Capping method and electronic capping machine for applying screw caps

Abstract

Capping method for applying screw caps to containers, including the steps of: acquiring (101), at a predetermined rate, at least values of quantities that identify significant phases of the cycle and are related with the rotary motion; forming (102), with the acquired values, data strings each relating to a capping head (10a... 10n) and to one of a plurality of successive capping cycles; creating a database of such strings; obtaining from the strings time-varying status indexes; defining for such status indexes ranges of values denoting a regularly performed capping cycle; verifying whether or not an instant value of a status index falls within the respective range; storing the outcomes of the verifications into the database; generating, at least in case of a number of negative outcomes exceeding a threshold, alarm flags indicating the possible future arising of problems in one or more components of a capping machine (1, 1A).

Description

[0001] CAPPING METHOD AND ELECTRONIC CAPPING MACHINE FOR APPLYING SCREW CAPS

[0002] DESCRIPTION

[0003] Technical Field

[0004] This invention relates to the treatment and packaging of liquids, and more particularly it relates to a capping method and an electronic capping machine for applying screw caps, providing for a monitoring and a predictive analysis of the performance.

[0005] Background Art

[0006] In capping machines for applying screw caps, each capping head must perform simultaneously a rotary motion and a vertical translatory motion. In electronic capping machines, at least the rotary motion is applied by an electric motor, from which information allowing tracing some capping parameters, in particular the torque applied to the cap, can be obtained. The vertical translatory motion can be applied by an electric linear motor or by a mechanical cam.

[0007] In conventional electronic capping machines, however, the data obtained were generically used for carrying out a cursory analysis of the quality of capping and recognizing malfunctions, and they were not always saved and recorded in a systematic way and were often consulted mainly in case of macro problems for which accurate analysis was needed. It was therefore possible to intervene only when a malfunction was already evident.

[0008] EP 1103513 Al discloses a system for applying screw caps to bottles, in which, during capping of a bottle, data on the torque applied to a cap and on the angular position of the cap itself are collected in order to recognize as soon as possible whether the capping has been successful or not, so as to reject bottles with defective capping immediately after the capping itself has been completed.

[0009] WO 2021 / 008782 Al discloses an equipment for the treatment of liquids which implements a method of storing operating data of the equipment and using the stored data for preventive maintenance purposes.

[0010] Other solutions that provide the possibility of preventive / predictive maintenance in systems for packaging products, including beverages, are described, for example, in WO 2021260595 Al, US 2022269259 Al, US 2023109567 Al, US 2023266752 Al and EP 4116781 Al. Summary of Invention

[0011] An object of the present invention is to provide a capping method that overcomes the drawbacks of prior art, allowing not only for monitoring the quality of capping, but also a predictive analysis of the performance of a capping machine in which the method is implemented. In this case, it becomes possible to prevent malfunctions.

[0012] The object is achieved with a capping method for applying screw caps, including, during a capping cycle, the steps of:

[0013] - acquiring, at a predetermined rate, at least values of quantities that identify significant phases of the cycle and are related with a rotary motion applied to a cap for capping;

[0014] - forming, with the acquired values, data strings each relating to a capping head and to one of a plurality of successive capping cycles;

[0015] - creating a database of such strings;

[0016] - obtaining from the strings time-varying status indexes, and defining for such status indexes ranges of values denoting a regularly performed capping cycle;

[0017] - verifying whether or not an instant value of a status index falls within the respective range; and

[0018] - storing the outcomes of the verifications into the database and generating, at least in case of a number of negative outcomes exceeding a threshold, alarm flags indicating the possible future arising of problems in one or more components of a capping machine in which the method is implemented.

[0019] Preferably, also values of quantities related to a translatory motion applied to the cap simultaneously with the rotary motion are acquired and inputted into the strings.

[0020] According to a preferred feature of the invention, the quantities related with the rotary motion and used for forming the data strings include at least: current delivered under no-load conditions by a motor imparting the rotary motion; position of the head at which a cap tightening phase begins; position of the head at the end of the tightening phase (end of capping); extent of the travel performed by the head from a dead point to the position at which the tightening phase begins; extent of the travel performed by the head from a predetermined point of the cycle to the end-of-capping position; nominal electromagnetic torque delivered during the tightening phase; and the quantities related with the translatory motion include at least the vertical cap position and the axial force applied to the cap.

[0021] Advantageously, the strings further include identifiers of the head and the cycle they are related with, and a flag indicating the status at the end of capping.

[0022] In a preferred embodiment, the status indexes are moving time averages of individual quantities or combinations of quantities.

[0023] Advantageously, values of quantities that are related with operating modalities of the capping machine or an installation the capping machine is part of and are independent of the individual capping heads and of the individual capping cycles are used for obtaining the status indexes, such as: operating modality of the capping machine; any machine alarms; set production speed; parameters of the installation the capping machine is part of; status of the installation; actual production speed.

[0024] The present invention further relates to an electronic capping machine for implementing the method, having the features set out in the claims 12 to 18.

[0025] Brief Description of Drawings

[0026] These and other features and advantages of the present invention will become evident from the following description of preferred embodiments given by way of non-limiting examples with reference to the annexed drawings, wherein:

[0027] Fig.l shows a block diagram of a capping machine with means of monitoring and predictive analysis of the performance;

[0028] Fig.2 is a partial view of an electronic rotary capping machine with motorized control of the rotation of the capping heads only:

[0029] Fig.3 is a graph of capping during a significant part of a capping cycle;

[0030] Fig.4 is a graph of some capping parameters during a significant part of a capping cycle;

[0031] Fig.5 shows data strings obtained from the data collected from the capping heads and the data relating to the production line;

[0032] Fig.6 shows the data collected from a capping head at each capping cycle and the results of the phase of data preparation and reduction;

[0033] Fig.7 shows the use, for diagnostic and prognostic purposes, of the information obtained from the data collected from each capping head;

[0034] Fig.8 shows the use, for diagnostic and prognostic purposes, of the information obtained from the data collected from each capping head;

[0035] Fig.9 is a flowchart of the data acquisition phase during capping;

[0036] Fig.10 is a flowchart of the analysis of the performance of the capping machine;

[0037] Fig.11 is a view similar to Fig. 2 showing an electronic rotary capping machine with motorized control of both the translation and rotation of the capping heads; and Fig.12 shows graphs of some capping parameters in the case of a capping head where both the rotation and translation motions are applied by electric motors.

[0038] Description of Embodiments

[0039] Referring to Fig. 1, a capping machine 1 according to the invention comprises in a usual manner a plurality of capping heads 10a....1 On, from which, during each capping cycle (where "cycle" means the operations performed for a bottle or other container from the moment the cap engages the bottle to the moment the cap is fully tightened), values of quantities related with the operation of said capping heads are collected at a desired sampling rate, for example, every second, in order to subject them, in an analysis system 2, to processes that can provide useful information for diagnostics and predictive maintenance of the capping machine 1. The acquisition of data from the heads 10a.. ,10n is indicated by arrow A. For this analysis, data relating to the automation of the production line and independent of the heads and the cycle the capping machine 1 is part of are also collected. For this reason, arrow B representing this data flow is shown offset from the heads 10. The analyzed data will be discussed below. The data relating to each capping cycle provided by the heads are serialized, head by head, in a serializer 20 which feeds them to storage means (either local or distributed) 21, which form a database with the information relating to each head and each cycle. These means 21 also directly receive data relating to the automation of the production line, acquired at the same rate as the data relating to the individual heads. The stored data are then supplied to a data preparation and reduction block 22 which performs targeted processing for predictive analysis that allows preventive or predictive maintenance of the capping machine. In particular, the block 22 will compact the received data into a limited number of values, which vary over time, to arrive at a "status index" summarizing the proper functioning of a component or process. In the embodiment described below, this status index consists of moving time averages of single quantities or combinations of quantities. For obtaining the status indexes, the block 22 will also use data relating to the automation of the production line. The results of the processing are then also stored in the storage device 21. The analysis system 2 here is shown as an element separate from the control system 3 of the machine, but it may also be part thereof.

[0040] The mechanical structure of the capping machine 1 and of the capping heads 10a.. ,10n is entirely conventional and will not be described in detail. For the sake of clarity, however, a rotary (or turret) capping machine is shown as an example in Fig. 3, of the type in which only the rotary motion of the rototranslating shaft of the heads is driven by an electric actuator, with explicit indication of elements that will be mentioned in the following description, namely:

[0041] - the support 18 for a bottle neck;

[0042] - the cap-handling members 11 (capping cone or chuck);

[0043] - the motor 12 of the head 10;

[0044] - the rollers 13 which, during a capping cycle, guide the head 10 over the cam track

[0045] 17 regulating the vertical position of the heads;

[0046] - the motor drive belt 14, if provided;

[0047] - the sealing gasket 15 for the seat of the sliding piston of the head;

[0048] - the spring 16 for applying the compensating load (hereinafter referred to as "axial force").

[0049] For the sake of clarity, in the following description, the phases of the rotation cycle of interest for this purpose will be described with reference to a rotary capping machine as illustrated in Fig. 2.

[0050] Referring to Figs. 3 and 4, these show the rotation speed and the electromagnetic torque (hereinafter simply referred to as "torque") as a function of the angular position of the head (Master Pos.) during part of a capping cycle. During capping, typically, the motor 12 of the head is rotated at a speed related to the production speed of the machine and the current thereof is monitored, which, through a torque constant kt, is related to the delivered torque. When the cap engages the bottle and begins to screw on, the resisting torque increases. When the electromagnetic torque reaches a value set by the operator (deceleration torque), the reaching of which corresponds to the starting of a phase of tightening the cap, the motor performs a braking operation and continues the cycle at a lower speed (closure speed). At the end of the tightening phase (i.e. at the end of capping, before the capping cone disengages the cap), the torque reaches a value indicated as closure torque. It should be noted that the position of the head at this moment is not constant but is between a minimum value MIN and a maximum value MAX, as it depends on the moment at which the deceleration torque is detected, on the moment at which the closure torque is reached and on how the cap starts to engage the thread on the bottle.

[0051] The analyses performed by system 2 in an embodiment example of the invention will now be described with reference to Figs. 5 - 9. Any values given in these figures were obtained by using capping heads of the type described by the Applicant in WO 2024 / 052869 Al.

[0052] The data relating to each head inserted in the strings are, in addition to the identifiers of the head (Head, HeadNr) and of the cycle during which the data is collected (Count):

[0053] - the current under no-load conditions (NoLoad, NoLoadCurrent);

[0054] - the angular stroke of the head from a conventional and parameterizable point (hereinafter referred to as "dead point" in the description and claims) over the cam 17 until the deceleration torque is detected, i.e. to the end of the insertion phase and therefore the beginning of the tightening phase (S.Trns, SwitchTurns); typically, the dead point is a point on the cam where the cap does not yet touch the neck of the bottle but is very close to it;

[0055] - the angular stroke of the head from the dead point to the end of the tightening phase (L.Trns, LockTums);

[0056] - the angular position of the head until the end of the insertion and deceleration phase (SPos, SwitchPosition);

[0057] - the angular position of the head until the end of the tightening phase (LPos, LockPosition);

[0058] - the final torque or closure torque applied (torque, AppliedTorque).

[0059] The strings also contain an indication of the status at the end of closure (Status, ClosureStatus), i.e. at the outcome of the operation: a value 0 shall indicate a correct closure, a value 0 shall indicate an anomaly.

[0060] The data relating to the automation of the production line are, instead:

[0061] - the mode at which the machine is running (MachineMode), which in the case considered herein is "production ongoing"; - any machine alarms, none in the case considered herein;

[0062] - the set production speed (SetSpeed);

[0063] - a set of parameters (recipe) that depends on the machine / production line the capping machine 1 is part of and is independent of the individual heads and the individual cycles (Recipeld);

[0064] - a machine status (Production);

[0065] - the actual speed (Actual Speed).

[0066] In the data preparation and reduction phase:

[0067] - from the no-load current, an average value of the intrinsic mechanical friction in the components of the head is obtained (Average, Average Friction); the area of the cycle where this friction is reached is shown in Fig. 3;

[0068] - from the differences between the rotation performed by the cap until the end of the insertion step and until the end of the tightening phase of the various cycles (i.e. from the angles by which the rototranslating shaft of the head rotates around its own axis during the tightening phase), an average value (Average of Differences, Average Tightening Degrees) of the angle by which the cap is rotated between the reaching of the deceleration torque and end of capping is obtained;

[0069] - from the angular position of the head to the end of the tightening phase, the minimum and maximum values allowed for such position (Min & Max, Minimal / Maximum Tightening Position) are obtained;

[0070] - from the final torque, which may also vary from cycle to cycle, an average value (Average, Average Closure Torque) is obtained;

[0071] - from the status at the end of closure, a count (State counting) of the total number of capping cycles (total Closure cycles) is obtained and good or acceptable closures (Good / Acceptable Closures), the lack of the cap or bottle during a capping process (Lack of Cap or Bottle) or the failure to reach a valid torque (torque not reached) can be recognized.

[0072] Advantageously, the average values will be updated by using machine learning techniques.

[0073] The information relating to the average values of the torque and angle by which the cap is rotated for tightening allows for a diagnostics of the results that provides a historical trend of the closure torque and allows tracking of the drift of its values to prevent anomalies. The information relating to the final tightening positions and the average friction is used for maintenance, prognostics and the determination of any anomalies: in particular, the analysis of the final position is used to prevent wear of mechanical components, while friction tracking allows prediction of the need for maintenance.

[0074] Finally, the information relating to the status at the end of closure enables alarm diagnostics, providing a historical trend of the final status head by head and enabling predictive maintenance based on the drift of that status.

[0075] In more detail, the information on the average friction allows a predictive analysis based on the historical trends thereof. In particular, the average friction over time, related with the rotation speed of the head, allows to build a cloud of data characteristic of the correct operation. The deviation of the data from this cloud can be a symptom of impending problems, such as inadequate lubrication.

[0076] As far as the average value of the tightening angle is concerned, this remains essentially constant at a controlled speed as applied during capping: a drift of this value, with the same operating modality, could then indicate drifts in the tightening torques.

[0077] The analysis of the final position of the head over the cam allows in turn to recognize values outside the pre-established range, which values may be due to various mechanical factors, such as wear of the roller pistons, wear of the centering members, etc.

[0078] The information on the trends of the torque over time, obtained from the average values of the closure torque, allows viewing and comparing the historical trend of the tightening torque at the same set torque level.

[0079] Finally, a high value of the count of only acceptable closures will indicate impending problems.

[0080] Table 1 below indicates possible correlations between a drift of the values found with the analyses described with respect to the "optimal" values and the components of the capping machine indicated in Fig. 2. TABLE 1

[0081] The "average rotation" in the table corresponds to the average tightening angle mentioned above. If the belt 14 is not provided, a drift of the average friction will presumably indicate wear of the inner bearings of the motor, besides problems in lubrication and in the sealing gasket.

[0082] The quantities considered also allow predicting the onset of problems in other elements of a capping head. The capping method with predictive analysis of the performance according to the invention is shown in Figures 9 and 10. For the sake of clarity, the collection of data (Fig. 9) and the actual analysis (Fig. 10) have been shown separately from each other, even if, during normal operation of the capping machine, these operations take place simultaneously. There may, in any case, be a calibration phase in which an initial database is created.

[0083] For quantities other than the no-load current, the starting (step 100) of the data collection for a head in a capping cycle is represented by the recognition of the reaching of the deceleration torque (Fig. 3). From this moment on, the values of the quantities indicated in Figs. 5 and 6 are acquired and the relative data strings are constructed and stored in the database, either local or distributed, head by head (step 101). The operations are repeated identically for the subsequent cycles, and continue, for example, until the end of a certain production cycle (complete acquisition, step 103; stop, step 104).

[0084] For the actual analysis, after starting (step 200), the first operation will be the reading of the individual strings from the database 21 and the determination of the status indexes (step 210). In the shown example, in which the status indexes are moving averages, these will be in particular: MEDIAN (t) for the no-load current; MEDIALS (t) for the difference in angular strokes L.TRNS, S.TRNS; MINE (t), MAXL (t) for the final angle of closing; MEDIAT (t) for the torques; COUNTS (t) for the status.

[0085] One will then proceed to verify whether these indexes fall within the expected or obtained ranges (step 202). If the verification has a positive outcome (output YES of step 203), one will proceed for example until the end of production (analysis completed, step 205). If or when step 203 indicates a negative outcome, this fact will be stored. If this is a one-off event, the capping machine can also continue to operate regularly. However, if the reports of a negative outcome of the verification at step 203 become too frequent, an alarm of future anomaly will be generated and the personnel in charge, based on the component affected by the anomaly or the type of anomaly hypothesized, may also decide to immediately interrupt operation.

[0086] Two examples of anomaly prediction will now be described.

[0087] Example 1 : anomaly in the transmission belt

[0088] This prediction is based on the analysis of the value MEDIAN(t) of the no-load current. By indicating as MEDIAN(t=0) the value measured at the beginning of the installation, the belt is considered in good condition if MEDIAN(t) falls within an interval MEDIAN(t=0) ± X. For example, it is assumed that MEDIAN(t=0), converted into torque, is 0,6 Nm and that X = 25%. Therefore, at any data acquisition instant tl (measurement instant), the comparison at step 202 will give a positive result if MEDIAN(tl) > 4,5 or MEDIAN(tl) < 7,5. If MEDIAN(tl) > 7.5 it can be assumed that the belt is too tight, while if MEDIAN(tl) < 4.5 it can be assumed that the belt has loosened.

[0089] Example 2: anomaly in the container anti-rotation device For this example, the capping head is assumed to comprise a centering and antirotation device of the type described by the Applicant in WO 2021 / 260548 Al, which uses a clamp member equipped with retaining teeth.

[0090] In this example, the averages MINL(t), MAXL(t) of the minimum and maximum angles provided for the end-of-capping position are analyzed. The averages are assumed to be calculated over a 100-hour period and the corresponding values MAXL(100) and MINL(100) are assumed to be 250° e 214° (250° - 1 / 10 revolution), respectively.

[0091] If the retaining teeth start to wear, it is likely that, at the measurement time tl, MAXL(tl) exceeds 250°. A deviation greater than a certain percentage Y% is an indication of this future anomaly.

[0092] A value of MINL(tl) lower than 214° will instead indicate a crooked cap which causes an early end of tightening. In this case, too, a difference greater than Y% indicates a future anomaly. At least in this second case, it will be appropriate to also evaluate the number of anomalies found in a certain number of cycles, to decide whether it is an occasional event (which does not cause problems) or whether it is instead the symptom of a future malfunction.

[0093] As mentioned at the beginning, in electronic capping machines, also the vertical translatory motion can be imparted by an electric motor ("full servo" capping machines). For ease of understanding, a "full servo" turret 1A is shown in Fig. 11. Compared with the turret 1 of Fig. 2, this includes a rotary electric motor 12R and a linear electric motor 12L for driving rotation and translation, respectively. The motor 12R is obviously identical to the motor 12 of Fig. 2, while the motor 12L carries out the functions performed in the head 1 by the cam 17, the rollers 11 and the spring 14. The other elements are identical to those illustrated in Fig. 2.

[0094] In this case, it is also possible to monitor quantities related with the translatory motion, in particular the vertical position of the cap and the electromagnetic force of the motor 12L, thus obtaining other parameters to insert into the data strings. Fig. 12 shows the graphs of these two quantities, compared with a respective reference value.

[0095] As far as position is concerned (graph (a)), deviation between the measured and reference positions can indicate whether the cap is applied correctly: an occasional deviation will indicate a single anomaly (which does not cause concern), a prolonged deviation at a single head may foretell problems in the capping cone or its support. As far as axial force (referred to as "linear axis force" in graph (b)) is concerned, a first piece of data that can be extrapolated is a minimum and maximum position of reaching the maximum force. In the figure, the maximum force is reached when the real position begins to distance itself from the reference. As with the reaching of the maximum torque, there is an angular range within which the maximum force should fall: if the maximum force is reached too early with respect to the minimum angle, there will most likely be closure anomalies, while if it is reached beyond the maximum angle there will likely be a problem related to the neck support.

[0096] In addition, from the average force in some areas (framed in the figure) it is possible to obtain a friction value, in this case linked to the vertical sliding of the piston.

[0097] Table 2 below indicates possible correlations between a drift of the processed values of the quantities indicated above with respect to the "optimal" values and the components of the capping machine 1 A.

[0098] TABLE 2

[0099] It is evident that the above description is given solely as a non-limiting example and that variations and modifications are possible without departing from the scope of protection of the invention as defined in the following claims.

Claims

CLAIMS1. Capping method for applying screw caps to containers, wherein capping entails applying a rotary motion about an axis and a vertical translatory motion along the same axis to the caps, characterised in that it includes, during a capping cycle, the steps of:- acquiring (101), at a predetermined rate, at least values of quantities that identify significant phases of the cycle and are related with the rotary motion;- forming (102), with the acquired values, data strings each relating to a capping head (10a... lOn) and to one of a plurality of successive capping cycles;- creating a database of such strings;- obtaining from the strings time-varying status indexes, and defining for such status indexes ranges of values denoting a regularly performed capping cycle;- verifying whether or not an instant value of a status index falls within the respective range; and- storing the outcomes of the verifications into the database and generating, at least in case of a number of negative outcomes exceeding a threshold, flags indicating the possible future arising of problems in one or more components of a capping machine (i; 1A).

2. Method according to claim 1, wherein also values of quantities related with the translatory motion are acquired and introduced into the data strings.

3. Method according to claim 1 or 2, wherein the quantities related with the rotary motion include at least:- current delivered under no-load conditions by a motor (12) imparting the rotary motion;- position of the head (10a...1 On) at which a cap tightening phase begins;- position of the head (10a...1 On) at the end of the tightening phase (end of capping);- extent of the travel performed by the head (10a...1 On) from a dead point to the position at which the tightening phase begins;- extent of the travel performed by the head (10a...1 On) from the dead point to the end-of-capping position;- nominal torque delivered during the tightening phase.

4. Method according to any preceding claim, wherein the quantities related with the translatory motion include at least the vertical cap position and the axial force applied to the cap.

5. Method according to any preceding claim, wherein the strings include identifiers of the head and the cycle they are related with, and a flag indicating the status at the end of capping.

6. Method according to any preceding claim, wherein the status indexes are moving time averages of individual quantities or combinations of quantities and are updated by using machine-learning techniques.

7. Method according to claim 6 when dependent on claim 3, wherein said status indexes provide information at least on:- average value of rotary mechanical friction;- average value of the angle by which the cap is rotated between the beginning and the end of the tightening phase and the end of capping in the various cycles;- minimum and maximum values allowed for the angular position of the head at the end of the tightening phase;- average value of the final torque;- good or acceptable closures;- lack of cap or bottle during capping.

8. Method according to claim 6 when dependent on claim 4, wherein said status indexes provide information at least on:- average value of translatory mechanical friction; and- minimum and maximum values allowed for the position at which maximum axial force is reached.

9. Method according to any preceding claim, wherein values of quantities that are related with operating modalities of the capping machine (1; 1 A) or an installation the capping machine (1 ; 1 A) is part of and are independent of the individual capping heads (10a...1 On) and of the individual capping cycles are used for obtaining the statusindexes.

10. Method according to claim 9, wherein the quantities independent of the individual capping heads (10a... lOn) and of the individual capping cycles comprise at least: operating modality of the capping machine (1; 1A); any machine alarms; set production speed; parameters of the installation; status of the installation; actual production speed.

11. Method according to any preceding claim, wherein the values of the quantities that are related with the rotary motion and translatory motion and the values of the quantities independent of the individual capping heads (10a...1 On) and of the individual capping cycles are acquired at the same rate.

12. Electronic capping machine (1; 1A) for applying screw caps to containers, including one or more capping heads (10a...1 On) performing, during a capping cycle, a rotary motion about an axis simultaneously with a translatory motion along the same axis, wherein at least the rotary motion is imparted by an electric motor (12; 12R), characterised in that the head(s) (10a...1 On) is (are) associated with a system (2) for data acquisition and analysis including:- serialising means (20) for serialising values, acquired at a predetermined rate from each head (10a...1 On) and during a plurality of successive capping cycles, of quantities that are related at least with the rotary motion and identify significant phases of the cycle, and- data reduction and preparation means (22) arranged to:- form (102), with the acquired values, data strings each relating to a capping head (10a...1 On) and to one of a plurality of successive capping cycles;- create a database of such strings in a storage device (21);- obtain from the strings and store into the database time-varying status indexes, and define for such status indexes ranges of values denoting a regularly performed capping cycle;- verify whether or not an instant value of a status index falls within the respective range; and- store the outcomes of the verifications into the database and generate, at least in case of a number of negative outcomes exceeding a threshold, flags indicating the possible future arising of problems in one or more components of the capping machine (1).

13. Capping machine (1 A) according to claim 12, wherein also the translatory motion is imparted by an electric motor (12L) and the serializing and data reduction and preparation means (20, 22) are suitable to acquire and insert into the data strings also values of quantities related with the translatory motion.

14. Capping machine (1; 1A) according to claim 12 or 13, wherein the quantities related with the rotary motion comprise at least:- current delivered under no-load conditions by the motor (12; 12R) imparting the rotary motion;- position of the head (10a...1 On) at which a cap tightening phase begins;- position of the head (10a...1 On) at the end of capping;- extent of the travel performed by the head (10a...1 On) from a dead point to the position at which the tightening phase begins;- extent of the travel performed by the head (10a...1 On) from the dead point to the end- of-capping position;- nominal torque delivered during the tightening phase.

15. Capping machine (1; 1A) according to any of claims 12 to 14, wherein the quantities related with the translatory motion include at least the vertical cap position and the axial force applied to the cap.

16. Capping machine (1; 1 A) according to any of claims 12 to 15, wherein the strings include identifiers of the head and the cycle they are related with, and a flag indicating the status at the end of capping.

17. Capping machine (1; 1A) according to any of claims 12 to 16, wherein theserializing and data reduction and preparation means (20, 22) are suitable to acquire and use for obtaining the status indexes also values of quantities that are related with operating modalities of the capping machine (1; 1A) or an installation the capping machine (1; 1A) is part of and are independent of the individual capping heads (10a...1 On) and of the individual capping cycles.

18. Capping machine (1; 1A) according to claim 17, wherein the quantities independent of the individual capping heads (10a...1 On) and of the individual capping cycles include at least: - operating modality of the capping machine (1; 1A); any machine alarms; set production speed; parameters of the installation the capping machine (1; 1A) is part of; status of the installation; - actual production speed.

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