Injection Mould Construction

A molding according to the function of each of its parts can be divided into four sections 1. Introductory part of the plastic nozzle into the cavity cavity 2. penunjuang system (support system) 3. demolding system 4. heat transfer system

Mold Base Standard Part

In the manufacture of injection mold, mold base is an integral part, mold maker can make your own mold base or buy a standard mold base, the system of the mold base can be adjusted with the construction standards required, both for the two plate and three plate, stripper plate ejectors, hot runner and mold base for a screw, when the entire standard mold base is not there to meet the new final step is to make a special mold base.

Injection Mould Classification

classification or types of mold injection very depend on what we need to make the plastic parts, because every parts have specific and unique design. when design molds we must see what the influencing factor like geometry, number of cavities, ejection principle, plastic material and shape of part.

Injection Mold Cooling

This section is the most important part of the overall mold cylcle time, because in one cycle time, the process of heat exchange to spend about 70-80% of the total cycle time, thus setting the optimal heat transfer system will greatly affect the quality and cycle time of a product.

Undercut System : Cam, Angular, Lift Cavity, Loose core

cavity and core, and its derivatives when there are undercut on product, design and construction of a good core cavity and in accordance with the requirement could increase the life of tooling itself, reduce material consumption, reduce dependence on maintenance inserts, and can reduce the cost of making the mold so the mold cost per products also declined.

Sunday, September 13, 2009

Stripper Ejector Construction (step by step mold design) part 6

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.

Friday, September 4, 2009

Stripper Ejector Construction (step by step mold design) part 5

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