DE707612C - Method for producing hollow pellets on a tablet press - Google Patents

Description

Method for producing hollow-shaped compacts on a tablet press The invention has a method for making hollow shaped compacts on a Tablet press to the subject. The manufacture of hollow bodies from powdery or fibrous masses encountered particular difficulties in that as a result of the different heights of the material in the die, the distribution is not even If, as a result, the compact is also given an uneven density. Such Pressings then have mainly loose edges that crumble easily and therefore are useless. This fact occurs especially when processing fibrous Masses, for example fiber-containing Kunstbarzpreßmassen on. The one from the ram captured fibers and pressed onto the substrate leave a dodging and a Difficult to distribute according to the sides.

It has now been found that good results can be obtained if one into the filled die after its completion by the ram before compaction sends a blast of air, which the pressed material from its rest position in higher parts of the press room presses. The ram, which goes down without interruption, has as a result the ability to advance and distribute the pressed material.

One means of performing this procedure is to that the upper punch has openings on the underside, which are connected to a compressed air line stay in contact. A valve provided on the press is driven by the press drive controlled. The required compressed air can be taken from a compressed air cylinder.

You can also proceed in such a way that you get a Air pump provides that at the appropriate time by one exerted by the press drive Piston puff creates a puff of air.

The process is explained in the drawing, namely Fig. X a compact in the form of a cap made of powdery material, Fig. 2 the previous one Process of pressing "Fig. 3 the pressing process according to the present process, Fig. 4 a preform made from fiber-containing synthetic resin molding compound in the form of a Bearing shell.

Fig. 5 and 6 show the previous pressing process.

Fig. 7 shows the pressing process according to the present method.

Fig. 8 shows the ram in a side view, partly seen, represent.

It denotes a the upper punch and b the lower punch of a tablet press.

To produce a compact according to Fig. 1, the lower punch 7 separated and in two parts for the purpose of ejection. As can be seen from Fig. 2, the Filling of the die with the powdery material to be pressed is not evenly tight, as the Pressed material in the narrow annulus as a result of trapped air and also because of the The tightness of the space itself does not fall. There are therefore those marked with c Places only insufficiently filled.

Even the descending ram a cannot change anything, which presses the pressed material lying above the core more tightly and not towards the sides supplies enough material. The compact is therefore not solid at the edges at c and tends to crumble.

If one sends now at the moment when the upper punch a the die completes and compression has not yet taken place, a puff of air into the die, that pushes the material to be pressed into higher parts of the room, the punch that moves on without interruption, the possibility of pushing pressed material in front of you and to push into the annulus. This process is shown in Fig. 3. The Stamp a has a bore cl, the evil a hose connection piece e with a compressed air line connected is. The air blast is controlled by the press drive and takes place in the time when the die is completed. The pressed material lying over the core is whirled up and the pressed material after the 1 pages at f from the punch a pressed down, where it fills the annulus tightly.

In the example according to Fig. 5 to 8 it concerns the production a bearing shell-like preform made from a fiber-containing synthetic resin molding compound. So far, the punch compacted the mass resting on the bottom of the die without that this had the opportunity to distribute itself according to the sides and higher sufficient space to be filled. As Fig. 6 shows, the material to be pressed is strongly compressed at the point marked g, while the higher lying parts too little material is obtained at h, so that the compact does not have the desired height receive.

The edges will not solidify and will crumble.

Fig. 7 shows the blowing of a blast of air through the at the bottom of the Upper punch a provided openings i, which are connected to the bore d and the nozzle e are in communication with the compressed air line. These openings j are all over Distributed along the length of the stamp (Fig. 8).

The punch that pushes the material in front of it distributes it the bottom of the die, but the higher part, which forms the edges, so much material retains that they become sufficiently strong.

Depending on the size, shape and nature of the material to be pressed, the strength of the puff of air, the duration and the time of the same can be selected.

Claims (2)

PATENT CLAIMS: I. Process for producing hollow compacts on a tablet press, characterized in that in the filled die after the end of which a puff of air is sent by the ram before compression, which pushes the material to be pressed from its rest position into higher parts of the pressing chamber. 2. Device for carrying out the method according to claim 1, characterized characterized in that the upper punch of a tablet press on its underside a or has several openings in communication with a compressed air line which a blast of air controlled by the press drive is sent into the filling space.