If this isn’t your first time seeing a 3D printer, you’ll have probably heard someone say something along the lines of:
1) Buy 3D printer
2) Print another 3D printer
3) Return original 3D printer
Now anyone with a reasonable awareness of the capability of 3D printers and what goes into making one would realise that this is (mostly) a joke.
Now people have proven time and time again that 3D printing the mechanical components of a 3D printer is very much possible, but there's always one thing which still lives in the realm of the joke - electronics.
So I suppose what I have done here is brought this joke one step closer to not being a joke… because my 3D printer can print out circuit boards.
Note: Now if you’re interested in converting your printer into a PCB plotter then this instruction set should be seen more as a guideline of how I managed to make it work for me, so to advise your design choices. Every printer and slicing software are slightly different, so any mounting components will likely require a bit of creative thinking to make it work on your own set up.
Step 1: I Made a Video!
I made a video, just in case reading ain't your thing!
I've never made a video of this scale before but hopefully it does the job.
Otherwise keep scrolling to the written steps!
Step 2: Permanent Markers
I started off by looking for the finest
tipped permanent marker pens I could find. I found these STAEDTLER permanent Lumicolor markers on amazon, for less than £20 at the time, I also found black permanent markers in the related products but I preferred the blue as they had a stated tip width of around 0.4mm.
Permanent markers (Amazon link)
Once the pens arrived, I tested them out on a bit of scrap copper board to see if it would resist the ferric chloride I use as etchant. I found that Sharpie, blue Lumicolor and black Lumicolor all resisted the ferric chloride with little issue.
Step 3: Mounting the Pen to the Printer
The next part was to figure out how to mount the pen to the machine.
I have converted my machine to use the common E3D V6 extruder as the stock extruder packed in and was out of stock for around 7 months, so I was already made quite familiar with the available mounting points on the extruder axis.
I focused on using these two screws which fix the extruder assembly onto the force sensor included on my printer’s extruder carriage.
Some important points that I considered (and in fact, influenced the entire design) was how much force that was going to be applied to the pen tip. The mount needed some vertical movement so that the pen tip isn’t just crushed by the force of the bed pressing into it.
As well as how much wiggle room the pen had in its mount. If the pen has a small amount of wobble either angularly or in X or Y axis, then the drawn lines would be less accurate as the design is plotted, limiting the ultimate precision of the tool.
I have managed to solve both of these problems with a miniature linear rail.
I will be honest, I didn’t buy this thing. I managed to get it by discussing my design with some of my engineer friends when one of them pulled this out of a drawer and donated it to me. I don’t even know how much it would cost if someone wanted to buy one.
This linear rail is precisely machined to the point where I can’t detect any wobble of the rail and is smooth enough that the weight of the pen mount will pull it down under its own weight.
There are always alternatives though, a quick search for “Miniature linear rail” on banggood brought this to surface. It’s a bit long but nothing a Dremel can’t sort out. Other than that the dimensions of the rail seem like a reasonable candidate for the design. Cheap too.
Miniature rail (Banggood)
I then designed the pen mount to hold onto the pen with a snug fit when pressed in, with suitable screw holes in order to mount it to the linear rail and then subsequently to the mounting bracket.
I also quickly mocked up a little bracket to hold the unused extruder assembly. I didn’t want to unplug it as it caused the machine the shut down with sensor errors. Besides, one of the best ways to shorten the life of your electrical connectors is to make and break connections over and over.
Step 4: Tricking Your Printer Into Plotting
By now I had a pen stuck to my machine and I needed to figure out exactly how I was going to trick my machine into drawing pretty pictures for me.
My first thought was relatively simple, design a 3D model and make it one or two layers thick. That way when the machine tries to print the part, it actually makes the pen trace the entire surface area that I had designed. There was a slight issue with this though, as with my standard slicing settings the extruder simply moves over gaps, but with the pen in place, it will leave a line that traces these moves. I dug through my slicer settings and found a Z lift feature used to minimise oozing from leaky extruders.
I set the value to something high enough that the pen tip will be removed from the surface of the part where ‘gaps’
exist in the design.
While I was making my own slicing profile for the plotter I also turned all temperature settings on the extruder and heated bed down to room temperature as heating isn’t necessary in this process.
I changed my nozzle diameter down to 0.3 in the settings to better match my pen tip diameter. I chose a slightly smaller value to ensure that there was overlap in the lines drawn on large infilled areas. It’s possible that this creates an issue where the fresh line of ink redissolves and damages part of the previous line but I haven’t spent a huge amount of time optimising this process and haven’t fully investigated that concern.
With the slicing profiles set, I proceeded to test the plotter on some paper, then some scrap copper board I had laying around to iron out the kinks in the plotting.
But to summarise the important bits:
> LIFT Z (set to like 5mm +)
> Temperatures set low (otherwise youll heat your bed and extruder for nothing)
> Change nozzle diameter at your discretion (smaller value, higher plot resolution... until a point)
Step 5: Position Your Plot
The position of your plot is quite important when using your soon to be plotter.
We need to know where the machine is going to start drawing our plot and place our copper clad board in that position. To do this I follow a few simple steps:
1) Make a square that is the same size (or slightly larger) than your plot
2) Choose a location for it in your slicing software, if you have a grid that helps otherwise use fixed x/y coordinates
3) Plot the square onto the print bed (might want to cover it with paper or tape when doing this)
4) Position and secure your copper clad board to the print bed using the plotted square as a guide
5) Position your true plot in the same position as your square guide plot
6) Hope youve done it right and start plotting! (dry runs are advisable if you are unsure on your accuracy)
Step 6: Plot Your PCB!
So the next few things to do is iron out any kinks in the plot setting or your pen mount, check for defects and when you have the time try to adjust your set up to eliminate them.
But honestly, we're more or less done. If your plot comes off of the printer cleanly then you may want to inspect your traces and fill in any holes or cut any shorts left behind in the pen ink by hand.
The great thing is once this process is tuned it is clean, safe and relatively quick. Any mistakes are normally followed by some acetone, wirewool and then resticking to the bed for another crack at it.
Step 7: Etch Your PCB!
Now this is not an etching tutorial, so I am hoping that you know how this part goes.
I grabbed the relevant PPE and my favourite etchant - Ferric Chloride. "Favourite" just because that's all I've used.
Dropped the board in a tub, poured on the etchant and shook it about a bit for around 30mins (I did the etch cold, would have been quicker warm).
The output can be seen in the images above. All in all, not too bad if I do say so myself.
I tried to be as honest as possible in displaying defects in the etch, just to show that I have found a method, but not the method. I'm sure there is a ton of fine tuning to be done to get this process up to the next level.
The ink does resist the etchant very well but does seem to break down where it is thinner.
Personally I like to leave the ink on the PCB after etching as a form of silk screen, and it does shift when you go to solder your boards!
I have noticed that the ink as resist only seems to work on copper and brass (I've only had success here) but did not work on steel. I think it's possibly due to the copper content, but honestly I don't know.
Tell me what you think and if you have any questions let me know. I appreciate that this isn't a Lego grade instruction set.