SK139399A3 - Method and punch for perforating cementitious tiles and so obtained cementitious tiles - Google Patents

Abstract

A cementitious tile (54) is perforated using a punch (10) of elongate section having a leading face (16) with a saw tooth profile along its length. The punch (10) may also be used to produce indentations (A) which look like perforations when in situ. Circular punches (10) also having a saw tooth profile may be used. The tooth depth is preferable less than 2 mm and the included angle of the tooth profile between 90 DEG and 150 DEG . The punches (10) produce exceptionally clean edges in the tile (54).

Description

Perforator for perforating the binder plates, perforating process and perforated plates

Technical field

The present invention relates to binder boards having good properties, a process for preparing such boards and a die assembly of the process.

BACKGROUND OF THE INVENTION

Plates made by applying gypsum on a certain substrate are generally called gypsum boards. Conventional gypsum plasterboards based on paper are used for interior cladding, either as a backing or as a finish.

Gypsum is used very successfully in various ways, for example in the form of ceiling slabs. However, it has not found wider use where the ability to absorb sound is required as a priority. GB-A-2203772 discloses a gypsum board having relatively good properties. The plate is perforated by a plurality of holes or cross-sections. These are covered on one side of the board with a fabric which forms part of the board. WO-A-87 / OOH6 discloses acoustic plasterboard perforated by regular cross-sections. However, it was necessary to improve the acoustic properties of the drywall and at the same time to increase the aesthetic appearance.

SUMMARY OF THE INVENTION

Known perforated gypsum boards have edges of perforated edges often obscure, possibly because the fibers of the underlying material overlap them.

The present invention provides an acoustically absorbent plate with perforated apertures that pass through the binder mass. This plate is enhanced by at least some perforated apertures having unusually sharp and clearly visible edges. At least some of the apertured apertures preferably have the form of slits and some preferably have a circular profile.

As used herein, the term slits are generally perforated longitudinally shaped holes with irregular edges and an aspect ratio (slot length to maximum width ratio) of at most 6: 1, preferably no more than 4: 1. : first

The backing layer preferably forms part of the front side of the board (e.g. in the form of a paper backing) with a plurality of embossed depressions extending through the layer to the binder mass. The surface of this layer is thus disturbed and the typical appearance of gypsum boards is the result.

The perforated openings, possibly extending over the entire width of the board, are preferably covered on the back side of the board than the underlying surface. In the most preferred embodiment, the perforation is covered with an acoustically absorbent material, preferably in the form of a coating, for example acoustic paper or felt.

The present invention further relates to a die-cutter having a longitudinal profile for perforating plates comprising binder material, wherein the functional side profile of the die-cutter is serrated over its entire length.

I

The ram is preferably adapted to perforate the apertures in the form of slits.

The side faces of the striker are preferably corrugated over their entire width and have rounded edges.

The pitch of the serrated profile is preferably substantially the same as the ripple spacing of the sides of the ram.

The present invention further relates to a perforator for perforating plates comprising binder material, the functional side of which has a serrated profile with rounded edges and a depth of teeth.

which is not more than 2 mm.

The tooth depth of the dies according to the invention is preferably not more than 2 mm.

The angle between the teeth Ba preferably ranges between 90 ° and 150 °. The serrated profile of the functional side of the striker is terminated at both ends of its longitudinal dimension by a tooth tip.

In one embodiment of the invention, the striker may have a circular profile.

The present invention further relates to an acoustic absorbent dock comprising a binder mass with a plurality of perforated apertures that pass through the binder mass. The cut quality index of the perforated apertures is greater than 0.98, which is given as the ratio of the number of pixels on the perimeter of the digritalized feathered hole image after the smoothing process to the number of pixels of the dilated image of the perimeter before the smoothing process. The smoothing process consists of four levels of binary degradation, followed by binary expansion.

The present invention further relates to a composite die for perforating apertures in the form of slits. A portion of the punches of the composite punch is in the form of shorter punching punches, and the portion is in the form of longer punches that form perforated holes extending across the entire width of the plate. The rammers are attached to the die die, with the punching punches projecting slightly less than the long die punches over the die die. More preferably, die punches having a circular profile are perforated in the die die to perforate the circular holes.

The long punches are longer than the punch punches preferably at least by the width of the binder plate so that the long punches penetrate the entire width of the binder board before the punching dies have come to the surface thereof. That is, perforation of the holes over the entire width of the plate is done before the depressions are pressed, thus minimizing the pressure necessary for the proper functioning of the assembled punch.

Preferably, the die assembly further comprises a separating plate and a base plate, between which a perforated plate is inserted. In the separating plate there are openings through which the strippers pass into the gypsum board and in the base plate there are openings into which the strippers penetrate after perforation of the inserted board.

The invention also includes a process for perforating an acoustically absorbent gypsum board. This process consists of the following steps:

Placing the plasterboard flat on the profiled surface of the die die with the punches of the present invention. Preferably, at least some of the strippers have a profile such that the holes formed are in the form of slits.

Perforating the plate by applying pressure between the die die and the backing plate so that the punches penetrate the gypsum board.

Separating the die die from the perforated plate.

Preferably, a portion of the punches of the composite punch is in the form of shorter punching punches, and the portion is in the form of longer punches that extend over the entire width of the perforated plate. As part of the procedure, all die punches penetrate the perforating plate, with shorter punching punches penetrating into the plate but not penetrating the full width of the die, while longer punching dies penetrate the plate from one side to the other.

When the plate to be perforated has a certain backing layer, the die die is preferably applied to the backing surface.

In a preferred method, the flat surface of the perforated plate is coated after perforation and embossing of the depression. The substrate pressed into the wells can thus remain unpainted, especially in the case of roller coating. Such a coating makes it possible to distinguish the recess from the rest of the board.

In a particularly preferred method, the fine wells are extruded by a roller with spokes protruding. As a result, a very pleasant appearance is obtained in combination with perforations in the form of slits and depressions.

The invention further solves how to adjust the ceiling with perforated plates. A ceiling that has a substantially uniform appearance may not have the same acoustic characteristics over its entire area. A combination of boards according to the invention and boards having the same appearance may be used, which are not perforated over the entire width of the board but have only recesses in the form of slits. Thus, the ceilings can be adjusted according to the desired acoustic properties, for example a ceiling suitable especially for an auditorium where good acoustic word transmission is required.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described in more detail by way of example with reference to the accompanying drawings.

Fig. 1 shows an overall view of a rammer according to the present invention.

Fig. 2 shows a cross-section through the striker of Fig. 1.

Fig. 3 shows a side view of the striker of Fig. 1 and 2.

Fig. 4 schematically shows a die die in a die assembly according to the invention without a blow-through.

Fig. 5 schematically shows a cross-section of a composite punch according to the invention for treating a plate according to the invention.

Fig. 6 shows a portion of a plate according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The ram 10 in FIG. 1, 2 and 3 is solid and is made of high carbon steel. The rammer has a slightly bent elongated profile and is shaped to be perforated in the form of slots. The surface of the lateral sides 12 is undulated with rounded edges 14. In another embodiment, the edges of the ram are tapered to the back, and the holes made by the ram have a more complex edge than the holes punched out in the ram. 1, 2 and 3. The functional part 16, which first comes into contact with the plate when perforating, has a serrated profile over its entire length. The spacing of the serrated profile is 3 mm and coincides with the spacing of the undulating sides. Preferably, the clamped angle alpha is 120 ° and it has been found that this angle allows perforations with sharp and clean edges. FIG. 3, it is best to see that the serrated profile of the functional portion Ifi is terminated at both ends by the apex of the tooth 1fi.

The edges of the teeth of the punching machine, both for perforating and for pushing the recesses into the plate, should form an angle of between 115 ° and 150 °, preferably between 120 ° and 130 °. Tooth depth, i. the distance between the apex and the lower part of the tooth is preferably up to 1.5 mm, more preferably 1 mm.

The extent of this angle alpha should be between 90 ° and 150 "", preferably between 110 "» and 130 °, and more preferably 120 «» in the case of a striker intended to make complete perforated holes. The tooth depth may be up to 2000 mm, preferably 1 mm.

When fully perforated, the angles between the teeth and the depth of the punching teeth are not so important. The depth of the recess is important in the extrusion of the wells. The shadow cast by the edge of the well-printed well is very similar to the shadow of the edge of the fully perforated hole. This makes it possible to interchange perforated plates and plates with embossed depressions without compromising the aesthetic effect. Even when embossing the depressions, the teeth can penetrate the bottom sheet of the board paper when both the alpha angle and the tooth depth are very large. As a result, there is an undesirable aesthetic appearance and possible deterioration in acoustic properties.

In practice, the rammers U2 are attached to the die die 22 shown in Fig. 4. In the die die there are openings 22 corresponding to different shapes of the ramming machine 10 and circular holes 24 for the ramming machines of circular shape. The ram breakers also have a functional portion provided with a serrated profile b with preferably clamped angles, such as a striker with a longitudinal functional portion in Fig. 3.

In addition, it has been fly-off that by means of a die-cutter with a profile for circular holes, which has priority, ea can make the same clean cross-sections as with a die-cutter for holes of longitudinal shape. When an embossing die 20 with a plurality of punching holes 22,22 is used, a large number of embossed patterns can be achieved by only modifying the die or playing some of the punches without the need for another die.

The embossing die 20 may be provided with long gypsum boards over the entire perforating die for extending to a certain depth, but the perforating die for its width, or short recesses in the form of recesses, that the die die plate 00b do not penetrate the full width of the board.

The rammers 10 as well as the holes 22, 42 in the embossing die are made very precisely so that the rammers can be firmly seated in the die. The total tolerance is approximately 5 nanometers (i.e., 2.5 nanometers around the circumference of the circular opening). This makes it possible to accurately reproduce the perforated patterns on the plates.

In FIG. 5 shows a portion of a compound punch 40 with long punches 42 and short punch punches 44 embedded in the die die 20. The punches 42 are the same as in FIG. 1, 2 and 3 and the embossing die 20 is identical to the die of FIG. 4th

The die assembly 40 also comprises a top separating plate 46 with holes 40, 40 having dimensions corresponding to the long die struts 42 and the short punching dies 44. Another part of the die assembly 40 comprises the lower holes 02 corresponding to the long profiles. 04 is firmly interposed between the separating plate 40 and the bottom plate 00 of the die assembly. The embossing die 20 is pushed to the plate 04, whereby the punching and then punches exert a pressure of approximately 1.5 MN / m ² on the plate. The long punches 42 penetrate the holes 40 in the separator plate into the plasterboard. The punch assemblies are pushed out of the holes 52 in the bottom plate 50 of the die assembly

In practice, thrusting 42 plugs of the plasterboard. Thus, the plate 54 is perforated before the short punches 44 are engaged in the process. The embossing die 18 is advanced further to the plate 54, the short punches 44 penetrate through the holes 43 in the separating plate 43 into the co-carton. After extruding the paper substrate ££. The plasterboard 54 with the short punch punches 44 is perforated and the embossing die 1 is removed.

The dimensions of the long rammers 42 and the dimensions of the corresponding apertures 52. in the lower dock 5Ώ of the die assembly should be selected such that the paper substrate (if any) of the plasterboard 54 is cut off at the points of penetration of the rammers through the plasterboards. from the bottom plate. When the top of the board has a certain substrate (e.g. paper), the clearance between the rewinders 42 »44 and the holes 48 and 43 'in the separating board has a decisive influence on the final appearance of the board. When it is too small, the perforated holes and recesses will have sharp delimited edges; when the clearance is greater, the perforated holes and wells will have less pronounced edges and visible fibers of the substrate.

The apertures 52 in the bottom plate 50 of the die assembly are preferably made with the same accuracy as the dies 42, 44 and the holes for attaching the dies to the die 23 so that the dies will penetrate very tightly through the holes of the bottom plate and clean carved edges. After the perforation, the surface treatment of the board can be supplemented by fine wells by means of a roller with spikes arranged in a bow on its circumference. These spikes have a much smaller diameter than the punches 42, 44, and therefore the pressure required to penetrate them into the plasterboard is much less than the pressure required for the perforation itself.

Gypsum board ££ after perforating with XQ die assembly. is shown in FIG. 6. The plate has recesses in the form of slits ' and circular perforated holes fi. The ratio of the recesses in the form of slots to circular acoustic openings is preferably from 2: 1 to 1: 2. It has been found that 6% of the total surface area of the board should be perirated to achieve satisfactory acoustic properties without substantial mass loss. The elastic appearance can be achieved by additionally perforating 6% of the total area of the front side of the board in the form of depressions that do not extend over the entire width of the board.

The acoustic properties of the boards may be varied by varying the percentage of the perforated surface treated. The appearance of the boards can remain unchanged by replacing the complete perforation with recesses that do not significantly affect the acoustic properties of the boards.

Both surfaces of the gypsum board perforated by the strippers according to the invention are characterized by very clean openings. The result manifests itself in a very attractive appearance which cannot be achieved by the prior art methods.

One of the ways in which the plasterboard of the present invention can be used is to adjust the ceilings. It may be desirable to adjust the ceiling with sound absorbing docks so that the panels in the different parts of the ceiling have different acoustic properties. The plates may have a similar appearance to the plates perforated according to the invention, and this may be achieved by extruding the recesses in the form of slits. These slabs ea can use b slabs perforated according to the invention in the construction of a ceiling having a uniform appearance, but with different acoustic properties in the individual CaBts.

As already mentioned, dies according to the invention Ba can make perforated holes or embossed depressions in the gypsum board with extremely clean, sharp and well-defined edges.

Edge cleanliness and sharpness can be measured and a quantitative measure of edge quality can be derived accordingly.

It has been found that the thick opening always has a larger circumference with respect to its uneven edge. In the case of a circular hole, the ideal circumference is 2ir D. In the case of a very uneven edge, the actual circumference may be of the order of 2.5ir D, where D is the diameter of the hole.

Since the diameter values will vary with the shape of the hole and its size, we have developed a method for deriving the absolute degree of purity of smoothing its circumference.

A digital circuit was created, for example, by counting the aperture using the aperture image procedure and measuring its pixels (pixel = smallest largest angle from the appropriate illumination of the image element) at the aperture circumference as the circumferential smoothing of the circumference. The measurement can be done as an Optimas 5.2 image analysis system with a Cohu high performance CCD camera on a Kaiser copy standard film. A 50 mm CoBmicar TV lens with a δ / 5.6 together with a 10 mm rim was used. The column height with the camera was on a tripod 42.2 mm and the resulting magnification was 5.325 x. Proper lighting is needed to achieve satisfactory results. This is achieved by using four 75-watt bulbs positioned as far apart as possible.

I can detect two pairs of bulbs on either side of the samples, 56 cm from the optical axis, the bulbs being 30 cm apart and 12.5 cm above the plate surface. As the circuit smooths, its length increases and Ba increases the number of pixels of the circuit. The cut quality is then defined as the ratio of the dimensions of the circumference after smoothing to the dimension of the original circumference. It should be remembered that a large value means a smooth cut, because the length of the perimeter has not greatly increased by smoothing.

The value will change b by the amount of smoothing done. For our purposes, the measurement is defined as the ratio of the number of pixels of the circuit in four smoothing steps performed using the standard smoothing algorithm.

To achieve repeatable results, the final cut quality index is understood as the mean of a plurality of measurements (e.g., 16) with a continuous rotation of the samples of 45 ° every few measurements.

In this way, the ideal circuit would be denoted by index 1 and the quality of the circuit deteriorates as the index value decreases. We found out. That aperture made by the preferred puncher of Figs. 1 to 3 with a clamped tooth angle 120 and a background tooth depth 1 that is converted to pixels mm has a cut quality index of 0.99, whereas with the punchers of the prior art an index of 0 can be achieved. 90. In order to make the cut aesthetically acceptable, we decided that the quality index must be 0.98 or more.

The smoothing algorithm used is a standard binary digest followed by a binary extension. The first stage consists of one decomposition and then one extension. According to binary morphology, decomposition is called a process in which the number of foreground pixels associated with 8 background pixels (i.e., pixels adjacent to left, right, up, down, and diagonals) is reduced. Extension is the opposite of decomposition. After segmenting the gray scale image into a binary image, the 8-pixel pixels connected by the foreground b pixels are recognized through the enlargement process and are foreground. Finally, the resulting extension bitmap is copied to the grabber frame.

The dither operation is performed by the dither filter, which performs the gray scale conversion to binary (black and white only), and then performs the binary dither operation. Then the bitmap is copied back. The filter uses the following arguments:

ArgO: NULL uses the current partition

Arg2: NULL use implicit foreground lower value (s) Arg3: NULL use implicit foreground upper value (s) Arg4: NULL use implicit 3X3 square structuring element

Arg6: NULL each pixel is in a rectangular Arg4 X Arg5 structuring element

Arg7: NULL coordinate origin X is placed in width / 2 Arg8: NULL coordinate origin Y is placed in height / 2

The augmentation operation is done by an expansion filter that enlarges the foreground areas of the image by converting the gray scale to binary (black and white only) and then does the augmentation operation itself. The extension bitmap is then copied back. The following arguments are used:

ArgO: NULL uses the current partition

Arg2: NULL uses the default lower foreground value (s)

Arg3: NULL uses the default foreground upper value (s)

Arg4: NULL uses the default 3X3 Square Structure element

Arg6: NULL each pixel is in a rectangular Arg4 X Arg5 of the Structuring element

Arg7: The NULL origin of the X coordinate is placed on Slrka / 2

Arg8: The NULL origin of the Y coordinate is placed at height / 2

A contour outline filter is also used to make white borders around the foreground region. This feature first divides the gray image into foreground and background components. In the resulting binary image, the foreground pixels that remain associated with the 4 background pixels remain unchanged. All other pixels change in the background. Thus, a foreground boundary is provided, associated with 8 pixels. This image bitmap is then copied back to the grabber frame. This filter uses the following arguments:

ArgO: NULL uses the current partition

Argl: NULL uses the default lower foreground value (s)

Arg2: NULL uses the default foreground upper value (s)

The following are Optimas macros, which show that 4 repetitions of the smoothing algorithm are used. The first step has already been described. In the second step two decompositions and then two extensions are used, in the third step three decompositions and then three extensions and so on.

We have decided that perforated apertures in which the quality index of 0.98 or greater have been achieved have acceptable cut quality. This value was obtained as an average of 16 series of measurements, with 4 repetitions of the smoothing algorithm at a magnification of 5,325 times as part of each series as described above.

We also decided that in the case of unacceptable cut quality, the quality index value is less than 0.98. The following results were achieved:

sample hole shape average value standard cost the circuit in X variation 16 fields (n - 1) S and D circular and pilot extended 0.90 0,024 Gyptone Quatro 20 square 0.97 0,010 Gyptone rectangular Line 4 slots 0.97 0,020 Yoshino Board round 0.96 0,018 , the punch according to this invention circular and extended 0.99 0,100

Image analysis - Smoothing algorithm Optimae

GrayToBinary (, 0.0,67.0);

OutlinerFilter C);

Histogram (NULL);

MacroMessage (ArBO / HistogramStats);

UndoO i

BINB lterations = l;

ErodeFilter (ΒΙΝΒ-ilterations);

DilateFilter (, BINB_ilterations);

BINB i1terations Lion

OutlineFi 1 ter O;

Histogram (NULL);

MacroMessage (ArBo | HistogramStats [0] / 255);

Undo ();

BINB literátions = 2;

ErodeFilter (BINB-ilterations);

DilateFilter (, ΒΙΝΒ-ilterations);

BINB_ilterations = lj

OutlineFilter ();

Histogram (NULL);

MacroMessage (ArBo | HistogramStats [0] / 255);

Undo ();

BINB_ilterations = 3;

ErodeFilter (ΒΙΝΒ-ilteration);

DilateFilter (, ΒΙΝΒ-ilterations);

BINB_ilterations = l;

OutlineFilter ();

Histogram (NULL);

MacroMessage (ArBo | HistogramStats [0] / 255);

Undo;

BINB_ilterations = 4;

ErodeFilter (ΒΙΝΒ-ilterations);

DilateFilter (, ΒΙΝΒ-ilterations);

BINB literátiοηβ = 1;

OutlineFilter O;

Histogram (NULL);

MacroMessage (ArBolHietogramStats [0] / 255)

X? 02

Claims (35)

1. A punching device for perforating connective plates, a method of perforating and thus perforated plates, a punching device having a longitudinal cross-section and its functional part is provided with a serrated profile on the entire circumference. A puncher according to claim 1, characterized in that both ends of the punching functional part are terminated by a tooth tip. A puncher according to claim 1 or 2, characterized in that the angle between the teeth of the serrated profile is in the range of 90 ° to 150 °. A punching machine according to claim 3, characterized in that the angle between the teeth of the serrated profile is in the range of 115 ° to 150 °. A punching machine according to claim 4, characterized in that the angle between the teeth of the serrated profile is approximately 120 ». I 6. A ramming machine according to any of the foregoing of claim a č u j UCE s a T that depth zuba j e lower or the equal to 2 mm. 7.Damper according to claim 6, s n and no u j UCE because of tooth depth is lower or be equal 1.5 mm. A punching machine according to claim 7, characterized in that the depth of the tooth is less than or equal to 1 mm. A pusher according to any preceding claim, wherein the stabbing side thereof has an undulating surface over the entire length of the pusher. A puncher according to claim 9, characterized in that the spacing of the serrated profile is substantially coincident with the spacing of the undulating side surface. The punching machine according to claim 10, wherein the pitch of the serrated profile and the undulating surface of the underside of the side face are approximately 3 mm. A piercer according to any preceding claim, characterized in that the edges of the stabbing sides are rounded. A puncher according to any preceding claim, characterized in that the profile of the puncher is shaped such that the perforated holes are in the form of slits. A puncher according to any preceding claim, wherein the puncher is solid. 15. A punching machine for perforating a board comprising a binder, the functional part of which has a serrated profile, rounded edges, the depth of the teeth being not more than 2 mm. A die assembly for perforating a binder plate, the die assembly including a die die and punches mounted on the die die, the punches according to any one of claims 1 to 15. 17. The die assembly of claim 16, wherein the rammers extend substantially in the same direction. The punch assembly of claim 16 or 17 is. characterized in that at least some of the strippers are shorter punch struts for penetrating the binder plate, these shorter punch struts are attached to the die die and their functional portions are spaced from the die die at a smaller distance than the functional parts of the long breakers. 19. The die assembly of claim 18, wherein the long punches are longer than the shorter punch punches at least by the thickness of the binder plate to be perforated so that the long punches penetrate the plate before the plate contacts the plate. shorter punching tools. ZO. A method of perforating an acoustically absorbent board with a binder comprising the following steps: - applying the plasterboard flat on the profiled surface of the die matrix b by the rammers of the present invention, at least some of these rammers are according to claims 1 to 8, - perforating the board by applying pressure between the die die and the backing plate so that the punches penetrate the plasterboard; - separating the die die from the perforated plate. 21. The method of claim 20 wherein said board is gypsum plasterboard. The method of claim 21, further comprising perforating the plate with substantially circular openings. Method according to claim 19, 20 or 21, characterized in that the strippers are short punch strippers and long strippers, the penetration of all strippers into the board is perforated as part thereof, so that the short strippers penetrate the board but do not penetrate through them all. width, and long punches penetrate the entire width of the board. Method according to any one of claims 19 to 23, characterized in that the board has a substrate. A method according to claim 24, characterized in that the die die is pressed on the side of the plate b by the substrate. The method of any one of claims 19 to 25, wherein the coating of the planar surface of the plate after the die die is removed is another part of the method. The method according to any one of claims 19 to 26, wherein the extrusion of the fine wells by a roller with the spokes protruding is another part of the method. The method of any one of claims 19 to 27, wherein covering the perforated holes on one side of the board is another component of the method. Method according to claim 28, characterized in that the openings are covered by a sound absorbing material. A method according to any one of claims 19 to 29, characterized in that the perforated holes extending over the entire width of the plate are made before the punch punches penetrate the plate. 31. A sound absorbing board comprising a binder mass with a plurality of perforated apertures extending through the binder mass, the cut quality index of the perforated apertures being greater than 0.98, wherein the pixel quality index of the perforated aperture to the aperture aperture pixels is defined as the ratio of the digitized image circumference to the amount of smoothing on the periphery of the digitized image perforated prior to the smoothing operation, the smoothing operation consisting of four decomposition steps followed by a binary extension. binary 32. The binder board of claim 31, wherein the cut quality index is at least 0.99. 33. The binder board of claim 31 or 32, wherein the cut quality index is calculated as the mean of a plurality of cut quality index measurements. 34. The binder board of claim 33, wherein the mean value is calculated from 16 series of cut quality index measurements. Binding board according to any one of claims 33 to 34, characterized in that the points are scanned by a digital camera or by magnification. 5.325 x. A ramming machine which substantially corresponds to the description with reference to FIG. 1,2 and 3. A die assembly substantially corresponding to description b with reference to FIG. 4 and 5. 38. A method of perforation substantially corresponding to the description.