Sleeve ejector system

This system use when part have tolerance or good dimension so, so we can’t put ejector in those face, or ejector prohibited in that face other reason is part have hole and face that can touch with ejector is very small and surrounding the hole. Look at picture below

Red face indicated that ejector is prohibited, for that reason the only way to eject those part is using sleeve ejector that will located at green face (look at picture)

Basic construction of sleeve ejector system is like picture below

 

How Sleeve Ejector Works

Basic mechanism of sleeve ejector is how to make insert pin doesn’t move when sleeve ejector move to eject the product.

Picture above shown step by step when sleeve ejector moving to eject part, the main part on those picture are product (yellow) sleeve ejector (green), core insert pin (white at center of sleeve ejector) mold base core (light blue at side sleeve core), cavity insert (dark blue), cavity pin insert (pink at center of dark blue), and cavity mold base (light blue surrounding cavity insert pin.

A.     After plastic material injected at cavity insert then cooling water/liquid will flow to transfer heat from mold to liquid. At this position mold base still close, just seconds before ejecting process begin.

B.     Ejecting process begin, first mold will open, core insert include cavity insert will move to backward, because shrinkage of material always move to inner side, product will stick in core insert pin.

C.     Sleeve core move forward when ejecting process begin, sleeve core will eject the product, and the product will leave core insert pin, because core insert pin doesn’t move forward.

After sleeve core move same as ejector stroke, product will drop, and.. Gotcha.. you get the product.

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3D and Drawing ejector simple construction in mold with video

simple and cost effectively ejector system i try to design, it using very minimum part, using this ejector system just have 3 ejector pin, by understanding minimum part to make ejector system, we can develops more complex ejector system. see picture below



this ejector system is same with previous post, i just completely the picture with isometric picture, drawing sample and 3D movie, so i hope we could more understand in ejector system. below is drafting picture of those 3D picture



little different from previous post, this ejector system use long ejector rod, ejector rods type is very depend the type of machine, stack mold, basic injection mold have different ejector rod type, although the basic system is same.



video above shown simple 3D model of ejector system, at those video is not include bolts that connected ejector plate and ejector baking plate, also bolts that connected bottom plate to core plate.
i hope by using those video is more easy to learn mold design.

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Ejector Component List for ejector pin type

Each type of mold have their own ejector system characteristics, such as : one step ejector, two step ejector, stripper ejector system, pin and blade ejector system, gas ejector, and vacum ejector. from various ejector system that available all of that type have main part or main component. picture below shown common and main component for ejector system. this image size about 700X500 px, click the picture to enlarge.



picture above shown side view of ejector system, the target is to eject the product (black) from core insert after mold open. when the ejector system work and push the product to outer parting line the side view picture is like below



Ejector working system
with above system, how could the ejector push the product? below i will try to explain step by step
1. after cavity of mold injected with plastic material, and cooled moldbase will open, and product have to eject from the core insert.see the open condition of molds.
2. after mold base in open condition like picture below

rod from injection machine will push the ejector rod,because ejector rod connected to ejector plate, ejector plate will move forward.
3. ejector guide pin will guide those moving, to prevent scratch and guide the moving more easily use ejector guide bush, ejector pin and ejector guide bush will have little friction.
4. ejector pin clamped between two ejector plate, because that ejector pin will also move forward push the product.
5. after product take it out from cavity, mold base will moving close again.
6. and because at the return pin have spring, spring and closing mold will guide ejector back to the position (1)

Ejector Component List
this list is standard minimum to make ejector system
1. Ejector plate, place for ejector and ejector guide bush, shoulder bolts and return pin.
2. Ejector Backing Plate, place for clamping the ejector and push back the ejector.
3. return pin, push the ejector plate and ejector backing plate to first position.
4. spring in return pin, to make sure and holds the ejector plate so it's always in back position, when in assembling process, it can lift up the ejector pin, and ejector plate so the position always in back, give the little preloads to ejector plate to make sure the ejector plate position.
5. shoulder bolts, first time lock in assembling molds
6. ejector pin, eject and push the product from core.
7. ejector guide pin, guide the moving of ejector plate.
8. ejector guide pin bush, to make sliding and prevent large contact when moving.
9. support pillar, to prevent large deflection of core plate when injecting the plastic material process held.
10. ejector rod, contact with rod in injection machine, this also passing force from injection machine to ejector plate.
11. ejector bolts, to tie up between ejector plate and ejector backing plate.

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