EP1176091B1 - Method for checking machine parameters of stretch foil packaging machines and check-foil used - Google Patents

Abstract

The procedure for the checking of machine parameters of stretch film packing machine entails fitting a test film roll on the packing machine instead of the feed roll and then wrapping an item of goods with the test film. The test film has a print marking in order to determine the longitudinal stretch of the film created during the packing process. The markings on the test film may be circular in their initial form, or may be lines parallel to the transverse and/or longitudinal direction of the film. An Independent claim is included for the aforesaid test film.

Description

The invention relates to a method for checking machine parameters a stretch film packaging machine with which a packaged goods, preferably stored on pallets, with one of a supply roll drawn stretch film is wrapped.

The invention further relates to a test film for implementation this procedure.

In the case of stretch film packaging machines, the packaging goods delivered to the machine, and to secure the frequently out several parts of existing packaged goods and / or for splash water protection the packaged goods are stretched from a supply roll (also called stretch film) and this with a Preliminary stretching of several 100% wrapped around the packaged goods.

The stretch films typically used are polyethylene films, that of the supply roll over a brake roll and one Subsequent drive roller withdrawn while stretching the same and wrapped around the packaged goods with further stretching becomes.

Conventional stretch film packaging machines have a turntable on which the packaged goods can be stored, as well as a vertically movable film dispenser that over the height of the packaged goods can be moved, so that at usual Film widths of approx. 50 cm also significantly higher packaging goods can be completely wrapped.

In operation, the film dispenser remains stationary (however movable in height) on a column, which is usually also the control keyboard and the control for the packaging machine includes. The packaged goods are from the turntable rotated at high speed, and the film wraps according to the procedure of the film dispenser the column from bottom to top or from top to bottom around the Packaged goods around.

In an alternative type of stretch film packaging machine, that work fully automatically, the packaged goods are on one Transport track is conveyed into the packaging machine and remains then stand in the packaging position for the packaging process. The film dispenser is on one of the machine frame the packaging machine carried and vertical in its Height-adjustable support ring is mounted and moves under the surrender of the Packaging film around the packaged goods at high speed around.

Such machines enable extremely high packaging speeds reach so that a so-called Euro pallet can be wrapped with stretch film within 60 seconds can.

Here too, the film is pre-stretched between 100 and 250% set, the film also in the film dispenser first via a brake roller and then a drive roller to be led.

The moving masses are with both types of packaging machines relatively high, and in particular very high torques occur on. Correspondingly strong drives and brake units are necessary.

In addition, for a satisfactory packaging result ensure that the speed at which the stretch film is donated from the supply roll, either the speed of rotation of the pallet or the speed of rotation the dispensing device on the support ring itself is adapted.

Experience has shown that this requires a very precise setting of the individual speeds or braking forces on each other, and these parameters must be regularly coordinated.

If the individual parameters deviate too much from the target values, this can lead to film tearing, which leads to impairment the packaging performance of stretch film packaging machines leads. Of course, a film tear through an inadequately manufactured film must be caused so that this makes the search for the error even more complicated.

Certain foils used for wrapping the pallets due to their adhesive properties when wrapped around the pallets were, with a truck loading, that the pallets stuck together so that the trucks sometimes no longer could be unloaded. In this context, foils developed, the outside of a wrapped pallet Side was made slippery. Such a film has the property if during the winding process with the brake roller or the drive roller (donor roller) with its lubricated Side comes into contact, sliding and thus the function of the winding system to be practically canceled.

Hardly any film breaks are observed with this film However, the result is an uncontrollable film consumption, this type of film is also considerable is more expensive than the usual stretch films.

The present invention therefore proposes a method for Checking machine parameters of stretch film packaging machines with which the correctness of the machine parameters to be coordinated can be easily checked.

For this purpose, the method according to the invention is used instead the supply roll with the stretch film a test film roll used on the stretch film packaging machine and that Packaged goods wrapped with the test film without first touching the Machine parameters something is changed. It is used as a test film uses a film that is normally used for packaging stretch film used corresponds, however, a printing with a mark on the basis of which the wrapping longitudinal expansion of the goods to be packaged and with a corresponding Design of the marking also the transverse stretch of the film can be determined.

With a simple check, this procedure currently shows that whether the machine parameters of the stretch film packaging machine are correctly coordinated, or whether, for example the speed of the turntable is not too Dispensing speed of the film dispenser fits.

This test can be done very easily by any employee who has the Operate the stretch film packaging machine in normal operation can be done so that he can decide very easily whether he is a maintenance technician for the stretch wrap machine must consult in the event that he is inadequate and achieved unsatisfactory packaging results or even noticed film tears.

Both the film dispenser and the test device can be used on the test film check the pre-stretching carried out, as well as the ultimately read the full elongation on the packaged goods, so that it also provides information about the interaction the speed of rotation of the turntable or the speed of rotation the film dispenser on the support ring and the Dispensing speed of the film dispenser determined can be.

After depending on the quality of the film material used a so-called neckdown, i.e. a narrowing of the film width when stretching, takes place, is preferred at one inventive method a test film with a mark used, which occurs when wrapping the packaged goods Neckdown of the film makes it readable.

Suitable markings for determining the longitudinal expansion of the The film or neckdown make the same markings in a circular shape. An alternative preferred form of the markings on the test film are marking strips that are parallel run to the transverse direction of the film and / or the longitudinal direction of the film.

The marking of the test film particularly preferably indicates the original state a continuous grid, with the individual Grid elements preferably rectangular, more preferred Have a square shape.

The invention further relates to a test film for checking the Machine parameters of stretch film packaging machines that can be used in the method described above.

As described above, the test film according to the invention has Marks on themselves when stretching the film lengthways change, and this change leaves immediate Conclusions about a correct setting of the different Machine parameters too.

Preferred embodiments of the test sheet have been described above already in connection with the inventive method in Described individually.

Figur 1

einen ersten Typ einer Streckfolienverpackungsmaschine;

Figur 2

einen zweiten Typ einer Streckfolienvepackungsmaschine; und

Figuren 3a bis 3c und 4a bis 4c

verschiedene Ausführungsformen von erfindungsgemäßen Prüffolien im Ursprungszustand bzw. in gestrecktem Zustand.

The invention is explained in more detail below with reference to the drawing. They show in detail:

Figure 1

a first type of stretch film packaging machine;

Figure 2

a second type of stretch film packaging machine; and

Figures 3a to 3c and 4a to 4c

Different embodiments of test foils according to the invention in the original state or in the stretched state.

Figure 1 shows an overall designated by the reference numeral 10 semi-automatic stretch film packaging machine with one Turntable 12, on which a packaged goods 14 - shown here in the form of a pallet loaded with packages. Connected to the turntable is a support column 16 on which one Pressure plate 18 is attached via a support arm 20, which the packaged goods are loaded from above and when turning the packaged goods 14 together with the turntable 12 at the beginning of Packing process a falling apart of the stack of packages Avoid packaging goods 14 helps.

On the column 16 is also a film dispenser 22 in adjustable in height from which a film 24 runs out, which with the rotating turntable revolves around the packaged goods 14 wraps. Around the entire height range of the packaged goods 14 to be able to coat, the film dispenser 22 move in height, so that from the lower end to the upper Part of the packaging good 14 a complete wrap is made possible with foil. A coordination of the speed of rotation of the turntable 12 with the film dispensing speed of Foil dispenser 22 is done by an electronic control 26, which is also housed in the column 16.

That of the film dispenser 22 from a supply roll (not shown in detail here) peeled packaging film 24 of the film dispenser 22 is first in the Range between 100 and 250% pre-stretched and then under another Elongation (stretching) is wrapped around the packaged goods 14.

The total stretch (total stretch) of the packaging film can for example, reach about 350% up to the break point.

In Figure 2 is another type of stretch film packaging machine shown, which in contrast to the machine of Figure 1 works fully automatically. The stretch film machine shown in Figure 2 is provided with the reference number 30 overall and has a cage-like machine frame 32 through which A transport route 34 runs in the lower part. On the Transport route 34 or the roller conveyor 34 become the packaging goods 36, again in the form of a package shown loaded pallet, transported to and removed after packing. During the transport to and from the stretch film packaging machine 1 is done manually this is fully automatic in the machine type shown in FIG. 2 respectively.

The packaged goods 36 are initially in the packaging position conveyed and stands still while on the machine frame 32 a film dispensing device 38 movable on one Support ring 40 is mounted. The support ring 40 itself again within a frame 42 vertically movable on the cage-like Machine frame 32 held.

For packaging the packaged goods with stretch film 44, which by dispenser 38 is dispensed, the film dispenser moves 38 around the packaged goods 36 in a circle, whereby the frame 42 moved continuously up (or from top to bottom) is so that the total height of the packaged goods 36th can be covered with packaging film 44.

Here, too, the stretch film is from the film dispenser 38 preferably pre-stretched and experienced again by 100 to 250% their final stretch during the packaging process itself, so that, in the end, stretching to the breaking point can be achieved.

For the adjustment of the film dispensing speed, the height adjustment the frame 44 and the rotational speed of the Foil dispenser 38 on ring 40 is an electronic control 46 responsible.

Is critical in the machine according to Figure 1 and in the Machine according to Figure 2, the exact coordination of the dispensing speed and the application speed of the film on Packaged goods, a process in which the film that is already comes stretched out of the film dispenser 22 or 38, again is stretched considerably further.

Is the dispensing speed of the film dispenser 22 or 38 not exactly to the speed of rotation of the turntable 12 or adapted to the speed of rotation of the film dispenser 38 on the ring 40, there is a waste of foil material because this is not stretched sufficiently and is therefore not applied sparingly becomes a tear or if it is stretched too much the packaging film, what the packaging throughput or the packaging performance of the machine is significantly reduced. The packaging process must then be interrupted at this point become, i.e. the packaging goods on the machine of the Figure 1 must be stopped or the film dispenser must be in slowed down its run on the support ring 40 around the packaged goods 36 the film has to be attached to the packaging and the packaging process is started again become.

This underlines the importance of the correct setting of the different machine parameters to each other to achieve an optimal Packaging result and optimal packaging performance too to reach.

This is crucial for the speed at which the film dispenser is dispensed 22 or 38 is the friction that the film 24 or 44 applies the brake roller of the respective film dispensing device. The commonly used polyethylene films have a relative high friction against the brake roller material of the film dispenser, however, this can contaminate Brake roller surfaces very easily compared to other conditions to lead. Is the braking power of the operating personnel here Brake roller not adjusted, too much film is used, while, on the other hand, the brake voltage is often used when adjusting the brake roller with the ones usually available on site Means cannot be precisely controlled, so that in the If the braking effect of the braking roller is too strong, result in film tears consequences.

The present invention proposes a test method for this with which it can be checked very easily whether the individual Machine parameters sufficient for the type of film used are coordinated. Such a film is schematic shown in Figures 3 and 4, with the letter a designated partial figures first the film in its original condition represent the representations with the letter b the pre-stretched film and the representations with the letter c the film in the finally stretched state as it is on the packaged goods is applied. The films shown in Figures 3 and 4 50, 52 typically have web widths of 25 to 50 cm and according to the invention have markings which are the result the longitudinal expansion of the film and the so-called neckdown, i.e. a decrease in width due to stretching the film, make it easy to read. These are preferred Grid lines, as shown in Figure 3, or circular Markings 56, as shown in Figure 4. Of course any number of modifications to this are conceivable without that this has to be done in detail here. Important is in any case, that the longitudinal expansion of the film is determined what can be done in the given examples simply by the Distances of the transverse lines in the film of Figure 3 and the Diameter of the initially circular markings on the film Figure 4 - measured in the longitudinal direction of the film web - precipitates.

The neckdown can be done with the foils of Figures 3 and 4 can also be read by looking at the cross lines of the grid line 54 on their distance in the state of the film 50 'or 50 '' checks or the diameter of the initially circular Markings 56 in the state transverse to the longitudinal direction of the foils 52 'or 52' 'checks.

An expansion ratio of the film can be read off from this immediately and with the specifications typical for the machine and with the specifications for the packaging film used to compare. The machine operator immediately receives information about whether his machine with the set machine parameters works in the permitted area or not and he can, if necessary Then tear off the film tears whether this due to poorly set machine parameters done or due to an error in the film itself.

In addition, he has a measure immediately available with which he can check whether the machine he is using is the packaging film uses economically or excess film used for packaging.

The distance between those running transverse to the longitudinal direction of the film is preferred Marking strips or the diameter of the marking serving circles so that after Are even less than the distance between the brake and Drive roller of the respective film dispenser, so that also read the pre-stretching of the film and with the final drawing. In this case are then also the operating parameters of the film dispenser readable on the test film.

Claims (12)

1. A method for checking machine parameters of a stretch film wrapping machine, with which an item to be wrapped (14), which is preferably stored on palettes (12), is wrapped with a stretch film (24) drawn from a supply reel (22),
   characterised in that instead of the supply reel, a test film reel (50, 52) is used on the stretch film wrapping machine and the item to be wrapped (14) is wrapped with the test film (50, 52), with the test film (50, 52) having printing with a marking (54, 56) by means of which the longitudinal extension of the film (50, 52) occurring during the wrapping operation can be determined.
2. A method according to Claim 1,
   characterised in that the test film comprises a marking (54, 56) by means of which the neckdown of the film occurring during the wrapping operation can be determined.
3. A method according to Claim 1 or 2,
   characterised in that the markings (56) of the test film have a circular shape in the original state.
4. A method according to Claim 1 or 2,
   characterised in that the markings (54) of the test film comprise marking strips running parallel to the transverse direction of the film and/or to the longitudinal direction of the film in the original state.
5. A method according to one of Claims 1 to 4,
   characterised in that the marking (54) of the test film forms a continuous grid in the original state.
6. A method according to Claim 5,
   characterised in that the grid (56) is based on a rectangular shape.
7. A test film for checking machine parameters of stretch film wrapping machines,
   characterised in that the test film (50, 52) comprises printing with a marking (54, 56) by means of which the longitudinal extension of the film (50, 52) which occurs during the wrapping operation can be determined.
8. A test film according to Claim 7,
   characterised in that the test film comprises a marking (54, 56) by means of which the reduction in the width of the film (neckdown) that occurs during the wrapping operation can be determined.
9. A test film according to Claim 7 or 8,
   characterised in that the markings (56) of the test film have a circular shape in the original state.
10. A test film according to one of Claims 7 to 9,
    characterised in that the markings (54) of the test film comprise marking strips which run parallel to the film in the transverse direction and/or in the longitudinal direction of the film in the original state.
11. A test film according to one of Claims 7 to 10,
    characterised in that the marking (54) of the test film forms a regular continuous grid in the original state.
12. A test film according to Claim 11,
    characterised in that the grid line (56) of the test film is rectangular, in particular square, in the original state.

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