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
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/17—Component parts, details or accessories; Auxiliary operations
  • B29C45/46—Means for plasticising or homogenising the moulding material or forcing it into the mould
  • B29C45/58—Details
  • B29C45/62—Barrels or cylinders
• • 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
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/17—Component parts, details or accessories; Auxiliary operations
  • B29C45/46—Means for plasticising or homogenising the moulding material or forcing it into the mould
  • B29C45/58—Details
  • B29C45/60—Screws
• • 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
  • B29C48/2564—Screw 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
  • B29C48/36—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
  • B29C48/6801—Barrels or cylinders characterised by the material or their manufacturing process
• • 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
  • B29C48/682—Barrels or cylinders for twin screws
• • 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
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion

Definitions

• the invention relates to a method for producing a wear-resistant work space, preferably for injection molding machines and for single- and twin-screw extruders, also of conical design, and to a wear-resistant work space produced according to this method, according to the preamble of claim 1.
• a housing made of relatively soft structural steel is either provided with an insert made of hardened tool steel or with an insert ejected with a hard alloy on the workspace-side surface. Hard alloys are often thrown directly into the housing. Further measures for wear protection which are carried out on a large scale are the production of a complete housing from hardened tool steel and the nitriding of the workspace-side surface of housings from nitridable tempering steel. It is common to all known housings that the wear-resistant material is metallic.
• the conveying elements are also known to be made from nitriding steel and through-hardened tool steel become. Snails are known to be armored on the webs by hard metal alloy welding or to be completely protected against wear by chemical, galvanic or thermal treatment of hard layers.
• the invention has for its object to provide a method for producing a wear-resistant work space, preferably for injection molding machines and for single- and twin-screw extruders, also of conical design, and a wear-resistant work space produced by this method, the wear resistance and the mechanical strength of the work area is guaranteed even under extreme stresses in terms of pressure, temperature, abrasion, adhesion and corrosion.
• a carrier housing made of steel is lined on the inside with one or more inserts made of technical ceramics and that the conveyor elements consist of a carrier shaft made of steel, onto which one or more molded bodies made of technical ceramics are pushed.
• the dimensions of the work spaces lined with technical ceramics can reach diameters of more than 10 cm and lengths of more than 1 m, whereby not only cylindrical work spaces but also those with an outer boundary in the form of an open eight are possible .
• the method according to the invention enables simple and material-specific Assembly of the ceramic insert or inserts in the carrier housing made of steel or the ceramic molded body on the carrier shaft made of steel.
• the surface of the working space produced in the method according to claim 2 has the material-specific properties of technical ceramics, as there are: a high level of hardness and thus high resistance to abrasive and adhesive wear, a lattice structure which is different from that of metals, which is too low Adhesion tendency towards metal contributes, furthermore a high temperature resistance and a high resistance to aggressive media.
• the method according to claim 3 has the advantage that it can be carried out quickly and economically.
• connection with claim 4 it has the advantage that the ceramic insert or inserts are placed under pressure prestress from the outside after the temperature has been equalized with the carrier tube.
• the use of adhesive increases the strength of the connection to the carrier tube.
• This method is to be used in particular when high torques have to be transmitted during later use, but the degree of shrinkage cannot be increased accordingly, because otherwise the temperature differences necessary for joining would destroy the ceramic due to the thermal stresses generated.
• the method according to claim 5 is to be used when the working space is only exposed to relatively low pressure loads in practical operation. It has the advantage that there are no tight tolerances in the manufacture of the inner surface of the carrier housing and the outer surface of the ceramic insert or inserts.
• a correspondingly high injection pressure can prevent the material from being subsequently placed in the gap and even a certain amount of prestressing can be applied.
• the ceramic insert or inserts are additionally pressurized from the outside.
• the thermal and mechanical properties of the material can be adapted to the requirements by a suitable choice or mixture of the mineral and / or metallic fillers.
• Closing the gap according to claim 7 prevents the material from being squeezed out of the gap during temperature compensation between the carrier housing and ceramic insert or inserts.
• the method according to claim 8 it is achieved that the ceramic insert DZW. the inserts are biased axially to pressure after the temperature has been equalized with the carrier housing or after it has cooled.
• the method has the advantage that the ceramic insert or inserts, which generally have a lower thermal expansion than steel, are not destroyed by tensile stresses in practical operation.
• the carrier shaft produced by the method according to claim 9 can each have different profiles. Kei 1 we 1 lenprof i 1, serrated profile, polygon profile, parallel keys and all other types of positive power transmission. Therefore, several molded parts made of ceramic are necessary because the conveying elements, in this case screws, are usually subjected to high torsional stress. A single or only a very few shaped bodies over the entire length of the carrier wave would break due to the brittleness of the ceramic. In contrast, a plurality of shaped bodies can move against one another when the support shaft is twisted and are therefore subject to a significantly lower load. A solid ceramic molded body is inexpensive to manufacture. Gluing or soldering a steel bushing has the advantage that stress peaks in the shaft-hub connection resulting from overload and / or manufacturing errors are reduced by the steel bushing and breakage of the brittle ceramic is thereby prevented.
• the wear-resistant working space according to claim 10, in which the inner surface of the housing consists of metallic material, has the advantage that such a housing can be manufactured inexpensively.
• This solution is useful because the housing is usually subject to a much lower wear than the conveyor elements.
• the load drops again because the favorable running properties of the pairing of metal and ceramic come into play.
• the conveyor element or elements consist entirely of metallic material.
• This design is based on the concept that the conveying elements are regarded as real wear parts that are relatively easy and quick to replace.
• the wear-resistant work space according to claim 11 with a circular cross section or a cross section corresponding to the shape of an open inside has the advantage that the carrier recess is very easy to manufacture by drilling and honing and that the outer surface of the ceramic insert or inserts is also easy to machine by grinding.
• polygonal and oval cross sections offer the advantage that the torque transmission from the ceramic insert or inserts to the carrier housing takes place in a coherent manner.
• Inserts with a profile according to claim 12 on the inside are so-called grooved bushes or, in short, grooved bushes. They are used in single-screw extruders, on which plastics with inorganic and therefore hard pigments are often processed, and are therefore components which are extremely subject to wear.
• the technical ceramics with their high hardness have the advantage that they can withstand the abrasive wear better than steels.
• Fig.l shows a cross section through an inventive
• FIG. 5 shows a longitudinal section through a housing according to the invention with a plurality of ceramic inserts and stops
• FIG. 6 shows a longitudinal section through a housing according to the invention, which is only partially lined with ceramic inserts
• FIG. 7 shows a cross section through a housing according to the invention with positive torque transmission from the ceramic insert or inserts to the carrier housing, c
• FIG. 10 shows a view of a conveyor element according to the invention, which is wear-protected over the entire length with ceramic molded bodies,
• FIG. 11 shows a view of a conveyor element according to the invention, which is wear-protected only in the front area with ceramic molded bodies,
• FIG.12a - in side view, Fig.12b - in top view, 13 shows a processing machine with a wear-resistant working space according to the invention;
• FIG. 13a shows an enlarged partial section
• Fig.l shows part of the wear-resistant working space according to the invention, namely a housing lined with a ceramic insert or inserts 10 for single-shaft extruders or injection molding machines.
• the ceramic insert or inserts 10 are shrunk into a carrier housing 1, so that the force transmission from the ceramic insert or inserts 10 to the carrier housing 1 takes place by frictional engagement.
• the shrink bandage is designed such that the ceramic insert or inserts 10 remain under pressure prestress in the work area even under maximum stresses due to temperature and internal pressure. If high torques are to be expected during later use, additional gluing of the components is recommended.
• the most advantageous method is to provide the ceramic insert or inserts 10 with a thin layer of adhesive 19 on the outer surface before being inserted into the carrier housing. A slight profiling of the outer surface to accommodate a certain adhesive reservoir is also recommended.
• Fig. 2 also shows a housing for single-shaft extruders or injection molding machines.
• the outside dimensions of the ceramic insert or inserts 11 are a few millimeters smaller than the inside dimensions of the carrier housing 2 at room temperature.
• the resulting gap between the components is filled with a hardening or hardenable material 20.
• no tight tolerances in the manufacture of the inner surface of the carrier housing 2 and the outer surface of the ceramic insert or inserts 11 are observed.
• high thermal stresses in the ceramic parts are avoided and premature shrinkage is excluded.
• a flowable material 21 is used to fill the gap, which can additionally contain mineral and / or metallic powder as a filler. From the manufacturing process, it is advantageous to place the carrier housing 2 on one end face and to insert the ceramic insert or inserts 11 from above. The carrier housing 2 is continuously heated from the outside, while the ceramic insert or inserts 11 are cooled from the inside. Then the gap is poured out from above. In order to ensure that the gap is filled completely in the case of viscous materials and / or high temperatures of the carrier housing, the material 20 can be sprayed through a tube, the opening of which is guided in the gap with spiral movements from bottom to top. The temperature gradient between the carrier tube 2 and the ceramic insert or inserts 11 is maintained until the material 20 has hardened. During the curing time, the material 20 can be pressurized from above by an appropriate device.
• the hardening or hardenable material 22 is free-flowing or plastic. It is pressed in gradually from above by means of a die adapted to the shape of the gap.
• the thermal and mechanical properties of the material 22 can be adapted to the requirements of thermal conductivity and compressive strength by the suitable choice or mixture of the mineral and / or metallic fillers.
• the ceramic inserts 12 are preloaded axially with a tie rod from the end. This prevents gaps that could result from the generally lower thermal expansion of ceramics compared to steel. If high torques are to be expected in practical use, the components are also glued with adhesive 19 in addition to shrinking.
• the individual inserts 12 can consist of different ceramic and / or metallic materials, depending on the requirements. Plastic processing machines are known to have very different wear mechanisms in the different zones of the work space, to which the materials react differently. In addition, where the housing for pressure transducers or for degassing has to have side openings, the very brittle types of ceramic cannot be used. With the ring flange 25 and the threaded bores 26, two possibilities are indicated as to how the drive and tool side connection can be made. In the case of extruders, a complete housing is often composed of several so-called feet.
• Figure 4 also shows a housing in longitudinal section.
• the embodiment is characterized in that only a single, continuous ceramic insert 13 is received by the carrier housing 4.
• the methods for filling the gap between carrier housing 4 and ceramic insert 13 have already been described in the explanation of FIG.
• the external threads 27 are intended to indicate the connection to the tool or drive part. Because of the enormous number of housing and machine designs, a detailed description of the connections is also omitted below.
• 4a and 4b show two ways of closing the gap between the carrier housing 4 and the ceramic insert 13. close, namely once by welding the locking ring 23 with a weld 28 or by screwing into a thread 29. Of course, one side of the gap is closed before the material 20 is introduced.
• the housing according to the invention in FIG. 5 has, as a special feature, two stops 24 with which the ceramic inserts 14, which are longer at room temperature than the carrier housing 5, are prestressed in this pressure.
• the stops 24 are screwed or welded on immediately after the gap is filled with hardening or hardenable material 20 while the temperature difference is still present and thus prevent the formation of gaps between the ceramic inserts 14.
• the stops 24 are also connecting flanges. Since they come into contact with the material to be processed on the inside, the inside surface is also protected against wear.
• FIG. 6 again shows a housing according to the invention in longitudinal section. Part of the inner surface of the carrier housing 6 is itself a work space. Only the beginning and end of the housing are particularly protected against wear by shrinking in ceramic inserts 15 and possibly additional gluing with adhesive 19. This concept only makes sense if the beginning and / or end of the housing are really under the greatest stress, which is more often the case. It can also be used to regenerate worn-out housings in these areas.
• FIG. 7 shows an exemplary embodiment of a housing according to the invention, in which the torque is transmitted from the ceramic insert or inserts 16 to the carrier housing 7 by positive locking.
• the force transmission from the ceramic insert or inserts 17 to the carrier housing 8 takes place frictionally and can be supported by gluing the components, since it is a shrink fit become.
• the recess of the carrier housing 8 is very easy to manufacture by drilling and honing.
• the outer surface of the ceramic insert or inserts 17 can also be easily machined by grinding.
• Fig. 9 also shows a housing for twin-screw extruders.
• the method is also used here in which hardening or hardening material 20 is poured or pressed into the gap between carrier housing 9 and ceramic insert or inserts 18.
• the torque transmission from the ceramic insert or inserts 18 to the carrier housing 9 takes place in this embodiment by positive locking.
• FIG. 10 shows the other part of the working space according to the invention, namely a conveying element. It consists of the carrier shaft 30, onto which a plurality of solid ceramic bodies 33 are pushed. The torque is transmitted positively via a shaft-hub profile 37. The screwed-in tip 32 and a shoulder are used for axial fixation.
• Several ceramic molded bodies 33 are necessary because the conveying elements, in the present case a screw, are usually subjected to high torsional stress. A single or only a few shaped bodies 33 over the entire length of the carrier wave would break due to the brittleness and the high elastic modulus of the technical ceramics. In contrast, several shaped bodies can move against each other when the carrier shaft is twisted and are therefore subject to a significantly lower load.
• the exemplary embodiment in FIG. 11 also shows a snail. This time only the front part is particularly protected against wear by pushed-on ceramic molded bodies 34. The rest consists conventionally of metallic material. This concept makes sense if, as in thermoset processing, for example, wear occurs mainly at the screw tip. Worms worn under such stresses can also be regenerated according to this principle.
• the shaped ceramic body is a screw element, but it can also be designed as a mixing part or kneading disc or block.
• FIG. 13 shows a processing machine with a wear-resistant working space 43 according to the invention the housing 41 described in FIG. 3 and the conveying element 42 described in FIG. 10.
• the connecting flange 25, the filling funnel 44 and the drive unit 45 are shown.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
• Laminated Bodies (AREA)
• Injection Moulding Of Plastics Or The Like (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6247798

Family Applications (1)

Country Status (3)

Families Citing this family (13)

Family Cites Families (10)

• 1984
  • 1984-10-12 DE DE3437559A patent/DE3437559A1/de active Granted
• 1985
  • 1985-09-25 WO PCT/DE1985/000335 patent/WO1986002313A1/de unknown
  • 1985-09-25 EP EP85904802A patent/EP0197074A1/de not_active Withdrawn

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events