дефекты обрезанного пояска уплотнителя и диаметр обрезки превышает номинальный диаметр уплотнителя (или т. н. "ограничителя" , а на самом деле пробки)
Stopper/pistons for syringes are well known in the prior art. Before the syringe is actuated, the stopper/piston performs the function of a stopper, isolating the fluid contained in the syringe body, and then during actuation, it transforms into a piston, pushing the fluid out of the syringe body, generally through a needle.
The stopper/piston thus needs to guarantee sealing, and it is thus generally made of rubber or some other similar elastomer. A drawback with that type of material relates to the risks of interaction between the material of the stopper/piston and the fluid to be dispensed, in particular during the storage stage, where such interaction might possibly spoil said fluid. In order to limit the risks of interaction, it has been proposed to coat the front surface of the stopper/piston, i.e. the surface in contact with the fluid while storing and while dispensing the fluid, with an appropriate coating. In particular, it has thus been proposed to have a thin film of ethylene tetrafluoroethylene (ETFE) on the front surface of the stopper/piston. That technique makes it possible to limit the risks of interaction between the material of the stopper/piston and the fluid. However, applying said film makes the manufacturing method more complex, and requires a cutting zone on the stopper/piston after molding, which is to be avoided.

https://sealing.datwyler.com/uploads/download/OCP-InJentle-f...
Despite the fact that the trim edge is
not intended to be a sealing rill, it is a significant
contributor to the frictional forces
for the ISO standard design.
http://www.ondrugdelivery.com/publications/Prefilled Syringe...
die trimming
https://www.compamed.de/profile_download/k-U2FsdGVkX19qohBpL...
Plunger stoppers
We offer you a wide range of plunger stoppers suitable for all our
Gx RTF® syringe types. Stoppers are made from pharmaceutical
elastomers and are available in different qualities: Bulk, ready-tosterilize
or ready-to-use. According to your needs, packaging options
vary from nested plunger stoppers to PE bags.
https://www.lonstroff.com/files/cto_layout/img/downloads/SRI...
4. Установка пробок
После того как готовые шприцы наполнены, необходимо установить пробки [рис. 9] и штоки.


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Note added at 14 hrs (2019-03-12 10:00:48 GMT)
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http://www.freepatentsonline.com/y2017/0368264.html