Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
  • B22F5/007—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of moulds

Definitions

• the invention relates to a method for producing an injection mold made of metal for the limited mass production of injection molded parts with dimensions of typically greater than 1 mm.
• the term "limited mass production” is used for the purpose of this description for the production of series with quantities in the order of magnitude of preferably 1000 to 100000 injection molded parts.
• conventional injection molds can produce around ten times larger series, while the so-called rapid tooling or rapid prototyping processes are suitable for around ten times smaller series.
• provisional tools made of various materials are often used to produce small quantities of prototypes or pre-series and small series.
• Cast resin tools or even wooden molds in casting or thermoforming technology have been common for a long time.
• the injection molding process has always brought a short-term end to the use of such provisional materials due to the high pressures in the mold. Recently, the interest in tools that can be produced quickly and inexpensively has increased again.
• the invention is therefore based on the object of producing an injection molding tool which, on the one hand, can be produced quickly and inexpensively and, on the other hand, the production larger series than tools made of "soft materials" allow.
• this is achieved by a method of the type mentioned at the outset, which is distinguished by the fact that a model of the injection-molded part to be produced is placed in a standard mold, the mold is poured out with the placed model by means of powder injection molding, the molded part is debindered and then sintered becomes.
• Fig.l is a schematic representation of the process steps for producing an injection mold for the manufacture of a plastic gear
• a model 1 of the injection molded part 2 to be produced in the present case a plastic gear wheel, can be produced in various ways.
• the necessary dimensional additions to compensate for the shrinkage during sintering are known from powder injection molding technology.
• a shape of the model is produced on the basis of CAD construction documents 3 by means of the known stereolithography 4 and the synthetic resin model 1 is cast in this in a casting process 5 which is also known per se.
• this model is placed or assembled in a standard mold 6.
• the mold is then closed and poured out using powder injection molding.
• the resulting molded part 7 represents a so-called green body and is very easy to machine in this state.
• the next step is the debinding of the molded part, which can be carried out in various ways, for example by thermal decomposition, solvent extraction, catalytic debinding, etc.
• sintering follows, ie a pressure-free compression of the molded part, whereby approximately the theoretical density of the metallic material is reached.
• the result is an injection molding tool 8 made of metal, which permits production on the order of 100,000 injection molded parts.
• the advantages of this process lie in the relatively short time required from the design drawing to the finished tool. Typically, this doesn't take more than two weeks.
• the process is extremely inexpensive. A tool that is manufactured using this process costs around 20 to 30% of a conventional production tool.
• a further advantage lies in the possibility shown in FIG. 2 of producing a plurality of shaped parts 9, 10, 11 of the same type and storing them in the state of green bodies. Because of the simple reworkability in this state, they can be adapted very quickly to necessary changes if necessary. This means that the reworking, changes or repairs of the tool that are feared in conventional injection molding technology are no longer a problem.

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Powder Metallurgy (AREA)
• Injection Moulding Of Plastics Or The Like (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Dry Formation Of Fiberboard And The Like (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=4202549

Family Applications (1)

Country Status (10)

Families Citing this family (1)

Family Cites Families (8)

• 1999
  • 1999-05-18 SK SK1725-2000A patent/SK17252000A3/sk unknown
  • 1999-05-18 JP JP2000549439A patent/JP2002515359A/ja active Pending
  • 1999-05-18 WO PCT/CH1999/000211 patent/WO1999059790A1/de not_active Application Discontinuation
  • 1999-05-18 MX MXPA00011177A patent/MXPA00011177A/es not_active Application Discontinuation
  • 1999-05-18 BR BR9910562-4A patent/BR9910562A/pt not_active Application Discontinuation
  • 1999-05-18 AU AU35932/99A patent/AU3593299A/en not_active Abandoned
  • 1999-05-18 CA CA002332798A patent/CA2332798A1/en not_active Abandoned
  • 1999-05-18 CN CN99806058A patent/CN1301211A/zh active Pending
  • 1999-05-18 EP EP99917736A patent/EP1082200A1/de not_active Ceased
  • 1999-05-18 HU HU0102028A patent/HUP0102028A2/hu unknown

Non-Patent Citations (1)

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