3D print could test sample before CNC to check the appearance.
E.g. mold industry, 3D print could raise the efficient, safe time and money to print a sample.
3D print could help researcher high speed sample print, make sure the product to reduce the time period for waiting work days.
The sample is showed by bicycle water bottle holder, it only spend half day to print it.
3D print helps designer to check the appearance in time then modify the problems.
E.g. board game
3D print could print a customize medical appliance help patient in time.
E.g. swimming correcting support, chopsticks support, door support, all of them are helper for rheumatoid arthritis patients.
Senior high Physical class use the Archimedes principle to transfer the material and discuss about it.
By 3d print samples, students print a mold then talk about the experimental issue.