Provided there are enough instructors available, no special knowledge is necessary before starting the project - the children learn everything "on the fly". Spatial imagination and previous work with any CAD program is an advantage.
The goal of the project is to familiarize children with the entire process of 3D printing – measurement, design, slicing, printing and postprocessing. At the same time, develop cooperation in the group and also explore regional history (pre-war Czechoslovak fortifications in Králíky area - the reasons for its construction, the principle of operation and its fate). The project also serves as an introduction to a campaign game on this topic. The tangible result will be a diorama of part of the Bouda artillery fortress, specifically objects K-S 21 (infantry casemate), K-S 22 (heavy artillery turret object) and K-S 23 (observation post).
HW: 3D printer, PC
SW: Tinkercad, Fusion360, PrusaSlicer
Additional material:
- postprocessing of models – sandpaper, knife, instant glue, alcohol paints, brush
- model landscape - solid board as a base, polystyrene, synthetic mesh reinforcement and screed glue, disperse glue, model grass, twigs, wire and others - according to the effort that will be devoted to the landscape
Time required for preparation:
(planning, finding documentation of fortress objects) – 3h
time spent working on the project: approx. 22h
approximate printing time:
Body of one object 10.5-12h (infill 10%, layer height 0.15mm, PETG)
All details (we printed at once) 2.5h (infill 10%, layer height 0.07mm, PLA)
1, Measurement in the field (time required – 3 hours)
As part of the day-long trip, we visited the museum at the Bouda artillery fortress, where the motivation and commissioning of the entire project took place.
For their own measurements, the children were divided into groups, within which they tried to measure and draw as best as possible the shape of the fortification objects and create the basis for 3D modeling. Considering that the fortification dates from the late 1930s, the time have taken its toll on it. Some elements (armored cloches, concrete "nails" around them) were not preserved at all (or were not even installed), so it was not possible to even measure them. Therefore, the children were invited to, apart from focusing on the current situation, also try to think about the meaning of the given object and the reconstruction of the form it was originally supposed to have.
2, Comparison of drawings with available documentation and corrections (time required – 2 hours)
We visited the city library, where there is plenty of literature with technical drawings of the fortress objects (Instructions - preparation works). These drawings served as the basis for 3D modeling - the data measured in the field were mainly used to determine the scale and size of smaller elements (the drawings are not dimensioned in the literature). An evaluation of the success of the reconstruction of the buildings was also carried out.
3. Introductory meeting – familiarization with Tikercad and the 3D printer, division of tasks (time required – 4 hours)
At the mass meeting, we introduced the smaller children (with the help of the bigger ones) to Tinkercad and the basic tools (demonstration and individual practice in the form of a competition - solving a simple task in time). After about two hours, a demonstration of slicing and 3D printing of an object modeled by the children (a key ring) took place.
At the time of printing, the tasks were divided (the model divided into smaller parts - body and details), the scale was specified (for modeling 1:100 for easy calculation, for printing, due to the dimensions of the printing area of our 3D printer, the models scale was further reduced to 60 percent). It was also necessary to agree on the "interface" - the way in which the details will be connected to the model - for example, the shape and dimensions of the recess for the port holes and the clearance that will be used so that the printed port hole fits into it precisely.
4, Modeling (time required for one part – 30 min – 6 hours)
Modeling took place in smaller groups, for the most complex parts (body of objects) mostly independently at home. Tinkercad was used for simple details, Fusion360 for object bodies. An example of the procedure for each kind of software is given in the appendix.
5, Slicing, 3D printing (time required for one part 2-12 hours (see above)
Slicing and setting up the printer was carried out in groups under the supervision of a designated instructor responsible for printing. Each group brought their model on a flash drive, prepared the print and set up and turned on the printer.
6, Postprocessing (time required 6 hours)
Each group picked up a printed model from print-instructor mentioned above and cleaned it of burrs. At the joint meeting, details were added to the bodies of the objects and whole models were painted. The finished objects were then placed in a simplified model landscape, created on the basis of data from the “mapy.cz” GIS portal.
RESULT SUMMARY
The project met the goals set. The children were introduced to the entire 3D printing process, learning to use Tinkercad, Fusion360, PrusaSlicer and a 3D printer. In addition, they developed cooperation in the group, learned new things about local history, and the project introduced them to a campaign game. In our specific situation, it was very beneficial for us in every way.
On the other hand, we are aware of the problems that would arise if the project were used, for example, in teaching - modeling the "bodies" of objects is incomparably more demanding than details (port holes, etc.). In an age-homogeneous group of children (class), this would make some pupils very busy, while others would be bored. Due to the shape of the objects, only limited group of tools is practiced in Fusion360 (sketching, extrusion, rotation, fillet, freeform), other interesting tools are not used. Regarding resulting model, if it were only about the quality of the printout (while maintaining the scale we used), it would be more feasible not to divide the model into body and details - because these come out too tiny for printing and later processing - this would, of course, diminish aspect of planning and cooperation in a group.
The author hasn't provided the model origin yet.