WO2012033449A1

WO2012033449A1 - Pulp mould arrangement

Info

Publication number: WO2012033449A1
Application number: PCT/SE2011/051070
Authority: WO
Inventors: Björn Nilsson; John Shand
Original assignee: Pakit International Trading Company Inc.
Priority date: 2010-09-07
Filing date: 2011-09-05
Publication date: 2012-03-15
Also published as: EP2614185A4; CN103348062A; EP2614185A1

Abstract

The present invention relates to a mould arrangement including a loose sintered metal mould (10, 20) having a front or moulding side (13) and an opposite rear side (14), the rear side (14) being secured to a base plate (16), wherein the base plate (16) includes a plurality of elongated channels (17, 18) including at least one suction channel (17) for delivering suction pressure to the mould (10, 20) via at least one transversally directed suction opening (170), and at least one of said channels (18) includes a heating rod (53).

Description

PULP MOULD ARRANGEMENT

TECHNICAL FIELD BACKGROUND

Packagings of moulded pulp are used in a wide variety of fields and provide an environmental friendly packaging solution that is biodegradable. Products from moulded pulp are often used as protective packagings for consumer goods like for instance cellular phones, computer equipment, DVD players as well as other electronic consumer goods and other products that need a packaging protection. Furthermore moulded pulp objects can be used in the food industry as hamburger shells, cups for liquid content, dinner plates etc. Moreover moulded pulp objects can be used to make up structural cores of lightweight sandwich panels or other lightweight load bearing structures. The shape of these products is often complicated and in many cases they have a short expected time presence in the market. Furthermore the production series may be of relative small size, why a low production cost of the pulp mould is an advantage, as also fast and cost effective, way of manufacturing a mould.

In traditional pulp moulding lines, se for example US 6210 531, there is a fibre containing slurry which is supplied to a moulding die, e.g. by means of vacuum. The fibres are contained by a wire mesh applied on the moulding surface of the moulding die and some of the water is sucked away through the moulding die commonly by adding a vacuum source at the bottom of the mould. Thereafter the moulding die is gently pressed towards a complementary female part and at the end of the pressing the vacuum in the moulding die can be replaced by a gentle blow of air and at the same time a vacuum is applied at the complementary inversed shape, thereby enforcing a transfer of the moulded pulp object to the complementary female part. In the next step the moulded pulp object is transferred to a conveyor belt that transfers the moulded pulp object into an oven for drying.

Conventional pulp moulds which are used in the above described process are commonly constructed by using a main body covered by a wire mesh for the moulding surface. The wire mesh prevents fibres to be sucked out through the mould, but letting the water passing out. The main body is traditionally constructed by joining aluminium blocks containing several drilled holes for water passage and thereby achieving the preferred shape. The wire mesh is commonly added to the main body by means of welding. This is however complicated, time consuming and costly. Furthermore the grid from the wire mesh as well as the welding spots is often apparent in the surface structure of the resulting product giving an undesirable roughness in the final product. Furthermore the method of applying the wire mesh sets restrictions of the complexity of shapes for the moulding die making it impossible to form certain configurations in the shape.

WO2006057610 shows a loose sintered female and a male pulp mould having a plurality of drainage channels. Several pulp moulds are mounted on to a heat plate having a vacuum chamber arranged behind the heating plate. The heat plate have a high number of drilled holes each mating a drainage channel of the moulds thereby connecting the vacuum chamber to the drainage channels and thus providing a suction through the moulds.

OBJECTS OF THE INVENTION

SUMMARY OF THE INVENTION

At least one of the above stated objects and/or problems is solved by a pulp mould and/or method as defined by the independent claims. Thanks to the invention there is achieved an improved pulp mould and also a tool, partly thanks to the new pulp mould which may be produced in a much more cost efficient manner, which also may require less energy during its intended use and which may in an improved manner provide high quality pulp products. Furthermore the design may provide more compact arrangements presenting numerous advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a schematic view of a manufacturing process of a moulded fibrous product according to the invention,

2 shows a perspective view of the formation and pressing tools,

3 presents two male pulp moulds arranged for formation of fibre products, in accordance with a preferred embodiment of the invention,

Fig 4a shows a cross section according to line IVa in Fig. 3,

Fig, 4b shows a cross sectional zooming of the embodiment shown in Fig. 4a, Fig 5 shows a perspective view from above of a male pulp mould of Fig 3, Fig 6 shows a partly exploded view in perspective of one male pulp mould

according to the invention Fig. 7 presents a cross sectional view of pulp mould and base plate according to the invention, according to line VII in Fig. 5, and

Fig. 8a shows a planar view of the rear surface of a mould, and

Fig. 8b shows a planar top view of a base plate according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

In the forthcoming text when using directional terms such as upper or lower in relation to a pulp mould, the moulding surface of the pulp mould is seen as the top and the base plate as the bottom.

Fig. 1 is a schematic view of a manufacturing process for producing moulded fibrous products showing a forming section 1 for forming a moulded pulp object, a drying section 2 for drying the moulded pulp object, and a after treatment section 3 for subjecting the dried moulded pulp object to after treatment steps such as lamination, finishing the edges of the pulp objects, packing the pulp objects, etc. The forming section 1 includes a plurality of rotatable holders 4, each having two opposite located tool carriers 5. The holder 4 alternately have female 20 or male 10 pulp mould(s) mounted on the tool carriers 5, e.g. if the first holder has male moulds then the second holder has female moulds, and the third holder male moulds etc. The tool carrier 5 can be pushed out and pulled in, in relation to the holder 4, thereby enabling the opposing moulds to mate each other during operation. The means for pushing and pulling the tool carriers 5 can be achieved by means of various devices (known per se), e.g. include mechanical arm mechanism 6, and/or a telescoping mechanism (e.g. hydraulically operated), etc.

During operation, the pulp mould(s) 10 of the first holder 7 is immersed in the stock that is kept in the tank 9 to form a fibre object(s) on the pulp mould(s). The fibre object(s) is subsequently dewatered between opposing pairs of pulp moulds 10, 20 of the holders 4, until it is passed to the drying section 2 by the last holder 8. The dewatering between opposing pairs of pulp moulds 10, 20 is performed by pushing opposing tool carriers 5 with their female respectively male moulds against each other as is described in more detail in WO 2006057609/10, which are herewith introduced by means of reference. The dewatering operations are preferably performed under suction and heat. The first 7 and the last holder 8 rotate 90 degrees back and forth during operation, while the intermediate holders each rotate 180 degrees so that the fibre object(s) can be passed from the pulp mould(s) of the first holder 7, to the pulp mould(s) of the second, and so on till the last holder 8. The handover of the fibre object(s) between an opposing pair of pulp moulds 10, 20 can be done by releasing the suction through the delivering pulp mould(s) 10, 20, and optionally give it a gentle blow, while suction is applied through the receiving pulp mould(s) 20, 10.

The facing surfaces of opposing pulp moulds 10, 20 have complementary shapes with regard to the moulding surfaces thereof, however other characteristics of the moulds may differ depending on the positional order of the moulds, for instance the mould(s) of the first holder 7 may have a coarser structure of its moulding surfaces, than the opposing mould(s) of the second holder 4, and subsequent moulds 20, 10 of the following holders may have finer and finer surface structures. Further the suction means and/or the heating means may also vary between the holders, e.g. the pulp mould of the first holder 7 may have suction means but lack heating means. Figure 2 shows a holder 4 positioned in its support structure and related sub equipment, which will not be described in greater detail, e.g. means for rotating the holder around its axis, and means pushing and pulling the tool carrier 5 outwards and inwards. On the holder 4 there are arranged tool carriers 5, presenting some features of one embodiment according to the invention.

The tool carrier 5 comprises a plurality of locations 51 , where (in the herein shown embodiment) up to eighteen pulp moulds 10/20 can be placed side by side. Of course the invention is by no means limited to this number, but it is rather depending on outside production factors outside the scope of the present invention, i.e. the surface area of the tool carrier 5 can be increased or decreased and/or the bottom area of the pulp mould 10/20, could likewise be increased or decreased.

The tool carrier 5 in Fig. 2 comprises a rear carrier plate 54 onto which there are attached tool plates 50 representing six columns, where each column can support three pulp moulds 10, here exemplified by male pulp moulds 10 at the three locations 51 constituting a first column. The remaining columns are shown only with the bare tool plates 50 displaying the locations 51 whereat a female 20 or a male 10 pulp mould can be mounted. The tool plate 50 could be produced in almost any kind of material, but is preferable made from some kind of light weight material having good ability to fulfill all needs, e.g. aluminum. Preferably the two carriers 5 also comprise a layer of insulation in between the tool plate 51 and the carrier plate 54. Along one side of the tool carrier 5 there is arranged vacuum pipe 52 that extends substantially along the whole length of the tool carrier 5. From the vacuum pipe 52 there is arranged a number of branch pipes 52' positioned at each tool plate 50 respectively, to provide for vacuum to the pulp moulds 10/20 once mounted thereto, which will be described in more detail below.

The vacuum pipe 52 is fixedly attached to the tool carrier 5, necessitating a flexible connection (not shown) to the vacuum pump to enable the desired movement of the tool carrier 5.

Along another side of the tool carrier 5, preferably the side which is opposite the one along which said vacuum pipe 52 extends, there are arranged transversal heating rods 53 extending across the tool plates 50. In the example shown in Fig. 2 a set of four heating rods 53 is located across each tool plate 50, however it is obvious that the number of heating rods 53 above each tool plate 50 may be varied.

The pulp moulds 10/20 according to the invention include a loose sintered, porous metal mould 10 having a front or molding side 13 and an opposite flat rear side 14, where the rear side 14 is secured to a base plate 16 (see Figs. 4-8) made in a solid metal material. The pulp mould 10 includes a porous body with an inner permeable surface and an outer permeable moulding surface 13. The porous body is preferably a loose sintered body from metal powder. In particular copper based powders, preferably bronze powders have been shown to provide very good results, however other materials are also conceivable such as nickel based alloys, titanium, stainless steel etc. The porous body may be of metal particles of the similar sizes throughout the body or be layered by powder of different size and /or content, to fulfil different needs and mostly having a finer powder at the outer moulding surface. Regarding the sintering it is referred to document WO 2006057609/10 hereby incorporated by way of reference. Furthermore it is to be understood that the shape of the mould 10/20 is decided by the wanted shape of the fibrous object and that the shape of the embodiments are by means of example.

According to one embodiment the mould 10/20 is secured onto the base plate 16 by metal bonding, which can be achieved by sintering the two parts together. It is however also possible to attach the mould 10/20 in some other way, for instance by screwing. Preferably the mould 10/20 and the base plate 16 are made of the same metal material. This is especially advantageous in case securing is achieved by means of sintering, since using the same material means the mould 10/20 and the base plate 16 will have the same melting temperature. The interfit between a tool plate 50 and the mould 10/20 is illustrated in Fig. 3 and Fig. 4a, wherein is shown, in a schematic way, two male pulp 10 moulds adjacently arranged on a tool plate 50 and positioned onto transversal heating rods 53 arranged across said tool plate 50. For clarifying reasons the tool carrier 5 is not shown in Fig. 3, but merely the tool plate 50 and parts of the vacuum pipe 52 with branch pipes 52' and oppositely located heating rods 53.

As will be more clear from the following description of Figs. 4 - 8, base plate 16 of the mould 10 includes at least one heating channel 18 for a corresponding heating rod 53. The male moulds 10 are arranged on top of the tool plate 50 by means of introducing the heating rods 53 through the corresponding heating channels 18 arranged to elongate through said base plate 16. In order to position and attach the moulds 10 on the tool plate 50 the moulds are slided, one by one, onto and along the respective set of heating rods 53. This means the tools 10 are located and built up upon the tool plate 50 gradually, side by side, by means of being slided along the rods preferably until all locations 51 on the tool plate 50 are filled.

Simultaneously to being positioned onto the heating rods 53 the moulds 10 are also connected to the branch pipes 52' of the vacuum system, where said branch pipes 52' are arranged to match with connectors 172 on the base plate 16 and where each connector further leads to a vacuum channel 172 through the base plate body 16. Pulling of vacuum through the mould body 10 will be explained in more detail in connection to Figs. 4 - 8.

Once a mould 10 has been rightfully positioned in relation to the tool plate 50 by means of sliding the mould onto the heating rods 53, the mould is preferably also attached to the underlying tool plate 50, for instance by means of screwing. One way of

accomplishing this can be understood from looking at Fig. 3 wherein at the location lacking a mould 51 there are arranged a number of four screw holes in the tool plate 50. The screw holes in the tool plate 50 are intended to match with holes at the back of the base plate 16 so that connection of the mould 10/20 with the tool plate 50 can be made by screwing from the back of the tool plate 50 and into the matching holes in the base plate 16. Optionally the mould 10 and/or the tool plate 50 may be provided with positioning pins intended to facilitate mount fitting of the mould 10/20 onto the tool plate 50. Fig. 4a presents a cross section (in a schematic manner) according to line IVa in Fig. 3 drawn through two male moulds being attached to a tool plate 50, in accordance with the invention. The two male moulds 10, 10' have been positioned onto the tool plate 50 by introducing transversal heating rods 53 through corresponding heating channels 18 in the base plate body 16, 16' sliding the moulds 10, 10' to a desired location on the tool plate 50 whereat the moulds are connected to the tool plate 50, e.g. by means of screwing.

The vacuum pipe 52, arranged at one side of the tool plate 50, comprises a plurality of branch pipes 52' arranged to be connected to elongated suction channels 17 leading through the base plate 16 of the corresponding mould 10. The elongated suction channels 17 are extending parallel to the flat rear side of the mould 10. The elongated suction channels 17 are further connected to the sintered mould 10 via at least one suction opening 170, preferably more than one suction opening 170, between the suction channel 17 and the flat rear side 14 of the sintered mould. The vacuum pipe 52 can hereby deliver vacuum suction pressure to the sintered mould 10 from the branch pipes 52', through the thereto connected suction channels 17 and via said suction openings 170.

According to one embodiment the sintered mould body 10 includes a number of drainage channels/passages 150 each having a pointed end at the portion meeting the surface 13 which is intended to support a fibre product. Although the drainage channels are shown with their pointed end nearby the upper surface 13 of the mould, it is possible to have the pointed end ending substantially anywhere within the body 10. The at least one suction opening 170 is preferably arranged to mate the bottom openings 150 of the plurality of drainage channels 15. It is preferred that the mating is a close match as possible and preferably every suction opening 170 always mate a corresponding bottom opening 150, but of course the invention is not limited to a perfect match rather the suction openings 170 could differ in diameters contra the bottom openings 150. The arrangement of a coupling 171, 172 between the vacuum suction channels 17 of two adjacent moulds 10 are further explained by the cross sectional zooming IVb of the embodiments shown in Fig. 4a. The opening of a vacuum suction channel 17 of a first mould 10 is provided with a tubular male connector 171, and the opening of a vacuum suction channel 17 of a second meeting mould 10' is provided with a sleeve-like female connector 172 having an inner diameter substantially corresponding to the outer diameter of the tubular male connector 171. Connection of the tubular male connector 171 and the sleeve-like female connector 172 will result in a substantially seal-tight coupling between the elongated suction channels 17, 17' of the two corresponding moulds 10, 10'. Obviously the female 172 and/or the male connector 171 might comprise further sealing means such as gaskets or the like for further safeguarding complete air-tight connection. As depicted in Fig 4a the same kind of coupling principle may preferably be used between the branch pipes 52' and the first mould 10, i.e. using a diameter of the branch pipe end that matches the female connection 172.

It is seen that the two juxtaposed moulds 10 in Figs 4a-4b respectively comprises suction channels 17 in the form of through bores passing through the entire base plate 16. However, the mould which is to be positioned at the outermost end of a column, at the opposing side of the vacuum pipe 52, may include a suction channel 17 in the form of blind bores, i.e. having a closed end for creating a closed vacuum system. Obviously the blind bore may be replaced by simply providing a sealing plug at the outermost open end of the end suction channel 17, which may be advantageous from a production perspective and may increase flexibility.

In Figs. 5-7 there are shown in different views, and in greater detail, one of the tools 10, here a male mould (NB. in the figures some hidden lines are shown, to increase clarity). As is evident for a skilled person the same inventive features are of course applicable to both the male and female moulds. The mould arrangement includes a loose sintered metal mould having a front/upper moulding surface 13 that is porous to enable vacuum to pass through, and an opposite flat rear side 14, the rear side 14 being secured to a base plate 16 made in a solid metal material. The base plate 16 includes at least one elongated suction channel 17 for delivering suction pressure to the mould 10, the suction channel/s 17 extending parallel to the flat rear side 14 of the mould 10 and being connected to the porous mould in at least one suction opening 170 representing a passage through the base plate 16, between the suction channel 17 and the porous mould body 11. The mould 10 is firmly secured to the solid base plate 16, preferably (but not exclusively) by means of metal bonding which is accomplished by melting a sintered mould 10 onto a base plate 16 of suitable material, such as bronze. Preferably after securing the mould 10, the base plate 16 is provided with at least one elongated suction channel 17 and at least one heating channel 18, for instance by means of drilling corresponding holes through the base plate 16. Of course it is also possible to drill the suction 17 and heating channels 18 before securing the mould 10 to the plate 16. From each suction channels 17 there are arranged a number of suction openings 170 facing the rear side 14 of the mould 10 for delivery of vacuum suction to the mould body 10. The suction openings 170 are preferably created in the solid base plate 16 before it is secured to the rear side 14 of a mould 10 which rear side 14 preferably is substantially flat and essentially impermeable. Normally suction openings 170 are created by means of drilling transversal holes in the upper side 162 of the base plate 16, into the suction channel/s 17 at positions corresponding to where the suction channel/s 17 are (or will later be) created longitudinally through the base plate 16.

Once the elongated, longitudinal suction channels 17 are drilled, e.g. after having sintered the mould 10 onto the base plate 16, the suction openings 170 will be connected to the main suction channel 17 and vacuum can be drawn there through. Each suction opening 170 is arranged to at least partly mate with an opening 150 of a corresponding drainage channel 15 leading to into (sometimes expending adjacent the rear side 14 of) the mould 10, as will be explained also in connection to Fig. 7. The drainage channels 15 are created in the mould 10 during sintering procedure by means of pointed elongated elements, e.g. nails, being positioned within the sinter particles. After sintering, the elements are removed from the mould body 10 leaving said drainage channels 15. The creating of the drainage channels 15 is described in WO 2006057609, also referred to above.

According to another way of producing the tool according to the invention, said mould 10 and said base plate 16 can be connected simultaneously to sintering the mould 10. In such a procedure the base plate 16 is first provided with transversal through holes 170, leading through the entire thickness of the base plate 16 presenting one opening at the upper side 162 and one opposite opening at the rear side 160. Sinter particles are poured into a basic mould, forming the body of the pulp mould 10, and the base plate 16 with the through holes 170 is subsequently positioned in contact with the particles corresponding to the rear side 14 of the mould 10. Said pointed elongated elements are then to be introduced through the holes 170 and further into the loose sinter particles, whereafter sintering is performed according to conventional know how. Sintering leads to that the base plate 16 is secured to the mould 10 by means of metal bonding. After cooling, the sintered body 10 is taken out of the basic mould and the sharp pointed elements are withdrawn from the mould through the holes 170 in the base plate 16, forming drainage channels 15 within the mould body 10. Hereby a substantially perfect match between the through holes 170 and the drainage channels 15 can be achieved. When attaching a base plate 16 comprising such through holes 170 onto a tool plate 50 it is desired that the rear side 160 is of the base plate 16 is sealed in an air tight manner, for instance by means of gaskets (not shown) positioned around each opening of the respective holes 170, or by means of a large sealing ring around the periphery of said rear side 160 of the base plate 16, surrounding all hole openings 170.

As is seen in Figs. 5-7 the base plate 16 includes a plurality of, (e.g. four) heating channels 18 and a plurality of (e.g. three) suction channels 17, but it is evident that more or fewer channels may be created. The suction channels 17 extend essentially parallel to each other and at essentially the same distance to the flat rear side 14 of the mould. Preferably the heating and suction channels 17 are arranged to alternate within the bronze plate in order to maximise distribution of heat and suction respectively within the mould 10.

The base plate 16 may comprise a thickness between 10-50 mm, preferably 20-30 mm. Further the diameter of the suction channels 17 can be within the interval 5-40 mm, preferably 10-30 and the diameter of the heating channels 18 can be within the interval 5-30 mm, preferably 10-25 mm. Preferably the heating rods 53 have a circular cross section and comprise dimensions that closely matches the heating rod channels 18 in order to maximise heat transfer from said heating rods 53 to the base plate 16 and further to the mould surface 13, (e.g. 015, "TP", output between 500-2000W each). In Fig. 6 there is shown an exploded view of male pulp mould 10 according to the one embodiment of invention. For illustrative purposes the base plate 16 in Fig. 6 is shown as transparent, displaying the through channels forming the heating 18 and suction channels 17 respectively.

The base plate 16 further includes a number of threaded screw holes 161 facing towards its rear side 160 and positioned in adjacent the base plates, periphery, intended for allowing fastening of the base plate 16 onto an underlying structure, e.g. a tool plate 50. The possibility of integrating the threaded screw holes 161 directly into the base plate 16 means that no extra flange for attachment is needed which leads to space savings and to very effective use of the carrier plate area since more area is used for production of paper products and less area is required for fastening of moulds 10/20.

In Fig. 7 there is seen a cross section according to line VII in Fig. 5. Herein is shown the suction openings 170 mating with the drainage channels 15 extending from the rear side 14 of the mould 10 towards the front or moulding side 13.

Each suction opening 170 is arranged to at least partly mate a corresponding drainage channel at the rear side 14 of the mould, preferably the number of suction openings in a vacuum channel is in the range of 3-20, more preferably 4-10. Preferably the rear side 14 of the mould 10 is fiat and impermeable except for the openings to the drainage channels. The surface can be made substantially impermeable by means of machining the rear surface 14 after sintering and before securing it onto a base plate 16. In figure 8a there is shown the rear side 14 of a mould 10 including the drainage channel openings 150 which are positioned so that they are substantially aligned with the position of corresponding suction channels 17 within the base plate 16 once said mould 10 is secured thereto. Further in Fig. 8b there is seen the upper side of the base plate 16 intended to meet the rear side 14 of the mould 10. According to the example of Fig. 8b a number of suction openings 170 are distributed along the extension of underlying suction channels 17. As is seen herein one end portion of each suction channel 17 comprises a larger diameter compared to the rest of the channel, whereby previously described sleeve-like female connector 172 can be fitted therein.

Since the heating rod/s 53 is embedded in the base plate 16 much less energy needs to be used to achieve the same temperature at the moulding surface 13 in comparison to the use of a heating plate positioned below the mould as known prior art. Further since the heat plate may be eliminated the pulp moulds may be positioned closer to the rotational centre of the pressing tools 4 which has several advantages: 1) the strike distance may be increased or each mating pressing tools 4 may be placed closer to one another maintaining the same strike distance, 2) the momentum required to rotate the pressing tools 4 is reduced since the weight distribution is moved closer to their rotational centre, thereby enabling a faster rotation and/or a rotation at lower power needs. 3) the arrangement according to the invention will lead to a very compact arrangement. 4) embedding the heating rod 53 into the base plate 16 will lead to good heat transfer to the moulding surface 13. Further since less energy is used less heat will also reach the machinery of the pressing tools 4. It may therefore be possible to further decrease the heat insulation plate as well as eliminate possible cooling element without risking undue heating of the machinery of the pressing tools, providing even better weight distribution.

The invention is not limited by the embodiments described above but may be varied within the scope of the appended claims. For instance, the skilled person realizes that a base plate 16 as used in accordance with the invention may also be arranged with grooves/minor channels (not shown) extending transversely in the surface that is in contact with the mould 10, as an alternative to or as a supplement to, merely using mating openings 150, 170. Hence, e.g. it is within the ambit of the invention that the mould surface 14 may be arranged with a larger number of openings 150 than the number of holes 170 in the base plate 16 and to connect the further amount of openings 150 to the channels 17 by means of grooves/channels in the surface of the base plate 16. Of course such an arrangement can also be performed the other way around, i.e. having channels in the surface 14 of the mould 10. Furthermore it is evident for the skilled person that there may be obtained a variety of advantages with the invention from the production perspective that may be used if desired, e.g. using a modular production of the base plates 16, e.g. having a certain number of through holes 17, 18, without the need of using all of said through holes 17, 18 for vacuum and heating respectively, since the function of the arrangement according to the invention may also work well even if some of said channels 17, 18 are not being used, depending on the need of drainage, etc in relation to the product that shall be produced. Furthermore the invention also provides the possibility to introduce more of flexible control for adapting production parameters to different needs, if desired, e.g. using different heat supplied to the different heating channels 18 being used and also using different vacuum levels in the different vacuum channels 17 being used, etc.

Claims

1. A mould arrangement including a loose sintered metal mould (10, 20) having a front or moulding side (13) and an opposite rear side (14), the rear side (14) being secured to a base plate (16), characterized in that base plate (16) includes a plurality of elongated channels (17, 18) including at least one suction channel (17) for delivering suction pressure to the mould (10, 20) via at least one transversally directed suction opening (170), and at least one of said channels (18) includes a heating rod (53).

A mould arrangement according to claim 1, characterized by each one of said channels (17, 18) having substantially the same cross sectional area along its whole extension within the base plate (16), preferably circular cross sections.

A mould arrangement according to claim 1 or 2, characterized in that at least one of said channels (18) includes a heating rod (53) having a cross section corresponding to the cross section of the channel (18).

A mould arrangement according to claim 3, characterized in that base plate (16) includes at least two suction channels (17) and that the at least one heating channel (18) is arranged between two adjacent suction channels (17).

A mould arrangement according to claim any of claims 1-4, characterized in that the channels (17, 18) extend parallel, and preferably also parallel in relation to a flat rear side (14) of the mould (10, 20).

A mould arrangement according to claim 5, characterized in that each set of channels (17, 18) extend at essentially the same distance to the flat rear side (14) of the mould (10).

A mould arrangement according to any preceding claim, characterized in that the suction channel (17) has a first opening in a first side wall of the base plate (16) for connecting to a source (52, 52') of suction and a second opening at an opposite, second side wall of the base plate (16). 8. A mould arrangement according to claim 7, characterized in that a

coupling arrangement (171, 172) is provided for connection to a corresponding suction channel (52', 170), preferably adapted to fit in an adjacent base plate (16) also supporting a mould (10^').

A mould arrangement according to any preceding claim, characterized i that the mould (10) is secured to the metal base plate (16) by means of metal bonding.

10. A mould arrangement according to any preceding claim, characterized in that the mould (10, 20) includes a plurality of drainage channels (15), each extending from the rear side (14) of the mould towards the front or molding side

(13).

11. A mould arrangement according to claim 10, characterized in that the at least one suction opening (170) in a vacuum channel (17) is arranged to at least partly mate a corresponding drainage channel (15) at the rear side (14) of the mould (10).

12. A mould arrangement according to claim 11, characterized by a plurality of suction openings (170) in each vacuum channel (17), preferably in the range of 3-20, more preferably 4-10.

13. A mould arrangement according to any preceding claim, characterized in that the rear side (14) of the mould (10) is impermeable except for the openings to the drainage channels (15).