Method for producing an injection device

Abstract

A method for producing an injection device are disclosed. The injection device comprises a hollow needle which is positioned in a basic body of the injection device. The injection device is produced by a two-stage injection process. At least one first slider and a second slider are provided in a tool block. Together with the tool block, the first slider and the second slider form free space, which defines a shape of a pre-injection molded part of the basic body of the injection device.

What is claimed is: 
     
         1 . A method for producing an injection device, the method comprising:
 inserting a hollow needle into a receptacle in a tool block of a tool;   inserting a second slider in an axial direction of the hollow needle, so that the second slider covers and seals an end of the hollow needle positioned in the receptacle;   inserting a first slider as far as it rests with a flat front end thereof against a surface of the second slider;   forming a pre-injection molded part of a basic body of the injection device by injecting a plastic material into the tool;   removing the second slider from the tool such that an opening is formed in the pre-injection molded part of the basic body;   providing a sealing geometry, so that the opening in the basic body is covered; and   closing the opening, by injecting plastic material into the tool.   
     
     
         2 . The method as claimed in  claim 1 , wherein a plunger is guided in the second slider and acts on the end of the hollow needle such that the hollow needle is pushed into a target position predetermined in the tool block and also the end of the hollow needle is sealed. 
     
     
         3 . The method as claimed in  claim 1 , wherein the first slider has a flat front end which, with its entire surface, rests against a surface of the second slider when the first slider is pushed into the tool as far as to the second slider, and wherein the surface of the second slider forms a stop for the first slider. 
     
     
         4 . The method as claimed in  claim 1 , wherein the surface of the second slider rests sealingly on the flat front end of the first slider in such a way that during injection of the plastic material into the tool no plastic material can enter between the surface of the second slider and the flat front end of the first slider. 
     
     
         5 . The method as claimed in  claim 1 , wherein a third slider, providing the sealing geometry, is inserted into the first guide after removal of the second slider from the tool, so that the opening formed by the second slider in the basic body of the pre-injection molded part of the injection device is covered from the interior of the basic body by the third slider. 
     
     
         6 . The method as claimed in  claim 5 , wherein the sealing geometry is formed by a slanted surface of a flat front end of the third slider, and wherein a front free end of the third slider protrudes a front edge of the opening. 
     
     
         7 . The method as claimed in  claim 1 , wherein after removal of the second slider from the tool, the first slider providing the sealing geometry is rotatable in the first guide such that, after the removal of the second slider from the tool the opening formed in the basic body after the removal of the second slider from the tool is covered from the interior of the basic body by the rotated first slider. 
     
     
         8 . The method as claimed in  claim 7 , wherein the sealing geometry is formed by a slanted surface of a flat free end of the first slider, and wherein the front flat end of the first slider protrudes a front edge of the opening.