Week - 5 - 2D meshing for Plastic components

                                                        CHALLENGE 7: 2D MESHING OF PLASTIC COMPONENTS

 

 

OBJECTIVE:

To conduct geometry cleanup and mesh the mid-surface for the Plastic Bottle Cap CAD model as per the given quality criteria.

CAD MODEL:

        

                                                  Model of Plastic Bottle Cap

PROCEDURE:

1. Importing CAD model:

• Open the geometry model. Use Topology option to clear the cons and check the model orientation using Entity Drawing Style in Menubar.

          

• Check and assign PID and Materials from Lists menu (if required).

2. Geometrical Clean-up:

• Check for geometrical errors using Checks Manager option. Execute the geometry after selecting the required options.

                                            

• Clear the errors using auto-fix option in Checks Manager from Tools menu.

         

• If the errors still persist, then they have to be corrected manually using TOPO options.

                

• Here the highlighted regions in the model indicates faces or cons that needs to be corrected.
• Rerun the geometry check again for zero errors.

        

3. Creating Mid-surface:

• Check the model thickness at different spots using Measure option in Utilities menu.

         

• Store the measurement data in Database if required.
• The given model has varying thickness throughout as per the measurement data shown above.

Extraction of mid-surface of the model can be done using Mid-Surface option/manual method from Topo menu. Initially we follow the auto-mid extraction using Mid-Surface (Casting) option.

     

     

This method obtains broken/deformed mid-surface for certain features as shown below.

     

     

We shall try to obtain proper mid-surface for all the features using manual method.

•  Offset option can be used to create mid-surface for features of uniform thickness.

          

          

• Middle option from Curves helps to form outlines of mid-surface for features/area with varying thickness.

        

• New Face option can be used to create the surface using the outlined curves.

        

  

  

• The feature shown below also can be formed using Curves and Cons projection.

         

         

         

        

• Inorder to replicate certain features around a surface, we have to create few reference points as shown below.

        

        

       

• Assign a new PID and thickness value for the created mid-surface.

        

• Store Lock the mid-surfaces and parent assembly model view separately.

4. Quality Criteria and Meshing:

• Change the Length Parameter to value 1 for both Perimeter and Macros.

         

•  Select and enter the values required in the Quality Criteria box from Utilities menu.

         

•  Input the required mesh length and minimum length in Mesh Parameters from Utilities menu.

         

• Select Classical Mesh option from Mesh module.
• Mesh the features sequentially and use Shadow Drawing Style to view the mesh quality deviations.
• Correct the mesh flow and quality using Mesh options.

         

         

        

5. Final Model:

         

RESULTS:

The given Plastic Bottle Cap model has been completely meshed by assigning thickness but certain elements has failed quality criteria due to constraints induced by triple cons.