Picture of 3D Printed Robot Arm

This robot arm is made almost entirely of 3D printed parts that snap together. It has three servo-controlled joints, plus a rotating base and gripper. The arm is controlled by a series of buttons that connect to an Arduino Uno hidden in the base. A simple circuit makes connecting the servos and buttons to the Arduino easy and makes set-up and assembly very quick.


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Step 1: Print the parts

Picture of Print the parts

The arm is about 20 inches long, so it takes a lot of time and material to print. The parts are sized to fit on the bed of the Afinia H479 printer, and some can be printed together on the same platform to save time. I used a resolution of 0.25mm and hollow fill for all the parts (other settings were set to the defaults). In addition, I found that I needed to use a raft to both help the part adhere to the print platform and help the printer compensate for my table, which was not perfectly level.

The total estimated print time for the arm is about 32.5 hours, although as mentioned earlier some parts can be printed together (the estimate was done using the print preview function of Afinia's software - my actual print time was difficult to calculate because I was still iterating through designs). Including the raft material, it uses 842.8g of filament, which means it can be printed from one 1kg roll.

Most of the parts have "flat" sides that should face the platform (see images). Many of them also have fairly delicate tabs for holding the cables, so take care when you remove the raft and support material. Study the stl file first to get an idea of where the most delicate areas are.

EDIT: I forgot to include one of the parts in the zipfolder, so I added it separately.

kushal2218 days ago

Instead of the power supply, Can I use a LiPo battery?

AkikoTech20 days ago

Total newbie here. Can you please define the following?

  • Various wires and connectors

This is all that i am stuck on. I just don't know exactly what to get so if someone could help point me in the right direction I would be very gratefull

bakhosrahme3 months ago
Can you use stepper motors instead?

Yes you could, but its unnecesarily complicated. With servos you can use direct control, for steppers you would need buttoms or some other way to get the possition, besides, you would need to modify the model for them to fit.

AtrusM1 month ago

This is amazing! I am curious, what software did you use do actually design the arm that you printed? I viewed the video in full-screen with the best resolution, but I could not actually read the application name at the top of the window.

After I follow your tutorial I want to try designing some things of my own!

Beaconsfield (author)  AtrusM1 month ago

Thanks! I designed the arm using Inventor. If you are just getting started with 3D design/CAD I would recommend Autodesk Fusion 360 - I think it's free for students and there are a ton of tutorials available.

BrookeH2 months ago


Great job on this. I am working on printing it out now. If the arm works well, I am planning on using it for another project.

Any chance you would be willing to provide your original design files?

I am using a MakerGear Mendel Prusa to print. I would agree with the other person here that created one of these, there is a lot of filing, sanding, and trimming to do. The issue is that it looks like the fit is real tight on the different tabs and slots. I run into this with my own designs.

With all of the variability in 3D printers out there, even with a fairly well tuned one, I end up designing "slop" into most joints. The tabs and slots work to align the parts for fasteners and/or glue. If possible I use screws/nuts/bolts instead of tabs and slots as well. While the tabs/slots are more convenient in terms of needed hardware on hand, It adds hours of sand-fit-sand-fit-trim-....

I am very impressed with the amount of design effort that must have gone into this.


Beaconsfield (author)  BrookeH1 month ago

Thank you! My goal for this project to use minimal/no fasteners to make a "truly" 3D printed arm. I agree that in general I would use nuts/bolts to make dealing with tolerances easier.

JohnR26 made it!2 months ago

Thanks for the awesome design. I built one using my Printrbot (and it actually works)! I will be using this as part of a 3D printing demo.

A few lessons learned: 1) make sure you calibrate your printer really well before printing any parts. I spent a lot of time sanding and filing to get the parts to fit. I don't think this was the fault of the design. 2) Most of the parts can be press-fit together, but I found super glue (cyanoacrylate) works great to make sure things stay put. 3) At first I thought I had built my parts too heavy, because the stepper motors could not hold up the weight of the arm. The problem was that my power supply didn't put out enough current to drive the steppers. Once I used the 5v output from an old computer power supply, things started working well.

Beaconsfield (author)  JohnR261 month ago

That's awesome! I'm glad you were able to make it work (even with the same colors!). I spent a long time getting the tolerances just right for my printer, but unfortunately every printer is a little different. And the steppers do take a ton of current. Great job!

bakhosrahme3 months ago
Can you use stepper motors instead?
iozenc5 months ago

Excellent work.

-Nate125-6 months ago
How much was the 3d printer? I love making stuff like this! Can the robot arm screw in a light bulb? Keep up the great work!
Beaconsfield (author)  -Nate125-6 months ago

The printer is about $1400 from Radioshack (

The arm can't turn a full 360 degrees, although if you were really good at operating it you could probably get it to re-grip and finish in a few turns. Maybe that will be the goal if I make a version 2...

pixel58 months ago

What software did you use that was shown on the video?

Beaconsfield (author)  pixel58 months ago

I used the software that is included in step 2 - just direct control of the servos using the buttons along the base.

Wow! If I had a 3D printer that would be the first thing that I would make. Would it work to install Sugru on the tips of the claws to enhance grip on objects?
Beaconsfield (author)  KyleTheCreator8 months ago

It definitely would! I spent a while picking up stuff (with varying degrees of success) and Sugru would have helped enormously.

3441851518 months ago

Can you provide source files? I want to make a bigger o'ne

Beaconsfield (author)  3441851518 months ago

There is a zip folder containing all the .stl files (meshes) for the parts at step 1. However, note that if you simply scale up the parts the servos and buttons won't fit. You also may run into issues where the servos aren't strong enough to move the arm anymore.

dka138 months ago
I so need to make this
treyes48 months ago

Just when can I win a 3D printer here in instructables I have created so many models waiting to be printed just like this

kenyer8 months ago

I love your design and color-sceme. Nice job!

It's so cool to see it in action!