Let’s be honest—when most engineers think about 3D printing, they’re still picturing prototypes or quick one-offs. But that’s not where additive manufacturing (AM) lives anymore. Today, we’re printing fixtures, functional assemblies, end-use parts, and short-run production at scale. And when you’re doing that, the design becomes everything.
This is where Design for Additive Manufacturing (DfAM) steps in. If you’re still designing parts like you’re going to mill them—or worse, injection mold them—you’re going to hit problems. Warping. Weak joints. Messy supports. And wasted time.
Let’s walk through the stuff that actually matters when designing for additive—no fluff, no marketing hype, just practical principles that will make your prints cleaner, stronger, and easier to scale.
It All Starts with Orientation
Orientation isn’t just about how the part sits on the bed—it changes how strong your part is. Since most 3D printers build layer by layer from the bottom up, your part is going to be strongest in the X-Y plane and weakest along the Z-axis. That’s just physics.
If you’re printing a bracket, and the load’s pulling across the layers, no problem. But if it’s pulling up and down—perpendicular to the layers—you’ve got a problem waiting to happen. So design with that in mind. Rotate your part before you regret it.
Thin Walls = Trouble (Thick Ones Too)
Wall thickness can make or break your part. Literally.
Too thin, and you’ll get fragile edges, print failures, or even total collapse mid-build. Too thick, and you trap heat, create internal stresses, or waste material.
A good rule of thumb? Start with 0.8–1.2 mm as a minimum, depending on the process. And be consistent—randomly going from 1 mm to 5 mm mid-part is a fast way to get warping or delamination.
Supports Are the Enemy (Sometimes)
Supports are necessary, especially in FDM and SLA. But they slow you down, chew through material, and can ruin surface finish on delicate features.
Try designing parts that don’t need supports:
- Chamfer sharp overhangs
- Use teardrop or diamond-shaped holes instead of circles
- Avoid features that hang out in mid-air
And whatever you do, don’t put fragile details under support material unless you want to spend your afternoon with a pair of pliers and a sinking feeling.
Think in Clearances, Not Just Dimensions
It’s easy to forget that 3D printing doesn’t give you perfect tolerances. Even industrial printers vary a bit depending on material, geometry, and orientation.
Need a hole for a bolt? Don’t design it at 6.000 mm and expect it to be a drop-in fit. Add some clearance—0.2 to 0.4 mm is a safe range for slip fits. Press fits? Undersize by a fraction. Always test if it’s a critical feature.
More Parts? Or One Smart Part?
One of the best parts about AM is you don’t have to design like you’re dealing with stock material. Why make three parts bolted together when you can just print one that does it all?
If you can consolidate multiple components into one build, do it. It saves assembly time, removes fasteners, and usually results in a stronger part. You can even print snap fits, clips, hinges, and alignment features directly into your design.
Materials Matter (A Lot More Than You Think)
If you’re picking material based on what you’ve heard is “popular,” stop right there.
TPU prints great but is terrible for load-bearing parts. ABS is strong but hates moisture and UV. PETG is easy to print, but it’s flexible compared to PC or carbon-filled nylon. And if you’re designing for high heat or flame resistance, there’s no substitute for ULTEM™ 9085 or PEI.
Match the material to the real-world conditions:
- Is it flexing or holding a load?
- Will it be outside? Exposed to chemicals?
- Does it need to be sterilized?
Data sheets help, but real-world testing wins.
Drain the Void
Powder-bed processes (like SLS or MJF) don’t need supports, but they do trap powder. Same with SLA—if you’ve got an enclosed volume, resin is going to get stuck. You’ll need to design drain holes—at least 2–3 mm wide—at the lowest points of internal cavities.
Forget that, and you’re left with a heavy, contaminated part or a cleaning nightmare.
Keep It Readable, Too
If you’re labeling parts with logos, serial numbers, or alignment marks, don’t go micro. Use a sans-serif font, keep your characters at least 2 mm tall and 0.4 mm deep, and put them somewhere they won’t get buried in support or blasted off during cleanup.
Nest Like You Mean It
If you’re printing more than one part—especially in SLS or MJF—you’ve got to start thinking about how parts nest together in the build. It’s not just about cramming them in; it’s about airflow, cooling, and clean separation.
Spacing matters. Orientation matters. And if you’re printing batches, consistency matters even more.
Use mirrored orientations to reduce warping. Keep parts off each other to avoid fusing. And track how you’re loading the build so you can repeat it reliably.
Printing for Production? Plan for Post-Processing
Here’s the secret: post-processing takes time. A lot of it, if you’re not careful.
When you’re designing a part, ask yourself:
- Can I reach the supports I’m going to need?
- Will I have to sand or machine this feature later?
- Is this surface visible, or does it need to look polished?
Plan ahead, and you’ll thank yourself later. Design parts that can be finished efficiently, and your production line will run smoother.
Wrap-Up: DfAM Is Just Good Engineering
At the end of the day, Design for Additive Manufacturing isn’t about gimmicks—it’s about smart, intentional engineering. It’s what separates parts that barely print from parts that perform, scale, and get approved.
So if you’re going to print something, don’t just ask if it’s printable. Ask if it’s designed to be printed well.
Want help dialing in your parts for additive?
At RapidMade, we work with engineers every day to optimize designs for real-world printing, performance, and production.
Visit for the best 3D printing services visit rapidmade.com or shoot us an email at info@rapidmade.com to get started.
