Week 9 - Attachment Feature Creation (Ribs & Screw Boss) - Challenge 1
Q) Creation of Door Handle with Ribs & Screw Bosses
1) Design Check - This includes the checking the given Class A surface for any gaps at the boundaries. There should be no gaps between the surface boundaries.
(i) Given Class A Surface
To perform design check operation, select boundary command and click on the given Class A surface.
Open surface edges are highlighted in green color, as observed from the figure, there are no surface gaps between boundaries. Therefore, this Class A Surface can be used for further operations of creating tooling direction, Class A , B and Solid body.
2) Creation of Tooling Direction
For tooling axis creation, all the axes directions i.e., x,y and z directions are to be checked for easy removal of the mould and low tooling costs.
Among all the directions, Y direction is the most preferable to be considered as tooling direction.
(ii) Creation of Tooling Axis by Bisecting Method
To create a tooling direction, bisecting lines are created using the faces that are closely parallel or at positive draft angles to Z direction. Since no faces exist in X direction that require clearance along Y direction, bisecting line is created by intersecting XY (Z direction)plane on the Class A Surface. This bisecting line is the Tooling direction.
The above image shows the bisecting line or mean generated using the faces with positive draft angle.
(c)Tooling Direction
3) Draft analysis
Draft analysis is performed on Class A surface to obtain the Main Tooling Axis. Materials option in customize view should be active before performing Draft analysis. Click on Draft analysis, a color code variant dialog box appears displaying colors, green for positive draft angle, the nominal draft angle for industrial applications is 3 deg. Therefore, 3 deg is provided, the red color indicates a draft angle between 3 and 0. The blue color indicates a negative draft angle.Click on the the compass option on the dialog box , click on the compass and drag it and align it onto the bisector, now click at any point on the surface. The entire surface on topside appears green, this indicates that all the faces can be cleared easily and the bisector created can be considered as the Main tooling axis.
Draft Analysis on CLASS A SURFACE
The Draft analysis on class A surface with color code variant can be observed from the figure.
4) Ribs & Screw Boss Creation
(i) Creation of RIB
The rib is created as per the design rules
Thickness 't' considered to create class B surface is 2.5mm
Height of rib = 5t = 5X2.5 = 12.5mm
Thickness of rib = 0.4xt = 0.4x2.5 = 1mm
Draft angle considered for Rib = 0.5 deg
Fillet radius = 0.25mm
Tip thickness = 0.5xt = 0.5x2.5 = 0.75mm
Design check for RIB
As can be observed from the above image that the created rib satisfies the design rules of the rib i.e, draft angle, base thickness, tip thickness, height, rib root diameter and fillet radius.
(ii) Creation of Screw boss
Design rules for Screw Boss
The screw boss is created as per the design rules
Thickness 't' considered to create class B surface is 2.5mm
The considered screw boss hole is M6, therefore inner dia = 5.2mm
Height of Screw boss = 5t = 5X2.5 = 12.5mm
Thickness of screw boss = 0.6xt = 0.6x2.5 = 1.5mm, therefore outer dia = 5.2+3 = 8.2mm
Draft angle considered for screw boss = 0.5 deg
Fillet radius = 0.25mm
As can be observed from the above image that the created rib satisfies the design rules of the rib i.e, draft angle, base thickness, height & fillet radius.
DRAFT ANALYSIS ON FINAL PLASTIC SOLID BODY
As observed from the figure, green color is for draft angle 0.5deg, red is for draft angle in between 0 and 0.5 deg for clearance of faces.
Views of final plastic component
Isometric view
Front view
Top view
Left view
Right view
