Designs We Love: 3D Printing
A lot of people think that you can create virtually any shape your mind can imagine using 3D printing technology. OK, so that’s sort of right, but not entirely. The hard part is coming up with aesthetically beautiful designs that also are functional for your application, structurally sound to achieve longevity, and are modeled to address the limitations of the medium. You can do a lot with 3D printing, but if you take these other factors into consideration, you’re on course to create designs that we love to see
Holes and Channels: Great Ideas for Negative Space
When designers include channels in their parts, they often don’t consider that these features don’t have to be simple round holes. That’s something that comes from years of designing for machining. Really, it can be any shape that provides proper support for the build.
Think of Roman architecture and the need for a keystone to hold up an arch to help avoid the pull of gravity. That means it works great to use shapes like diamonds (a square on its end), circular holes with a vertical rib for smaller diameter channels, a teardrop, or in the spirit of Valentine’s Day, it can even be an upside-down heart. Aww!
Interior Radii Rule
Some people like to look sharp, but with 3D-printed parts, it’s better to look smooth. Whenever possible, we love to see interior radii for edges and corners. That smooth contour not only looks great, but it also relieves the stress that builds up during the printing process. Aim for organic curves and avoid sudden changes in part thickness or you might end up with parts that have shift lines.
Support for Your Parts
Gravity is good. It keeps us plastered to the Earth so we don’t lose our place in grocery store lines. Where it’s tough is in printing parts. If you have a thick part that includes a bend, you’re not going to like the end-result if you try to create a downfacing surface that is less than 45 degrees (in other words, flatter—less vertical). The lower the angle, the more aggressive the stair-stepping and the more likely the downfacing surface will require support structure. So, remember the 45-degree rule and we’ll know you know what you’re doing.
Freedom of (Parts) Assembly
One of the coolest things about 3D printing is that you are only limited by your engineering/design knowledge, the material, and the process you choose to manufacture your parts (we offer six of them). If you are sick of dealing with using hardware and other techniques to merge small parts into big parts, rethink your design as a single, large part. What’s key here is that you usually can’t just take ten designs and crush them together into one CAD file. You have to look at the new fused assembly now as a single part and think through again which features are valuable, and which aren’t. When we see large parts that include nice transitions between what used to be individual parts, the homework you’ve done in considering additive manufacturing techniques is obvious—and often looks pretty cool.
Bridges You’ll Love
Like relationships, the stronger and closer your support system, the longer lasting your part. If your part has a long horizontal component to it, you need the structure to support it. Breaking up is hard to do if you remember that you need to consider the space between pillars you design to keep it structurally sound. For example, for DMLS, you need the spaces to be 0.079 in. (2mm) or less apart,
Thin Walls Don’t Always Make Great Parts
In design, thin often looks cool, sleek, and streamlined. But thin walls look awful when they crack off during end-use. Again, a great example is that if you need thin walls in your designs for DMLS parts, think of your customers and earn their love by using the 40:1 rule of height-to-wall thickness. For example, if you have a 0.1 in. (2.54mm) thick wall, the wall height shouldn’t be more than 4 in. (101.6mm) to maintain structural integrity. However, that 40:1 rule can be stretched a bit if the wall is more naturally self-stabilizing, like the wall of cylinder.
Pleasing the Customer
Every company’s objective is to please its customers. That’s kind of a no-brainer, but it’s amazing how much importance can be placed in the design phase of a product. Parts that are poorly designed for 3D printing won’t get you the love (and financial support) you crave from your customers.
So, those are some of the things we love to see in CAD models for 3D printing. Read about the design elements we love in our other service lines: CNC machining, injection molding, and sheet metal fabrication.