Week 9 - Project - Master Section Development

In our challenge we have received class A surface & master sections as an input to develop complete part with engineering features.

Using these inputs, we have made some correction to the surface & created main tooling axis.

The given part we also needed doghouse creation. There is side core axis which will confirms internal profile of the dog house. In the above image both main tooling axis & side core tooling is highlighted.

Class B surface-

Before going to creation of class B surface, first we need to create flanges for the part.

This exact process will be followed to create flange on another side

Class B surface has created using offset command in surface workbench of CATIA V5. The offset value will be calculated from the given master sections which is also equal to the part thickness i.e. 2mm.

Outer boundary of the class B surface is extrapolated so that we can will create close surface body using trim command.

Class C surface-

Using class A boundary, we have created class C surface with the help of sweep along the draft direction command.

The draft direction for this operation will be main tooling axis.

After creating surfaces at outer boundary of the class A, we have joined all class C surfaces.

After creating class B & C surfaces, trim command is used to with these two & class A surface to create close surface body.

This close surface will be used to create solid part through it using close surface command.

Engineering features are those which-

will give provision to get assembled with adjacent component,

will have provisions to get part located,

strengthen plastic part at local positions, etc.

These are the features which will be created intentionally on class B surface as they will be not visible.

All these features will follow standard rules for designing to have proper manufacturability.

Ribs are the engineering features which will add more strength to the plastic parts.

Create iso-constrained profile sketch for the creation of ribs

Extrude this profile & using split, Boolean union trim, etc. operations create ribs.

Also, apply proper draft as per design rule.

Use same process to create ribs at other side.

In plastic part manufacturing, part will be created by sending high pressure melted plastic into recess available between core half & cavity half & holding it for seconds to solidify. After solidifying part will be ejected from mold.

When developing parts for plastic injection molding, applying draft (or a taper) to the faces of the part is critical to improving the moldability of your part. Without it, parts run the risk of poor cosmetic finishes, and may bend, break, or warp due to molding stresses caused by the plastic cooling. Equally important, an absence of draft may prevent parts from ejecting from the mold, damaging not only the parts, but possibly the mold itself—a costly and time-consuming detour.

Draft analysis is used to evaluate or double check one's work. When making a part that will be molded, the analysis will verify that all surfaces are favorable for being pulled from a cavity. It may also highlight or give insight to "trouble" areas.

Simple parts may not need this. More complex parts that need multiple cores or slides, it becomes very helpful.

1. Draft analysis for class A surface-

As complete part is confirming that it will clear the draft except small patch in the corner.

In such situations, first need to check the tooling direction. Try to modify tooling axis so that all surface will confirms positive draft.

Otherwise, this information sent to the styling team & ask them to modify & improve this patch.

In some cases, this can be ignored as it is very small error.

2. Draft analysis for the solid part-

By neglecting error, observed in class A surface, solid part has created as explained in earlier sections.

The above images show A, B & C surfaces with draft analysis by considering 3deg draft angle.

This part is confirming draft analysis.

3. Draft analysis for Dog house outer surface-

For dog house there will be two axes are available main tooling axis & side core tooling axis.

Outer surface will be checked using main tooling axis with 1.5deg draft angle.

4. Draft analysis for Dog house inner surface-

While performing draft analysis for inner surface side core tooling axis can be used with 0.5deg draft angle.

5. Draft analysis for the 4-way locator-

For 4-way locator 0.5deg draft is considered.

6. Draft analysis for the ribs-

Different orientations of part & detailed tree structure of part-

Conclusion-

1. We have created class B & C surface using class A surface

2. We have created solid part using close surface body

3. We have created all necessary engineering B side features with proper draft