CZ304554B6 - Method of removing residual material from injection molding machine - Google Patents

Abstract

The present invention relates to a method of removing residual material from injection molding machine for the production of rubber products, where the molding machine is provided with a screw piston entering a horizontal section of the molding machine injection chamber being followed up with a vertical section thereof being terminated by an injection nozzle for injection of the material into a mold. First, path of air supply into the injection chamber and to the screw piston is cleared, the injection nozzle is screwed off and a device for compressed air supply is screwed onto thread of the injection nozzle. The injection chamber and the screw piston are subjected to the action of compressed air and subsequently the screw piston is let to move slowly out from the injection chamber. After the screw piston is completely out of the injection chamber, residual material adhering to the screw piston is removed manually, the device for compressed air supply is screwed off and a the injection nozzle is screwed back onto the injection nozzle thread. Prior feed of further material, the injection chamber and the screw piston are usually cleaned by the action of compressed air.

Description

Method for removing residual material in an injection molding machine

Technical field

BACKGROUND OF THE INVENTION The present invention relates to methods for removing residual material in an injection molding machine for the manufacture of rubber products, wherein the press is provided with a screw piston extending into a horizontal portion of the injection chamber followed by a vertical portion of the chamber terminated by an injection nozzle. The method is used in particular when changing the type of material used to make injection molded articles.

BACKGROUND OF THE INVENTION

The present method of removing residual material in injection molding machines for the manufacture of rubber products, wherein the presses are provided with a screw piston which is inserted into the horizontal part of the injection chamber and adjoins the vertical part of this chamber terminated by an injection nozzle for material injection into the mold. turned into adjustment mode, with the worm piston pulled out of the injection chamber, a belt of other material was twisted and slid into the injection chamber. Subsequently, the press was switched to manual operation and the new type of material was transferred until it was completely clean, without the remains of the former type of material, and the injection rate had to be set low. Obviously, the use of this method resulted in considerable losses of the new type of material until it was mixed with the residual old type of material and at the same time time losses occurred.

General cleaning of injection molding machines, especially for plastic injection molding machines with air hose, is known and published, for example, in a document by Miroslav Frančík entitled: “Optimization of the maintenance system in Kasko spol. s r.o. “, Diploma Thesis 2013, Tomas Bata University in Zlín. GB 527879 discloses a turret injection piston hydraulic press for plastics, comprising a rotating head with metering, forming and outlet zones, which cleans the pistons with brushes first and blows out the cleaned dirt with an air flow and is also provided with air supply to the mold cavities. However, this solution relates to a piston hydraulic machine, and the particular solution of the injection chamber and screw cleaning of the screw injection molding machine cannot be inferred from this solution, since it is a completely different design of the machine.

The object of the present invention is therefore a new solution which avoids material losses in the above mentioned screw injection molding machines for the manufacture of rubber products and furthermore saves the time that the old type of material had to be drained from the screw piston and the injection chamber.

The essence of the technical solution

The aim is achieved by the method according to the invention, which consists in making the air supply path to the injection chamber and to the worm piston clear, unscrewing the injection nozzle and screwing the compressed air supply device onto the injection nozzle thread. acting in the injection chamber and subsequently with the worm piston slowly moving out of the injection chamber, after removing the worm piston, the residual old material adhering at the end of the worm piston is removed manually, the compressed air supply device is unscrewed and the injection nozzle is screwed back nozzle.

In a preferred application of the method, the injection chamber and the worm piston are purged with compressed air before the new material is introduced.

The action of compressed air thus separates the old type of material from the walls of the injection chamber and from the worm piston and, after easy removal of this material, at a subsequent supply of the new type

In the injection chamber, the new material is clean and does not contain residues of the old type of material.

Example of technical solution

The Desma injection molding machine first produced the hydraulic seal 00055 of N3578 and then the hydraulic seal C22040 of N3584. First, the hydraulic seal Cl0055 was removed from the injection molding machine, the check valve was removed between the horizontal part and the vertical part of the injection chamber, making the air inlet to the injection chamber and to the worm piston clear, and then unscrewed the injection nozzle and threaded after injection. The quick-connect coupling of the compressed air supply tube, connected to the compressed air source of the injection molding machine, was screwed onto the nozzle. Subsequently, compressed air was introduced into the vertical and horizontal portions of the injection chamber via a tap on the compressed air supply tube and allowed to act for a few minutes on the walls of the chamber and on the surface of the worm piston.

The screw piston was then driven from the horizontal part of the injection chamber, and the bulk of the residual old type of material fell out of the injection chamber as the screw piston returned. The injection chamber and the worm piston surface were then cleaned by manual action of compressed air. However, it was also possible to use a pressurized air distribution in the work hall. After these operations, the compressed air supply hose was removed from the quick coupling and the quick coupling was unscrewed from the injection nozzle thread and the injection nozzle was screwed back onto the thread. Then, a mold for injecting the C22040 hydraulic seal of N3584 material was placed on the injection molding table, and a new type of material, hence the N3584 for injecting the C22040 hydraulic seal, could be fed to the inlet port of the horizontal portion of the injection chamber.

Claims (2)

PATENT CLAIMS CLAIMS 1. A method for removing residual material in an injection molding machine for the manufacture of rubber products, wherein the press is provided with a screw piston extending into a horizontal part of the injection chamber followed by a vertical part of the chamber terminated by an injection nozzle for injecting material into a mold; by clearing the air inlet path to the injection chamber and to the worm piston, unscrewing the injection nozzle and screwing the compressed air supply device into the injection nozzle thread, which is allowed to act in the injection chamber with the worm piston and then slowly leaving the worm piston leave the injection chamber, after removing the worm piston, the residual material adhering to the worm piston is removed by hand, the compressed air supply device is unscrewed and the injection nozzle is screwed on again nozzle. Method according to claim 1, characterized in that the injection chamber and the worm piston are purged with compressed air before feeding further material.