Please answer 🙏: how syringe is injection molded as draft angle is not possible in cylindrical tubular surfaces as even 1deg of draft will result in change in dia at other end of tube. So whats the solution for it???
given the polished core, poppet valve to relase vacuum as part is ejecting (unless there is an open end)there will no problem - but... There will need to be sufficient wall thickness to prevent buckling as it is stripped off the core with the stripper plate, and the tool should be kept fairly hot (40-50 deg C). You may find the problem will be getting a moulding machine with sufficient opening stroke (daylight) to mould and eject the part as it going to be quite a small shot weight and hence ideally a small tonnage press. Might be better to have vertical hydraulic core.... Syringes, btw are made from multicavity tooling (lots) - mainly from PP. Some of the newer metallocene catalysed PP's have quite high flexural modulus and may be better regarding stiffness for your application.
PP homopolymer should shrink about 2 to 2.5%. Over 4% means something is seriously wrong with your moulding process or design. I don't know if it will work, but if you want to attempt to eject of a zero draft core, you will need several things:- 1) The core will need to be well polished ONLY IN DIRECTION OF DRAW. 2) You will need a tube ejector. 3) You will need a poppet valve to allow air to blow the moulding off the core. 4) you will need to pull the core completely clear of the cavity before attempting to strip the moulding from the core. Other points that will help:- a) Use a low shrinkage grade. b) Use an elastomer modified or high impact grade that will stretch more easily to blow off the core. c) Use a grade that has extra mould release lubricant. To much causes a build up of deposit on the mould, but this may be a necessary evil to obtain the mould release level you require.
@@PLASTOTECH Do you make molds? I have a question:- Can we CAST the mold and do some little machining on it Instead of cnc Machining the Whole block of metal???
Ekdam Mast tarike se explain kiya.
Nice video.
Very nice.... & good technic..
Good explain sir ji
Mast sir
Please answer 🙏: how syringe is injection molded as draft angle is not possible in cylindrical tubular surfaces as even 1deg of draft will result in change in dia at other end of tube. So whats the solution for it???
given the polished core, poppet valve to relase vacuum as part is ejecting (unless there is an open end)there will no problem - but...
There will need to be sufficient wall thickness to prevent buckling as it is stripped off the core with the stripper plate, and the tool should be kept fairly hot (40-50 deg C).
You may find the problem will be getting a moulding machine with sufficient opening stroke (daylight) to mould and eject the part as it going to be quite a small shot weight and hence ideally a small tonnage press. Might be better to have vertical hydraulic core....
Syringes, btw are made from multicavity tooling (lots) - mainly from PP. Some of the newer metallocene catalysed PP's have quite high flexural modulus and may be better regarding stiffness for your application.
PP homopolymer should shrink about 2 to 2.5%. Over 4% means something is seriously wrong with your moulding process or design.
I don't know if it will work, but if you want to attempt to eject of a zero draft core, you will need several things:-
1) The core will need to be well polished ONLY IN DIRECTION OF DRAW.
2) You will need a tube ejector.
3) You will need a poppet valve to allow air to blow the moulding off the core.
4) you will need to pull the core completely clear of the cavity before attempting to strip the moulding from the core.
Other points that will help:-
a) Use a low shrinkage grade.
b) Use an elastomer modified or high impact grade that will stretch more easily to blow off the core.
c) Use a grade that has extra mould release lubricant. To much causes a build up of deposit on the mould, but this may be a necessary evil to obtain the mould release level you require.
@@PLASTOTECH Do you make molds?
I have a question:- Can we CAST the mold and do some little machining on it Instead of cnc Machining the Whole block of metal???
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