CAMm1 Moduloppgave: Espressokanne 1
The module exercise for CAMm1 is to start modelling the parts for an
espresso pot. The model is to be refined and completed in module CAMm2.
A DWF file containing a cross section of the parts, some of them partially
completed is used as the starting point. For this exercise 5 parts will be modelled:
bottom half of the pot, upper half of the pot, lid, knob and handle.
The necessary measurements are taken on each part on the DWF file. Personally,
I prefer to focus on a single part at a time and first take all the dimensions
I expect to need to model the part. This also helps me decide how to model the
part in Inventor.
Starting in Inventor, the first step it to setup the project.
Once the project is setup correctly, modelling of the parts starts. Sketches
are one of the main tools in Inventor. The main thought behind the modelling
process is to select the tools to achieve the global geometry, at the same time
selecting which features will be included on the initial modelling staged, and
which will be included later as part of refining the model. This goes hand in
hand with selecting the important dimensions from the DWF file.
While sketching, it is always important to ensure "fully
constrained" sketches. This helps avoid having problems with the model afterwards,
especially when the complexity increases.
The sketch is then used in an extrusion with taper angle.
A second extrusion is used for the threaded cylinder.
The
model is refined by adding chamfers to the edges accordingly.
In addition, the external thread is added.
Finally, a control is made on the part. I like using the "shaded with
edges" visual style to quickly and clearly see all the features in the
part.
The upper half of the pot was modelled starting with a couple of extrusions,
but since this part has more features, I used a third extrusion to make the
handle support, a sweep to make the pouring beak, and a revolution to make the
internal cones.
The grip was done with just two extrusions, since each could include all the
necessary dimensions.
The lid was probably the most complex part of the exercise, both in terms of
the shape itself and of the amount of features needed to model it. It took some
trial and error in order to select the correct modelling tools as well as
establishing the correct order in the model to reach the correct outcome.
Finally, the knob was a modelled straight forward using a loft for the
inverted cone, an extrusion for the upper part, and fillets and a threaded hole
for the detailed features.
The
assembly was then started, having the bottom half of the pot as the
"grounded" part.
The upper half of the pot is placed using the threaded cylinders as
location reference (insert) and planes to lock relative rotation of the parts.
The handle is placed with mate constrains on the geometry.
For the lid, the holes are used as first constrain. Planes are then used to
fix the relative angle towards the other parts in the assembly.
Finally, the knob is placed on the lid.
All parts are double-checked to be fully constrained, especially so that they are not able to rotate in place.
I was very pleased with the result, although it is still to be finished in the next module. Modelling in Inventor is an interesting process since it combines the selection of the modelling tool with the order in which they are placed. It is always very helpful to think of the real-life fabrication process since in most cases they relate 1:1 to the modelling sequence, although it is important also sometimes deviate from this thought and focus on the 3D modelling.
The working plan is updated accordingly. Some parts took longer to complete
since I was interested in exploring alternatives and I had to redo some
sketches that became problematic.
Overall, a very interesting and fun module exercise.
