Week - 4 - 2D meshing for Plastic components

AIM:

To create a mid surface for all the componets after checking the geometrical errors and mesh the mid surface with the proper quality criteria for the plastic model bottle cap. 

OBJECTIVES:

• To practice how to create a mid surface.
• To practice how to mesh the componets without quality failures.
• mesh the model with agood mesh flow.                                                                                                                                                                                                                                                                                                      PROCEDURE: 

• IMPORT CAD GEOMETRY
• to open the cad geometry file>open
• after opening the CAD geometry inspect the geometry very well before start  working.
• identified the given bottle cap model is complex and having variying thickness also.
• we have to mesh the parts seperately by the following steps.
• GEOMETRY CLEAN-UP
• perform cons resolution.
• assign perimeter length as 1mm.
• classic>length>perimeter length
• to visualise the model in same colour and details go for orient.
• topo>faces>orient
• check the geometry for the cons 
• tools>geometry>execute
• if there are triple cons and double cons relese them into single cons.
• tripple cons>topo>cons>release
• double cons>faces >topo
• MID SURFACE GENERATION
• measure the thickness using measuring tool.
• start from below outer circle of thr component.
• using project project the line and go for ofset.
• extract mid surface
• topo>offset>selact the face using required selecting tool as feature angle or macro area>give the offset value 
• extract the mid surface without deleting the new faces.
• using inot or not option or extract midsurface by hiding the parent geometry.
• always keep PIDs seperately
• set pid>new pid
• there are complex ribs using middle multi extract the midsurface .
• then rotate the rib intto 360 degree for other ribs
• transform>copy>rotate
• give created ONG cordinates and steps and degree.
• getting midsurface for round projection from inner circle use middle tool
• curve>middle>select lines and create middle line then project in to face.
• then extract new surface as mid surface
• faces>new>coons
• extract other midsurfaces using offset
• use middle muti for extracting midsurface for parts which have variying thickness.
• give perimeter lenth as 1mm
• classic>length>perimeter length
• give mesh parameter 
• target element length as 1mm and minumum length as.5mm.
• give quality criteria.
• give the given values for wapage,aspect ratio,skewness,jacobian,min and max length,triangle percentage
• perform geometry clean-up
• avoid near hotpoints 
• topo>hotpoints>delete
• inset hot points if required 
• topo>hotpoints>insert
• avoid construction line if any
• topo>faces>cut
• join lines if needed
• topo>faces>join
• delete unwanted hotspots
• topo>hotspot>delete
• 

• 
• SHELL OR SOLID MESHING
• give proper mesh to the elements.
• classic>best and select the fa
• ce for meshing
• use classic>spot mesh if needed.
• if the elements are symmetrical use transform option for easy mesh align.
• give mesh bottom to upside one by one feature.
• mesh every entity.
• ELEMENT QUALITY CHECK
• check the qualities and improve the quality failures if any.
• if there is any error it will be visible as off elements.
• analyse the quality criteria we are given and correct the failures.
• MESH IMPROVEMENT
• improve the mesh to get a good mesh flow.
• reconstruct the mesh for better mesh flow.
• classic>shellmesh>reconstruction and use selection tool as macro area for easy selection of faces.
• classic>shell mesh>smooth for smoothening the mesh flow.
• avoid trias from the edges or feature lines.
• avoid opposite trias.
• always keep minimum number of trias for better mesh flow.
• avoid cloud of traias if any.
• avoid neighbouring trias.
• always keep trias forwarding to same direction for better mesh flow.
• use classic>elements>split for these mesh improvement.
• swap the tria or drag the trias into better position using split command.
• keep a good mesh flow.
• use transform option for meshing the symmetrical elements.
• delete the identical parts of the element,
• transform>copy
• then give mesh to the other identical part and then copy to the symmetrical part.
• always keep clean mesh flow.

RESULT:

•  extracted the mid surface of bottle cap model successfully.
• successfully imported the mesh with given quality criteria.
• completed the bottle cap model with a good mesh flow.