JPH0236347B2 - NIJIKAATSUDAIKASUTOSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a secondary pressure die casting device, which detects the amount of hot water supplied to the injection sleeve, which greatly affects the quality of cast products, based on the thickness of the biscuit, and performs secondary pressure die casting. This ensures that the pressure effect is exerted to prevent the production of defective products.

In order to prevent the formation of blowholes, a method of applying secondary pressure to the inside of the mold is used.

In this case, it goes without saying that the secondary pressurization pressure must be transmitted to the part where the blow holes occur inside the product before the molten metal in the mold solidifies. This appears as fluctuations in the quality of the product, and this causes large fluctuations in product quality.

The variation in the amount of hot water supplied is based on the ladle's working accuracy, and it is practically impossible to maintain a constant amount of hot water during use.

Generally, the injection cylinder of a die-casting machine is switched from low-speed injection to high-speed injection to fill the cavity with hot water.

Therefore, when the amount of hot water supplied is large, the molten metal is filled into the cavity while the injection cylinder is injecting at a low speed, which takes a long time to fill and the product is likely to have poor water flow, or conversely, the amount of hot water supplied is low. In this case, even if the injection cylinder is switched to high-speed injection, the force of the injection cylinder is not sufficiently transmitted to the cavity because the biscuit inside the sleeve is thin, resulting in a filling failure.

Even if secondary pressurization is performed on the above-mentioned incompletely filled product, the amount of advance of the secondary pressurization plunger reaches the stroke end and pressurization is performed with insufficient pressurizing volume, resulting in pressurization failure.

The present invention operates the secondary pressurizing means only when the amount of biscuits remaining in the sleeve during filling with hot water is within a certain allowable range.

The configuration of the device of the present invention is such that after the injection cylinder is switched to high-speed injection, a first switch and a second switch for detecting the biscuit thickness are arranged along the rod of the cylinder, and the first switch is activated. After that, if the second switch does not operate within a predetermined period of time, a hydraulic circuit for secondary pressurization is formed.

In the figure, 1 is the injection cylinder, 2 is the rod, and 3 is the injection cylinder.
4 is a plunger tip, 4 is a sleeve, 5 is an inlet, and 6 is a ladle.

7 is a fixed mold, 8 is a movable mold, 9 is an extrusion plate, 10 is a cylinder for secondary pressurization, and 11 is a plunger.

The hot water injected into the sleeve 4 by the ladle 6 is pushed by the plunger tip 3 and into the cavity 12.
filled inside.

When the amount of hot water is normal, a certain amount of biscuit 13 is placed between the end face of the splitter 8a and the tip of the tip 3.
remains.

Reference numeral 14 denotes a mounting rod provided along the rod of the cylinder, on which a large number of limit switches are mounted in series.

That is, 15 is a rod fixed position detection switch;
6 is a low speed/high speed changeover switch, 17 is a first switch, and 18 is a second switch, and these detection signals are input to a controller 19.

When the first switch is turned ON, a timer (not shown) of the controller is activated, and if there is no input from the second switch within a predetermined set time, the switching valve 20 in the secondary pressurizing hydraulic circuit is switched to standby. The speed of the pressure oil being adjusted by the flow control valve 21 and the pressure reducing valve 2
The secondary pressurizing cylinder 10 is operated with the pressure adjusted in step 2.

In the present invention, if the first switch does not operate, it goes without saying that secondary pressurization is not performed;
If the switch is activated within the set time, it is assumed that the amount of hot water is insufficient and secondary pressurization will not be performed.

Of course, each switch can be adjusted in position along the mounting rod, and the position of each switch can be adjusted depending on the product shape, material, wall thickness,
Adjusted according to temperature etc.

Further, the timer for setting the delay time is not particularly limited, and a known timer is sufficient.

Further, the secondary pressurization speed is adjusted by the flow rate control valve 21.

As described above, according to the present invention, by controlling the residual biscuit thickness during the hot water supply process and maintaining the amount of filling in the cavity within a certain allowable range, the secondary pressurizing effect can be reliably exerted. It is.

In other words, when the first switch confirms that the amount is below the maximum allowable filling amount, a timing start signal for starting secondary pressurization is obtained, and if the second switch is not activated within the set time, secondary pressurization is started. pressure is applied and is stopped by actuation of the second switch.

Therefore, in the present invention, since the incompletely filled products are discharged without being subjected to secondary pressurization, the product accuracy is improved and the yield is greatly improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the apparatus of the present invention. 13 is a biscuit, 17 is the first switch, 18
is the second switch.

Claims (1)

[Claims] 1. In a die-casting machine equipped with a secondary pressurizing cylinder, a first switch and a second switch are mounted adjacently to a mounting rod disposed along a piston rod of an injection cylinder, and the first switch is adjustable in position.
Activation of the switch starts a delay timer for activating the secondary pressurizing cylinder, and when the second switch is activated within the set time of the timer, the secondary pressurizing cylinder becomes inactive. The secondary pressure die-casting apparatus is configured such that the first switch is fixed at a position where the thickness of the residual biscuit in the injection sleeve is a maximum allowable value, and the second switch is fixed at a position where the thickness of the residual biscuit within the injection sleeve is a minimum allowable value.