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Multi-tool circuit printer

An open source circuit board printer based on the Jubilee multihead motion platform

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My aim with this project is to create a printer that will print circuits as easily as a 3D printer creates mechanical objects

Goal 1:
Get an extruder working to extruder silver paste with manual Z axis zeroing

Goal 2:
Finesse gerber conversion to g-code

Goal 3:
Automatic XYZ zeroing

Goal 4:
Visual inspection of printed traces with OpenCV on a Jetson Nano

Goals

The goal of a circuit printer has been something I have wanted to do for a while. The commercial company Voltera.io has something similar, but their system is not open source and has a rather small bed area. I am making something similar with a more open set of hardware. 

My background is in printed electronics, and it also is my current day job so I have quite a bit of experience in this area. 

Requirements: 

In order to connect to most microcontrollers, we need to print traces that are capable of ~100-150um separations. This requires:

1. An ink with a highly consistent particle size, 

2. A dispensing method precise enough and capable of 50-100 psi pressures

3. A motion system with a Z axis that can account do sub-30 micron precision. 

The last point is important since extrusion dispensing consistency is highly reliant on having a very consistent distance between the syringe tip and the substrate. 

I'm currently evaluating a few options for the extrusion that are open source, I'll keep posting as I get them tested..

Potential future goals: 

Pick and place

  • Lights and picamera added to toolhead

    Nathan01/02/2021 at 00:39 0 comments

    I'm on a tear this week. 

    Things I did  yesterday and today: 

    • Added a downward facing camera for alignment of the printhead to the camera. This allows registered prints. 
    • Added a flex cable holder for the camera cable 
    • Added lights to the side and hooked up to the tool-changer
    • Hooked up a Jetson Nano to the case back for image processing

    A photo with the lights, but without the camera ribbon cable guide installed. 

  • First print with the time-pressure dispense method

    Nathan01/01/2021 at 00:35 2 comments

    I'm slowly but surely working my way up to silver ink printing. I was able to print another set of lines using time-pressure dispensing. This method involves using pressure from an air pump to dispense the conductive material. The main drawback of time-pressure dispensing is the associated tools - it requires an air pump. The current design I would prefer to use is the stepper extrusion method which uses a stepper-driven plunger to extrude the ink. This method requires a way to retract the plunger to a specific point after printing is finished however, which I have yet to work out. Stall detection perhaps? 

  • First prints!

    Nathan12/30/2020 at 00:51 0 comments

    I was finally able to hit a big milestone, the first successful prints. I printed a series of lines across the sheet. 

    For my first prints I used a 150um tip. I'm currently testing extrusion and retraction distances. 

    Going to need a way to filter out the fumes from curing, as well as a way to get mesh bed leveling working and auto Z height compensation. Right now it's manual, and the bed is so even that I'm not seeing any issues, which speaks a lot about the E3D's mechanical design. On the other hand I did have to almost immediately fix the Z endstop, just like on the Jubilee. Those endstop switches break if you look at them the wrong way. 

    I still have more work to dial in the retraction settings. I'm also considering a time-pressure method of extrusion, but that would require a compressor, so I'm going to hold off for now. 

  • Update on the extruder development

    Nathan12/07/2020 at 01:13 0 comments

    So it's been a while since I've put an update on here, but I have been busy. 

    I made about three revisions of the paste extruder, that all use a luer lock syringe to hold the ink, and a stepper motor and M3 screw for the linear motion. 

    I'm in the process of working on getting the z zeroing to work. The luer-lock tip has to be re-zeroed after each changeout, and the Z deviation the traces can stand is in the range of below 50 microns, ideally 20microns. 

  • Toolchanger carriage redesign for a BLTouch

    Nathan03/22/2020 at 01:57 0 comments

    After testing the Z zero and seeing the compensation was not precise enough with a limit switch, I redesigned the limit switch to hold a BLTouch. Made a mistake on the first one, so had to redesign, didn't allow for the screw height in the first version. Tried to take a shortcut by not adding all the hardware and finishing the modeling and it costed me a few hours, and a second print. 

  • Z zero variance testing

    Nathan03/20/2020 at 16:24 0 comments

    Fixed the Z zeroing issue, but looks like my temporary Z sensor - a limit switch - is nowhere near precise enough, it varies by ~1mm after probing. I've been a bit busy the last two days building a jubilee for a co-worker, but waiting on a part to come in so I'll focus more on extrusion and getting the BL-Touch working this weekend. 

  • First successful toolchange

    Nathan03/16/2020 at 15:47 0 comments

    Success! I have mounted a syringe onto a tool mount and demonstrated a successful toolchange with the syringe mounted. Turns out the steps/mm was incorrect, and I had to disable checking the extruder heater status to get the toolchange to work, but after some help from the Jubilee discord channel I got it working. Now time to test the syringe dispensing. 

    I also need to verify the Z zeroing is consistent enough to maintain a consistent height above, hoping to do that soon this week. I bought some acrylic inks with a similar viscosity as the silver ink I'm planning on using when everything is working.

    Still have a few issues: 

    1. The bed leveling route is compensating the opposite way it is supposed to and is increasing the bed angle instead of decreasing it, might be just due to the motors being switched. 
    2. Also need to add another Z zero sensor onto the toolchange carriage instead of the tool. The original sensor broke the second time I used it so I had to improvise. 
    3. The syringe does not work backwards, and it not very precise. I need to modify the syringe design.

  • Syringe mount design finished

    Nathan03/13/2020 at 15:00 0 comments

    A few updates, I've gotten a few things done: 

    1. Fixed the Z zeroing - modified the bed.g file

    2. Changed the tool mount to be smaller & shorter. Printed successfully and assembled (left) shown next to the original (right)

    3. Designed and printed a 5cc syringe adapter - press fit, and the top portion is just slightly too big but it's really close. Also made an adapter for makerbeam that screws onto the detachable plate.

    Printed parts

    Mount with syringe

    Syringe on the tool plate 

    Mounted and ready for a toolchange

  • Jubilee Z zeroing test

    Nathan03/12/2020 at 15:29 0 comments

    I tested the Z zeroing with the sensor in a different location - I mounted it on the tool instead of the tool mount. Looks like I need to change the Z zero points. Also not sure how I'm going to zero the syringe in the end, was thinking maybe a piezo touch plate? I'm open to ideas if anyone has any, but for now it will probably be a piezo or maybe a contact switch that only requires a light pressure.

    Still haven't been able to get the BLTouch working yet mostly due to a lack of time, I'm focusing on the extruder now. 

    Also - still working on getting the toolchanging working. The jubilee has a torque based toolchanger, and I found an issue where the locking is failing because the torque is too low, so I have had to reprint the v-groove locking plate a few times.

  • Extruder choices

    Nathan03/04/2020 at 21:30 0 comments

    I've looked at a few choices for the extruder, the one I built first isn't going to work. Looks like I'm going to need the syringe to be held in place better, this design seems to be better for less precise designs, maybe for larger volumes that don't have to be as precise. 

    Ystruder - looks promising, but a little more than I need, includes a force sensor and control electronics. Might do this later on if I need feedback on the pressure

    https://www.sciencedirect.com/science/article/pii/S2468067219300471

    Open source syringe pump - I've printed a few parts to this one already but they aren't quite exact enough so I"ll need to adjust the designs and reprint. I like that it supports different syringe volumes. 

    https://www.appropedia.org/Open-source_syringe_pump

    Also bought a pneumatic solenoid valve that I'm going to test, it's the most similar to systems I've used before. Should be able to handle the highest viscosity fluids in my experience. Might be a little harder to integrate into an existing print workflow, and also requires a pump so it's not as cheap. 

    https://www.amazon.com/gp/product/B07SJFV7S3/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

    Any suggestions from the community? Previous similar projects that used precision syringe extrusion? 

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Discussions

Dan Maloney wrote 03/02/2020 at 17:49 point

What does the extruder dispense the silver past onto?

  Are you sure? yes | no

Nathan wrote 03/02/2020 at 18:23 point

The current plan is Kapton and PET, but I will run some tests on fr4 first since that is easier to zero the z axis on. Has to withstand cure temps of ~150C

  Are you sure? yes | no

Jarrett wrote 03/03/2020 at 03:06 point

Glass would be cool

  Are you sure? yes | no

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