Everyone knows that getting your first layer right is 90% of the battle to getting a successful 3D print. Even if your temperatures and everything else are correct, if your nozzle height is off you will get bad adhesion on the first layer.
Setting it up is actually pretty simple, but it can be confusing. In this video I explain, in very deep detail, what all the parameters and settings do that control nozzle height on your first layer so that you can get perfect first layers. In this video I am using a Cartesian style machine, a Prusa i3 MK2, and Marlin as the firmware – but the principles will remain constant for most printing systems.
After banging on about it for months, I finally get around to trying ABS filament on my DIY Prusa. I heard lots of bad things about trying to print ABS, especially without an enclosure, so I was ready for the worst. Expectations were set low 😉
In this video I go through, in quite a lot of detail (!), my initial slicer settings, run some test prints and think about the results….
Really the only part of my Prusa i3 MK2 clone build that didn’t function as it should out of the box was the LCD Module with builtin SD card reader, rotary encoder, buzzer and stop button.
In this video I discuss how I tracked down the issues and fixed them. I also changed the ribbon cables for shielded cables as I needed them for how I was mounting the module – but it also assisted with preventing corruption.
The model I have is pictured below and its full title is a Bigtreetech RepRapDiscount Full Graphic Smart Controller.
Bigtreetech LCD Module, RepRapDiscount Full Graphic Smart Controller
During my trawling of the internet trying to find specific data for this LCD, (which I didn’t..) I used information from the documents below to build my own schematics, which are at the bottom of this post.
For anyone wishing to tear apart an HDMI cable to use as a shielded cable to the LCD Module, here is a pin diagram for a standard HDMI cable. (Although that isn’t much use as we are only using it as a general shielded multi-core cable! A decent HDMI cable has 7 single cores, and 4 twisted pairs inside their own separate shielding. This gives us 15 conductors, ignoring the shielding. The one I chose also had a metal braided wrap around the whole thing – I earthed them all to building earth)
I discuss in the video how to arrive at these delays (noops), but below is how I finally set them to avoid corruption of the LCD. I have inserted these 3 lines into my Configuration.h file.
Finally the schematics I drew up after confirming all the routing of wires from Arduino, through RAMPS, through connectors and into the various parts on the Bigtreetech LCD module.
Bigtreetech 128×64 LCD for RAMPS Schematic
RAMPS Aux3 Aux4 LCD Adapter Schematic with Arduino Pins
Continuing with my mission this week to actually finish the electrics on my DIY Prusa i3 MK2 3D Printer, in this video I make some modifications to the RAMPS board and the Arduino.
On the RAMPS I need to remove the 4 pin power connector. Now that the RAMPS board is not carrying the current to the heated bed it isn’t really a safety issue (although it might be if yours is carrying heated bed power…) but it just simply takes up too much space for how I want to mount it. And a soldered connection is more reliable that a connector, well usually!
I am also junking the polyfuses. Again not so much a safety issue now as there is only a little current going through them, but even so the 5 Amp one still feeds everything apart from the heated bed so they have to go. Replacing them with a simple blade fuse holder and fuses – you know,  like off of cars n stuff 🙂
In the last video I created a separate MOSFET board to handle power to the heated bed. The gate of the MOSFET is driven high by pin D8 of the Arduino, so I also add a signal wire from D8 that can then attach to my off-board MOSFET.
Lastly, I remove the DC jack on the Arduino. It isn’t being used or causing any issues, but I just don’t like it… well no, it got in the way of my board mounts.
That just leaves fixing the corrupted garbage that appears on the LCD after a couple of minutes. After quite a lot of time spent (more than quite a lot..), I have fixed it. That will be the subject of my next video.
I have changed my mind a few times about how I plan to finish off my Prusa i3 MK2 clone 3D printer… but now I have settled on a plan! None of it was particularly complicated, but I just want to arrange things in such a way that they are safe, tidy and give me the best result.
As I plan to add a physical brace to the Z Axis frame, IÂ want to combine that with a suitable housing for all the electronics. With the actual brace made I can start finishing off the electronics!!!
There are few items I want to do:-
Fix the issues with LCD corruption – presumably cause by electrical noise
Remove the Polyfuses and provide alternative
Integrate the Raspberry Pi in with the other electronics so it is a permanent feature on the printer, including power
Add in additional temp sensors to the electronics and power supplies that will kill the power if anything looks dodgy
Power the Heated Bed with 24V instead of 12V – but keep this 24V separate from the RAMPS board
The last of these is the item I am doing first – and it the subject of this video.
Below is my rough schematic showing how I will wire the RAMPS, Arduino and also a small external board that will perform the heated bed power switching. Beneath that the calculations I made to conclude that the AUIRFB8409 Mosfet would work fine:
Rough Schematic of an external board to switch power to the 24V heated bed, showing relevant parts of the RAMPS and Arduino
Main considerations in choosing the AUIRFB8049 Mosfet, with calculations
Well after the failure of the first print I was kind of pleased!!! Until it failed it was printing way better than I had expected for a first print.
There were a few issues, as well as the failure of course, to take care of. So I had a close look at what didn’t work, print quality and the cause of the failure.
The Heated Bed is heating up very slowly and struggles to maintain temperature
When the G Code is loaded from Slic3r and the print button is pressed, nothing happens.
There were a few sections of a couple of layers missing – and of course it ended missing layer(s) altogether which led to the failure
I come up with fixes to all these issues and try to print 3D Benchy for a second time….
In this video I finally get to make the first print… I know how it turned out but you will have to watch to see 😉
Before the printing fun could begin, I needed to take care of some minor things, and one slightly more important thing – the power supply for the heated bed!
For the moment all power for the printer is temporary so I make use of a 12v power supply that I already had. It doesn’t have the output to deliver power to all, but it should take care of the heated bed and I will continue to use the lab supply for the rest.
I also made a few final (before first print!!) changes to Configuration.h and slice up the model using the Prusa version of Slic3r that you can download here. (Also contains the version of Pronterface I am using).
If you want to see how my Configutation.h looks at this stage – grab it here .
I power on the printer for the first time and set up the Limit Switches, Axis Movement, End Stops, Bed Extents, Bed Levelling, Z Probe/Bed Sensor and do the Extruder Calibration!
I spent quite some time going through the Marlin documentation to see what each possible configuration instruction could do. I had already done a very basic run through of the Configuration.h file in this video/post but now it was time to get it spot on.
One side benefit of the exercise is that I can see I will need to change the way I mount the heated bed. Most importantly the nyloc nuts sitting on top reduce the Y axis extents by nearly 25%!!!!. But secondly the ply wood under the bed allows the nuts to squash the edges down too much, resulting in the opposite bed bend to that I had before! Still, good enough for a first print 😉
So before getting all carried away and wiring in the Arduino and RAMPS I thought it might be a good idea to make sure the Arduino actually works!
As I already work with Arduinos, I have the Arduino IDE installed. If you don’t you can go and grab it from here.
I uploaded a simple blinky sketch and all looks good so I also create a short sketch to wipe all data, if any, lurking in the EEPROM. Just in case it later confuses Marlin.
After downloading the latest version of Marlin I spent quite some time going through the configuration.h sketch file making some basic changes for an initial start up. If anyone is interested in a copy of that, you can download it here. (You might want to change it so my name doesn’t show up on your printer’s LCD all the time!!)
There are a lot of resources on the internet for the configuration of Marlin, here are the main ones I used:-
I double checked to make sure I still had the u8glib library installed in the IDE, which I did, but if you don’t you can get it here or install via the Library manager.
After I was somewhat sure the firmware config was about right for an initial startup, I compiled it and uploaded it to the Mega clone. All seemed good!!!
