Challenge

Week - 4 - 2D meshing for Plastic components

Objective :

Checking for the Geometrical Errors .
Extracting the midsurface with suitable Midsurfacing Techniques .
Meshing of the same component with Target element Length of 1 unit and with proper mesh flow .
Checking for the Quality critria provided .
Assigning the PID and the Thickness to the Mesh .

CAD Model :

Procedure :

For this Model , Midsurface is extracted Manually as this is the Plastice ciomponent , and has varying thickness.
We will not get Proper midsurface from it .
For Top side rib midsurface extraction , initially curves are created as this surface have varying surface can be seen below as ,

For this Curves are created at middle of the upper face and the middle of lower cons .

Then Using the New surface with Cons Option , the new surface is created as ,

In the same way midsurface for some other surfaces is extracted .
But for the Same thickness surfaces , The midsurface is extracted using the Offset Tool , which offsets the selected face of the surface and offsets it at the user defined distance.
The Upper surface of the bottle cap model is offseted by the 1.53/2 distance ( 0.765 unit ) as the thickness of the this surfaces has 1.53 units .
The negative sign indicates the Surface is offseted in the opposite direction of the arrow shown .

For extraction of the midsurface of the threads of the model , Initially the curve is created at middle of the top face surface .
WHich will create spiral like Cons as ,

Now isolating midsurface extracted previously the support surface of the Threads.
And This curves is then projected on the support midsurface .
And using the New surface tool , with cons option New midsurface for the threads is created as ,

For midsurface of the Tooths are created in the same way , initially the Middle curve is created on the front face .
The rear edge of the surface is then projected on the lower midsurface as ,

Using this , Cirve and the projected edge as Cons , new surface is created which is midsurface of the Tooths .

But its onle for the one Tooths , There are total 26 same tooths on the same round surface , which are need to create .
Same process for midsurface creation for the Tooths is time consuming .
For lowering the time required , same Tooth midsurface can be Copied and transfer in rotating way .
For rotating this midsurface , we need to create two points .
This Points are created using the Two Circles at diffrent level .

This Two Points will acts as Axis of rotation for rotating the Tooths Midsurface .
Using the Transform Tool , This Tooths are copied and rotated in 360 degree on the Round parent surface .
Using this Axis of rotaion , Tooth is rotated using the 25 Steps more and at an angle of 360/26 degree.

Now for Middle fillet midsurface extraction , its thickness is measured by creating the spot weld and projecting it on opposite face which is 1.24 unit .
Upper Face is the Offseted in the opposite direction of the Arrow at distance of 1.24/2 unit .

Outside ribs Midsurface extraction is done by taking the middle of the Two side surfaces of the ribs using the Miidle Tool as ,

Now at bottom there is region where element would fail for the minimum length .

For avoiding this minimum length elemental failure , in that region new surface is created equivalance to the fail minimum length of the element .

Now after correcting and extracting the midsurface for all the Surfaces , Meshing is done with the Traget elemental length of the 1 unit and 0.5 unit , 3 unit for length range for minimum length and Maximum length respectively .

Thickness is also assigned by creating the various properties with various Thickness as ,

Results :

Bottle Cap model with fully mesh Can be seen below as ,

After assigning the Thickness properly to all the surface the model can be seen like below ,

Conclusion :

For this Model the midsurface is extracted Manually as Auto midsurface wasn't giving proper surface .
Midsurface is extracted for all the Surfaces using different Midsurface extraction Techniques like Middle Surface Tool , Offset Surface Tool , New Surfaces with Cons etc.
Meshing is done with passing most of the elements with Quality criteria pass .
Some elements are Failed for the Minimum length because of the less constrain .
This Elements Can not be removed because of the two surface and triple Cons.
Thickness is assigned to the model with proper thickness for all the Surfaces .
The final Model is attached below .

Ship work like this
in your own course.