Have inside the Injection Mold Tooling that buy along with form cooling water is made quickly
- source:YESCOM CNC Machining
1 production mould chooses pulverous metallurgy industry to electroanalysis commonly usedly with the framework material of pulverous material mould iron pink, granuality is <53 μ M, particle shape is irregular graininess (2) seeing a picture. Felt chaste tree chooses material of high polymer powder, its granuality is less than 12 μ M. 2 kinds of powder are used three-dimensional the machine that mix pink undertakes mixture, the powder after mixing regards figuration as pulverous raw material. Graph 2 electroanalysis photograph of appearance of form of iron pink SEM 1.
The semifinished product of production mould form of semifinished product of 2 moulds form is finished on system of figuration of the HARP-II that in You Huazhong university of science and technology develops SLS, this system uses 50wc02 laser, laser power is successive and adjustable. In inputting model of texture of mould CAD three-dimensional substance SLS system with STL file format, if the graph is shown 3 times,the cooling aqueduct of the mould distributings. Can see from inside the graph, aqueduct follows the appearance change of the spare parts, and wall of spare parts of press close to, the turning of aqueduct is pliable arc shape, and be in the interior of the mould, use groovy method to cannot undertake machining to its. (A) static model (B) movable mould pursues 3 move, the main craft parameter of figuration of distributinging SLS system is the cooling aqueduct of static model interior ply of span of speed of laser power, scanning, scanning, monolayer and warm-up temperature. Warm-up temperature should approach the melting point of binder, can reduce the laser power that figuration place needs already so, the level that can avoid scanning hind again is out of shape as a result of what bigger environmental difference in temperature causes. The binder material in experimenting through be opposite undertakes showing differring scanning measuring heat (DSC) analysis, this resinous melting point is controlled in 65 ℃ , because this warm-up temperature is controlled,control in 53 ℃ . Efficiency of integrated consideration figuration and SLS make the ingredient of effect of a flight of stairs, ply of the monolayer in figuration is 0.
1mm, scanning speed is 2000mm/s, scanning span is 0.
1mm, it is commonly used value. The felt state of binder and laser energy density are relevant, if the expression of energy density is formulary (1) place is shown. Normal MARGIN of · of E=P/(SP of ρ of 0cm 0cm 0pt" Align=left> : 0cm 0cm 0pt"> among them P is laser power, SP is scanning speed, SCSP is scanning span, ρ E is laser energy density. Adjust laser power in order to change energy density, the intensity of the spare parts is the same as laser power only relevant. Ultimate laser power is 14W certainly, the intensity of form semifinished product can be amounted to 14.
95MPa. The felt state picture of the metallic powder grain after laser felt is shown 4 times like the graph, visible, metallic powder basically wraps Fu for colophony place felt. Form semifinished product follows the existence in form refrigeration aqueduct not the inattentive powder of agglomeration, can attract dirt facility with vacuum its epispastic. The photograph of appearance of pulverous SEM form of semifinished product of form of graph 4 SLS 1.
The pyrolysis of the defatted binder material of semifinished product of 3 moulds form is analysed (TGA) undertakes below nitrogen environment, rate-of-rise of air temperature is 10 ℃ / Min, till temperature achieves colophony to be decomposed completely, its TGA curve is shown 5 times like the graph. Can see from inside TGA curve: 230 ℃ begin binder decompose, 460 ℃ of 400 ～ temperature paragraph, decompose most acuteness, decompose a quantity to occupy the 70 ％ above of gross; Resorcinol solution speed reduces 730 ℃ of 460 ～ gradually, 730 ℃ left and right sides is decomposed end. Accordingly, curve of TGA of according to resinous, the amount is disclosed when form semifinished product is defatted big and the temperature with rapid rate paragraph, heating up time is a bit a few longer, can make sure colophony is in this temperature paragraph those who disclose a part is complete decompose, and slow down is decomposed enrage the acuteness degree that body appears, avoid aerification to expand the concussion of grain of pair of metal of form semifinished product. The experiment sets defatted highest temperature for 800 ℃ , curve of according to TGA, colophony can be decomposed completely, can make form semifinished product gets pre-burning writtens guarantee, join through agglomeration neck between metallic grain and have particular strength, and can carry. Graph 5 colophony (in nitrogen) TGA curve 1.
The form of high temperature agglomeration of 4 defatted base is put in vacuum furnace to undertake high temperature agglomeration after base is defatted, increase the strength of form semifinished product. The highest temperature of agglomeration is 1180 ℃ . Before 800 ℃ with 20 ℃ / the rate-of-rise of air temperature of Min warms up more quickly; Later, with 200 ℃ / H rate-of-rise of air temperature arrives 1180 ℃ , and heat preservation 1h. The porosity of semifinished product of the form after agglomeration is 46 ％ left and right sides, ra is the exterior surface roughness of agglomeration base 2.
5 ～ 5.
0 μ M, the mould after agglomeration is shown 6 times like the graph. (A) static model (B) movable mould pursues the mould photograph after 6 vacuum agglomeration 1.
Epoxy resin of 5 macerate modified puts semifinished product of form of agglomeration of mould high temperature and ooze stuff in together but the warm-up in the constant temperature box of vacuumize, temperature is 110 ℃ . Make the same score form semifinished product put expect of ooze liquid container is medium, the plane that makes the fluid face of ooze makings is close to cooling aqueduct lower edge (7) seeing a picture, get on what liquid ooze makings brushs form semifinished product after that the surface, can assure aqueduct so not by liquid fill. Vacuumize macerate, vacuum is spent maintain in 0.
09MPa, in order to improve macerate efficiency. After the semifinished product of liquid infiltration form of mould surface is medium, brush another again, and vacuumize macerate. Relapse for many times so, till exterior liquid no longer till infiltration form semifinished product disappears, explain colophony has filled hole of form semifinished product. With the colophony rub-up with redundant surface of semifinished product of form of filter paper general, in putting form semifinished product constant temperature case, solidify falls in 160 ℃ 4 ～ 6h. The mould after colophony solidify is shown 8 times like the graph. Macerate colophony improved mould appearance bright and clean degree, through polishing processing of the surface, exterior surface roughness can amount to Ra< μ M. Graph 7 colophony dip breaks through sketch map to pursue the mould after 8 dip break through colophony pursues the TGA curve of the 9 colophony material that are solidify hind. Can see from inside the graph, when 150 ℃ , have quality loss hardly, when temperature rises to 200 ℃ , resinous decomposes a quantity to be less than 5 ％ , because this can satisfy requirement of general Injection Mold Tooling the working temperature of 150 ℃ of 100 ～ . Graph 2 moulds intensity and precision analyse curve of TGA of the colophony after 9 solidify the intensity of the mould basically originates the solidify after the high temperature agglomeration of defatted form semifinished product and macerate modified epoxy resin. After high temperature agglomeration, the mould is porous material, the intensity of porous material but by experience formula (2) expresses: Normal Align=left> ) (2)normal > : σ is the intensity of porous material; σ 0 it is corresponding the intensity that at porous material compact material pledges; F(ρ ) it is the function related to porous material density, c is invariable. From formula (can see in 2) , the intensity of porous material sends density with its relevant. Can mix through the metallic powder with fine figuration those who reduce binder content to improve data of form semifinished product is compact degree, increase its strength thereby. Macerate colophony and after solidify, if the graph is shown 10 times,the metallographic of material of mould form semifinished product organizes optical metallograph, among them bright color is a metal, dark look is the colophony after solidify. Colophony also is coexist with poriferous form and metal, do not have as a result of two kinds of material strict directional, because this is below the action of directional force, both existence interaction, the intensity of mould material is strength of afore-mentioned two kinds of porous material nonlinear the result of overlay. The pattern that makes by afore-mentioned material is tall without intensity of pure metal mould, because this suits small lot production only. The graph organizes metallographic photograph and photograph of SLS form semifinished product to compare after colophony of macerate of 10 moulds material, the shrinkage of long, broad direction is final mould respectively 2.
8 ％ and 3.
2 ％ , tall to systole is 5.
7 ％ . Contractive reason has the following at 2 o'clock: Of grain of high polymer binder take off except; High temperature agglomeration. Former and OK the content through reducing binder and refine binder grain to make its distributing in the hole in metallic grain and do not hold surplus space to try to improve; Latter can be passed reduce intensity of share of loss of high temperature firing temperature to come true. In addition, still can feedback contractive information to undertake to CAD three-dimensional model dimension compensation will control systole. 3 conclusion use indirect SLS method, it is figuration raw material with common iron pink, via high temperature agglomeration and macerate modified epoxy resin, can make Injection Mold Tooling. This kind of method is integrated the advantage of the quick sex of RP&M technology and SLS technology oneself, can be in a week make piece have inside put is multiple the Injection Mold Tooling that along with form cooling water, this kind of mould can rise the efficiency that note model and plastic quality. The intensity as a result of this kind of mould not as good as compact metal mould is tall, because this agrees with only the production of small lot, and the precision of the mould remains at rising further. CNC Milling CNC Machining