DE1919435C - Hot runner injection mold for plastic bodies - Google Patents

Description

The object of the invention is to provide a

60 hot runner injection mold, the distribution plate including its interchangeable parts without Loss of precision is much easier and therefore

The invention relates to a hot runner half faster and cheaper to manufacture and for the Ge-injection tool for plastic bodies with one of the custom can be prepared. For this purpose, the injection unit facing an injection molding machine, those parts of the distributor plate that have a special th clamping plate, one made with precision using spacers and preserved in this condition Die plate connected to the clamping plate must be parted, namely the valve needles, their guides Shape and one between the clamping plate and the bushing as well as the connection of the distributor

plate channel with the sprue nozzles of the die plate All the antechamber sleeves should be designed in such a way that SS them in an economical way as serial products and kept in stock. In addition Sört not only that the number of interchangeable S is limited to a minimum and to loose TeUe is completely dispensed with, but also that substitute Share with a few, ubiquitous helping beings in the simplest way can be installed and removed, and above all that for the one-tandfrei Function of the hot runner injection mold

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solved in that each guide sleeve is screwed into the distributor plate from the clamping plate and each spring plate is plugged onto the end of each valve needle protruding from the FUh-Sngsbüdise, that each Vorka.nn, c, büch * with a collar lying outside the distributor plate is a The hole in the die plate leading to the sprue nozzle is tightly sealed and that each prechamber bushing consists of a bushing with the collar and an inserted into the bushing, the longitudinal duct extending up to the sprue nozzle _with external thermal conductivity.

In a hot runner injection mold of this type, those parts whose production requires particular precision, namely the valve needle, its guide branch and the ducts that connect the distributor plate with the sprue nozzle producing the pre-chamber bushing, including _the tube inserted into it, can be produced in stock as a Senentede. Since all of these are turned parts, they can be produced relatively cheaply with the required precision using relatively simple devices and machines, including on automatic machines. In the case of the guide bush, only its guide hole requires special precision because d, c the hole receiving it can easily be sealed via the external collar. When producing the distributor plate, coaxial threaded bores with the same threads are to be provided in the run or extension of each channel leading to a sprue nozzle on opposite sides of the distributor plate, which the guide bushing with the valve needle and the antechamber bushing with the pipe are then used. It is quite possible to keep valve needles and tubes of different lengths and different cross-sections with adapted guide and antechamber bushings in stock in order to adapt a distributor plate quickly and easily to different tasks.

Ladders result from the design of the replaceable expensive parts. There are advantages for the use of the distributor plate, provided that a nozzle needle can be exchanged together with its guide bushing and can be removed from the distributor plate from any side and inserted into it, and that both in the form of change as in the reaction of the associated with the mold manifold plate tng of an all the Stira _üchsen herzu- ^ _α nearest without itfeinfrdie manner _"B through gemeiniwerden can

^ Characteristics aer aen _{It zd}

^ g ^ ÄSi adjacent tSS ^ SÄ injection mold in one

«^. ^ Exchangeable parts of the distributor

Plate according to FjfrJ · c _Dritz tool according to Fig. 1 In the case of the "" JJ ^^ g * ^ * die plate 2 one is clamped only in ^the * ufa ^ Pgg ^^ ₃ ^ ₁ , divisible shape "* f JJJ ^ ne number of shape - «The, ^^ ^lat * ² J ^ f _nu " _an e is shown. Ia? Ditagen2 * wo g ^ Ä ' _a sprue nozzle plate inserted into the die ^ J? ^ S & £ X 2 e ^ valued ο ^ ^ _d

2 ^ The jgj ™ ft. ¹ ^ injection molding "machine plastic * ₅ (not ^ _ff ^zeicnne J.3 _h ^" L x _{4 a 4b} fed the

m de ^ { _,, “4 have passed. Da arranged advantage ^ "^ _{ß (} f _{üse 2 b lead} the ^ e. ^ Each d« z ^ em r An ^ gu ^^ ^ ^ ^

K anaJe J «* ™? ^^ i _{centra en} axial channel connectedness

Wf ^ A ₅ ShI plastic mass from the de x, m denjta plasüsc ^^ ^ ^ _je _

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we. scnlossenen introduced s ^^ ™ a _{required large} amount NATURAL

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point-shaped sprue, the toffkörpem little \ _χ ^ _{nd the} Angußdüsen 2 ft by 5 is closed, the _ßdüse by the under ^ "plastics material for a short time of £ _{2 b} are possible _Suspended above,

their ^ " \ _{with their the} sprue nozzle 2 b

.? V. "Lhaftteil 5 ft with a close fit in a Jg ^ nen Scha ^ SJ ^ g ^ _{6 guide} , _d i _e

45 axial bo g _{f her} . _{n the enve} , _terte end

\ ^ONDTR _iln ^P _dur ^ _ed before the channel that 4c of distribution "is _ngese TZT, and this bore with ^e | _{d covenant you, verse} chließt.

Channel 4 ″ leading to 2 b _{is separated from the channel} c by a ″ ″ _a of valve needle 5. ^un _{the Führungsb} üchse 6 vorste-Au, ^{the au} ^ _Angußd u _se 2 ft averted stem Hende ^. ^ J is _in 7 ^g _{ederte arterial 7 up,} on the one

Ventilnadd ^ 5 gg ^ ^ _{g rf} ^

pressure. ueger valve needle S through the

J " ¹ ^^ * ^ ⁸ _Rin gbundes 5 a acting pressure 60 d« ^ merseUe ^ _KanaUf) supplied Kunstderdurth üe ^ _temporarily lifted.

. _{d between the nozzle} 2b leading to the sprue nozzle

renden £ j " ^a » · " _high warmth element.tverrno-

⁶ⁱ ^ SS

is held in the end of a bushing 10, which · ^by: the die plate 2 is inserted forth in the distributor plate. 4 This sleeve 10 with inserted tube corresponds in its function to the usual antechamber sleeves.

The outer annular collar 10 a of the bushes 10 forms the necessary seal between the die plate! and the distributor plate 4. This means that the otherwise customary metallic sealing rings that are clamped between the die plate 2 and the distributor plate 4 and enclose the feeds to the sprue nozzles 2 b are dispensable.

In a known manner, the end of the pipe 9 protruding into the channel 4 α leading to the sprue nozzle 2 b forms with the wall of the nozzle bore an insulating gap 11 which fills with plastic compound during operation of the tool and thus provides effective protection against undesired cooling of the through the for Forming sprue nozzle leading channel Aa supplied plastic compound.

To approximately facing away on b from the feed nozzle 2 shaft part 5 b along flowing plastic mass to create and to prevent an undesirable pressure build-β behind the annular collar 5 is a lightest possible way out to the outside, the guide sleeve 6 having at least one radial, to the outside opens leakage bore 6 a provided.

The design of the hot runner injection molding tool also allows individual mold cavities to be created in a simple manner to be taken out of service by replacing the associated sleeves 10 with a plug each will.

1 sheet of drawings

Claims (4)

Heatable divider plate arranged on the die plate, claims: the axial connecting the nozzle of the injection unit and the sprue nozzle arranged in the die plate 1. Hot runner injection mold for plastic and radial channels, wherein in each of the axial channels leading to the sprue nozzle with one of the injection unit of an injection molding machine, a mounting plate facing the casting machine, a valve needle is arranged, which is connected to the spacer via a spring element Clamping plate and a bound die plate, supported against the clamping plate, of a divisible shape and spring in contact with a sprue nozzle forming a valve seat is held between the clamping and die plate The injection unit is provided with a collar and is axially displaceably guided in the die plate on the guide bushing Axial channels each have a valve needle leading to directly in front of the valve seat, which extends over a spring longitudinal channel, which is supported against a spring in a spring that is screwed into the distributor plate and one screwed against the clamping plate from the die plate the sprue pre-chamber liner is arranged.
nozzle-forming valve seat is held, which is the case of a known hot runner injection molding tool Clamping plate facing end in this way, the valve needle with the spring plate provided with a collar is axially ao firmly connected, and its guide is guided in the distribution and whose guide sleeve serving the die plate is in the end facing the distribution plate through one of these The end of the plate, which surrounds the end facing the die plate at a distance, is inserted immediately, of which the longitudinal channel leading up to directly in front of the valve seat also extends in front of the valve seat, which in one end of the manifold into the distributor plate Pre-chamber liner is screwed in.
Die plate screwed in antechamber from this type of formation of the valve needle bushing is arranged, thereby identified as well as from the training and arrangement of the guide, that each guide bushing (6) of the bushing for this needle and the antechamberdcr Clamping plate (1) into the distributor bushing results in certain disadvantages, not only plate (4) screwed in and each spring plate (7) 30 the production of the hot runner injection mold komauf the one protruding from the guide bushing (6) and make it more expensive, but also the end of the hand Each valve needle (S) is attached, making it difficult to use. So do the each prechamber liner (9, 10, 10 a) with an example of the protruding from the distributor plate and outside the distributor plate (4) lying collar in the holes leading to the sprue nozzle (10 a) a drilling die plate projecting parts of the antechamber bushes leading to the sprue nozzle (2 ft) tion in the die plate (2) tightly closes a corresponding number of these parts as well as the and that each prechamber sleeve (9,10,10 a) from them receiving bores of the die plate umeiner the collar (10a) having sleeve (10) closing individual seals required, the guide and one in the bushing (10), the rungs bushes must each have one of their ends up to the sprue nozzle (2 ft) extending longitudinal 40 connection of a longitudinal channel to a transverse channel bilkanal forming tube (9) with good thermal conductivity and, for reasons of sealing, with a tight fit fortune exists. be inserted into the distributor plate. Your manufacture 2. Hot runner injection molding tool according to claim 1, and fitting are consequently difficult and thereby characterized in that each valve needle (S) demand the utmost precision not only with regard to the in its central area a guide bore in the axial 45, but also in its outer channel (4 c) sliding annular collar (5 α). fangs. 3. Hot runner injection molding tool according to claim 1, particularly disadvantageous is that the characterized in that valve needles known per se and the guide bushes of various types a valve needle guide opening into the open air, which sides are inserted into the distributor plate. Leakage bores (6 ö) radially through the collar 50. This means that a joint expansion of a guide is possible Extend the guide bush (6). only with the valve needle stuck in it 4. Hot runner injection mold according to claim 1, after destruction of the needle by severing the characterized in that each of the in each spring plate possible, for what then as well as for Prechamber bushing (9, 10, 10 a) inserted separate removal of these parts in the event of damage Pipes (9) inside the die plate (2) of 55 or for cleaning the guide surfaces the distributors known insulating gap (11) um- lerplatte both from the clamping plate and from give is. the die plate and also the antechamber must be removed.