JP3052857U - BMC injection molding machine - Google Patents

Abstract

(57) [Problem] A sliding surface of a supply plunger and / or an injection plunger and a cylinder member is fixed or bitten by solidified BMC. SOLUTION: Styrene monomer is instilled on a sliding surface between a supply plunger and / or an injection plunger and a cylinder member.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a device for preventing a plunger and a cylinder from biting in an injection molding machine of BMC (Bulk Molding Compound).

[0002]

[Prior art]

 BMC is obtained by adding calcium carbonate, glass fiber, silica, styrene monomer and the like as a filler to unsaturated polyester and kneading it in a mud or putty shape. The BMC injection molding machine includes a pressure hopper that supplies the BMC to the heating cylinder and a cylinder member of the heating cylinder that fills the mold with the supplied material. The pressure hopper has a supply plunger, and the heating cylinder has an injection plunger. It is slidably fitted.

[0003]

[Problems to be solved by the invention]

 However, BMC intrudes into the gap between the plunger and the cylinder member and solidifies, so that the plunger is stuck and does not operate, or the plunger or the cylinder member is bitten and damaged. For this reason, the gap size between the plunger and the cylinder member was variously selected and manufactured, but a fundamental solution has not been reached.

[0004]

[Means for Solving the Problems]

 Therefore, styrene monomer, which is a component of BMC, is instilled in a gap between the supply plunger and / or the injection plunger and a cylinder member into which the plunger is slidably inserted.

[0005]

[Embodiment of the invention]

 Embodiments of the present invention will be described in detail with reference to the drawings. Reference numeral 1 denotes an injection plunger, which is slidably fitted in the heating cylinder 2. The illustrated injection plunger 1 shows a state in which the injection plunger 1 is retracted at the end. The BMC supplied to the heating cylinder 2 by a predetermined amount is injected and filled into a mold attached to a mold clamping device (not shown) from a nozzle 3 screwed to a tip end of the heating cylinder 2 as the injection plunger 1 advances.

The heating cylinder 2 is fixed to a frame 7, and the injection plunger 1 is driven forward and backward by an injection cylinder (not shown) provided on the frame 7. The pressure hopper 8 is fixed to the heating cylinder 2 by a flange 6 or the like, the upper surface thereof is open, and a supply plunger 9 is detachably provided at an open end. When the BMC is charged into the pressure hopper 8, the supply plunger 9 is separated upward from the pressure hopper 8.

The heating cylinder 2, the nozzle 3, and the pressure hopper 8 are supplied with a heat medium of a predetermined temperature from a separately provided temperature control device for controlling the temperature of the BMC material to an appropriate temperature. Feed to the control passage.

The upper end surface of the pressure hopper 8 is a tapered surface 14 inclined inward. The pressure hopper 8 has a supply hole 15 which is opened at an intermediate portion of the tapered surface 14 and is formed at a plurality of positions in a circumferential direction substantially horizontally. A tank 10 storing styrene monomer is provided above the supply hole 15, and the styrene monomer flows into the supply hole 15 through a valve 12 from a pipe 11 communicating with the tank 10. The tapered surface 14 allows the styrene monomer flowing out of the supply hole 15 to be evenly distributed around the circumference, effectively penetrates into the gap between the pressure hopper 8 and the supply plunger 9, and allows the supply plunger 9 to be easily inserted into the pressure hopper 8. Has an effect.

When the injection plunger 1 is at the retreat limit position, a supply hole 16 opening at the tip of the injection plunger 1 is provided at the rear of the heating cylinder 2 at an angle, and the supply hole 16 is inserted into the injection plunger 1. Another through-hole 17 is formed vertically from the opening. Styrene monomer flows into the supply hole 16 from the pipe 11 through the valve 13. The through hole 17 is used for cleaning when the supply hole 16 is closed by BMC.

The valves 12 and 13 may be manually opened and closed, but are preferably electromagnetic valves, and are automatically opened for a predetermined period of time at a predetermined number of molding cycles or at predetermined time intervals by a timer. In addition, it is possible to prevent the plunger and the cylinder member from sticking or biting by instilling styrene monomer and moistening the solidified and stuck BMC. It is preferable to provide both the supply hole 15 and the supply hole 16, but it goes without saying that only one of them may be provided.

[0011]

[Effect of the invention]

 With the configuration described above, the solidified and sticky BMC can be moistened to prevent the plunger and the cylinder member from sticking or biting.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a BMC injection molding machine of the present invention.

[Description of Signs] 1 ‥‥‥ Injection plunger 2 ‥‥‥ Heating cylinder 3 ノ ズ ル Nozzle 8 圧 力 Pressure hopper 9 供給 Supply plunger 10 タ ン ク Tank 11 管 Pipes 12, 13 路 Valve 14テ ー パ Tapered surface 15, 16 ‥‥ Supply hole 17 貫通 Through hole

Claims (1)

[Utility model registration claims] 1. A BMC injection molding machine comprising a supply plunger for supplying a material to a heating cylinder and an injection plunger for injecting the supplied material, wherein the supply plunger and / or the injection plunger are slidably fitted with the plunger. A BMC injection molding machine characterized in that styrene monomer is dropped into a gap between the cylinder member to be inserted.