Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/285—Feeding the extrusion material to the extruder
  • B29C48/288—Feeding the extrusion material to the extruder in solid form, e.g. powder or granules
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C31/00—Handling, e.g. feeding of the material to be shaped, storage of plastics material before moulding; Automation, i.e. automated handling lines in plastics processing plants, e.g. using manipulators or robots
  • B29C31/02—Dispensing from vessels, e.g. hoppers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/255—Flow control means, e.g. valves
  • B29C48/2552—Flow control means, e.g. valves provided in the feeding, melting, plasticising or pumping zone, e.g. screw, barrel, gear-pump or ram
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/256—Exchangeable extruder parts
  • B29C48/2567—Hopper or feeder parts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/285—Feeding the extrusion material to the extruder
  • B29C48/287—Raw material pre-treatment while feeding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
  • B29C48/50—Details of extruders
  • B29C48/68—Barrels or cylinders
  • B29C48/685—Barrels or cylinders characterised by their inner surfaces, e.g. having grooves, projections or threads
  • B29C48/686—Barrels or cylinders characterised by their inner surfaces, e.g. having grooves, projections or threads having grooves or cavities
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
  • B29C64/30—Auxiliary operations or equipment
  • B29C64/307—Handling of material to be used in additive manufacturing
  • B29C64/321—Feeding
  • B29C64/329—Feeding using hoppers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y30/00—Apparatus for additive manufacturing; Details thereof or accessories therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/285—Feeding the extrusion material to the extruder
  • B29C48/288—Feeding the extrusion material to the extruder in solid form, e.g. powder or granules
  • B29C48/2886—Feeding the extrusion material to the extruder in solid form, e.g. powder or granules of fillers or of fibrous materials, e.g. short-fibre reinforcements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
  • B29K2105/25—Solid
  • B29K2105/251—Particles, powder or granules

Definitions

• the proposed solution relates in particular to a filling device for supplying processing material to an extruder screw, in particular an extruder screw for additive manufacturing with metal, ceramic and/or plastic injection molding granulates.
• Screw extruders are mainly used in the series production of components using injection molding and die casting.
• the extruder screw, injection nozzle and die are usually in a horizontal line to each other.
• the filling with material which is mainly in the form of granules or powder, usually takes place in the rearmost part of the screw extruder, in what is known as the feed zone.
• the material is fed directly vertically onto the extruder screw via a hopper that sits on a section of the extruder pipe. Due to a sufficiently large cross-section in the hopper, which prevents bridging, the material falls onto the screw and is drawn in by gravity.
• so-called three-zone screw extruders are usually used, which draw in the material and convey it to the die.
• the material is compressed, deaerated and homogenized. Then pressure is built up to fill the matrix.
• the feed zone of the screw extruder is often designed as a tube section in a barrel of the screw extruder.
• a funnel is arranged on this pipe section through which the material can be fed to the screw.
• the minimum cross-section of the pipe section and funnel should be selected so that no bridging of the granulated material can occur. This depends heavily on the angle of repose and the coefficient of friction of the bulk material used.
• DE 10 2014 018 081 A1 describes a 3D printer device for the additive manufacturing of metallic components.
• a screw extruder is also used here, which processes processing material in the form of granules.
• the thermoplastically deformable processing material is extruded in layers using a vertically arranged screw extruder in order to create a three-dimensional component.
• DE 102014018081 A1 does not contain any more detailed information on conveying the processing material to the extruder screw.
• screw extruders for additive manufacturing is mainly limited by their weight and size, which typically depend heavily on the length of the extruder screw, since the screw extruders either have to be designed to be mobile or the entire construction area has to be moved. However, the latter variant makes it necessary to significantly oversize the entire 3D printing device.
• a device and a method for the extrusion of processing material are already known from DE 10 2017 114 841 A1, with which a compression of granular processing material can be increased in order to be able to extrude a dense and continuous strand of material.
• a crushing tool is provided in a funnel of a filling device.
• the processing material is comminuted in a targeted manner via this comminution tool under the effect of the rotating extruder screw, as a result of which a bulk density in the area of the extruder screw can be increased in particular.
• a filling device for supplying processing material to at least one extruder screw is proposed specially designed funnel.
• the hopper is set up to guide the processing material along a feed direction to the extruder screw.
• the funnel extends along a funnel axis, which runs parallel to a longitudinal axis of the extruder screw when the filling device is installed as intended.
• the proposed funnel has, on a funnel wall extending around the funnel axis, a plurality of indentations which each extend axially with respect to the funnel axis.
• the funnel axis of the proposed filling device In the mounted state of the filling device on an extruder device for the additive manufacturing of a component, the funnel axis of the proposed filling device thus runs parallel to a typically vertical longitudinal axis of the extruder screw.
• the funnel wall of the funnel then has a number of axially extending indentations and thus cavities.
• the indentations consequently jump back radially outwards and thus represent a local enlargement of a funnel opening of the funnel.
• the funnel can be designed as a separately manufactured, one-piece component that can be used interchangeably on an extruder device with at least one extruder screw.
• the funnel can be designed as part of an exchangeable feeder that can be prefabricated and mounted on an extruder device for additive manufacturing.
• the indentations on the hopper wall are arranged in succession along a peripheral line around the hopper axis.
• the indentations can in particular be arranged in a uniformly distributed manner on the funnel wall, in particular evenly distributed along a circular peripheral line.
• the cross-sectional geometry of the indentations is fundamentally variable.
• the indentations are curved radially outwards in a cross section (transverse to the axis of the funnel), relative to the axis of the funnel. This includes in particular a cross-sectionally concave design of the indentations on the funnel wall.
• At least one of the indentations can be designed to taper radially.
• a radial depth of the indentation decreases, in particular continuously, with increasing axial extent along the funnel axis in at least one end section, but optionally also viewed over the entire longitudinal extent of the respective indentation. There is thus less space available for the processing material along the axis of the funnel via the respective indentation.
• the individual indentations are dimensioned in such a way that the width of an indentation, measured along a circumferential line around the hopper axis, corresponds to at least a maximum width or a maximum diameter of a granule grain of the granular processing material, granulate grains can enter the indentations at one (upper) end of the hopper get inside and are then forced to move axially downwards along the indentations under the action of the rotating extruder screw.
• the width and depth of an indentation are thus matched, for example, to granules of a granular processing material in such a way that conveyor chambers are formed in the funnel of the extruder device, which are each bordered radially on the outside by an indentation and radially on the inside by the extruder screw and the individual granules in the operation of the extruder device in these conveying chambers - matched to the (mean) dimensions of the granules - are kept and locked against displacement from these conveying chambers.
• a width of an indentation does not exceed a maximum width or a maximum diameter of a granulate grain by more than 20%.
• An indentation provided on the hopper wall can be designed to receive a granular processing material, the maximum outer dimension of which does not exceed 15 mm.
• a granule of the processing material thus has no external dimension (width, length, fleas or diameter) that is greater than 15 mm and an indentation is dimensioned such that it has a width and radial depth at an upper funnel end which is of the order of the maximum dimension of the granulate to be processed.
• the proposed solution for the processing of plastic granules with a reference diameter of 1.5 to 6 mm, in particular 3 mm, long fiber granules with a reference height of up to 15 mm, in particular 9 to 12 mm or ceramic granules with a reference diameter of 1, 5 to 8 mm, in particular 3 mm or 5 mm, is advantageous in order to obtain a (more) uniform extrusion pattern. Consequently, the width and depth of an indentation are each in the range of 1.875 to 18.75 mm.
• all indentations of the hopper wall are designed to taper radially.
• a radial tapering of all indentations on the funnel wall can, for example, at one end of the funnel, make the funnel wall circumferentially smooth, i.e. like a smooth pipe section.
• At least one of the indentations can be designed to taper axially.
• a width of the indentations measured in the circumferential direction decreases, in particular continuously, with increasing axial extent along the funnel axis in at least one end section, but possibly also considered over the entire longitudinal extent of the indentations.
• an indentation for example, becomes narrower towards one end of the funnel. It can also be provided here that all indentations on the funnel wall are designed to taper axially.
• indentations are designed to taper both axially and radially, both a width measured in the circumferential direction and a radial depth of an indentation decrease towards a funnel end.
• the funnel wall formed with the indentations can define an inner peripheral line and an outer peripheral line in cross section.
• the inner peripheral line is tangent to the radially innermost areas of the funnel wall and thus describes a minimum opening cross section for the extruder screw intended funnel opening of the funnel.
• the outer peripheral line touches the radially outermost regions of the indentations.
• the outer peripheral line thus circumscribes, for example, a maximum outer diameter of a virtual circular cylinder or a virtual truncated cone in which the funnel wall with the indentations extends from a first (upper) funnel end to a second (lower) funnel end.
• the funnel opening tapers along the funnel axis, so that the minimum opening cross section decreases along the funnel axis.
• a conical narrowing of the funnel opening can be provided.
• the cross section available for the extruder screw and defined by a diameter of the hopper opening thus decreases towards one end of the hopper.
• a hopper designed in this way can be combined with a conically tapering extruder screw.
• a diameter of the outer peripheral line can decrease along the funnel axis while maintaining the minimum opening cross section.
• a diameter of the outer peripheral line thus decreases viewed over the cross sections along the hopper axis, while the minimum opening cross section of the hopper opening provided for the extruder screw and thus a diameter of the inner peripheral line along the hopper axis remains unchanged.
• an extruder screw in the extruder device equipped with the filling device then consequently has a constant screw diameter.
• two indentations adjoin one another along a peripheral line around the longitudinal axis of the funnel.
• the two indentations thus merge directly into one another.
• all of the indentations along the peripheral line which are arranged distributed uniformly around the axis of the funnel, can also directly adjoin each other in pairs.
• a separating edge extending longitudinally (ie along the axis of the funnel) is then formed between adjacent indentations, for example.
• Such a separating edge can then also be designed as a comminution edge and in particular as a rib on which granular processing material is comminuted, in particular shattered, under the action of the extruder screw.
• a shearing effect can thus be generated in a targeted manner under the effect of the rotating extruder screw via a separating edge formed accordingly between two indentations.
• a connecting section can be formed between two indentations along a peripheral line around the funnel axis. Such a connecting section is consequently not designed as an indentation.
• a corresponding connecting section can be shaped differently in comparison to the two adjacent indentations.
• the connecting section provided between two indentations, relative to the hopper axis projects radially inwards and thus in the direction of a hopper opening defined by the hopper for the extruder screw. This includes, in particular, that the connecting section simply protrudes radially further inwards in comparison to the adjacent indentations.
• the connecting section can define a flat or curved wall surface.
• the connecting section is then, for example, curved radially inwards in relation to the funnel axis.
• a convexly curved connecting section between two concavely curved indentations is provided in a cross section of the funnel.
• a continuous transition can be provided in the circumferential direction, so that there is no separating edge between a connecting section that is convexly curved radially inward and a concave indentation that is curved radially outward.
• a non-curved connecting section can be configured to extend in the cross section of the funnel along a section of a circular line around the axis of the funnel and define a flat wall surface.
• a discontinuous or continuous transition can then likewise be formed at a transition between such a connecting section and an adjoining indentation, with a discontinuous transition also including the formation of a longitudinally extending separating edge.
• a separating edge between a connecting section and an indentation can then also be designed as a crushing edge and in particular a rib and accordingly be set up and provided in particular to crush at least part of the granular processing material entering the funnel when the extruder screw rotates.
• the indentations on the hopper By distributing the indentations on the hopper according to the above formula, taking into account the material to be processed, not only are as many indentations as possible formed on the circumference, but the dimensions of the indentations can also be easily designed so that granulate grains are held in the indentations during operation of the extruder device and are blocked from moving out of these pumping rooms.
• At least two indentations can be provided on the funnel wall of the proposed filling device.
• at least four indentations are provided on the hopper wall.
• the funnel can have 4 to 9, in particular 5 to 7, indentations distributed over the circumference. With more than three indentations or cavities, a flower-shaped cross section of the funnel can then also be realized, for example.
• the proposed solution also includes an extruder device with at least one extruder screw and at least one embodiment variant of a proposed filling device.
• the extruder device can be designed as a 3D printing device or 3D printer.
• the proposed extruder device is therefore intended in particular for an additive manufacturing process in which a component is manufactured additively using the processing material extruded with the aid of the extruder screw.
• FIG. 1 shows a perspective view of an insert for a filling device with a first embodiment variant of a funnel which is flower-shaped in cross-section and has a plurality of ones on the circumference
• FIG. 2 shows an alternatively designed insert with a funnel that is also flower-shaped in cross section
• FIG. 3 shows a further embodiment variant of the insert with a differently designed funnel which is flower-shaped in cross-section
• Figure 4A is a cross-sectional view of a funnel
• FIG. 4B shows a perspective view of the funnel of FIG. 4A or the funnel opening defined thereby and an outer lateral surface
• FIG. 4C shows a detail of the cross-sectional view of FIG. 4A on an enlarged scale
• FIGS. 5A-5C detail and schematic longitudinal sections through the funnel opening to illustrate different funnel opening geometries
• FIGS. 6A-6C show different cross sections for embodiment variants of a proposed funnel with and without separating edges between two adjacent indentations, in particular adjoining one another;
• Figure 7A is a longitudinal section showing an extruder screw positioned in the hopper opening of the hopper;
• FIG. 7B in a view corresponding to FIG. 7A, shows a differently designed hopper with a conically tapering extruder screw
• FIG. 8 shows a perspective view of an example of a granulate of a thermoplastic material to be processed with the proposed solution
• FIG. 9 shows a proposed embodiment variant of a filling device, in which an insert according to FIGS. 1, 2 and 3 and a funnel according to FIGS. 4A to 7B are used.
• FIG. 9 shows an embodiment variant of a proposed extruder device in the form of a vertical extruder 1.
• the vertical extruder 1 with an extruder screw 2 can only be seen in its upper area.
• the extruder 1 is connected to a filling device B with a material reservoir in the form of a bunker 3 .
• the bunker 3 is provided with a feed ramp 4, which is used for the trouble-free trickling of granular processing material.
• the feed ramp 4 is a compact unit which is connected to a bunker wall 301 in the upper area.
• a (filling) hopper 5 rests directly against the extruder screw 2, with the granular processing material being conveyed from the feed ramp 4 into the hopper 5 under the action of gravity.
• FIG. 4 illustrates an upper limit for opening 80.
• This horizontal feed area 6 is the lower limit for the opening 80.
• the opening 80 serves to accommodate a feed device 8 and is dimensioned according to the size of the feed device 8 .
• the feed device 8 has a pneumatically, hydraulically, mechanically or electrically driven flow cylinder 801, a connecting rod 802 and a slide 803.
• the slide 803 is guided over the horizontally running feed area 6 along an adjustment direction V in the direction of a filling area of the extruder 1 .
• the slide 803 On its side facing the inside of the extruder, the slide 803 has an inclined surface 803a which follows the angle of the feed ramp 4. This surface 803a merges into a ramming surface 803b, which runs perpendicular and parallel to the bunker wall 301.
• the ramming surface 803b is at least large enough to correspond to the size of the granules to be processed.
• the granulate trickling in can compact in connection with the granulate pressed back onto the feed ramp 4 and thus form a wall W of powder which prevents the supply of new granulate to the extruder screw 2 .
• the feed device 8 prevents that Granulate is pressed back onto the feed ramp 4 when the slide 803 is advanced.
• the stroke of the lifting cylinder 801 is dimensioned in such a way that granules can fall vertically out of the bunker 3 when retracted.
• the stroke length of the cylinder 801 corresponds, based on the retracted state of the lifting cylinder 801, to the distance between the upper edge 501 of the hopper 5 and the vertical ramming surface 803b of the slide 8.
• the feed device 8 pierces through blockages of the wall W and trickling granulate is actively conveyed into the funnel 5.
• the feed device 8 thus conveys the processing material returned to the hopper 5 counter to a feed direction ZR under the action of the extruder screw 2, together with the processing material trickling out of the bunker 3 in the direction of the extruder screw 2 rotating extruder screw 2 recycled processing material mixed with from the bunker 3 additionally supplied processing material. In this way, less compression of the processing material is necessary via the extruder screw 2 and the extruder screw 2 can be made shorter.
• the funnel 5 is designed with a large number of indentations 51.2 on a funnel wall 51.
• the peripheral hopper wall 51 provided with the indentations 51.2 defines a minimum opening cross section for a hopper opening through which the extruder screw 2 extends along the hopper axis T from an upper end of the hopper to a lower end of the hopper.
• the funnel 5 can be formed on an exchangeable insert, for which different variants are illustrated by way of example in FIGS. 1, 2 and 3.
• the funnel wall 51 has six evenly distributed, axially extending indentations 51.2 on the circumference.
• the axially extending indentations 51.2 are each curved radially outwards and are therefore designed as recesses on the funnel wall 51 that are concave in cross section.
• Each indentation 51.2 has a semicircular cross-sectional area such that a bulge of an indentation 51.2 forms a contour that follows a semicircular line and runs symmetrically to a straight line running radially with respect to the funnel axis T.
• Each indentation 51.2 tapers radially towards a funnel end 512 of the funnel 5.
• each indentation 51.2 considers a radial depth of an indentation 51.2 with increasing axial extension along the funnel axis T continuously. Furthermore, a diameter measured in the circumferential direction and thus a width of each indentation 51.2 is only a maximum of 20% larger than a maximum dimension of a granule grain of the granular processing material to be fed to the extruder screw 2 with the filling device B. At the upper end of the funnel 5, the width or diameter of an indentation 51.2 is dimensioned such that a granulate grain can still fall from above into the respective indentation 51.2. At an upper end of the funnel, a single grain of granulate can thus get into a cavity defined by an indentation 51.2.
• the funnel 5 with its indentations 51.2 is dimensioned in such a way that a grain of granulate can no longer easily (ie without being destroyed and thus without having been crushed) get out of an indentation 51.2 again.
• the granules are thus held in a plurality of defined conveying chambers matched to the (average) dimensions of the granules and blocked against displacement from these conveying chambers, which are bordered radially on the outside by an indentation 51.2 and radially on the inside by the extruder screw 2. In this way, as the extruder screw 2 rotates, a single grain of granulate is forced to move axially along the hopper 5 downwards.
• indentations 51.2 and connecting sections 51.1 thus continuously merge into one another along a curved peripheral line.
• the convex, radially inwardly curved connecting sections 51.1 are dimensioned such that no granulate grain of the processing material to be processed fits into a resulting gap between a connecting section 51.1 and an extruder screw 2 rotating in the funnel opening of the funnel 5.
• a gap between a connecting section 51.1 and the extruder screw 2 is therefore dimensioned so small that no granulate grain fits into this gap.
• the insert E with the funnel 5 is designed differently.
• the indentations 51.2 directly adjoin each other and are separated from each other in pairs by a separating edge 511 extending along the axis T of the funnel.
• This separating edge 511 acts as a crushing edge within the funnel 5 and can be designed as an axially extending sharp-edged rib. at which, under the action of the rotating extruder screw 2, a granulate is smashed and thus comminuted.
• the number of indentations 51.2 distributed uniformly around the circumference is significantly increased compared to the embodiment variant of FIG. More than fifteen indentations 51.2 are provided here.
• the area of the feed area 6 is enlarged compared to the variant in FIG.
• the feed area 6 with feed edge sections 6A, 6B extends over a larger peripheral area at the upper end of the funnel 5.
• the feed area 6 in Figure 2 is also designed in such a way that the Feeding area 6 (in plan view) ends laterally in each case in the area of an indentation 51.2.
• the longitudinally extending indentations 51.2 of the variant embodiment of FIG. 3 are also tapered in the axial direction.
• An end section of each indentation 51.2 thus tapers in the direction of the lower end 512 of the funnel.
• the indentations 51.2 of the embodiment variant in FIG. 3 continue to taper radially, so that a radial depth of each indentation 51.2 decreases continuously in the direction of the lower end 512 of the funnel.
• FIG. 4A shows a plan view of a cross section through a funnel 5 with indentations 51.2 distributed over the circumference, between which convexly curved connecting sections 51.1 are located in the manner of bulges extend.
• the indentations 51.2 and connecting sections 51.1 merge into one another on the funnel wall 51 according to a geometrically continuous function.
• the funnel 5 runs according to the perspective view of Figure 4B down to the end of the funnel 512 with respect to an outer peripheral line 51 B, the radially outermost areas of the indentations 512 tangent, conical. While a diameter of the outer peripheral line 51 B decreases continuously along the funnel axis T towards the lower funnel end 512 (due to the radial tapering of the individual indentations 51.2), the diameter of an inner peripheral line 51 A, which touches the radially innermost areas of the funnel wall 51, remains , unchanged along the funnel axis T. A minimum opening cross section for the extruder screw 2 along the funnel axis T thus always remains the same.
• the diameter of the inner peripheral line 51A is denoted by D 2 in FIG. 4C.
• This diameter D 2 corresponds to the sum of a diameter D 3 of the extruder screw 2 and a defined gap dimension in the form of a radial distance s between the extruder screw 2 and the circumferential, radially inwardly curved connecting sections 51.1 or the convex ones defined in cross section that point radially inwards Bulging of the funnel wall 51.
• this radial distance s is smaller than a minimum dimension of a granulate grain which, as a result, does not fit into a gap between the extruder screw 2 and a bulging 51.1 without being crushed. For example, if a granule grain G has a size Fl and a diameter D 4 according to FIG. 8, then s ⁇ D 4 and s ⁇ Fl apply.
• each indentation 51.2 follows a semicircular line in cross section, so that each indentation 51.2 circumscribes a semicircular cross-sectional area.
• a diameter di (varying along the funnel axis T) of the corresponding hemispherical circle consequently defines a radial depth of each indentation 51.1.
• the centers of the individual half circles of the indentations 51.1 lie on a circumferential line with the diameter Di (with Di>D 2 ). Consequently, the diameter of the outer peripheral line 51B is then given by Di+di/2.
• the diameter di is dimensioned such that a grain of granulate G can fall from above into the respective indentation 51.2, as shown in FIG.
• di > D 4 or di > Fl should apply.
• An outer lateral surface of the funnel wall 51 also tapers with the outer peripheral line 51B.
• the lateral surface is thus obtained as a linear surface interpolation from the arrangement of the indentations 51.1, which are semicircular in cross section, or the recesses formed therewith, including the intermediate transitions to the bulges 51.1 to form a circle. which results from the outer diameter D 3 of a screw blade of the extruder screw 2.
• the outer peripheral line 51B can run conically along the hopper axis T and in this respect along an extension or conveying direction -z according to the longitudinal section of FIG. 5A in the direction of the lower end 512 of the hopper.
• An outer diameter of the funnel 5 thus decreases linearly and is therefore designed to decrease following a first-order function. But this is not mandatory. For example, a course corresponding to a curve of at least the second order corresponding to FIG. 5B is also possible.
• a radial tapering of the indentations 51.2 has proven to be advantageous, for example, especially with regard to granular processing material made of or with comparatively tough thermoplastics. With other processing materials, however, it can also be advantageous if the indentations 51.2 do not taper radially along the funnel axis T. An outer peripheral line 51B then remains unchanged in its diameter in a longitudinal section corresponding to FIG. 5C.
• FIGS. 6A, 6B and 6C again show different configurations of the funnel wall 51 and in particular of the areas between two adjacent indentations 51.2.
• an axially running separating edge 511 extends between two indentations 51.2.
• the separating edges 511 lie on a circular line with diameter D 2 in FIG. 4C.
• the separating edges 511 act as comminuting edges and can in particular be designed as ribs projecting radially in the direction of the extruder screw 2, on which granular processing material is comminuted when the extruder screw 2 rotates about the funnel axis T during operation of the extruder device.
• connecting sections 51.3 are each formed with a flat wall surface between adjacent indentations 51.2. At the transition from a connecting section 51.3 to an adjacent indentation 51.2, a discontinuous transition is provided in the present case, so that a separating edge 511 is also formed between a connecting section 51.3 and an adjacent indentation 51.2.
• FIGS. 6A and 6B with separating edges 511 are compared with the embodiment variant of FIG. 6C, in which the indentations 51.2 each transition continuously and thus without separating edges into convex bulges 51.1 and thus radially inwardly curved connecting sections 51.1.
• a diameter of the inner peripheral line 51A along the funnel axis T can remain the same.
• a diameter D 3 of the extruder screw 2 thus always remains unchanged.
• an embodiment variant is also possible in which a diameter D 3 is continuously reduced along the funnel axis T.
• the funnel opening thus runs conically in the z-direction. Accordingly, the extruder screw 2 then also has a conical course in the longitudinal section of FIG. 7B.
• the incoming granular material G falls into the funnel 5 without any problems and is conveyed further by the extruder screw 2 .
• the (inner) hopper wall 51 in the hopper 5, which is designed with indentations 51.2, prevents the supplied processing material at the edge of the extruder screw 2 from only moving in the circumferential direction, i.e. only with the rotation of the extruder screw 2, and not being conveyed downwards will.
• a movement in the axial direction is caused by the blocking of the movement in the circumferential direction.
• the processing material cannot be conveyed further in its entirety and is conveyed downwards axially along the funnel axis T on the inner wall of the hopper 51, optionally additionally comminuted on separating edges 511.
• the hardness of the screw shaft of the extruder screw 2 and the hopper wall 51 is typically greater than the hardness of the processing material to be processed.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Robotics (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
• Injection Moulding Of Plastics Or The Like (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)

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• 2021
  • 2021-07-14 DE DE102021207518.5A patent/DE102021207518A1/de active Pending
• 2022
  • 2022-06-30 CN CN202280043424.9A patent/CN117500652A/zh active Pending
  • 2022-06-30 WO PCT/EP2022/068074 patent/WO2023285156A1/de not_active Ceased
  • 2022-06-30 EP EP22743777.9A patent/EP4370303A1/de active Pending
  • 2022-06-30 US US18/577,552 patent/US20240246277A1/en active Pending
  • 2022-06-30 JP JP2024501762A patent/JP2024526332A/ja not_active Withdrawn

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