Tapping into 3D Printed Parts

[KohKohPuffs]

Thinking about making a custom, 3D-printed part. However, it would require making a thread (6-32 or 8-32, I can't remember off the top of my head).

Anyways, would this be a feasible task? I know that delrin can be threaded into, and like the filament used in 3D printers, delrin is made of plastic. If this is something that can be done, what filament was used, and with what print settings?

Thanks

[pilleya]

Originally Posted by KohKohPuffs

I know that delrin can be threaded into, and like the filament used in 3D printers, delrin is made of plastic. If this is something that can be done, what filament was used, and with what print settings?

Delrin is an entirely different material to PLA or ABS and is much easier to machine and is supremely stronger, and would definitely be capable of holding a thread. Delrin is known as an "engineering plastic" for these reasons.

I think it is important to make the distinction between an "engineering plastic" and a material like PLA or ABS.

In regards to tapping a thread into 3D printed material, I don't think that the type of plastic is the issue, it is more method of printing. A printer that uses PLA or ABS prints in layers, meaning that these layers are points of weakness, the thread would have to go through these layers and would be reliant on these for strength. If a part is 3d printed with the hole that is going to be tapped already on the model, there will be concentric circle infill around this and this is the major point of weakness. Ideally the thread and print head nozzle diameter, would have to be selected to ensure that the edge of the thread was not a the point where two of the concentric circles join.

I think it could be feasible, but it would most likely be unsuitable for a high stress/load component.

What you could do is design the component in such as way, that you can use a nut embedded in the print to hold the thread. Make a nut shaped/sized hidden void in the middle of the print. Just before the printer, starts to make the lid of the void, pause the print and place a nut into void. It will then print over the nut and enclose it inside the print

[artdutra04]

Unless you are looking to use a very course thread, don't tap into the 3D printed part directly. Instead, use threaded inserts such as Helicoils:
http://www.mcmaster.com/#helicoils

I've used Helicoils before in FDM 3D printed parts with good success.

[Fusion_Clint]

Depends on your printer, some may even be able to print the threads for you.

If you plan on drilling and tapping, you have to make sure the hole placement will have enough "stuff" for you to tap the threads into. As most 3D printers, use some form of internal honeycombing technique on the parts to conserve filament.

If the part is designed right what you ask is possible, however you must consider if the materiel your 3D printer uses is strong enough for the task.

[Roboshant]

I don't know how good of an idea this is for a 3d printed plastic part but: Make a hole in the 3d printed part from one side that is the size of the outside of a nut that matches the size you need (in the CAD file of the part itself), or just make a circular hole the size of the diameter of the nut. After this is done secure it in place using epoxy or other methods (3d print over it lol). This would mimic tapping it, although I have absolutely no Idea how well it would work (might be worth trying). I now this is completely anecdotal evidence but, I did this on a wood part for a non-FRC related project and it seemed to hold up pretty good. Good luck!

[KohKohPuffs]

Originally Posted by pilleya

Delrin is an entirely different material to PLA or ABS and is much easier to machine and is supremely stronger, and would definitely be capable of holding a thread. Delrin is known as an "engineering plastic" for these reasons.

I think it is important to make the distinction between an "engineering plastic" and a material like PLA or ABS.

In regards to tapping a thread into 3D printed material, I don't think that the type of plastic is the issue, it is more method of printing. A printer that uses PLA or ABS prints in layers, meaning that these layers are points of weakness, the thread would have to go through these layers and would be reliant on these for strength. If a part is 3d printed with the hole that is going to be tapped already on the model, there will be concentric circle infill around this and this is the major point of weakness. Ideally the thread and print head nozzle diameter, would have to be selected to ensure that the edge of the thread was not a the point where two of the concentric circles join.

I think it could be feasible, but it would most likely be unsuitable for a high stress/load component.

What you could do is design the component in such as way, that you can use a nut embedded in the print to hold the thread. Make a nut shaped/sized hidden void in the middle of the print. Just before the printer, starts to make the lid of the void, pause the print and place a nut into void. It will then print over the nut and enclose it inside the print

Oh wait, I didn't mean 3d printing the thread. I meant making the 3d printed part, then using a tap/die set to make the threads.

Of course, the layers are going to be an issue with this, but if this is possible, then I got access to at least 3 or 4 3d printers with the part I'm thinking about

[IronicDeadBird]

Originally Posted by KohKohPuffs

Thinking about making a custom, 3D-printed part. However, it would require making a thread (6-32 or 8-32, I can't remember off the top of my head).

Anyways, would this be a feasible task? I know that delrin can be threaded into, and like the filament used in 3D printers, delrin is made of plastic. If this is something that can be done, what filament was used, and with what print settings?

Thanks

What are you planning on doing with said part if you don't mind me asking?

[KohKohPuffs]

Originally Posted by IronicDeadBird

What are you planning on doing with said part if you don't mind me asking?

My team has a tradition for keeping things secret, but I will say that this is going to be interacting with a piston from FESTO, which has around 55-58 lbs of force. At this point, it's dependent on how strong the part is going to be.

[mwmac]

Last year we used brass threaded inserts that we installed using a soldering iron to heat the insert and press into place in the 3D printed part. Worked well for us...

[IronicDeadBird]

Originally Posted by KohKohPuffs

My team has a tradition for keeping things secret, but I will say that this is going to be interacting with a piston from FESTO, which has around 55-58 lbs of force. At this point, it's dependent on how strong the part is going to be.

What kind of printer are you using?

[pilleya]

Originally Posted by KohKohPuffs

Oh wait, I didn't mean 3d printing the thread. I meant making the 3d printed part, then using a tap/die set to make the threads.

Although rather impractical, 3D printing can work for printing threads as long as they are reasonably large. I obviously wouldn't suggest using them for anything that requires strength, but for securing motor controllers etc, 3D printed nuts and bolts could make a lightweight replacement for steel (Or just use zipties and double sided tape!)

I built my own 3D printer a few years ago, so I often print quite pointless things, such as nuts and bolts.

http://imgur.com/rCDYqYE

[Nate Laverdure]

On our 2015 robot, the big yellow gear is an FDMed ABS plastic part with a tapped hole used for a set screw. Here's another. These parts were modeled with holes sized for 75% thread, printed with 2-3 shell layers and 20-30% infill, and carefully tapped. Worked fine for this extremely low-load application.

Originally Posted by pilleya

I think it is important to make the distinction between an "engineering plastic" and a material like PLA or ABS.

This resource is great for understanding the distinction between types and grades of plastics. Hangs in my office.

[pilleya]

Originally Posted by KohKohPuffs

interacting with a piston from FESTO, which has around 55-58 lbs of force. At this point, it's dependent on how strong the part is going to be.

If used as a rod end, I don't really think a 3D printed part will work, because all the force, is trying to pull the thread out the the 3D printed part, the chance of success is dependent on how long the thread is.

[MrBasse]

Could you run a hex hole in the opposite side of your part and then place a nut in that hole? We used this for a camera mount where the nut was press fit into a hole and it allowed the bolt to thread through from the other side.

[sdangelo]

My team did this with PLA for a part that supports the entire weight of our FTC robot (~12 lbs) over four screws that are roughly that size. It's been working just fine for us, but we don't have nearly as much force on it as you intend to. It was printed on a Makerbot Replicator 2x and I think we used the standard settings for temperature and layer height, but we increased the infill to maybe 20 or 30% and the number of shells to 3. I think the infill won't really matter for tapping something; the number of shells is going to determine the thickness of the plastic around the holes that you want to tap.

Here's a picture of the part with the screws in it. Our mountain-climbing mechanism goes on the top and the bottom attaches to our robot's bellypan.
https://drive.google.com/file/d/0Bzk...ew?usp=sharing