Arduino 3D Wire Bending Machine

In this tutorial  I will show you how I built an Arduino based 3D wire bending machine. This is actually a typical mechatronic system because it involves mechanical, electrical and computer engineering. So therefore I believe many engineering students or anyone who is new into mechatronics found this project interesting.

Overview

Here’s the working principle of this 3D wire bending machine. So first, the wire goes through a series rollers, or straighteners. Using a stepper motor the wire is precisely fed to the wire bending mechanism which also uses a stepper motor as well as a small servo for the bending process.

There’s also another stepper motor, called the Z-axis, which actually enables the machine to create three dimensional forms. Of course, the brain of the machine is an Arduino board which along with the other electronics components is attached on a custom designed PCB.

As for the program, I made few custom functions for making various shapes, like a star, a cube and a simple stand, as well as a manual mode where we can make the wire forms by entering commands through the serial monitor.

DIY 3D Wire Bending Machine 3D Model

As usual, I started by making the project using a 3D modeling software. You can download and the 3D model below.

For some of the parts, like the gears, the bearing pillow blocks and some shaft couplers I used a 3D printer to make them. The STL files of these parts, which are used for 3D printing, can be downloaded from the files above.

My new 3D printer, Creality CR-10, did a great job and printed the parts with great quality. Here’s a link to this 3D printer in case you want to check it out.

Building the Wire Bending Machine

I continued with preparing the other parts, for which I used MDF and plywood. So once I took all dimensions from the 3D model, using a circular saw, I cut the pieces to size. I used 8 mm tick MDF and 18 mm tick plywood. Once I got them ready I started with the assembly. First I made the base out of two MDF plates and 4 plywood columns. For securing them I used a wood glue and some screws.

Next on the top panel I attached the 3D printed bearing pillow blocks using some 8 mm bolts and nuts. We can notice here that I added 3 mm tick MDF plates between the top and the pillow blocks so that I get the proper height. Now in these blocks we can fit the 6202 bearings.

Their outer diameter is 35 mm and the inner diameter is 15 mm. So now, through these bearings, we need to insert a 15 mm hollow shaft so that the wire could pass through it. This shaft is actually the Z-axis, which enables to bending mechanism to rotate around the wire and in that way make three dimensional forms. I used a copper tube for that purpose and its length needs to be around 30 cm.

In between the two bearings I also inserted a 3D printed gear with module of 1.5 and 30 teeth. The gear has custom design slots where we can insert M3 nuts and then using M3 bolts we can tighten the gear to the shaft.

Next we need install the Z-axis stepper motor. For that purpose I 3D printed a custom mounting bracket. So I secured the stepper to the bracket using M3 bolts, and then inserted the 18 teeth gear on the motors shaft. I used the same method for securing the gear to the shaft as shown earlier.

Then using a 6 mm drill I made two holes on the top on which the mounting bracket will be secured. We can notice that the bracket instead of holes, has slots which enables the two gears to be properly paired.

I moved on with installing the stepper motor for the feeder mechanism. This motor will be directly mounted on the top plate, so I drilled the appropriate holes on it. Then using four bolts I secured the stepper to the plate, and in case you wonder what those nuts do here, they actually act as distance nuts because the bolts I had were longer and couldn’t fit into the motors threads.

So now on the shaft of this stepper we need to insert the feeder. For that purpose I 3D printed a custom shaft coupler on which I inserted a copper tube which will actually be the contact surface of the feeder.

Then on the opposite side of the motor I inserted a lever, on which I attached a bearing which will press against the feeder. For getting enough grip so the feeder could move the wire, I will attach a piece of plywood with a T-nut on it, and then using a bolt we will be able control the grip of the feeder.

The next step is making the wire straightening system. Using three M8 bolts I secured a piece of plywood that I previously drilled according to the 3D model. Now on top of it I inserted the rollers. I made the rollers out of bearings and 3D printed grooved outer rings.

Three rollers go on this side, and two rollers on the other side. For the other side I made a slot in the plywood piece so that the bolts stay flush with the piece. Now using just two bolts we can pair the two side, and using the nuts we can tighten the straighteners appropriately.

Once finished with this step, I added two more pieces of plywood in front and after the straighteners which will serve as wire guides.

Ok, so now we can move on with making the wire bending mechanism. First on a piece of MDF we need to attach the bender motor.  Before I did that, the MDF piece that I had needed some shaping, so using a handsaw, a coping saw and a rasp I easily got the desired shape. Then using a 38 mm hole saw I made an opening for the bigger stepper that we will use for the bending, a NEMA 23 stepper motor. Also I drilled some smaller holes needed for attaching the other parts.

I secured the NEMA 23 stepper using M4 bolts and nuts and on its output shaft I attached a gear with module of 2.5 and 18 teeth. This gear will be paired with bigger 30 teeth gear which is a custom designed gear with integrated plate for mounting a MG996R servo. This servo will move a rack and pinion mechanism, which is actually a pin which will pop out of the gear and it will serve for bending the wire. Using a 5 minutes epoxy I secured a bearing onto the gear and also added a piece of copper tube onto the rack which will be the contact surface when bending the wire.

After the epoxy dried out, I paired the two gears by securing the bigger gear in place with a M8 bolt and a nuts. Then I inserted the rack and the servo in placed, and secured it using the screws provided in the servos package. Then I secured the pinion gear onto the round horn of the servo using two M3 bolts and nuts.