Table of Contents
Introduction
Have you ever had the opportunity to build Ikea furniture? You see it on display in the store; it looks simple enough, but then you get home, and no matter what you do, it doesn’t turn out how you’d like it to. Sometimes hardware is missing, or holes are not where they should be, and no matter how closely you follow the instructions, the finished product is still wobbly. Well, we suggest glue. It will help your Ikea furniture look more professional and be more stable. There’s always a solution to a problem. But what if there wasn’t a problem, to begin with? What if the accuracy of your project needs is there when you start production? We want your parts to be durable without needing glue.
We want to be your go-to-market manufacturing team, so we’ve outlined a few things to consider when designing parts that use tapping and threading for additive manufacturing. If you have specific questions, don’t hesitate to ask!
Types of Threads and Tapping
Screws can be an efficient and effective way to combine two or more pieces. Below you’ll find several different ways they can be used to connect digitally manufactured parts.
3D Printed Threads
3D printed screws and screw threads can be customized and do not have to follow standardized sizes.
Design Tip: If you are designing external threads, remember to minimize the support structures on surfaces that have threads.
Pros:
- design freedom
- non-corrosive and can be lighter weight than metal
Cons:
- less solid
- may not be suitable for smaller sizes
- will eventually wear down with assembly and disassembly
Auto Tapping
No threads in tapped holes; screws will self thread during assembly.
Design Tip: Wood screws are ideal because they’re designed to use without preexisting threads.
Pros:
- saves time during assembly
- holds parts up well
Cons:
- tearing can occur if walls are not thick enough
- consider the hardness of material when determining the size of tapping
- does not hold up well for assembly and disassembly (one-time assembly)
Direct Nut Insert
Nuts are pushed into hexagonal holes past a plastic hook (which holds the nut in place).
Design Tip: The hook should be wide enough to keep the nut in place but not interfere with the screw.
Pros:
- ability to change out nuts and screws
- easy to assemble and disassemble
Cons:
- several parts are necessary
- extra time for assembly
3D Printed Pockets
Insert the nut into the pocket and align the screw through the hole on the top.
Design Tip: The pocket should be large enough to insert or remove the nut but should not allow the nut to spin.
Pros:
- ability to change out nuts and screws
- easy to assemble and disassemble
Cons:
- several parts are necessary
- extra time for assembly
Threaded Inserts
Threaded metal inserts are equipped with exterior ridges used to grip the additive manufactured portion of the part. Interior threads make final assembly easy.
Design tip: Use a soldering iron when pressing into the 3D printed part.
Pros: easy assembly and disassembly and better for smaller threads
Cons: added assembly time and cost
Manual Tapping
These are also not shown in the image above. This process adds the threads after the print by manually tapping the holes.
Design tip: Use a soldering iron when pressing into the 3d printed part.
Pros: cleaner than 3D printed threads and better for assembly and disassembly
Cons: added assembly time and cost
Thread Specifications
Several measurements can be used to determine the needs of your project and the size of the drill necessary. If you’re not using 3D printing to build the screws and tap the holes, most hardware websites will have these numbers for you. For example, at https://www.fastenal.com/, you’ll find product specifications.
Designing 3D Printed Threads in Fusion 360
External Thread
In this example, we will be making an M10 thread.
- Make a 10-millimeter circle. (sketch>circle>center diameter circle>pop-up box 10mm)
- Make the circle into a cylinder. (create>extrude>choose how long the screw should be)
- Create the thread. (create>thread>click on your cylinder)
- In the thread box to the right, add your parameters. (check the model and make sure the size is 10.0mm)
Internal Thread
We will now make the nut that fits the M10 screw.
- Create another circle that is 10 millimeters. (sketch>circle>center diameter circle>pop-up box 10mm)
- Create a larger circle over the circle you just created. (sketch>circle>center diameter circle>pop-up box 15mm)
- Extrude the outer circle. (create>extrude>about 5mm)
- Create the thread. (create>thread>click on inner circle)
- In the thread box to the right, add your parameters. (check the model and make sure the size is 10.0mm)
