New Mods On The Plus V2/V2.2 Hybrid
I’ve always looked at cable carriers or drag chain as a good way to keep wiring nice and organized. It also helps to put less wear on your wiring which is important due to the constant movements while printing. I had to not only take on the task of printing a bunch of pieces that make up the drag chain but, I also had to custom design mounts for my PB Plus v2. I also had a little more challenge than most as I have dual extruders which means almost twice the amount of wiring going to the carriage.
I came up with a dual drag cable setup that uses one cable setup on each side instead of printing one massive drag cable and trying to fit all my wiring within it. This setup also makes it a little bit easier when replacing individual cables if needed. I also took the opportunity to upgrade the thickness of the wiring, particularly the more power hungry stuff. In order to complete this mod I also extended some of the cabling using a kit that I found on ebay for $7. The kit came with 10×4 pin, 10×3 pin and 10×2 pin 70 cm cables which is more than enough to do this mod as well as some wiring I needed for the JunkBot Build.
Using this drag chain helps to create soft bends in the wiring which helps the internal wires to last longer. I also added several new strain reliefs which help me tell where the wiring will be the most stressed during operation. This makes future replacements a lot easier because it is more likely to eventually fail in a location that is easy to replace.
For the wiring that goes to the extruder, I decided to do one on each side instead of the typical way of doing it. Typically you will have one cable carrier for each axis. Mine is setup to have two for the x and z axiss. This lets me divide up the extra cabling associated with having two extruders. In some ways its more difficult and in others its easier to do it this way. I’ve completed all the required connections and all I have left is to fire up my printer after I double check the wiring.
I started putting my plus through the paces and its working great so far. I printed out a top support bracket in the above pictures. I tested each axis to see its range of movement. Below you can see the z axis at 250mm with a lot more space to go. All I have left is to make a system for the y axis.
I’ve also been having some issues with my z axis due to worn out rods. This is translating into a wobbly carriage which has effected print quality. A friend of mine made a bet that printing a bearing setup that goes right above the aluminum couplers would help tame some of the issues. I had been skeptical about it but, I figured that I would give it a shot. To get these thrust bearing setups just right literally gave me a headache. Lots of sanding, fitting and refitting was required. Im just now waiting for the first print to finish so I can see if all this work actually made a noticeable difference or not.
These thrust bearings have made a noticeable difference. Those in combination with the new drag cables and a few other mods have my Printrbot Plus V2 hybrid operating better than ever. Im also running at almost twice the speed that I usually operated at. This translates into better quality prints at a much faster pace.
After using the new thrust bearing setup for a bit I figured it was time to design some proper top joiners with matching 608 bearings. I looked extensively on thingiverse but, I was unable to come up with much that would work well with my setup. I also wanted something with a little bit of a personality, so to speak. I designed a model on sketchup that would work great. I made it so it can be flipped to sandwich each other instead of designing two separate pieces. I added some curves to its design which helps to use less plastic when printed as well as a better look than it would ifni made it square.
I printed the two bottom pieces first. They required a little bit of sanding as I made them to be a very tight fit so that they wouldn’t slide down the 12mm rods. I installed the bottom pieces and now I am printing off the top two pieces for added strength. Im sure they would work fine without the tops but I will test them out to see if there is a noticeable difference. I already noticed the wobble in my z axis essentially disappeared upon installing the two bottom pieces.
Updates: March 25th 2014 (New heated bed and PSU)
You know we couldn’t stop there. We still needed to update our new bed with a heated bed. Since our Plus V2 hybrid is a dedicated printer in our prototyping lab we decided to add another dedicated 16.5 amp 203w power supply to be used solely by our heated bed. We decided to give the mk2 platform a shot to see how it stood up against our older 24v silicone bed. I will update with heating times.
We also added an auto relay to keep everything off of the Printrboard which will help it to not have to work so hard. Another addition was hardboard, it serves as a strong base for our heated bed. Because we didn’t use a SSR or Solid State Relay we had to add a diode in order to protect the Printrboard from reverse emf. Most people recommend to use a 1N4001 diode but, after doing some research I found that any diode in that series will work. We had a 1N4004 diode available, so thats what we used.
An important note is the Printrboards polarity on the heater pins output. For one reason or another they show the 2 pins closest to the corner of the board as red. We all know that red typically means positive but, this isnt the case on the Printrboard Rev D. The two pins closest to the corner of the board are negative even though they are shown as red within many diagrams. Usually polarity within this mosfet isn’t that important but, it becomes important with the use of a diode.
The power supply we added still has quite a bit of power to spare even when using the heated bed. Mk2 beds are rated to pull about 10-11 amps when they first turn on. Our supply is rated at 16.5 so we have a bit of room to power our new IP camera as well as a new adjustable led light. The new led lights and camera are mounted on the back of the bed so we can check on prints when we are in another room in the house or shop. We don’t recommend that you let your printer run unattended as it can be a potential fire hazard if things go awry.
Update: March 27th 2014
I have finally had time to finish up everything with the mk2 heated bed add on. I tested it out and the auto relay works great. It definitely heats up faster than running it off of the board. The dedicated power supply is mounted on the left side of my Plus hybrid. Right now I’m running 3 power supplies, technically 4 if you count the Printrstands cooling system. I could run the setup with less and I plan to do so once I finish my y cable to 4 pin setup.
I will be using the 25amp 350 watt psu for the Printrboard, extrudrboard, hotend #1 & hotend #2. Then I will keep the 16.5 amp 203 watt psu running the heated bed as well as task lights and other accessories. I’ve also added a 60mm directional fan that I can move around where ever it is needed for specific types of prints. I definitely like the quick heat up times with the dedicated power supply going to the bed.
Update: March 28th 2014
The new heated bed works like a dream and the best part is that the whole setup only costs about $10-12. I got the heated bed with leds and resister already installed for $5 with shipping included. I had the spare auto relay, wiring and diode in the scrap pile. I also snagged the xbox psu for $3 and payed a few more dollars for assorted parts. You can snag a lot of decent parts on ebay for cheap if you are patient and you know what you can buy for cheap as well as what you should never go cheap on. Things like hotends and motors are important investments. Otherwise you spend more time fighting the parts vs the prints.
Update: April 1st 2014
I made new mounts for my printrboard as well as my extrudrboard which controls the extra extruder. I also added better cooling for the two boards and better task lighting so I can see my prints. I added a set of 3 leds on the extruder due to the premature failure of my old task lights caused by the temps near the hotend. This time I mouhted the new leds on the top of the extruder to help shield them from temperature exposure. I took a couple new pics so you can see the modifications. I will add more info onnthe mods ASAP.
Posted from RepRap Squad HQ