3D PRINTING OF UNIVERSAL JOINT: AN ACADEMIC PROJECT

A universal coupling/joint is used to facilitate rotation between shafts which are inclined to each other. The angle between the two shafts is called the operating angle. It Is generally, but not necessarily, constant during operation. In order to achieve perfect rotation, 2 joints are generally used with an intermediate shaft in between.

The method used in making this joint was FDM 3D PRINTING. It is a rapid manufacturing method which can quickly make intricate and complex shapes which are otherwise, very cumbersome in case of conventional machining processes.

3D printing is used to manufacture the universal coupling as our project. The 3D printing machine used here is a FDM 3D PRINTING machine which uses ABS material. Considering the volume (in cc) of our entire assembly, the total cost (including taxes and cost of support material) was Rs. 811. The total time taken for the 3d printing process was approximately 5-6 hours, excluding the time taken to manually remove the support material stuck on the finished surfaces.

The general procedure for the 3d printing of the universal joint involved the following steps:
 We used the Solidworks model of a universal joint and scaled down its overall dimensions.
The dimensions were reduced proportionally in a manner such that the distance between
the 2 extreme ends of the assembly does not exceed 5 cm.
 The design of the individual components and the overall assembly was submitted to the labin-
charge of the 3d printing machine. The models were converted to .stl files and their net
volume (in cc) and weight was calculated (for cost purposes).
 The machine calculated an estimate of 5-6 hours for the entire process.
 After the printing was done, we used sharp pins and needles to remove the support
materials. Since it is a relatively small model, the support material were stuck and had to be
removed, especially from the holes.
 Using drilling, the hole of the fork component was enlarged to properly insert the collar pin
and assembling the other components.

The miniature universal joint can be used to rotate small shafts which are not properly oriented to each other. It can also be used to support rotation between shafts which are parallel but not in the same level. This can be achieved by used 2 universal joints. Being made of ABS, there are lesser chances of rusting and chemical degradation by acids and abrasive chemicals. The total manufacture time required for the joint was 5-6 hours. For a universal joint of the size mentioned here, it would take much more time if conventional machining processes were used. The method can be easily used as an alternative to machining processes.