Week 8 - Challenge 1 - Draft Analysis on a Fan Cover

Draft Analysis on a Fan Cover Model

Aim: - The aim of this report is to perform a draft analysis on a fan cover model in catiaV5 (Computer-aided three-dimensional interactive application).

Objective: -

1. To create the tooling axis for the fan cover model meeting the requirements of the draft angle.
2. To perform a draft analysis on the fan cover model to confirm the appropriate draft angle.
3. To publish the class A surface and tooling axis using the publication commad in the software.
4. To explain the bisecting method used in order to create the tooling axis for the fan cover model.

Theory: -

1. Tooling axis creation for fan cover model: -

The tooling axis indicates the direction along which the tooling or the manufacturing of the component will be done. In catia, the tooling axis is used to create a solid model from the surface body using the sweep option. There are many methods for the creation of the tooling axis and bisecting method is one of them.

figure 01: - Example of tooling axis direction

figure 02: - Use of tooling axis in catia

The steps involved in creating tooling axis using the bisecting method are as follow: -

1. Check continuity or quality of class A surface
2. Selection of best possible tooling direction
3. Creating dummy tooling axis
4. Tooling clearance for respective directions
5. Creating final tooling axis

step1: -

Product designers should check the continuity or quality of the class A surface given by the class A engineer. They should ensure that there are no gaps between the surfaces using the boundary or the join command in catia.

figure 03: - Checking the continuity

step2: -

The tooling direction should be in such a way that it should cover the complete component along with its holes, undercuts, etc. in the main tooling. The product designer should also avoid side cores because the side cores generally increase the manufacturing cost of the component.

figure 04: - Fan Cover Model

figure 05: - xz direction

One cannot select the xz direction shown in figure 05 because it is not covering the hole which is at the top of the component in the main tooling. To cover that hole, one needs to make a side core for it which will cost high for the manufacturing of the component. Hence, xz direction is not suitable to be the tooling direction.

figure 06: - yz direction

One can also not select the yz direction shown in figure 06 because it is also not covering the hole which is at the top of the component in the main tooling. To cover that hole, one needs to make a side core for it which will cost high for the manufacturing of the component. Hence, yz direction is also not suitable to be the tooling direction.

figure 07: - xy direction

One can select the xy direction shown in figure 07 because all parts along with the hole are getting clear in the main tooling without any side cores. Hence, xy direction is the best possible direction in this case.

step3: -

The dummy tooling axis is a line or an axis created at the center of the hole along xy direction as shown in figure 08. The dummy tooling axis is used just as a reference and it is not the real tooling axis.

figure 08: - Dummy tooling axis

step4: -

After selecting the main tooling direction, it is important for a product designer to see that all the surfaces along xy, xz and yz should be clear in the main tooling. Now, the surfaces perpendicular to the tooling axis is quite easy for manufacturing in the main tooling but the surfaces with a draft angle that are non-perpendicular or parallel to the tooling axis are a little difficult to manufacture in the main tooling. Hence, 2 tooling clearances for direction xz and yz will be created bisecting the surfaces with a draft angle that are non-perpendicular or parallel to the tooling axis which further will be bisected to form the main tooling axis.

figure 09: - Tooling clearance for xz direction

Line 1 and Line 2 representing the non-perpendicular or parallel surfaces with a draft angle as shown in figure 09 will be bisected to form line 3 which is the tooling clearance for xz direction

figure 10: - Tooling clearance for yz direction

Line 1 and Line 2 representing the non-perpendicular or parallel surfaces with a draft angle as shown in figure 10 will be bisected to form line 3 which is the tooling clearance for yz direction.

step5: -

The bisected line for xz and yz directions will be again bisected to form the main tooling axis as shown in figure 11.

figure 11: - Main Tooling Axis

2. Publication: -

The important parts of the model are easy to search using publication command in catia.

figure 12: - Fan cover model and tooling axis are easy to search

3. Draft analysis on fan cover model: -

Draft: - Draft is providing angles or tapers on product features such as walls, ribs, posts, and bosses that lie parallel to the direction of release from the mold that eases the part ejection.

Draft is required on all parts in the direction of mold movement in order to allow parts to realease or eject from the mold properly. Draft is the angle in which the part is tappered to allow it to release. As the part cools, it tends to shrink to the core side of the mold. Adding draft helps the part to release. 3 degree is the nominal draft. Whereas, 0.5 degree can also be manufactured at ribs. 7 degree for the textured faces.

figure 13: - Example of draft

Draft analysis is used to confirm the appropiate draft angle required for the component that is to be manufacture. Quick analysis mode, show or hide color scale, and analysis under the running point are the three main features used in the draft analysis. The color scale shows the draft angle for different colored areas and the analysis under the running point shows the draft angle at different points.

figure 14: - show or hide color scale

figure 15: - Analysis under the running point

Screenshots of the Draft analysis report: -

1. Image of the complete Draft analysis: -

2. Images of the color scale variant: -

3. Model with the proper color code of the draft angle in various orientations (Isometric, Front, Side, and Top View): -

Conclusion: -

1. Confirming the appropiate draft angle required for the component to be manufacture is one of the important aspect before continuing the design further.
2. Adding draft helps the part to realease from the mold.
3. Draft is important because it prevents the damage happens to the component while coming out of the mold.