syringe

Hi,

I like to design medical syringe sealing,
And make analysis.
Does anyone can help me?

Danny

 

To be honest, it sounds like English is your second language &
something is lost in the translation.

I am not quite sure what you are trying to do.

1. Just measuring a stock syringe and modeling it is one hour's work
in solidworks. I've done that on disposable syringes, so I know it is
easy. It is a good practice project.

2. Analysis: That is vague. There is stress analysis, mold flow ,
mold fill, shrink, failure analysis, materials compatibility analysis &
others like human engineering analysis/design which might be considered
analysis.

Can you define better what you are tryingto do?

Bo

 

Danny,

Can you explain further please?. We need to know if you are asking
about how to model the syringe or how to do FEA analysis.

 

OK
I sorry about my English.
I would like to know how much oversize take in the plunger,
And how to put the restraints on the part.
Danny

 

1. The amount of "oversize" (interference fit) of the rubber plunger
tip will depend on the exact grade and hardness of elastomer used, and
its thickness over the solid support, and the pressure that the seal
must withstand (pounds per square inch). There is no easy answer here.
In addition to everything else, some neoprene or similar rubber
compounds that are used on disposable syringes are not inert with some
of the chemicals used, and those reactions can cause swelling of the
rubber which makes for an even tighter fit as exposure time increases.

2. If by "restraints" you mean the undercut in the rubber tip or
undercut inside the ID of the barrel to keep the plunger/piston from
easily becoming separated from the barrel, again it depends on the
materials used. Polycarbonate will require less undercut than a softer
disposable Polypropylene.

Both of these things you ask about require either a "follow the leader"
approach where you use the same basics as the major competitor, or you
start doing your own experiments if that is necessary to optimize for
your usage.

Myself, I have just copied what exist in disposables for my models, as
I am not trying to do an improved design or produce syringes myself.

Bo