<\/span><\/h2>\n\n\n\nA sphere is a shape that we commonly encounter in our daily life in objects such as basketballs and marbles. In fact, despite not being a perfect sphere, our very Earth is a spherical object.<\/p>\n\n\n\n
Compared to all the complex models you can print with a 3D printer, a sphere is merely a simple shape without any nuances.<\/p>\n\n\n\n
So, why is 3D printing a proper sphere is considered to be one of the most challenging things to do?<\/p>\n\n\n\n
Simply put, the answer is gravity<\/strong>. If you take a closer look at a spherical object, you will realize that certain points of it don’t have any support <\/strong>below them.<\/p>\n\n\n\nThe difference becomes very apparent when you compare a spherical object to a cubic one, as a cubic object doesn’t have any parts that are sticking out.<\/p>\n\n\n\n
But how does this tie in to 3D printing a sphere being hard?<\/p>\n\n\n\n
If you ever watched your 3D printer as it’s printing, you might have noticed that it prints in layers where the printer moves from the bottom of the shape to the top<\/strong>. Each completed layer acts as a support<\/strong> for the next one, allowing the layer to stay on the object without succumbing to gravity<\/strong>.<\/p>\n\n\n\nNow, think about the shape of a sphere again. Until you reach the very center of the sphere, each 3D printed layer is larger than the previous one,<\/strong> meaning that these layers aren’t supported<\/strong> by anything. When layers aren’t supported, there is a chance that they succumb to gravity and fall depending on the angle formed between themselves and the previous layer.<\/p>\n\n\n\nThis phenomenon, called an overhang<\/strong>, is what makes 3D printing a sphere hard, and 3D spheres aren’t the only case where you will be experiencing this exact problem.<\/p>\n\n\n\n<\/span>What Are Overhangs, Bridges, and Supports?<\/span><\/h2>\n\n\n\nIn the 3D printing world, parts of objects that extend beyond the previous layer are called overhangs, <\/strong>and trying to 3D print a sphere is perhaps the first time a 3D printing beginner encounters this concept.<\/p>\n\n\n\nDue to not having any support below them, overhangs are incredibly susceptible to falling<\/strong> as gravity can eventually pull them down during the printing process.<\/p>\n\n\n\nFor more understandable examples, we can look at the shapes of the letters T and Y<\/strong>. The left and right pieces of these letters are overhangs, with the letter T having a 90-degree overhang<\/strong> and the letter Y having a 45-degree overhang<\/strong>.<\/p>\n\n\n\nAs the angle <\/strong>of the overhang increases<\/strong>, so does the likelihood <\/strong>of it falling, <\/strong>as it becomes harder for the overhang to find support.<\/p>\n\n\n\nWhile slightly different than overhangs we have talked about so far, bridges <\/strong>are also a type of overhang. The most common example for a bridge is the letter H<\/strong>, as the middle part of this letter doesn’t have any direct support <\/strong>below it despite being connected to two separate points<\/strong>. Compared to overhangs, bridges pose less of a risk to the integrity of your print.<\/p>\n\n\n\nSince overhangs <\/strong>are the enemy of a successful 3D printing process, it’s best to eliminate <\/strong>or at least minimize <\/strong>them as much as possible by manipulating the model in certain ways.<\/p>\n\n\n\nAn example of this would be to print the letter Y in a way that it lies flat on the 3D printer instead of printing it upright. With this simple modification, your model would contain no overhangs at all.<\/p>\n\n\n\n
That being said, it’s not always possible to manipulate your model in a way where it wouldn’t contain any overhangs, which is where supports <\/strong>step in.<\/p>\n\n\n\nSupports <\/strong>are extra 3D printed parts that are added to your model as a way of supporting overhangs. As their whole purpose is to prevent overhangs from falling, they are removed from the print after the printing process is over.<\/p>\n\n\n\nIf we use the example of the letter Y once again, adding two sets of supports to the left and right sides of the letter would allow the overhangs to stay in their place during the printing process.<\/p>\n\n\n\n
While supports are a necessary tool in complex models, problems related to overhangs in simpler models can often be remedied by simple modifications such as the orientation example we have just mentioned.<\/p>\n\n\n\n