Pin-point gates

Pin-point gating with ring-shaped marking, variable diameters... 

Pin-point gating flattened by shut-off valve, leaving ring-shaped mark on moulding... 

Flow behaviour High melt viscosity for unplasticised PVC. Injection speed not too high to avoid overheating through excessive shear rate. Sprue runners and gates as wide and short as possible. Avoid pin-point gates and sharp turns. 

In this effect very fine grooves show up on the moulded part, whieh are very similar to those of reeords. Concentric rings appear near pin-point gates, while maikings are parallel towards the end of the flowpath and/or behind the gate. This is shown in Figure 9.22. 

For pin-point gates, the transfer from the runner should always take the form of an accumulation base. The accumulation base prevents the highly viscous compound at the edge from being carried along, the plastic core of the runner is thus retained for longer (the gate does not freeze until later). 

Automated gate location technology was evaluated with cover part developed for automotive vehicle, 1 to 3 number of gates were evaluated for pin point gate at the flat top part of the cover, 1 side gate were also detected at the side edge as shown in Figure 4. 

After selecting the gating system, which depends on the elastomer used (process-ability, cost), and the product (function, geometry, number, etc.), the injection is defined. Types of injection include direct injection, pin-point injection, or a film gate at the manifold layer (in some cases). The choice depends on the infrastructure, such as the construction of the molding machine. 

Check the clock. In DC-DC converters you can simply look carefully at the SW node. It should be stable otherwise please read up some more on PCB routing and input decoupling in previous chapters, and then return to this point. When designing AC-DC converters, I used to look very hard at the signal coming out of the IC meant for driving the Gate of the switch (Pin called OUT on the 3842). 

For this reason, a pin gate, as shown schematically in Fig. 25 with the melt flow direction for filling drawn in, is useless. Besides, this would also mean an additional weak point at the resulting flow line. 

In contrast, the pin gate (Figure 4-2) is pulled off at its connecting point on the molded article, when this is removed. The pin gate thus leaves only a small mark on the molded part, requiring little or no finishing. Fully automatic degating is possible. 

The floor of the booth, 970 x 915 x 70 mm in size, made of the same material, and with a wall thickness of 8.5 mm, weighed 12.8 kg. In the HR system mould [1], a specially-made type X manifold (see Figure 9.1) with 18 mm channel diameter and a spacing of 480 X 480 mm for the four injection points was used. When foamed PC is injected, the condition of a very high injection rate and instant gate shut-off following injection of a set quantity of melt must be observed. Because of this, 6.5 mm diameter gates with valve pins driven by double-action hydraulic cylinders (Incoe) were used. 

TC identifies and breaks combinational feedback loops automatically. The selection of the point in the combinational feedback loop chosen is reported in the check test output. Heuristics have been incorporated into check test that determine the point at which combinational feedback loops are broken. Further, TC understands functionally broken loops. The nodes at which check test avoids breaking combinational feedback loops in order of priority are as follows tristate/bidir enable pins, pins directly feeding asynchronous inputs of sequential elements, pins directly feeding other inputs of sequential elements, and gates with a large fan-out. 

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