Question

Design the cooling system used to manufacture the leg of a table, shown in Fig.2. You will have to determine the required diameter D so that the leg can withstand 100 kg of axial loading. Once the diameter has been determined, you will need to determine the Revolutions per Minute (RPMs) of the fan needed to cool down the leg to 90-C in less than 2 minutes before it starts deforming after being 3D printed. Consider the leg of the table as being a cylinder of length L = 1 m made of ABS 3D printing material, which has a modulus of elasticity E= 1.4 x 109 Pa, density p= 1040 kg/m3 , specific heat cp = 2000 J/kg-K, thermal conductivity k=1.8 W/m-K, and an extruded temperature Ti= 230°C. Figure 2: Table When the leg is subject to an axial load, it will buckle if the force reaches the critical buckling load given by:

Answer 1

Ca) Using the cokmn bucklin ceons determine the coiticel diameter to nothstand loo ka o acial lbad. 100 k, Moduhs o ClashatyE 1-4x10 l00 x 7.8 N(F -g) Sok tion: Griven- Cribical load Per 980 N Substibite in equation ) 2EI Per L2 load forbo t end ficed De for Criical nead Le= o.5xL effective lengt e the Lo Consider iues Leagth cy inder Le O.5X1265 72 X 1.4 X101x I 0-5)2 180 So I -1 4 17-73 XID T2x1-4X101 where 64, 64 X 17.73x 10 D 4/361-22X10 O0245 M 24.5 Mm