DE2146831A1 - Method for pressing thermosetting plastics and device for carrying out the same - Google Patents

Description

2H6831

PATENTANWÄLTE 8902 Göggingen near Augsburg, September 16, 1971

_ _ ____. . von-Eichendorff-StraßelO

dr. ing. E. LIEBAU

niPI IW <~ CZ I IFRAII Our reference G.Lb/w Ϊ ¹ 8586

DIPPING. KS. L-ICtIiMU ₍ please specify in response)

Your sign

Sergio Farinelli

Via dei Chiaramonti Mr.

Milan / Italy

Process for pressing thermosetting plastics and device for implementation same.

The development of technology for thermosets (Bakelite, urea resin, etc.) has recently led to the so-called transfer pressing or injection molding out, with the molding compound is produced, which is created by a plasticizing device at horizontal arranged machines is obtained. After the material has become plastic in the plasticizing unit, moved the plasticizing screw with a certain stroke forwards, so that the mass from the end of the cylinder to the Exit is brought, which is then cut off with scissors or a cutting knife, which the latter also to it serves, the exit of the cylinder during the plastification phase to close.

The mass separated in this way forms the filling quantity, which is then conveyed forward to the piston of the transfer device must be in order to be injected into the die. A known solution to the mentioned problem is as follows:

The plasticizing unit is parallel to and above the Arranged piston of the transfer device. The capacity that exiting the plasticizing unit is pushed into a tube which is arranged in front of the outlet of the plasticizing unit is. After the fillet has been cut through the scissors or

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knife has been separated, the one containing the filling quantity The pipe is conveyed forward to the piston of the transfer device, whereupon a linear movement or a rotary movement is made about an axis parallel to the axis of the pipe. The piston of the transfer device is then moved forward, whereby the filling quantity is printed in the press tool and the injection process is carried out.

This arrangement has the disadvantage that that part of the filling quantity which was in contact with the scissors or the cutting knife during plasticizing and which, since it was longer, has been further ψ polymerized in the plasticizing unit and has therefore already begun to solidify, that part is that is first injected into the cavity of the press tool when the piston of the transfer device moves forward to carry out the transfer molding process.

This fact can lead to difficulties when pressing.

Another known solution to the problem is to place the plasticizing unit above and in an inclined position to be arranged to the piston of the transfer device. The sprue of the plasticize MatexL as will allow free exit from the . Plasticizing unit brought and falls, when it has been separated by the ^ scissors or the cutting knife, into a suitable receptacle which is arranged in front of the piston of the transfer device.

Before the transfer device moves forward, this receptacle is rotated by -1SO ^Ü with respect to its vertical axis, so that the part of the sprue which first enters the cavity of the press tool during the transfer molding process is the one that forms the plasticizing unit last leaves, while the more hardened part, which was in contact with the scissors or the cutting knife, does not reach the cavity, so that it is in the injection channels of the

Press tool remains.

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Such a design leads to the best results in transfer molding, however, there is the disadvantage that especially when the filling quantity to be sprayed is very short, this into one An unfavorable situation can arise if, after being cut off by the scissors or the cutting knife, in the front of the piston of the Transfer device arranged recording falls. The present invention resides in a solution which has the advantages of the two systems described above are combined and their deficiencies are avoided.

The plasticizing unit is parallel to the piston of the transfer device arranged. The plasticized fill quantity exiting the plasticizing unit enters one of the two Ends an open receptacle, which is arranged in front of the outlet of the plasticizing unit.

After it has been separated from the scissors or the cutting knife, the receptacle containing the sprue becomes a Displacement and rotation of 180 ° around a vertical axis granted by means known per se.

In this way, the advantage is achieved that the sprues, even if they have a short length, always correct for the Pistons are assigned to the transfer device and that, as a result of the rotation by 180 °, that part of the sprue into the cavity of the pressing tool is injected, which emerges last from the plasticizing unit and therefore hardens the least is, whereby the pressing process is facilitated.

In Figs. 1 to 4 of the accompanying drawings are the various Phases of the method described above are shown, but not as limiting the invention are to be interpreted.

Fig. 1 shows the plasticizing unit 1, the end of which through a pair of scissors or a cutting knife 3 closed

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is. Inside the plasticizing unit, the plasticized mass is ready for Transfer into the housing 4. The scissors "or the cutting knife 3 is then withdrawn, whereby the outlet of the plasticizing unit is released (Fig. 2) and the screw 2, which is moved forward, promotes the plasticized mass in the receptacle 4, whereby the filling quantity 5 is obtained, which then with Using the scissors or the cutting knife 3 is separated (Fig. 3). The one containing the filling quantity Recording 4 now carries out a displacement and a rotary movement by 180 °, as indicated in the drawing, whereby it is brought in front of the piston 6 of the transfer device (Fig. 4), which during its forward movement the filling quantity 5 during the transfer molding process in the pressing tool, not shown in the drawing promotes.

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Claims (7)

2H6831 claims 1.) Process for pressing thermosets by transfer molding with horizontally arranged press and plasticizing unit arranged parallel to the piston of the transfer device, characterized in that the filling amount of the plasticized mass in a both ends open receptacle is brought, which is arranged in front of the outlet of the plasticizing unit, which Recording, after the filling quantity has been cut off by scissors or a cutting knife, a sliding and rotational movement through 180 ° about a vertical axis is given by means known per se, so that in the end this movement, the receptacle containing the fill quantity of plasticized mass is in front of and in axial alignment with respect to the piston of the transfer device the press is located, which piston conveys the filling quantity into the pressing tool as it moves forward, which is arranged in the machine and causes the mass to be injected into the cavity of the pressing tool. 2. The method according to claim 1, characterized in that the sliding movement and the rotary movement happen at the same time as the recording. 3. The method according to claim 1, characterized in that the displacement movement and the Rotary movement in two successive phases go yourself. 4. The method according to the preceding claims, characterized in that the receptacle is cylindrical is. 209846/0620, - O - 2,683Ί 5. The method according to the preceding claims, characterized in that the plasticizing unit is marked ei c h η e t above the piston of the transfer device ■ is arranged. 6. The method according to claim 5, characterized in that the displacement and the rotary movement the recording take place simultaneously with a helical movement. 7. Device for performing the method according to the preceding claims. 209846/0620