CATIA-Week 8.6- Core & Cavity Design

AIM:

To create the core and cavity blocks for the switch bezel component.

OBJECTIVE:

• To create tooling axis
• Checking with draft analysis for created tooling axis
• Create a parting surface and parting line
• To construct a core & cavity side

DESIGN METHODOLOGY:

Tooling Axis Creation-

we need to check the surface gap between the class A surface by using join command or else boundary command. we need to ensure that there is no gap between the two surface and check the continuity of class A surface after that we analyze the tooling axis of the component

Tooling axis is the direction in which the mold opens or close.

First we need to find the best possible tooling direction by changing the planes at X, Y and Z. after that we need to analyze the surface that there is no gap(hole) in between the surface along with the tooling direction because it would cost more.

In SWITCH BEZEL there is already a only single surface available along with X direction. so first we extract pocket surface and place a center point for create a new axis system.

Along with new axis system we draw a sketch and cut a part with axis and intersect a CLASS A SURFACE and draw a line on edges and bisecting each other we get tooling axis on Y direction.

In case of X direction we have only one surface so we draw a sketch and cut a part with axis and intersect a CLASS A SURFACE and draw a line on available surface. after that we draw a line at 3 degrees from center point of the axis system to available surface because in plastic design it is a maximum allowance for draft(we can change it later as we get angle or other parameters) and we get that line as tooling axis on X direction.

after that bisecting each other tooling axis X and Y direction we get Final Tooling Axis.

Draft analysis :

The draft analysis technique is used to analyze whether our part model created in CAD is manufacturable based on the draft condition applied. Here the part should get easily removed from the Mold.

Before creating a feature draft analysis we need to change the material view mode in view mode customization.

First we use a compass to define the new current draft direction, picking up the compass from red dot and align with the tooling axis. in direction set by using lock command we lock the draft direction and as we move the mouse we get red cross as we click it gets green color.

In second tab color table- green indicates as a more than 2.9 degree, blue indicates 0 degree and red indicates a negative. as minimum draft angle is 3 degree so we will change accordingly.

By using analysis running point in display option we can check the minimum degree by moving the mouse on surface for that specific point.

As there is only one surface available on X direction and if it not green we will change sketch the tooling axis X direction and change the degree angle and try again draft analysis for that surface for it is clear or not(color is green or not).

Parting Surface:

Generally, injection mold has two major components: the movable halves and fixed halve. During injection molding process these halves are pressed tightly from a sealed hollow to avoid the melt flow leakage and maintain certain holding pressure, the pressed surface called as parting surface, usually parting surface is the biggest projection outline surface of the part.

Parting surface design directly affects the product quality, ease of construction and operation of the injection mold

Parting Line:

Parting line are where the two halves of the mold meet. This generally create a physical line on a part that is both visible and noticeable to the touch. These lines however can be hidden or minimized when placed along edges of the part. It is represented by dotted line in the below picture

CORE AND CAVITY DESIGN FOR SWITCH BEZEL:

Core Design:

A core is the one part of the mould.and it is responsible for half of the molded part. actually core is the projection of the body and cavity is the depression of the body. these core and cavity combines to form a mould. then the plastic material injected into these mould to get a part out.

• create a sketch of parting surface and extrude it
• extruded portion trim with parting surface with component area

• using fill command fill the upper portion.

• Now, join the all the surfaces and create a solid closed body.

Cavity Design:

The cavity is the part where the injector and filling of the molten plastic happens. The cavity block is prepared by trimming extrapolated B surface and same profile used in core for rectangular block to extrude along the tooling direction.

The achieved surface is filled and joined to create closed surface as shown picture

CORE AND CAVITY DESIGN:

The mold core and cavity are shaped sections in either half of the mold tool which give the plastic product its final shape. The hot molten material is injected into the core and cavity and then sets hard into shape. The design of the core and cavity is essential in the correct formation of the product. The sequence of events during the injection mold of a plastic part is called the injection molding cycle. The cycle begins when the mold closes, followed by the injection of the polymer into the mold cavity. A core is usually made of the best quality sand and is placed into the desired position in the mold cavity. Core prints are added to both sides of the pattern to create impressions that allow the core to be supported and held at both ends

Intersection of Core, Cavity & Solid Componenet:

MODEL RESULTS:

FRONT VIEW

TOP VIEW

SIDE VIEW

ISOMETRIC VIEW

CONCLUSION :

• The creation of Core, Cavity, Parting line and Parting surface were done.
• The Drafting analysis was performed.
• The solid component was created from the surface geometry.
• The Translation of Core and Cavity block was done inorder to observe their operation along Tooling axis,
• The necessary screenshots and files were attached.