Injection Mould Construction'>

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, December 21, 2008

Step by Step Mold Design (part 2), Insert Design

3:47 AM    1 comment
continuing with the previous post, now let's make some insert in core side, this insert very simple and easy in machining process. from the core block side we divide at the circle line of side of bowl, why ?, because we will eject the product using stripper plate, stripper plate construction will eject the product by touching the thin face in all around of bowl.

insert function
there are two function in of insert in this mold construction
1. to provide re change part, if the bowl shape doesn't good, we don't need to change all core side, but only the insert part. so this system is more cheaper when the part need good shape and good tolerance.
2. provide gas vent, and stripper construction, because the product need gas vent in bottom the side, and gas vent in stripper is not good, gas vent only can make with insert in core.

below is construction of insert part


Gas Vent Dimension and construction
gas vent can divide into 2 part, the accurate tolerance and not accurate tolerance part, the dimension of accurate tolerance is depending from plastic material that injected in molding, but generally is about 0,005 mm until 0,020 mm


Collar
at the end of insert part, there was a collar to prevent part move in Z axis, the dimension of collar is about diameter + 2mm and height is 4 mm
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Friday, December 19, 2008

step by step mold design of ejector plate type

11:41 AM  ,  No comments
PRODUCT
by sample complate design of bowl i'll try to explain easily how to design a mold, start with simple product a bowl like picture below


by looking the bowl, we can consider that bowl only need core cavity side without undercut release.

PARTING LINE
choosing the right parting line is important, parting line will separate core side and cavity side, becouse we only need core and cavity, the parting line is only one, between cavity and core, to make it, first,make the block then from subtract the product and split it by parting line that you define before


some CAD software also have instant cavity and core making feature, split and sweep feature so make the mold is easy by using those feature, after split it into cavity and core we have cavity side and core side of the mold.

Cavity Side

and below picture is core side


now we have cavity and core side, it still rough, without bolt, without gate, ejector and other part, the next step is make some insert part.
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