Week 8 - Challenge 4 - Coin Holder Design

Plastic Product Design: Coin Holder

Aim and Objective:

• Creating Tooling Axis following OEM Standards.
• Creating Class B Surface and Class C Surface using given Class A Surface as an input.
• Making Solid Part of 2.5mm thickness.
• Preforming Draft Analysis.

Class A Surafce:

• As a input Class A Surface can be in Distorted form or in Separate parts and we need to correct it.
• Either we can Join those parts together or Extract them and then Trim them together.
• Note: We as plastic design engineers are not allowed to make any changes in Class A Surface.

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Tooling Axis Ceration:

• Injection moulding includes Core, Cavity, and Sliders to make a plastic product.
• Core, Cavity, and Slider move/side in a particular direction which is called Tooling Axis.
• Tooling axis can be made using either by Bisection method or Plane as a reference.

Bisection Method:

• In a Bisection Method, we take intersection at XY and XZ plane.

• Using these intersections we make lines that are almost parallel to Z axis.

• These lines are then Bisected together to form a Final Tooling Axis.

Note: Reference to the above image, Final Tooling Axis is in White Colour.

Tooling Axis Using Plane as a Reference:

• Here a flat face is taken as reference and a point is created at the centre.
• A line is drawn from the point perpendicular to the face.

B Surface Creation:

• The Surface at which features like Ribs, Screw boss, Dog house, etc. are made to support external mountings is called Class B Surface.
• Class B Surface is made by simply extracting A Surface, offset it to desired thickness and trimming them together.

• Fillets are added to the surface at the end to avoid any error.
• Uniform thickness of the part should be maintained while adding fillets

Final Class B Surface.

Class C Surface:

• Class C surface is a connecting surface between Class A and Class B surface.
• Sweep with reference surface is used to create Class C surface
• Class A Surface is taken as a reference.

Solid Part With 2.5mm thickness:

• Class A, Class B and Class C Surface are trimmed/ Joined together to form a Final Trim

• The final trim is filled with a solid using the Close Surface command.

Draft Analysis:

• The draft is an angle provided to the part with respect to the tooling axis to reduce friction between Part and Mould.
• Part is provided with minimum 3 Degrees of draft.

• Select Compass icon on Direction pane
• Move Compass on the axis, make sure compass and axis are collinear.

• Areas highlighted in green can be cleared with mould.
• Areas highlighted in red needs modification, some daft angle must be provided to reduce friction between mould and component.

Conclusion and Observations:

• Tooling Axis was cearted following OEM Standards.
• Class B Surface and Class C Surface was make using the given Class A Surface as an input.
• Coin Holder of 2.5mm thickness was created.
• Draft Analysis was performed on Coin Holder.
  • It was observed that some areas are not provided with the proper draft, hence it may cause failure in making such component.