are difficult to machine as inseparable part of the mould or die cavity will most likely wear or break during the moulding or casting process

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Core extraction Tampere University of Technology Tuula Höök Theoretical background CAD tools in the exercise Cores 1 Mould structure Manufacturability Steps to follow Take the model start_cores_1.

Select the core side body, press the right mouse button and select the option Insert into New Part. Continue by viewing the core side from the machining and moulding or casting points of view.

1 Core extraction Tampere University of Technology Tuula Höök Theoretical background CAD tools in the exercise Cores 1 Mould structure Manufacturability Steps to follow Take the model start_cores_1.sldprt or the model start_with_tooling.sldprt. If you use the latter file, you need to save the core side of the part into a separate file before starting to work with it. Select the core side body, press the right mouse button and select the option Insert into New Part. Continue by viewing the core side from the machining and moulding or casting points of view. Select the details, which: are difficult to machine as inseparable part of the mould or die cavity will most likely wear or break during the moulding or casting process prevent the mould opening and / or the part ejection The first two details are typically some narrow projections or features, which separate from the rest of the cavity with a narrow recess. (See images.) The details, which prevent the mould opening and/or part ejection, require a moving core. Surface Modelling Offset Surface Extruded Surface Ruled Surface Extended Surface Surface Trim Surface Fill Surface Knit Fillet Mirror Circular Pattern Reference Axis Solid Modelling Tools Split Mould Tools Core Figure 1: Mould cavity with features, which separate from the rest of the cavity with very narrow recessions. When ever there are problems in using these tools, open SolidWorks help and try to find the solution there. Figure 2: A high projection in the middle of the mould cavity. Typical example of a place, where it is necessary to extract a fixed core as a separate piece. Cores 1-1

SolidWorks has a special tool for the core extraction purpose. The tool is Core and it is located within the mould tools.

Split the core with surfaces 1. Prepare offset surfaces from the outer surfaces of the feature you wish to extract as a separate fixed core.

Securing element can be simply a tapered face. The offset surfaces method is practical if you wish to prepare tapered cores.

If necessary, use ruled surfaces and surface fills to close openings. 4. Make a surface knit if necessary. 5. Split the mould plate with the formed surface body.

The mould or die back plate will secure the cores tightly. Split the core with the core tool 1.

For example with the Convert -tool. 2. Open the core tool. Select the sketch. If you wish to taper the core faces all over, give a draft angle as the parameter.

2 SolidWorks has a special tool for the core extraction purpose. The tool is Core and it is located within the mould tools. One option is to separate the cores with this tool. Another option is to separate the cores by splitting with surfaces. Try both options. Split the core with surfaces 1. Prepare offset surfaces from the outer surfaces of the feature you wish to extract as a separate fixed core. The offset distance should be 0 mm. 2. Extend the surface to shape the core base. The base extends through the cavity plate. It has some securing element. Securing element can be simply a tapered face. The offset surfaces method is practical if you wish to prepare tapered cores. Another basic option is to use a core with a straight base and a flange as the securing element. 3. If necessary, use ruled surfaces and surface fills to close openings. 4. Make a surface knit if necessary. 5. Split the mould plate with the formed surface body. The core will look like one in the image on the right. There is no need to prepare any fastening elements like flange in addition to the tapered shapes. The mould or die back plate will secure the cores tightly. Split the core with the core tool 1. Select the planar face in the bottom of the shape you wish to extract as a core (See image on the left). Sketch the core outer shapes to that planar face. For example with the Convert -tool. 2. Open the core tool. Select the sketch. If you wish to taper the core faces all over, give a draft angle as the parameter. You can also make the core base without a draft and put a flange around the bottom of the core. Then you simply do not use the draft angle at all. The Core -tool works best with undrafted faces. 3. The Core -tool separates the core body automatically from the cavity plate body. The core bodies are placed into a special Core Bodies folder. The undrafted core will look like one in the image on the right. The mould back plate will secure the core to its place. Cores 1-2

3 Moving cores Moving cores are extracted with the similar way as the fixed cores. There are no special tricks. The moving cores need a slide mechanism, a core pulling cylinder or some other construction, but the basic technique in extracting the cores is similar. The core moving mechanisms require different shaping methods, but these are discussed later in the moving core mechanism exercises. Shaped core end Sometimes it is desired to prepare a core, which extends inside the cavity wall. An example of the structure is shown in the image on the right. This kind of core is shaped with the SolidWorks surface tools. The structure prevents flashing between the core and the cavity wall. Learning Objectives Learn to find the shapes, which will need a separate fixed and/or moving core Different basic core shapes: drafted and straight core with a flange Learn to use surfaces for splitting solid bodies CAD tools to learn Surface Modelling: Offset Surface, Extruded Surface, Ruled Surface, Extended Surface, Surface Trim, Surface Fill, Surface Knit, Fillet, Mirror, Circular Pattern, Reference Axis Solid Modelling Tools: Split Mould Tools: Core Evaluation criteria Accepted One extracted moving core, one extracted fixed core and the cavity plate with cut holes for the cores Roundings are at reasonable places Excellent One extracted moving core, one extracted fixed core and the cavity plate with cut holes for the cores Fixed cores are prepared with the core tool and also with splitting surfaces There are two core types: straight and drafted Straight core is equipped with a collar and the hole is also shaped Roundings are at reasonable places Cores 1-3

CAD tools quick guide Offset Extrude Ruled Surface This tool

If the curvature is too small compared to the wall thickness the

It is also possible that in this case it is not possible to form

This tool makes a linear surface extrude from a sketch.

If no angle is defined, the extrusion takes the direction of a

4 CAD tools quick guide Offset Extrude Ruled Surface This tool prepares an offset surface from an existing surface. If the curvature is too small compared to the wall thickness the result can be a set of twisted surfaces. It is also possible that in this case it is not possible to form the offset surface at all. This tool makes a linear surface extrude from a sketch. You can define a draft angle to the extrusion. If no angle is defined, the extrusion takes the direction of a normal of the sketch plane. With this tool you can prepare a swept or an extruded surface from part edges. You have different options in guiding the surface. Cores 1-4

Extend Trim Fill Knit With this tool you can extend an existing surface.

The extension continues the shape and direction of the original surface.

The tool requires two surfaces, a surface and a plane or a surface and a

Solid is cut with Cut with surface -tool.

You may select the border condition either to contact or tangent.

5 Extend Trim Fill Knit With this tool you can extend an existing surface. The result is a single surface body. The extension continues the shape and direction of the original surface. This tool trims a surface with another surface. The tool requires two surfaces, a surface and a plane or a surface and a sketch. A combination of a surface and a solid will not do. Solid is cut with Cut with surface -tool. This tool forms a surface inside a sketch or selected solid or surface edges. You may select the border condition either to contact or tangent. This tool knits two or more separate surface bodies together and forms one knitted surface body. If the surfaces form a closed sphere, you can form a solid from these surfaces directly with the knitting tool. Cores 1-5

6 Features Fillet Pattern/Mirror Mirror Pattern/Mirror Circular Pattern This tool rounds a corner in an existing single surface object. This tool mirrors features or bodies through a plane or a face and copies them. This tool copies one or more features or bodies around an axis. Give the total number of instances as a parameter. Cores 1-6

Reference Geometry Axis Features Split Molds Core This tool

You can either consume some of the resulting bodies, save

7 Reference Geometry Axis Features Split Molds Core This tool prepares an axis to be used as a reference for example for a circular pattern. Use edge, center of a conical face, points or planes to define the axis position and direction. This tool splits a solid body into several solid bodies. You can either consume some of the resulting bodies, save them to separate files use them as part of the ongoing modelling. With this tool you can extract a core body from the cavity plate body with ease. The tool is very well suitable for extracting straight end cores, but not drafted cores. Cores 1-7

CATIA Wireframe & Surfaces TABLE OF CONTENTS

CATIA Wireframe & Surfaces TABLE OF CONTENTS TABLE OF CONTENTS Introduction... 1 Wireframe & Surfaces... 2 Pull Down Menus... 3 Edit... 3 Insert... 4 Tools... 6 Generative Shape Design Workbench... 7 Bottom Toolbar... 9 Tools... 9 Analysis... 10