Additive Wire-Laying

After making my machine suited for the "Velocity Extruding" I wanted to go one step further in using Additive Manufacturing. I recently tested printing over a copper wire, and since I've had this idea for a long time I needed to get it out of my head.

The basic idea is that there should be a slew-ring rotating in the direction of the movement. This rotation will put a wire always right in front of the nozzle, just before being covered with plastic. Then you'd be able to manufacture PCB's in an additive way. You lay the wire (or equivalent) where you need one. strange shaped coils? RFID/NFC antennae?


I have bought a BeBoPr-Bridge a while ago, and when I met Bas Laarhoven (another Bas) the maker of the BeBoPr, he pointed me to the already available expansion for a fifth axis. The BeBoPr can be expanded with the "PEPPER" which are in fact 5 stepper drivers on one board, current adjustable via software, and also decay mode depending on the activity. That means when the machine is idle, the current in the motor is lowered so the friggin noise is less. One problem, I didn't have one at the moment.

First thought was that I could access the pins for the PEPPER and add an external stepper driver. There was one problem, and that was that the already mounted stepper drivers needed to have the "enabled" pin removed, since those signals were used for the STP and DIR pf the fifth motor. (I actually got this info from Bas-L. Below is the quick version, in real life it took a little more time).

See picture below, I bent one pin of a 8 way header, and routed the enable pin from the stepper driver to my breadboard to enable later on:


The addition of this header in between elevates the stepper driver so that there now is room at the J5 connector to connect wires.


Below is the end result. Wires from the enable pins on the stepper drivers, as well as the ENABLE pin, B_DIR pin and B_STP pin (J5.15, J5.4 and J5.5) going out at the right of the picture.

IMG_0514Now the 5th stepper driver is wired, I needed 12V, 5V and GND and looked at the bottom side of the board. It's all there.


Last but certainly not least, the wired breadboard.


This was the electronically hardware part, The mechanical hardware part was also quickly finished, at least with the normal engineering iterations. Last point on the list was getting the slew ring to rotate in the direction of the movement.

For this the direction of travel is needed. Since I have a linear delta machine, I cannot take the positions of the towers (joints) since they are not the actual x, y and z (cartesian) coordinates.

Turned out that the HAL pins I needed from Machinekit/linuxCNC did not exist, at least the reading of x, y and z position is in a branch that has yet to be merged, and I decided not to wait for that. So I took the calculation of the x-y-z position from the kinematics file and put it in a component I can then use in my HAL file. Not the most refined way, but speed is paramount.

This component produces x-y-z coordinates, That position gets a derivative (speed) and is fed into a component that calculates the angle of movement with respect to the positive x-axis. That in turn is used for generating a position command for the slew drive.

See it in action?

As you can see, there needs to be more functionality, cutting of the wire, connecting the wire to components, homing, fine-tuning etc. But that are just "details" and with time and engineering those issues can be solved.

I hope it's some use to you. Don't hold me accountable for the machine you make. Before you can easily make things with this there needs to be some new kind of software, but that's not something on my list for the near future, because that will take up too much of my time for now.

Special thanks to Bas-L, Machinekit user list and EMC user list.

I release this idea under the CERN OHL 1.2 licence. I need to clean up the code and the 3D models, but once done I'll do a pull request for Machinekit, and put the CAD models somewhere for download. I'll update this post when I do.

If you have applications or ideas you can use with this or other technology, publish them and generate prior art. Keep that technology free to use and share so the bad companies can't patent all the logical and sensible things and prevent you using it, now or in the future.

Example applications:

  • Coils
  • Antenna's
  • PCB's
  • Flexible PCB's (FPC's)
  • embed tubes and other filament types into plastic or other materials, like starch, organic printable stuff etc. etc.
  • Use dissolvable PVA as an intermediate to bring wire/chips into tissue
  • Please elaborate in the comments.