Threaded Inserts for 3D Printed Parts: Installation Techniques, Materials, & Strength Testing

Adding threaded inserts to 3D printed parts opens up new realms of mechanical and assembly possibilities. But how exactly do you reliably integrate those deceptively simple-looking hardware? What type of inserts work best for 3D printing? And what strength can you actually expect?

In this guide, I’ll demystify threaded insert implementation for 3D printed components. I’ll explain what inserts are, recommend optimal materials and sizes, highlight ideal design considerations, and detail a foolproof insertion process – including lessons learned from my own trials and errors.

Threaded inserts provide the best way to incorporate removable screws into projects like enclosures and furniture. By integrating a durable threaded metal insert, you can attach and detach screwed components without wearing out the plastic or wood hosting material. This makes inserts an ideal solution for incorporating detachable and serviceable elements into your 3D printed designs.

So let’s conquer this functional 3D printing technique together. By learning from my past mistakes, you can fast-track your success.

How to install Threaded Inserts into 3D Printed Components

Step 1: Design holes in CAD

• Check manufacturer specs for hole diameter
• When I first started with inserts, I just guessed at hole sizes. Big mistake! Always check the specs from the manufacturer to get the proper hole diameter.
• Hole is normally slightly undersized
• The holes are usually slightly undersized compared to the insert’s outer threads. This allows the material to deform and grab the insert.
• Print tests parts to find ideal diameter
• Don’t skip printing test parts! Because of shrinkage and resolution limits, the designed diameter won’t match the printed diameter. Test pieces help dial in the ideal hole size.

Step 2: Adjust slicer settings

• Increase perimeter shells to 4-6 layers
• Increasing perimeter shells to 4-6 layers leaves more material for the insert to grab onto. I learned this the hard way after a few inserts pulled out too easily!
• Minimize infill and supports near holes
• Minimizing infill and supports near holes prevents having to clear out melted plastic threads after insertion. I wasted a lot of time digging melted supports out of holes in my early prints.

Step 3: Increase hole depth

• Add 20-50% more depth than insert length
• Adding 20-50% more hole depth than the insert length leaves room for the melted plastic to go somewhere during insertion.
• Allows space for displaced material
• Without enough extra depth, the displaced material can squeeze out the hole backside and block the insert. I’ve had to drill out a few botched inserts when I forgot to allow extra depth.

Step 4: Heat up soldering iron

• Heat to 10-20°C above printing temp
• Heating 10-20°C above printing temp lets me insert smoothly without overmelting. I used to just max out my iron temperature and warped a lot of prints!
• Allow 2-3 mins to fully reach temp (Prevents overheating and warping)
• I ruined some prints by not giving my iron enough time to fully reach temperature. A few minutes warm-up prevents this amateur mistake.

Step 5: Press in insert

• Use installation tip on soldering iron
• Using the right insertion tip shapes the heat transfer and prevents sticking. Regular soldering tips stuck inside my inserts too often!
• Press gently, letting heat melt walls
• Pressing gently prevents cracks in the plastic and lets the heat do the work. Jamming inserts in too quickly caused damage in my early prints.
• Go slowly, about 5-15 seconds
• Taking 5-15 seconds allows even heating for a smooth insertion. Rushing this melted holes way too big. Patience pays off!

Step 6: Seat insert

• Press until top is 0.5mm below surface
• Pressing until the insert is slightly below the surface leaves room for the final press fit.
• Molten plastic may flare up
• Flaring plastic during insertion is normal! It gets trimmed in the next step.

Step 7: Invert and press flush

• Immediately remove heat source
• Removing the heat source prevents over-melting the plastic. I learned not to leave the iron on too long!
• Invert part and press onto flat metal when possible
• Pressing the part onto a flat metal plate forces the insert flush with the top surface for a clean finish.

Step 8: Allow part to cool

• Wait at least 30 seconds before handling to let plastic re-harden
• It’s always best to wait for the plastic to cool and fully re-harden in order to avoid burning yourself and also to allow the plastic to regain it’s strength.

Step 9: Clear excess material (new step)

• Use a drill bit slightly smaller than screw diameter to clear any excess material pushed to bottom of hole during insertion
• This prevents blockages  and clears the path to allow screws to fully seat
• Apply light pressure and back drill out debris a few times
• After inserting the insert, I learned the hard way that you often need to clear excess material pushed to the bottom of the hole before installing screws – this prevents debris from blocking full screw insertion.

Step 9: Install screws

• Use hand tools, avoid over-tightening (vital)
• Hand tools allow a controlled torque. I made the mistake too many times of using Power drivers to force screws into the inserts and I over torqued the insert every time.
• Sometimes the screw and the insert will seize together and the threads between the insert and the 3d printed part will fail.
• Allow cooling between adjustments
• Allowing the insert to cool between adjustments prevents accumulating heat damage.

Step 10: Test inserts

• Check pull-out and torque strength
• Testing pull-out and torque strength validates your design and process. I save myself headaches by testing before committing to a finalize Piece!
• Tweak design/process as needed
• Tweaking based on results improves reliability. My designs evolved hugely thanks to iterative testing and refinements.

Unlocking the Full Potential of Threaded Inserts in Your Designs

When I first started using threaded inserts, I didn’t fully appreciate the wide range of applications that can really benefit from them. My mindset was that they were primarily for hardcore engineering projects. Boy, was I wrong! After experimenting with inserts in various applications over the years, I’ve realized they are useful for so much more than high-tech machinery.

Some of the most impactful uses I’ve found are in furniture, enclosures, cabinetry, crates, partitions, displays, and decorative woodturned pieces. What do these all have in common? They require removable screws and bolts without wearing out the hosting material after repeated assembly and disassembly. The durable metal inserts localize wear and reinforce soft materials like wood, plastic, and particle board.

So don’t limit yourself to thinking threaded inserts are just useful for your latest robotic prototype! They have great applications in everyday objects where you need strong, reliable mechanical attachments. I’ve come to really appreciate the versatility of inserts for adding functionality and longevity to projects both complex and simple. They’re a key tool in my shop that constantly unlocks new capabilities in my work!

Mitigating Risks When Integrating Threaded Inserts into Projects

When I first started using threaded inserts in my projects, I didn’t fully appreciate some of the potential drawbacks or risks that can come with them. At first glance, they seem like an easy upgrade over basic nuts and bolts – just insert them into your material and you’ve got durable threads ready for repeated assembly. But I soon realized it wasn’t quite that simple.

One issue I ran into was over-torquing the inserts during installation. If you put too much pressure inserting them into the material, they can get firmly stuck with the screw inside unable to be removed. Not fun when you need to take your project apart! I’ve also found that threaded inserts require extra tools that I didn’t initially account for. You’ll likely need an insert installation tool, drill guides, and maybe even a soldering iron for plastic. This added complexity surprised me at first.

Finally, you need to carefully consider the thickness of the material you’re installing inserts into. They require a certain amount of space, especially in 3D printed parts where the melted plastic has to go somewhere inside the print. I’ve run into fit issues a few times by not accounting for this displaced material.

So in summary, threaded inserts are an amazing solution in many cases, but you have to weigh the potential for over-torquing, extra tooling needs, and fitment challenges before jumping in. I still use them all the time, but with a bit more planning upfront!

Understanding the Strength and Limitations of Threaded Inserts in 3D Printed Materials

Jumping into using threaded inserts with my 3D printed components, I had no idea what to expect in terms of strength. My initial assumption was that the inserts would provide industrial-level pull-out and torque strength just like when installed in metals.

After some trial and error, I’ve learned that inserts in 3D printed plastics offer medium-level strength at best. On a scale from 1-5, I’d rate the pull-out strength as just a 2 out of 5. You can achieve around 100-150 lbs of force with good design and heat-setting, but plastics are no match for wood or metal. The torque strength comes in a bit higher at 3 out of 5 – good enough for basic applications but not for hardcore engineering tasks.

To get the most out of inserts in 3D printed parts, you need to carefully consider the insert type, print orientation, number of perimeters, post-processing, and a bunch of other factors. For lightweight consumer gadgets or prototypes, the strength of inserts in plastic is totally fine. But if you need heavy-duty performance, stronger materials like aluminum or steel are a must! The days of me assuming plastic-mounted inserts can support a huge book case are over!

The Diverse Benefits of Threaded Inserts in 3D Printing Applications

When I first got into the idea of 3d printing I found out the people were using threaded inserts into their components. I didn’t fully appreciate the wide range of applications that incorporate threaded inserts. After experimenting with the idea threaded inserts, I started to see them being used in various applications. I’ve realized they are useful for so much more than high-tech machinery.

• Custom 3D Printed Enclosures: Need to frequently access the internals of your printed electronic enclosure? Threaded inserts ensure that lids or panels can be removed and replaced without wearing out the threads.
• Mechanical Assemblies: From gears to levers, if your 3D printed parts need to move or bear weight, threaded inserts are your best bet for a robust connection.
• Robotics: Building a robot? Reinforce those joints with threaded inserts to withstand the rigors of operation.
• Drones and RC Vehicles: For the hobbyists crafting custom drones or RC vehicles, threaded inserts guarantee that components, especially those needing regular checks or battery swaps, stay firmly together.
• Prototyping: Designers, take note! When creating prototypes or mock-ups, threaded inserts can help you simulate the final product’s functionality to perfection.
• Mounts and Stands: Whether it’s a bespoke camera mount or a unique tablet stand, threaded inserts ensure stability and adjustability.

What do these all have in common? They require removable screws and bolts without wearing out the hosting material after repeated assembly and disassembly. The durable metal inserts localize wear and reinforce soft materials.

So don’t limit yourself to thinking threaded inserts are just useful for your latest robotic prototype! They have great applications in everyday objects where you need strong, reliable mechanical attachments. I’ve come to really appreciate the versatility of inserts for adding functionality and longevity to projects both complex and simple.

Choosing Wisely: When Threaded Inserts Might Not Be the Best Fit for Your 3D Printing Project

When I first started using threaded inserts, I assumed they were a universal solution suitable for any application needing mechanical fasteners. However, given the idea some more thought, I’ve realized inserts don’t make sense in every situation.

While threaded inserts offer numerous advantages in many 3D printing applications, there are certain scenarios where their use might not be beneficial or necessary. Here’s a list of applications where threaded inserts might not be the best choice:

1. Single-use or Disposable Items: For 3D printed objects intended for short-term or one-time use, the added durability from threaded inserts might be overkill and not cost-effective.
2. Purely Decorative Items: Objects designed solely for aesthetic purposes, like sculptures or decorative wall hangings, typically don’t require the reinforced strength that threaded inserts provide.
3. Lightweight, Non-functional Models: If you’re printing a model for visualization, like an architectural mock-up or a concept prototype that won’t undergo any functional testing, threaded inserts might be unnecessary.
4. Projects with Ultra-thin Walls: In designs where the walls are too thin, there might not be enough material to accommodate a threaded insert without compromising the structure.
5. Flexible or Soft Materials: For 3D prints using flexible filaments, the elasticity of the material might not hold the threaded insert securely.
6. Items with Integrated Snap-fit Joints: In designs that utilize snap-fit connections, the inclusion of threaded inserts might be redundant.
7. Short-term Testing Prototypes: If you’re creating a rapid prototype just to test a concept or shape, and not its functional durability, threaded inserts might not be needed.

I now consider factors like material thickness, surface finish, assembly method, operating environment, weight limits, and part geometry. It’s essential to evaluate the purpose and requirements of each 3D printing project to determine whether threaded inserts would add value or if they might be an unnecessary addition. It’s all about picking the best fastening method for the product and its requirements.

Choosing the Right Threaded Inserts for 3D Printing: Material Matters and Top Recommendations

When I began my journey with threaded inserts in 3D printing, I naively opted for the most affordable options available, not considering the importance of material compatibility. This oversight led to some disappointing outcomes with my printed assemblies. However, with experience, I’ve discerned the optimal insert materials for various 3D printed plastics:

• Stainless Steel Inserts: These are a top choice for many of my projects. They offer corrosion resistance and mesh well with the layered structure of printed plastics.
• Brass Inserts: Particularly from brands like Ruthex, these are excellent for heat transfer during insertion and bond seamlessly with numerous filaments.
• Nickel-Plated Steel Inserts: When working with flexible materials like TPU, these inserts provide enhanced grip and longevity.
• Helical Coil Inserts: These are particularly versatile, adapting well to the irregularities in printed layers, ensuring a snug fit.
• Plain Steel Inserts: I’ve learned to approach these with caution. While they might be cost-effective, they’re prone to corrosion, especially in humid environments.
• Avoid Uncoated Aluminum Inserts: I’ve had these oxidize over time in printed parts, reducing strength.

In conclusion, it’s not just about picking any insert; it’s about selecting the right one tailored to the specific 3D printed material and its intended use. The key is understanding factors like corrosion resistance, friction, thermal properties, dimensions, and ductility to choose inserts compatible with the specific 3D printed material and application. The days of just blindly grabbing the cheapest inserts off the shelf are over; now, it’s about quality and compatibility, with brands like Ruthex leading the way.

Optimizing Size Selection: Navigating the Range of Threaded Inserts for 3D Printing Projects

When I first started using threaded inserts in my 3D prints, I didn’t think much about size limitations – I just grabbed whatever insert best matched my bolt size needed. But I quickly realized you can’t always just slap a giant 1″ insert into a tiny widget! Through lots of trial and error, I’ve found inserts generally range from miniscule M1 sizes up to chunky 1″ industrial beasts. However, the most practical sizes for most prints tend to be M3 to M6 or #4-40 to 1/4″-20.

Anything smaller than M3 is tricky to properly install in 3D printed holes, while larger inserts need more heat input during insertion to avoid melting too much plastic. And excessively long inserts have issues conducting heat all the way down their length. Sticking to those mid-size inserts provides a good usable thread depth while still enabling consistent heat-setting into printed parts. On rare occasions when my part absolutely requires miniature or mammoth inserts, I’ll work outside that range with extra care. But for most day-to-day prints, I now stick to those proven, Goldilocks-zone insert sizes.

More tips and methods on installing threaded inserts

While the core insertion steps are relatively simple, consistently excellent results require care and finesse. Through trial and error, I’ve compiled a few extra procedural tips that take insert integration to the next level.

• Optimize Grip with Sandpaper: For a better grip, roughen the outer surface of the insert slightly using sandpaper before installation. This adds a micro-texture for the plastic to adhere to.
• Secure with Cyanoacrylate Glue: For plastics that bond well with adhesives, consider adding a drop of cyanoacrylate glue around the top edge of the insert. This provides an extra layer of security against pull-out.
• Support Thin Walls with Indentation: If you’re working with thin-walled prints, use a punch tool on the backside to create an indentation or boss. This method stiffens the area, providing better support for the insert.
• Maintain Soldering Iron Temperature: Ensure your soldering iron fully reheats between insert installations. Operating with insufficient heat can result in poor melting and seating of the insert.
• Prioritize Safety with Gloves: Always wear gloves during the installation process. Both molten plastic and heated inserts can reach temperatures that pose burn risks.
• Pre-Heat Inserts: Before pressing the insert into the plastic, pre-heating it for a few seconds can make the installation smoother and reduce the risk of warping the surrounding plastic.
• Use a Depth Stop: When using a soldering iron or similar tool, consider attaching a depth stop or marker to ensure consistent insertion depth across multiple installations.
• Alignment is Key: Ensure that the insert is perpendicular to the surface when pressing it in. Misaligned inserts can weaken the connection and cause stress on the plastic.
• Test Before Finalizing: Before committing to a design, print a small test piece with the intended hole size for the insert. This allows you to refine the fit before printing the final part.
• Avoid Overheating: Too much heat can degrade the plastic’s properties. It’s essential to find a balance between melting the plastic enough for the insert and not overheating it.
• Consider Post-Processing: After installing the insert, post-processing methods like acetone vapor smoothing (for ABS) can help seal the insert and improve the part’s aesthetics.
• Use a Flat Surface: When pressing the insert, do it on a flat, stable surface to ensure even pressure and reduce the risk of warping the part.
• Keep a Removal Tool Handy: In case of a misaligned or improperly seated insert, having a tool like needle-nose pliers can help in removing and repositioning the insert without damaging the part.

Mastering Insert Integration Opens New Possibilities

And there you have it – a comprehensive guide to mastering threaded insert integration based on lessons I learned the hard way early on. From ideal design practices to material considerations, controlled insertion techniques, post-processing, and pro tips, we’ve covered the full journey to achieving durable, reliable inserts in 3D printed parts. Remember to take your time, use the right tools, select compatible inserts, allow for cooling, and don’t be afraid to test and refine the process. Proper insert implementation can elevate your prints to new levels of mechanical functionality. Let me know in the comments if you found this helpful or have any other insertion struggles I can address. I’m always happy to lend a hand so you can avoid my past pitfalls on the road to 3D printing success!