Incorporating Screw Threads into Fused Deposition Modeling Parts

Incorporating Screw Threads into Fused Deposition Modeling PartsIncorporating Screw Threads Into FDM Parts
Screw threads are one of the most common components used for fastening parts in an assembly or attaching pipe tubing together. Here are five ways to incorporate screw threads into Fused Deposition Modeling parts, followed by some useful applications.

Threads directly from the FDM machine
Depending on the pitch and helical profile, it may be possible to design your desired thread right into the CAD file. Typically, large pitched threads on parts used for functional prototyping or fit testing can come right from the FDM machine, as long as the forces they experience are relatively low.

Drilling and tapping
Taps can be created in FDM parts by drilling and tapping a hole either directly into the center of the raster fill, or into a designated area made just for this post-process. I suggest bulking up the drilling area so it mimics a solid block of plastic; threads will hold together better throughout the layers.

Heli-coil inserts
Heli-coil inserts provide a sturdy alternative to the methods above. They’re great at dispersing the extra stress brought on by the standard tapered pipe thread and provide a good medium to seal other standard pipe components to when sealing is important.

Heat stakes or ultrasonic weld inserts
These inserts come in various shapes and sizes, and with features that protect against pull-out or spin-out failures. Using energy, these inserts are melted into the plastic, which forms a solid block around the insert, adding strength and durability. These are the preferred methods of creating screw threads in FDM parts.

Press-fit inserts
Press-fit inserts are easy to install and are good for tensile loads. They can withstand some torsional loads, but tend to spin out at high torsional stresses. The first three methods are great ways to increase functionality of FDM parts, especially for rapid prototyping. They can help analyze designs and determine the points of largest stress.

For digital manufacturing, the benefits of inserts become apparent. Since some high-performance inserts include a taper and require a customized bit for production, FDM becomes a great bridge-to-tooling and low-volume-production asset.

When a part requires a particular thread and a few types of inserts must be tested before going to production, the ability to adjust the pilot hole on the fly becomes valuable. Instead of making multiple specialized bits to test many inserts, create the pilot hole directly on the FDM machine and test with values that mimic those of injection molded parts. This will prove cost-effective after multiple design iterations.

It’s worth noting that the study of how inserts perform in FDM parts is ongoing. As more and more users across industries experiment with inserts, I’d love to hear about your experiences.

Comments

  1. My 2 adult children have studied 3D animation. I have been a computer user since 1993, and today decide to 3D print, with .STL and .OBJ thanks to printm3d.com MICRO

    I plan to use demo 3 month tryals, and a drive(HDD) image to reset the date of pc every 3 months... Still realising internet is needed for most advanced programmin and assembling of different file formats and object parts across many software for project results ( one of many as I learn for the first time)

    first being able to be offline ( cost of data without starting from scratch) I pay 4oo Kbps / h 5$ for 200 mb. The printer and delivery fine tech specs of printable area fine.

    Projects like 48" B17 balsa parts, electronic and mechanical control of vertical blinds , mechanised tank in scenery maybe a robotic house dog by end of year, one 13$ spool at a time + electronics programming (eprom flaching with cobol 0art zuma/part ibot or some to'ys heart/brain's) maybe even remote control 8 cervo including IR /gyroscopes/ laser pointer room recognition, switch articulated sensort for a bobcat house sweeper that gets the dust above baseboards (automatically) most fragments are there suffice modify by 1o % for copy wright issues.

    Let me start by modifying one .Stl ring, to add 2mm thread in the object (lots of reading for me to come)

    This is a test as a watchmaker I have the real life tap, and must test printer. By what I collected, many formats in many languages asside english for the arboressence/win 8 file naming tree, many parts as a printing package, where I have to modify accel diametres all in abs, and add, hollow points for weight, (miniaturise for practicality), metal incerpts and make tooling for miniaturised applications.

    Wish me luck so far all I need is in my computer for a total of 1.58gigs, and now the chematics / 3D renderred parts need to be specific to my need ( am capable as a watchmaker). Lots of books as formats collected in 3 user languages (spoken)=character set imports win8... And .sldprt .sldasm .dwg .catpart .catproduct .ipt .iam .igs .step .scad .cgr .stp (printer can do stl and obj)
    To start reading about a single tap thread path standard filet travel path, print screw, modify ring screw insertion point to later refine with tap.
    As can I do this project with arduinos...

    Electronics and programming for assembly on proto board seem str8 forward (beyond copy wright), most stuff I've seen in my life is ancient so printing miniature tools weee.

    My favorit abs spool color green less hard to look at ;)

  2. Wow printing assembled parts!!!

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