Its been awhile. I have a few projects I am working on now but taking my good ol' time. The one I would like to build using the Raspberry Pi utilizes the 7 segment display from Adafruit. I think they look really well on any project and are really easy to use.
This has the I2C backpack and they have a great tutorial on using them. Only need 4 connections and you'll be up and running.
+3.3V, GND, SData, SClock
The other project I did has a lot of design work and I am starting to acquire and build the parts, pretty excited and I'll be posting on that in the near future. Uses some strain gages with an Arduino.
I had an interesting failure the other week. I use a 12 Volt battery pack to power some steppers when I am developing a project. At some point the positive and negative lead touched and the next time I went to use it, the end terminals on the pack had melted through the plastic. I decided to upgrade myself to converting an ATX power supply into a bench top power supply to supply +3.3, +5.5, +12 and -12 volts.
There are a bunch of references for building them. First thing I did was find a supply laying around I could use. You can reference the diagram below for the color coding of the ATX supplies.
The same color lines should be soldered together for wiring the supply to get the max amount of current the supply can provide. Once you get the ground and voltage wires together you are a left with a few others. My supply did not have a -5 V. The BROWN wire is the +3.3V sense with needs to be tied in with the +3.3V line. The GREEN wire is soldered to the switch on my supply. The PURPLE wire attaches to the red LED and the GRAY wire attaches to the green LED.
The schematic would be as follows. I did not utilize the fuses in line. The resistors are required for the LEDs and I bought a round switch. Wiring for all other components is correct. I used 2 5 Watt resistors in series in place of the one 10 Watt. Some supplies require an initial load in order to turn on.
I had difficulty using binder posts with the amount of ground wires my supply had. I decided to not utilize all of them as most of the things I will use my supply for do not draw a significant amount of current.
I used a project box from Radioshack and layed out what I wanted my box to look like.
I cut the project box out using a template and installed all the components. I soldered all the wires to the appropriate place and still need to create labels. It is important to heat shrink all the wires so the do not contact at any mount.
The red led will turn on when the ATX supply is plugged in. The green led will signify the switch is turned on, supplying power to the rails. Everything worked great and I was very pleased with how everything turned out.
Quick answer to if the cooling fan made a difference is yes. I made the famous octopus yesterday and it was the first time I had consistent extrusion throughout the print.
Clean octopus print from utilizing my cooling fan
I can't really think of a con to adding a cooling fan to your hot head. Even if you don't have issues majority of the time. The plastic stays cooled higher above the nozzle so
I did not get the extrusion issues on my hob bolt with material getting soft
The plastic is melted only at the nozzle so it makes it less "stringy" and I had cleaner lines and layers
Possibly prevent ever overheating (flow is pretty low though)
I have not tried with ABS but this helped my PLA prints. Originally I was a little worried it would cool too much and the resistor would not keep up but my mount is high enough it does not flow over the metal nozzle and there were no issues at all. Overall I say a small $ for the benefits. The fan only costed me about $3-4 and I had rest of material laying around.
One recommendation to me was when printing PLA add a cooling fan to the black section of my hot end. I've had a only a few instances now where my extruder had spotty performance. One instance there was a bulge in my filament that could not go through the diameter. This required an additional disassembly of my extruder. It is my understanding the heat can conduct up the filament and get soft near the hob bolt. To avoid this I purchased a small 40x40 mm fan to provide cooling over the PEEK material of my J-head. Makerfarm recently came out with a new extruder but I have the "older" model so I had no holes in my extruder to mount my fan. I decided to make a fan mount that is retained by the two X-axis bolt holes used for the X-axis stop.
Front View with 2 holes for the fan
Back view where there is an angled section to match the wood cutout of the X-assembly
I measured up the dimensions of the X-assembly and modeled it. I added 2 bolt holes on the side for the screws that attached it to the X axis assembly and matched the angled section of the X-assembly to prevent it from rotating about the bolts. There was one weal spot in my print where my extruder crapped out for a few layers.
Fan attached to mount
My motor has a 3rd wire which is used on a motherboard as a tachometer. In this case I will not use it but thought it be fun to have if I ever wanted to do anything with it. My motor is 12 V so I can hook it right up to my RAMPS board on the 5A power terminal. It will run all the time but I think I'll put a small switch in the line and mount it to my printer so I can turn the fan off and on.
Fan mount attached to the X assembly
I am really pleased with how it turned out. The weak section of my print actually broke on one side but still is really stable. I may print another one later. The fan does not blow over the hot end, only over the black section of my extruder. It is a very small amount of flow and should help. You can download the .STL file for the Fan Mount.
It has been over a month now since I wrote my last blurb. Life has been rather busy but I ended getting the Prusa i3 8" Printer from Makerfarm.
It comes as a kit but it was a lot of fun to build. Only additional items you will need are a piece of glass to print on and an ATX computer power supply to run 12V to power the board and printer. I assembled mine and did a few of the initial test prints to see how well I did assembling. I am completely new to this so I was not familiar with print temperatures and calibrating so my first prints were very crude. I contact Colin at Makerfarm for some pointers and he was very helpful and quick to respond. I checked the calibration and did some maintenance on my machine. It ended up I had to completely disassemble my extruder but this was rather painless. When I originally built it, I had a tough time putting the components together. In my case the plastic idler did not contact the filament and I did not have enough preload on my springs to extrude the plastic so I ended up with a few good layers of print, then a few bad and back to a few good.You can see in my print how spotty it was and offset.
My new prints are much improved now that I trimmed some material off my extruder and the fits are much better. I am working on my first large scale object but I printed a small piece last night that turned out very well. It has nice edges and a great radius on the one section.
I am still learning how to more effectively use Sli3er which creates the Gcode for the printer. Overall I love my printer and I think it was a great buy for the price. It took some work getting it honed in but you get to become more familiar with the machine itself. Highly recommend this printer to anyone else. I'll continue to post projects that I am working on and parts that I create. I'll manage a way for everyone to access my .STL files as well.
