The invention relates to a moulding apparatus as specified in the preamble of claim 1.

Such a moulding apparatus is known from EPA 89203003.2. For the moulding of electronic components, chips, moulding apparatus are used wherein the so-called lead frame is placed into a mould wherein the mould has recesses for receiving the parts for moulding, and in addition cavities are arranged in the mould wherein measured quantities of moulding material are placed and wherein by supplying heat and exerting pressure in these cavities the moulding material becomes liquid, moves via channels intended for that purpose to the parts for moulding and, curing there, encapsulates the lead frame. The lead frame is subsequently removed from the moulding apparatus and subjected to further processing.

It is the object of the invention to carry moulding material in the form of cylindrical pellets from the reservoir to a desired discharge point which connects onto the above mentioned cavities.

This is achieved according to the invention by means placed between the reservoir and the means for placing moulding material into the mould for aligning the pellet¬ like moulding material in a predetermined direction and guiding it to a discharge point and for separating out material aligned in a position other than the desired position.

Thus achieved is that only those pellets of mould material located in the desired alignment are supplied to the said cavity, while incorrectly aligned pellets are ejected.

In preference the aligning and separation means are formed by an approximately vertical wall and a rotatable revolving body which is disposed close to the wall and the generator of which encloses a small angle with the plane of the wall.

Pellets of moulding material supplied to the revolving body fall between the wall and the revolving body. The rotating pellet has a turning moment having a component in the direction of the axis of rotation of the revolving body and a component perpendicular thereto. The pellet will therefore execute a rotating movement in the direction of the axis of rotation of the revolving body. Together with the movement component in the direction of the axis of rotation of the revolving body there results a helical path of movement over the surface of the revolving body.

The revolving body is preferably a cone, the top of which is oriented to the point of discharge. The pellet separated out in this manner can be fed back to the reservoir. It is also possible for the revolving body to be a cylinder, wherein the wall does not then run parallel to the axis of rotation and therefore the cylinder wall.

Practical tests have shown that in this manner the pellets of moulding material are supplied aligned with a high degree of probability in the correct manner to the discharge point and therefore to the cavity connecting thereto.

The invention will be further elucidated with reference to the drawings. Fig. 1 shows a perspective view of a moulding apparatus according to the invention; and fig. 2 shows in perspective view an embodiment of the aligning and separation means.

Mounted on the frame 100 of the machine is a fixedly positioned table 101. The table 101 bears a fixed lower mould half 102. The upper mould half 103 is movable relative to the lower half 102 using pull rods 104, 105 which are connected to the upper half 103 by the respective nut

connections, 106, 107. The pull rods 104, 105 are movable relative to the fixed table 101 via bearings, for example 108.

The driving of the upper half of the mould 103 takes place from an electromotor 109. Driven by means of the worm box 110 are the angle lever systems 111, 112. The angle lever systems are coupled on the one side to a movable underplate 113 and on the other side to a plate 116 fixedly connected to the table 101 by means of columns 114, 115. When the electromotor rotates the underplate 113 is moved vertically, for example in the direction of the arrow PI, which movement is transmitted via the pull rods 104, 105 onto the upper mould half 103. At the end of the stroke the arms of the angle lever system 111, 112 lie practically in one line so that a very great closing force is achieved. The input carriage 117 is movable over the guide rails 118, 119. The driving of the input carriage 117 takes place from the electromotor 120.

Lead frames are supplied from a supply cassette and are carried up over belts 122, 123 as far as a stop 124. During the position of the input carriage outside the mould the input carriage is filled from a so-called pellet-filling carriage 125 with pellet-shaped moulding material which is taken from a separating unit 126. For a reliable take-over of pellet-shaped moulding material by the input carriage 117 from the pellet transporting carriage 125 use is made in both carriages of pin-shaped guiding means 127. The mutual movements are controlled using a sensor 128.

The cleaning-discharge unit 129 is likewise movable over the rails 118, 119 between the position outside the mould die and the position inside the mould die. The unit 129 consists of a cleaning-brushing device 130 and a discharge member 131. The cleaning device 130 brushes both mould halves after use and simultaneously sucks up brushed- off remnants. Co-acting with the unit is a break-off plate 132 which subjects the finished product to an after- processing.

The means for aligning and discharging the pellet¬ like moulding material 152 in fig. 1 are shown on a larger scale and in more detail in fig. 2. Cylindrical pieces of moulding material 152 are fed from the supply reservoir 151 to a conveyor belt 160 which carries the material up to a discharge point 161, whereafter they fall one by one from the conveyor belt onto the cone wall 153. The cone rotates in the direction indicated by the arrow PI. The cone is directed towards the discharge point 154. Arranged along the cone wall is an approximately vertical wall 155 of material with a relatively low frictional resistance compared to the material of the cone wall. The cylindrical pieces of moulding material move in the direction of the arrow P2. Due to the rotation of the cone the cylindrical pieces of moulding material acquire a component directed in the direction P2 and a component providing the cylindrical piece of moulding material a rotating movement in the direction of the axis of the cone. Both movement components are the result of the fact that the turning moment of the cylindrical piece of moulding material does not run parallel to the cone axis. Cylindrical pieces of moulding material not aligned in lengthwise direction, for example 156, are ejected before reaching the discharge point 154. The cylindrical pieces incorrectly aligned in roughly transverse direction of the axis of rotation lie almost stationary and are carried along in the rotation direction of the cone by the friction with the cylinder wall. The piece of cylindrical moulding material then tips over the cone body and can be carried back to the reservoir. Those pieces of cylindrical moulding material that are aligned in longitudinal direction are carried via the discharge chute 157 to the separating unit 126.

By selecting a discontinuous tapering of the cone wall, the following is achieved. A cylinder supplied to the cone wall is positioned in the correct direction on the relatively less sharply tapering portion of the wall adjoining the base. On the more sharply tapering portion of the cone wall connecting thereto the cylindrical piece of

moulding material is accelerated in its movement towards the top of the cone.

The wall portion adjoining the base lies at an angle of roughly 12.2° and the portion connecting thereto at an angle of roughly 15.08° to the axis of rotation.

Finally, it is noted that the cone wall may have lengthwise oriented grooves in order to further the transversely directed movement of incorrectly aligned pieces of cylindrical moulding material.

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