CN1006367B - Injection molding heated noozle with brazed in heating element and method of manufacture - Google Patents

Abstract

The present invention relates to an improved injection molding heating nozzle and a manufacturing method thereof. The nozzle is provided with an elongate main body, a melting stock hole penetrates through the center of the main body, and a spiral channel with variable torque is arranged on the outer column surface. A spiral electric heating element is embedded in a channel to form a whole, which can cause hot melting stock flowing through the melting stock hole to be kept within a narrow temperature range. The main body of the nozzle can be made by investment casting or cutting processing. The electric heating element is placed in the channel, nickel welding flux is placed on the electric heating element, and the electric heating element is put in a vacuum furnace to be heated and welded. High heat conducting nickel completely covers the electric heating element and is fused with a heating element and a slot wall. The whole nozzle with low cost can effectively radiate the heat of the electric heating element to prolong the service life of the electric heating element and uniformly heats along the melting stock hole.

Description

Injection molding heated noozle with brazed in heating element and method of manufacture

The present invention is relevant with injection moulding, is specifically related to the manufacture method of a kind of improved heated nozzle and heated nozzle.

Injection molding nozzle or cast gate sleeve pipe have a medium pore, the melt of pressurization is transported towards a cast gate that leads to die cavity, in the method for knowing in this specialty, use a spiral electrical heating elements heat supply, fusion temperature is remained in the scope of a permission.One of this method be that helical heating element is placed between the inside and outside sleeve, but this method has a shortcoming for example, at the air-gap of putting between two sleeves of heating element heater, plays heat insulator exactly.Recently, use the vacuum pressing and casting method, just can solve the heating element heater casting as the way in the high hot material of copper alloy and so on to this problem, United States Patent (USP) the 4th the applicant respectively on December 7th, 1980 and approval on October 26 nineteen eighty-two, 238, No. 671 and 4,355, in No. 460, done announcement.Though it is very good that this nozzle operation that is cast with heating element heater gets, manufacturing expense is quite high.

Certainly, in the heater strip or the heating tape heating of hollow sleeve or the insulation of pipe fitting outer take-up strap, be known, still, because efficient is low, therefore poor reliability realizes that it is unsafty that this method is used for injection molded nozzle.Along with the use to the plastic material that is difficult to die casting day by day increases, just having need be the temperature range that melt kept is reduced day by day.If temperature rises too high, just can cause the rotten of melt, and if descended when hanging down, just melt stops up, produce underproof product in system, under any situation, all need the running of system is stopped, clearing up.And, if at this moment not rapid desuperheat will cause overheated and burn out.Certain this danger is serious more when temperature is high more, still, if heat is not dissipated rapidly, just inevitable requirement can be made high temperature operation, provides enough heats from heating element heater.High-temperature itself will shorten the life-span of heating element heater, and if " focus " take place along the length of heater strip, situation is just more serious.Do not have to such an extent that be enforcement so twine the heating element heater of heating wire or ribbon heater, because to up-to-date high temperature engineering material, a heat of failing leaves quickly and evenly, to obtain efficient and reliability.

Therefore, one object of the present invention, be to overcome the above-mentioned shortcoming of a part at least, way is to propose a kind of improved nozzle and its manufacture method, nozzle that is disclosed in the patent of its cost than top the applicant who mentions and manufacture method are low quite a lot of, and heat can be delivered to and surround on the nozzle body on every side of melt hole quickly and evenly from heating element heater.

In order to reach this purpose, one aspect of the present invention is to propose a kind of injection molding heated nozzle, and this heated nozzle has a microscler metal master and the heating element heater that electric insulation is arranged; An entrance point is arranged in the metal master, a port of export, a longitudinally extending melt hole of from metal master, passing, melt import from entrance point, reach near the melt outlet of the port of export, and have one to be generally columniform outer surface, in cylindrical, be generally spiral conduit, from near first end the entrance point of main body, reach near second end of the port of export; The electric insulation heating element heater is embedded in the spirality conduit with a kind of highly heat-conductive material, highly heat-conductive material surrounds heating element heater and 11 integral body of conduit fusion, heating element heater has terminals to stretch out from first end of conduit, supply with the controllable current of heating element heater terminals, to main body heating around the melt conduit, the melt that in nozzle, passes through, remain in the predetermined temperature range.

Another aspect of the present invention, a kind of method of making the whole heated nozzle of injection moulding is proposed, its step comprises microscler steel main body of formation, the heating element heater of insulation is placed in the spirality conduit, highly heat-conductive material is put along establishing near the heating element heater of conduit, and main body is heated in vacuum drying oven; Microscler steel main body has an entrance point, port of export and one are generally columniform outer surface, main body has a melt hole, vertically passes in main body, from the central melt import of entrance point, arrive near a melt outlet of the port of export, be generally columniform outer surface, have one to be generally spiral conduit, on the face of cylinder, stretch, from near one first end the main body entrance point, lead near second end of the main body port of export; Put the spirality conduit of the heating element heater of insulation, around the main body of nozzle, heating element heater has terminals, stretches out from first end of conduit; When main body is heated in vacuum drying oven, under the temperature that is enough to the highly heat-conductive material fusing, heating a period of time, highly heat-conductive material and heating element heater are fused together in conduit, heating element heater is embedded in becomes as a whole in the conduit.

Other purpose of the present invention and advantage are read following narration with reference to accompanying drawing, just can have gained some understanding.The accompanying drawing content simply is described below:

Fig. 1 is a partial sectional view of an injection molding apparatus, the nozzle in desirable embodiment of diagram the present invention;

Fig. 2,3 and 4 is the cutaway view of the manufacturing process of the nozzle among Fig. 1;

Fig. 5 is the tray that is used for the placement nozzle that heats at vacuum drying oven;

Fig. 6 is the local isometric views of the port of export of nozzle shown in Figure 1;

Fig. 7 is the cutaway view of electrical connector shown in Figure 1.

At first referring to Fig. 1, this illustrates a nozzle 10, and is wherein porose 12, transports the pressurization melt, and melt is supplied with by an injection (mo(u)lding) machine 14, by cast gate 16, flows into a die cavity 18.Nozzle 10 be embedded in the cavity plate 20 and the cast gate 16 that passes cavity plate 20 over against.Heated nozzle 10 usefulness solderings are welded on the insulation casing 22, and this sleeve pipe is located to nozzle, and a nozzle and the adiabatic air-gap 24 between the cavity plate 20 around it are provided, and cavity plate 20 is by the water quench of passing through in cooling element 26.A cylinder seal 28 that the V-arrangement cross section is arranged is arranged, in seal seats, stretch, bridge on space 24, hereinafter will do more detailed narration around nozzle 10.

Nozzle 10 has an elongate body 30, wherein has one to be generally columniform outer surface 32, extends to the port of export 36 from entrance point 34.In this embodiment, the port of export 36 has a trochoidal surface 38, forms a tip 40, stretches facing to cast gate 16, as the thermal spike cast gate.Yet in different gating apparatus, the cast gate of other planform can also be arranged, such as the seamed edge cast gate.There are first middle body 42 and one second short tilting part 44 in melt hole 12.First 42 at entrance point 34 places, includes the nozzle-end 48 of injection (mo(u)lding) machine 14 from recessed nozzle carrier 46 beginnings of entrance point 34 in.Second portion 44 outwards stretches from first 42, arrives a melt outlet 50 on the trochoidal surface 38.

The outer surface 32 of nozzle body 30 has one to be generally spiral conduit 52, and in the ordinary course of things near first end 54 the entrance point 34 of main body 30, near second end 56 the main body port of export 36 stretches.In this embodiment, conduit 52 has one first spiral part 57, since first end 54, stretches around the cylindrical outer surface 32 of main body, and a second portion 58 is arranged, and is stretched over second end, 56 places on the trochoidal surface 38 of the main body port of export 36.As shown in Figure 6, these first and second parts 57,58 of conduit 52, by below cylinder seal 28, hole that connects from main body 30 or passage 59 connect them.Can see the pitch of first spiral part 57, not necessarily must be evenly, in the present embodiment, the place, end needs bigger heat, so pitch is tight gradually towards two ends.The second portion 58 of conduit 52, crooked around trochoidal surface 38, at the trochoidal surface place, require outlet 50 heating around the melt hole, conduit is always to being issued to most advanced and sophisticated 40.Have one to be generally spiral heating element heater 60, be placed in conduit 52 and the passage 59, use the highly heat-conductive material 61 such as nickel, heating element heater is embedded in conduit 52 and the passage 59, highly heat-conductive material 61 fuses between heating element heater 60 and main body 30.In the present embodiment, heating element heater 60 is double electrothermal filaments, and evanohm resistive conductor 62 is arranged, and passes through from the flame proof electrical insulating powder material 64 that is placed on 66 li in a steel box, and this dusty material is just like the magnesium oxide powder of compacting.Heating element heater 60 has the cold joint line end 68 of an expansion, stretches out from first end 54 of conduit 52.As known, the heating element heater reduced, and magnesium oxide powder 64 compactings, to improve its heat transfer performance.The end of high resistance heating wire 62 near conduit 52 first ends 54, is connected (figure does not show) with the terminals lead 70 of the increase diameter that stretches out from cold joint line end 68.The adapter sleeve 72 of hollow is installed on the insulation casing 22, and the cold joint line end 68 of protection heating element heater prevents accidental damage.The design of cold joint line end 68 and adapter sleeve 72 is that the mode that can cut off is inserted a plug 73, described in hereinafter.There is a hole 74 to tilt to stretch into 30 li of the main bodys of nozzle 10, inserts a thermocouple 76, measure near the temperature the port of export 36 in the mode that can extract.Thermocouple has a lead-out wire 78, passes through the air-gap 24 between outer surface 32 and cavity plate on every side 20, and draws on the next door of cold joint line end 68.

Referring to Fig. 2 to 5, can see in a desirable embodiment of the present invention the order of the manufacturing step of nozzle 10.Fig. 2 illustrates the microscler steel main body 30 of melt hole 12 and spiral channel 52, and main body is with suitable high-strength material manufacturing, and for example H13 tool steel or resistant material are such as stainless steel.Main body 30 the most handy investment castings can certainly be processed melt hole 12 and passage 59 with boring, and are being generally on the columniform outer surface 32, cutting conduit 52.Though to outer surface 32, above be stated as roughly cylindrical, in the present embodiment, cylindrical reality is outwards outstanding, forms a seal seats 80 of cylinder seal 28.And, narration once being arranged in as mentioned, this embodiment has the first and the second portion 57,58 of conduit 52, and the slant dilation passage 59 that these two parts are used in seal seats 80 belows connects.

Secondly, electrical heating elements 60 is inserted in the passage 59, and spirality conduit 52 centre circles around, cold joint line end 68 is stretched out from first end 54 of conduit.The width of conduit 52, diameter than heating element heater 60 is big slightly, but the diameter of depth ratio heating element heater 60 is quite a lot of greatly, concurrent now with heating element heater in conduit the time, with the length of a drift along conduit, with interval the conduit edge is beaten to turning in (burring), heating element heater is temporarily located, doing like this is to have easily.Then, above the heating element heater 60 of a string nickel soldering flux 82 in conduit be placed on, as shown in Figure 4.Heating element heater 60 from first end 54 of conduit 52, is stretched over cold joint line end 68 places of stretching out on this position the time, and then, the elongate body along the length in melt hole 12 around nozzle stretches.On this nickel soldering flux 82, spraying one deck acrylic paint coating is the fixed-site of nickel weldering brazing flux bar, the loss when reducing brazing filler metal then.The nozzle 10 that a plurality of assemblings are finished is placed in the tray 86 subsequently, puts into 84 heating of a vacuum drying oven, makes heating element heater 60 weldings in conduit 52.Importantly when the nozzle 10 that assembles is heated, time enough and temperature must be arranged,, under capillarity, flow in the groove 52, surround heating element heater 60 the fusion of nickel solder flux.It is found that, if correctly accomplish the words of above this point, the nickel of so high heat conduction will flow to heating element heater around, be embedded in heating element heater in the conduit fully, nickel is in whole length of conduit and heating element heater and conduit welding, form an overall structure, and do not leave over any air-gap, in order to avoid cause disadvantageous " focus ".Though also can adopt other high conductivity material to reach this purpose, find that the nickel solder flux especially can be satisfactory.In vacuum drying oven, carry out this brazing filler metal, be actually the fusion of a nickel and steel, can improve the radiating rate of thermal element so considerably, make structure very good.Above the heating element heater in conduit, must there be enough nickel to hide,, avoids heating element heater being burnt out in this side in order to heat is left.After brazing filler metal, nozzle 10 is taken out from vacuum drying oven, might need external surface grinding, remove any unnecessary material.Especially on the trochoidal surface 38 of the port of export 36 that contacts melt, need the cleaning excess stock.Then, as shown in the figure,, be installed on the nozzle body 30 insulation casing 22 and adapter sleeve 72.The copper brazing agent is placed between the seam, again nozzle 10 is re-applied in the vacuum drying oven 84, insulation casing 22 and adapter sleeve 72 are burn-on, form an integral unit.In this case, soldering flux is a copper, and the fusion temperature of copper is lower than the fusion temperature of the nickel solder flux of original use.Therefore, second heating process carried out under lower temperature, and this temperature is enough to melting copper, but can not melt nickel.

In use, nozzle 10 is installed in the injection molding apparatus by Fig. 1.A plug 73 usefulness leads 88, be connected with the power supply that suitable control is arranged, be screwed on the cold joint line end 68 with screw then.As shown in Figure 7, plug 73 has two brass sleeve 90, one ends to be crimped on the extension lead 88, and opening 92 is arranged on the other end, inserts terminals lead 70 under the frictional force effect.Outside the brass sleeve pipe 90, cover insulating ceramics 94 and stainless steel tube 96.A threaded sleeve 98 is arranged, be screwed on the adapter sleeve 72, plug 73 is locked tightly in the position.A silicon rubber filling part 100 is arranged,, also have a plastics draw, make moisture seal and use in order to reduce the tension force on lead 88 ends.

After nozzle 10 is heated to the predetermined temperature of doing by job requirement,,, supply with the pressurized heat melt by the nozzle tip 48 of injection (mo(u)lding) machine 14 just according to the infusion cycles in the conventional method.The melt that ejects passes through from melt hole 12, flows out from exporting 50, fills in the space 104 of trochoidal surface 38, and injects die cavity 18 by cast gate 16 and go.Be expelled to the melt that goes in the space 104 during beginning, sealed 28 stops, can not flow to air-gap 24, and some hardens near cold cavity plate, has played heat insulating function.After die cavity 18 is full of, temporarily keep expulsion pressure to make it closely, then release pressure.After a cooling stage, model parting line 106 to be opened, product has been cast.Then model is closed again, add injection pressure again, this circulation is repeated continuously.Mention in the above, under the situation of the lower material of stability in use is increasing, melt is being passed through from system, when arriving cast gate 16, keep the narrow temperature of melt, become more and more important.Soldering nozzle of the present invention provides until the temperature control degree of necessity of the overall process of nozzle tip is still cast comparing in nozzle body, the sizable reduction of manufacturing cost with the past with heating element heater.Though the present invention has been done above-listed narration to particular, should not be construed as and contain the restriction meaning.For being familiar with this professional people, also therefore it is contemplated that many variations and modification.For example, the obvious port of export 36 of nozzle body can be because of the cast gate of various form, and other structural form is arranged, the double electrothermal filament of heating element heater shown in also can be above, and use single heating wire.Though and for the ease of explaining orally the injection molding apparatus of only having told about a monotype chamber, obviously nozzle can also be used for the equipment in many types of chamber.Now propose the invention of opposing of accompanying Claim book and determine scope.

Claims (12)

1, a kind of injection moulding heated nozzle, comprise an elongated metal master, an entrance point and a port of export are wherein arranged, a longitudinally extending melt hole in main body is arranged, be stretched over the port of export from entrance point, comprise that also a spirality heating element heater that insulation is arranged is around metal master, heating element heater has terminals, do controllable power supply, to main body heating around the melt conduit, keep melt in a predetermined temperature range, from nozzle (10), to flow out, the entrance point (34) that it is characterized by main body (30) has a melt import, the port of export (36) has a melt outlet (50), main body has one to be generally columniform outer surface (32), wherein has one to be generally spiral conduit (52) and to stretch inside, near first end (54) main body (30) entrance point (34), reach near second end (56) of main body (30) port of export (36)

Heating element heater (60) is embedded in the spirality conduit (52), and fusion has highly heat-conductive material around the heating element heater 60, and they become as a whole, the cold joint line end (68) of heating element heater, first end (54) outside of stretching out conduit (52).

2, heated nozzle as claimed in claim 1 (10), the port of export (36) that it is characterized by main body (30) has a conical surface (38), form a tip (40), there are first (42) and second portion (44) in melt hole (12), first (42) stretches out from melt import (34) roughly in central authorities, and second portion (44) is quite short, from first's extending obliquely, reach the melt outlet (50) on the port of export (36) trochoidal surface (38).

3, heated nozzle as claimed in claim 2 (10), it is characterized by conduit (52) first (57) is arranged, cylindrical outer surface (32) from first end (54) around main body (30) stretches, second portion (58) is stretched over second end (56) on the trochoidal surface (38) of main body (30) port of export (36), a seal seats (80) is arranged, be placed on main body (30) cylindrical outer surface (32) around, accept near the heating element heater (60) of trochoidal surface (38) of main body (30) port of export (36), pass through in the connection conduit first (57) that heating element heater stretches below seal seats (80) and the passage (59) of second portion (58).

4, heated nozzle as claimed in claim 1 (10), it is characterized by melt hole (12) roughly stretches on the center line of main body (30), the port of export of main body (36) has some grooves, each bar groove is protruding from melt outlet (44) diametrically, pressurization melt from flow out by melt outlet (44) melt hole (12) can flow to one edge-gated (16) leading to a die cavity (18).

5, as each heated nozzle in the claim 1,3 or 4, it is characterized by the pitch that trends towards conduit (52) first ends (54) and second end (56), greater than the pitch of intermediate channel.

6, as the heated nozzle (10) among claim the 1,3 or the 4th, be characterized as main body and make with steel.

7, make the method for general injection shaping heated nozzle, the step that it is characterized by this method is as follows:

(a) form a microscler steel main body (30), an entrance point (34) is wherein arranged, a port of export (36), with one be generally columniform outer surface (32), main body (30) has a melt hole (12) vertically from wherein passing through, central melt import from entrance point (34), reach near the melt outlet (50) of the port of export (36), be generally columniform outer surface (38), there is one to be generally spiral conduit (52) and to stretch thereon, from near first end (54) the entrance point (34) of main body (30), reach near second end (56) of the main body port of export (36);

(b) an insulated electro heating element heater (60) is placed in the conduit (52), spirality stretches around the main body (30) of nozzle, and heating element heater (60) has a cold joint line end (68), stretch out from first end (54) of conduit (52),

(C) highly heat-conductive material is established along heating element heater and put near conduit;

(d) main body (30) is placed in the vacuum drying oven (84), under the temperature that is being enough to highly heat-conductive material fusing, heating a period of time, highly heat-conductive material in conduit and heating element heater (60) welding, heating element heater (60) is embedded in the conduit (52), forms an integral body.

8, method as claimed in claim 7 is characterized by step (a) and comprises the main body that forms steel with investment casting.

9, method as claimed in claim 7 is characterized by and comprises with automatic machine tool in the step (a) cut conduit on the outer surface of main body.

10, as the method for claim 8 or 9, it is characterized by and also have in addition a step, putting into before vacuum drying oven (84) heats, be coated in acrylic acid on the welding bead (bead) of highly heat-conductive material, add one deck cover layer.

11, as the method for claim 8 or 9, it is characterized by in addition step in addition, on a part of outer surface, cut at least, a level and smooth smart surface is provided.

12, as the method for claim 8 or 9, it is characterized by and comprise a step in addition, an insulation casing (22) is installed on nozzle, with an adapter sleeve (72), on necessary seam, add one deck soldering flux, its fusion temperature is lower than the fusion temperature of above-mentioned highly heat-conductive material, and in vacuum drying oven, carries out soldering with the temperature that is lower than above-mentioned highly heat-conductive material fusion temperature.

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