arranged on it breaks down the film  20 , which is transformed into particles, in principle non-abrasive, that are naturally discharged from the machine during the subsequent treatment. This is in particular friction between the lower plate  40  and the film  20  without any other addition of material or lubricant, in particular dry friction (unless the film produces lubricating particles when it breaks down). After the film has been eliminated (see  FIG. 4D ), the treatment continues according to a second phase, still under the influence of the aforementioned movement, and the parts  30  now in contact through their lower side directly against the upper side of the lower plate  40 , undergo the planned treatment on the machine, due to the contact of the parts with the lower plate  40 . 
     Reference is now made to  FIGS. 5A to 5D : in this case, the situation is represented of a single-side machine with destruction of the film  20  by dissolving during the start of the treatment, via a liquid in the form of an abrasive suspension (water-based or oil-based). It is a single-side machine with treatment of the parts by liquid, particularly an abrasive suspension. In this case,  FIGS. 5A to 5C  correspond respectively to similar situations to those described above with reference to  FIGS. 2A to 2C . Next, as illustrated in  FIG. 5D , the treatment is started, with the addition of a liquid  61  above the plate  40  (work space), particularly in the form of an abrasive suspension, which can in particular be hydrophilic or hydrophobic. By way of non-limiting example, a nozzle  61  is used to supply the liquid. 
     There are two phases during this treatment illustrated in  FIG. 5D : in a first phase corresponding to the start of the treatment, the presence of the liquid  61  allows the dissolving of the film  20 , which is transformed into particles, in principle non-abrasive, that are naturally discharged from the machine with the liquid during the subsequent treatment. After the film has been eliminated (see  FIG. 5D ), the treatment continues according to a second phase, still under the influence of the aforementioned movement and the liquid  61 , and the parts  30  now in contact through their lower side directly against the upper side of the lower plate  40 , undergo the planned treatment on the machine, due to the contact and the movement of the plate  40 . 
     Reference is now made to  FIGS. 6 to 8 , which show variants of the mounting of the loading assembly  10  loaded with parts  30  on the treatment machine. This is the situation described above in which not only is the film  20  bonded to the part holder  12 , but the parts  30  are also fixed to the film  20 . As a result, the loading assembly  10 ,  10 ′ or  10 ″ can be handled and loaded on the treatment machine with the film  20  facing upwards. The corresponding loading and treatment methods are those described above and illustrated with reference to  FIGS. 2 to 5 , with the exception of the differences described below.  FIG. 6  shows the loading assembly  10  with the parts  30 , therefore filled (as in  FIGS. 2B, 3B, 4B, 5B ). 
       FIG. 7  shows the case of this variant with the film  20  on top, once the loading assembly  10  loaded with parts  30  has been mounted on the lower plate  40  (as in  FIGS. 2C, 3C, 4C, 5C ), in this case the parts  30  are directly in contact with the lower plate  40  of the machine: thus, if it is a single-side machine, only the lower side of the parts is treated, and without friction between the film  20  and the machine plates, the film cannot be destroyed. In this case, it will be possible to remove the part holder  12  from the machine with the parts still secured to the loading assembly. Each part  30  must then simply be separated from the film after treatment. 
       FIG. 8  shows the case of this variant with the film  20  on top, once the loading assembly  10  loaded with parts  30  has been mounted on the lower plate  40  and the machine has been closed with an upper plate  50  (as in  FIGS. 2D and 3D ); in this case, the parts  30  are directly in contact with the lower plate  40  of the machine and the film  20  is in contact with the upper plate  50 . It is thus a double-side machine and in this case, the friction between the film  20  and the upper plate of the machine (with or without the addition of liquid) will destroy the film. 
     In the situations described with reference to  FIGS. 2, 3, 4 and 5 , when the treatment of the parts  30  is started, in the treatment machine, the lower plate is set in motion parallel to the plane thereof, by which the friction of the lower plate on the film eliminates the film. 
     In the cases set out above (excluding the case of  FIG. 7 ), when the treatment of said parts is started, the friction between the lower plate (upper in  FIG. 8 ) of the machine and the film thus causes the destruction of the film. 
     In the cases set out above with reference to  FIGS. 3 and 5 , the film  20  is soluble and when the treatment of the parts  30  is started, a liquid  61  is also supplied in the treatment zone, by which the soluble film  20  is dissolved by the liquid  61  and the parts  30  directly come into contact with the lower plate  40 . 
     In particular, the liquid can be just water, hot or cold, or an abrasive suspension. The abrasive particles can be varied and are those conventionally used, particularly diamond, silicon carbide (SiC), alumina (Al2O3), or cerium oxide powders, alone or as a mixture. 
     It will be understood that through the combination of the film  20  and the part holder  12 , a loading assembly  10  is formed that makes it possible to hold the parts  30  in the part holder  12 . It is therefore possible to prepare the loading assemblies  10  loaded with parts  30  in advance and store them, and then place them in the treatment machine. The time taken to load the machine is thus greatly reduced. 
     In a non-limiting manner, the parts  30  are intended for clockmaking, optics, microengineering, the automotive industry, aviation, etc. 
     In general, and in particular for the treatment method using a double-side machine, the parts  30  extend essentially in two dimensions, particularly with two flat sides parallel to each other. The term “flat” is used herein in the general geometrical sense, and roughness may exist. The term “parallel” is used herein in the general geometrical sense; a maximum possible relative inclination of the order of 5° may exist between the two sides in question. 
     REFERENCE NUMBERS USED IN THE FIGURES 
     
         
           10  Loading assembly 
           10 ′ Loading assembly 
           10 ″ Loading assembly 
           12  Part holder (planet gear) 
           12   a  First side of the part holder 
           12   b  Second side of the part holder 
           13  Central opening 
           14  Opening (cell) 
           16  outline 
           18  center 
           20  Film (continuous) 
           20 ″ Film (perforated) 
           21  Film (limited) 
           22  Film (individual) 
           23  Film (individual) 
           30  parts 
           40  Lower plate 
           41  Arrow (lower plate movement) 
           50  Upper plate 
           52  Arrow (upper plate movement) 
           60  Nozzle or liquid supply 
           61  Liquid