Injection Mold Design Tutorial, Technology and Engineering

now, after put sprue bush and locating ring at top plate, let's design core side, like cavity block, core block also need bolts to attach the core block to core plate, see picture below


at those picture i use M10 bolts type, this bolts use to attach the core block to mold base plate, don't forget to give chamfer of each side of core bolts, this chamfer very useful in assembly mold processing, this chamfer will become guide of core block when assembling to mold base plate.
for safety reason, you must also consider chamfer for other side to prevent scratch accident of operator when doing assembly process.



at last make packet at mold core plate, at those pocket give some Radius for machining process, this radius is must equal or more bigger than milling cutter radius that you want use in machining process, commonly more deep your pocket more large the radius of milling cutter.

next step let's put sprue bush at top plate until directly to product, beside sprue bush i put locating ring, this two part important become guide between mold and injection machine, sprue bush will guide molded plastic to runner, because this product use direct gate, runner also direct from runner to product. see picture below for detail



Locating Ring Type
i use 120 mm diameter of locating ring, with height 15 mm, from that height, 5 mm i put on moldbase, and 10 mm become guide when mold base attach to injection mold, 3D picture below will give briefly image of locating ring.



Sprue Bush

What is Gate ?
The entrance through which molten plastic flows into the cavity of the mold from the runner. This is where the flow or melting of molten plastic is controlled by control type of gate or gate dimension. It is positioned at the thickest area of a part.
other function of gate is the gate makes it easier for the runner, which will be unnecessary after molding, to be separated from the part.is recommended to consider gating options early in part design.

Direct Gate
direct gate or sprue gate we can define as connecting directly end sprue to the molding and used as a gate,
this type of gate is commonly used for single cavity molds, where sprue feeds the material to cavity molds directly rapidly with minimum pressure drop.
see more explanation of direct gate at link below
http://mould-technology.blogspot.com/2008/02/direct-gate-or-sprue-gate.html

on the step below we design bolts position to hold the cavity insert to top plate of mold base, i use M10, or you can use other bolts base on your strength calculation and available market, there are various bolts type available on the market, i prefer use socket head screw in mold design, see link below for reference about this type of bolts
http://www.engineersedge.com/iso_socket_head_screw.htm

Picture below shown Socket Cap Head Screw.























picture below shown cavity main insert and bolts position, i attach the bolts in 4 side symmetrically,



for easy machining process, don't forget this little tips but very important when designing mold, at corner side of pocket make sure you make Radius or half circle, so pocket can be process use in MC easily. i use half circle type in each corner.



Chamfer in Insert
to prevent accident when assembly process, safety reason and easy assembly of mold we need to make little chamfer in each edge of mold, with chamfer it also became guidance when assembly the cavity insert to mold base. see picture below for detail picture, i use C5 in symmetric chamfer and 3-10 in asymmetric chamfer.