Week 9 - Attachment Feature Creation - Challenge 1

ATTACHMENT FEATURE CREATION-RIBS ON COIN HOLDER

AIM- To Create an out featured rib on the coin holder.

OBJECTIVE-

• Create a rib on the coin holder following the design rules.
• Perform draft analysis.

INTRODUCTION-

RIB-Ribs are a feature in plastic injection molded parts. They are thin extensions that run perpendicular from a wall or plane. They are commonly used to provide additional support and strength to a part. Thickness and location are essential to rib design.

WHY NEED OF RIB IN PLASTIC COMPONENT?

If a rib is too thick on a part it can cause wrapping or sinkage in parts often cause the whole design to be rejected ribs solve this problem by providing additional support for inner wall.

The advantage of using ribs is that they increase the strength of a part without increasing the thickness of its walls.

DESIGN RULES-

• Nominal wall thickness of a plastic component is 3mm.
• A deviation ± 30 % of wall thickness is accepted.
• Ideal draft of a component is 3degree.
• Minimum for ribs is 0.5 degree.

RIB DESIGN RULE

Rib provide means to economical stiffness and strength of the mould part without increasing overall wall thickness.

CREATED MORE RIBS

• Taller ribs are prone buckling under loads.
• In those condition consider designing two or more shorter thinner ribs to provide with improved mould ability.
• Condition for addition ribs show in below image

PROCEDURE

Extract the base surface of the coin holder

The formula for the rib’s height should be smaller or = (wall thickness X 5)

2.5*5=12.5mm

Go to part design create body and get thicken to the rib.

Calculated wall thickness of rib

Rib thickness (w) =0.4*wall thickness (t)

= 1mm

Draft angle for the ribs should be greater than or equal to 0.5degree.

Assemble the rib part body inside the main body and give the fillet for all faces 0.25.

Fillet value should be 0.125X wall thickness(t) =0.3125

CREATING SECOND RIBS- Repeat all procedure once again to create more ribs.

Height/Width (mm) =3.1

12.5/width =3

Width=12.5/3=4.1

Here we can take 6mm

Creating intersection between the reference plane in XY direction and component part body.

Create the tri tangent circle by select the extracted curves and lines.

Checking the proper measurement and see our model satisfy the design rule or not. Now measure the height, thickness, distance.

DRAFT ANLAYSIS

• Changing view mode to material mode
• Go to insert <analysis<feature draft analysis.
• Drag the compass to the tooling axis and place properly.
• We give 0.45-degree draft for ribs.
• Analysis the color of if green that means it passes the desired rules and ready to manufacture.

DESIGN VIEW

ISOMETRIC VIEW

FRONT VIEW

RIGHT SIDE VIEW

TOP VIEW

TREE

CONCLUSION

Creation of ribs on coin holder successfully done by following all design rules.