About this 3D model

To start the year and stay in a playful spirit, I propose you the impression of a small catapult. Printed in ABS it allows, for example, to propel a piece of 2 cents between 4 and 5 meters. A power enough to assault a castle in Lego, or to challenge the skill of dad's colleagues to aim a goblet during the coffee break ... To achieve this object prefer the use of ABS because resistant to torsion and retaining a good spring effect. The PLA for example is less flexible and more fragile, so it is less suitable for this type of use. ABS of different origins has been tested without any problem, the only impact being a small variation in propulsion power. To maintain adhesion to the platen during printing, it is preferable to be able to maintain the tray between 100 ° and 110 °, all the more so if you use ventilation to solidify faster the parts with small cross section. To obtain a good cohesion of the layers and therefore a good resistance of the assembly, it is important that the deposited material is at a good temperature, the performance of the print head plays an important role in this operation. Prefer a filling from the inside to the outside which allows better maintenance of the cantilever areas, even if this degrades a little the external surface condition because the last deposit amplifies the defects of the previous ones. The fill rate of our example is 40% (a higher density allows a small power gain, but increases the printing time and the material consumed). I chose a crossed linear internal structure which seems to me more apt to resist the torsion of certain parts. Total printing time: 1h37 Https://youtu.be/671NCBFebXE More information: Https://www.genapart.com/2017/01/02/catapult-printed-assembly-sans-support/