(1) EDM
The method of EDM is to make EDM electrode with RPM prototype, and then make steel die with EDM. Its manufacturing process is generally: RPM prototype → 3D grinding wheel → graphite electrode → steel mold.
(2) Investment casting method
Investment casting can be used for mass production of hard molds. In this method, a wax mold is produced by an RPM prototype or a soft mold manufactured according to the prototype, and then a steel mold is manufactured by an investment casting process. Most RPM prototypes can be used as master molds for investment casting. Its technological route is: RP prototype (intermediate transition mold) → making wax mold → investment casting → forming/processing → mold.
(3) Ceramic mold precision casting method
In ceramic precision casting, the commonly used master molds (such as wood mold, gypsum mold and metal mold) have some problems, such as difficult processing, difficult guarantee of accuracy, long manufacturing cycle, short service life and high cost. Therefore, for parts with complex shapes, RP prototype technology can be directly used for ceramic mold casting, which can save working hours and reduce costs compared with traditional processing methods. The process route is: RP prototype → soft mold → disassembly of mother mold → pouring/shotcreting → pouring metal → forming/processing → mold.
(4) Metal spraying manufacturing method
The method for manufacturing the mold by metal spraying is to spray atomized metal on the surface of the RP prototype or transition model as the master mold by arc or plasma to form a metal hard shell layer. After moving to the master mold, metal-based synthetic material or epoxy resin is poured on the back of the metal shell to form a hard backing, and the mold consisting of the metal surface and the hard backing is obtained after post-treatment. The die made by this method has good mechanical properties and easy to ensure accuracy. It can manufacture molds with high working pressure, and the service life of the molds can reach 1000 ~ 30000 pieces.
(5) Manufacturing method of aluminum-based composite material
Taking the RP prototype as the master mold, soft materials such as silicone rubber were poured to form a soft mold, and then liquid aluminum-based synthetic materials at room temperature were poured into the soft mold to form a cavity, and the cavity was post-treated to make the mold. Because it is poured at room temperature, the large warping deformation caused by high temperature molten metal pouring is avoided, and the accuracy is easy to ensure. The service life of the injection mold made by this method is generally 500 ~ 5000 pieces (depending on the material and shape of the injection parts).
(6) Manufacturing method of chemically bonded ceramic materials
Taking the RP prototype as the master mold, soft materials such as silicone rubber were poured to form a soft mold, and then the chemically bonded ceramic material (CBC) was poured into the soft mold, solidified at 205℃ to form a cavity, and the mold was made after treatment. The service life of molds made by this method is generally 300 pieces. The process route is as follows: rapid forming paper master mold → (pouring soft materials such as silicone rubber, epoxy resin and polyurethane) to form soft mold → moving to the master mold → pouring chemically bonded ceramics (CBS) in the soft mold → curing CBS cavity at 205℃ → grinding the cavity surface and adding gating system and cooling system → small batch production of injection mold.
(7) Casting method
Using rapid prototyping as the model of wax mold or sand mold of paraffin casting mold, casting shell or sand mold is made, and then metal mold is poured, but casting mold usually needs polishing or a small amount of cutting.
(8) Steel wire mould
Steel wire mold is a mold that arranges thin steel wires in a certain direction along the rapid prototyping shape to form a mold cavity. Steel wire can be mechanically fastened, coated on steel wire or injected with epoxy resin or low melting point alloy as binder, and then compacted and solidified. The inner wall of the mold cavity can be cold sprayed with metal alloy to improve the service life and surface quality. Steel wire mould is not only suitable for producing plastic products, but also can be used for producing metal products.
(9) electroforming
The principle and technology of electroforming are similar to those of metal spraying. It is a method to make a mold by using electrochemical principle, depositing metal on the prototype surface through electrolyte, and then backing other filling materials. The mold made by electroforming method has good reproducibility and high dimensional accuracy, and is suitable for cavity molds with high accuracy, uniform shape and irregular appearance patterns, such as figure modeling molds, children's toys, shoe molds and so on.
Four. conclusion
In a word, rapid prototyping technology can not only avoid complicated mechanical cutting and ensure the accuracy of the mold, but also greatly shorten the mold making time and save the mold making cost. Compared with the traditional numerical control die method, the cycle and cost are reduced by about1/3 ~110, which is particularly advantageous for precision dies with complex shapes. However, at present, this mold manufacturing method still has the disadvantage of relatively short service life of the mold. Even the mold with hard lining on the metal surface is not as long as the real metal mold, so the rapid prototyping mold is suitable for single piece and small batch production.