I was poking around at Ultimachine.com while researching the RAMBo board and found some aluminum heat sinks made for stepper motor drivers. I couldn’t resist getting a set for my RAMBo board ;0)

       The heat sinks came with little squares of Akasa heat sink adhesive that is perfect for attaching them to the A4982 drivers.

       Ultimately these heat sinks are nothing but semiconductor jewelry although somehow they make a novice techie like me feel good inside ;0)

       After the heat sink install I buttoned up the enclosure for another printer test to see if temps were lowered and the jury is out on these little guys. It seems cooler however it is difficult to know how hot the driver chip really is underneath the heat sink :oP

       The next mod that I wanted to do was to upgrade the enclosure fan as well as the extruder fan. Both of the stock fans that came with the M2 are super loud and whine like a banshee. It isn't too bad for a little while but if you plan to have the printer inside the home or plan to work with it a lot you may consider changing out these two 40mm fans. I chose to use a ball bearing fan made by Evercool (Cat #EC4010M12CA) that has a bit less air flow than the stock fans but is at least three times as quiet as the stock fan.
       I used the stock wires from the old fan and soldered them to the new fan wires which I then covered with heat shrink tubing (seen below). The new fan has a three-wire configuration so I just clipped off the yellow sensor wire which is not needed.

       The next upgrade that I wanted to do was add a power switch to the power supply. Unfortunately there is no easy way to turn off the M2 other than unplugging the power supply so a switch is a great improvement to the operation of the machine.

       I installed a 120 volt 10 amp toggle switch and wired it in series with the black “hot” wire coming in from the power cord. I then soldered each connection and heat-shrinked all of the wires as seen below.

       Note: This mod may void your 6-month warranty with MakerGear so do this one at your own risk. Also make sure the switch you use has clearance between the metal enclosure of the power supply and it’s terminals or you may fry you new power supply :o/

       Now that the switch is installed it is soooo much easier to shut down the machine ;0)

       Now that I have got a few issues sorted out I wanted to get back to printing. I was now ready to start downloading 3D models from the internet so I logged into web sites like Thingiverse.com and Yeggi.com which have users that are willing to share 3D models that they have made for public use. Most of these files are in “STL” or steriolithography format (mesh files) which need to be processed into G-code before they can be printed on the M2.
       This is where I learned about “slicing” and how it is used to interpret the mesh files to make a G-code toolpath for 3D printing. For this operation I would need a slicing program of which I believe was already included with Repetier-Host called “Slic3r”. I decided that I would download a stand-alone copy of Slic3r Ver. 1.1.6 which has now been updated to 1.1.7 (of Which I didn’t care for personally). The software loaded easily and was pretty straightforward to understand.
       The tricky part was figuring out what settings to use for the M2 when slicing STL files. This of course is where the skill part comes in (for the user) and only experience will really help you understand how and why certain settings are used. I started out with baby steps and used some of the info I gleaned out of the MakerGear sample print G-code to help me decide what settings to use in Slic3r.
       For the most part there are really too many settings to discuss in this article however I can share a few basic ones to get started...

       First off, under “Print Settings > Layers and perimeters” I set the “Layer Height” to 0.25mm which is a good “middle of the road” setting for resolution. After that I set the “First Layer Height” to 0.25mm which is a good setting for general printing. You will also notice the other settings on the screen shot including the “Advanced - Seam Position” setting which is set to “Nearest”. This setting helps fix a toolpath bug that jitters the nozzle during printing certain shapes.

       Next under “Print Settings > Infill” I set the density to 30% which is a good all around infill for most objects.

       Under “Print Settings > Skirt and brim” I set up Slic3r to add a two loop skirt at a distance of 5mm from the model. Printing this skirt at the beginning of each print will help the extruder get the plastic flowing correctly.

       Next under “Filament Settings > Filament” I set the filament diameter to 1.78mm which is a good general setting for filament diameter. Raising this number (e.g. 1.80mm) will reduce the flow of plastic and lowering it will increase the flow. Again, these are all settings you can play with for hours and hours. In the “Temperature” window below you can see what I used for temperature settings for PLA filament (ABS is the following: Extruder 244°/242° and Bed 106°/102°)...

       Earlier in this article I had mentioned that I was aligning the build platform at .203mm from the extruder head which works OK for the most part. After the last few prints I had completed I figured out that if I add a negative Z offset to the sliced STL file I can make the filament stick better to the glass platform. A negative Z offset will put the nozzle closer to the glass (during the printing of a G-code file only, not when homing) and can be fine tuned with the software instead of the hardware.
       I figured out that adding a negative 0.05mm Z offset to the G-code instructions puts the extruder nozzle at 0.15mm away which seems to be perfect for a 0.25mm first layer height (see screen shot below of Slic3r). You may also notice the bed size, print center and G-code flavor settings used on this tab...

       Next under “Printer Settings > Custom G-code” I added a mix of special commands that I have seen others using that seem to work well with the M2. Under “Start G-code” I added these commands:

; start of custom G-code
G90 ; use absolute coordinates
G21 ; set units to millimeters
G92 E0 ; reset extrusion distance
M82 ; use absolute distances for extrusion
G28 ; home the axes
G92 X0 Y0 Z0 E0 ; tell the M2 that we're homed
; now extrude a bit of filament off the edge and wipe it off
G1 F5000 Y30 X30
G1 X220
G1 F100 E10
; end of custom G-code

For the “End G-code” I added these commands:

; start custom G-code
M104 S0 ; turn off temperature
M140 S0 ; turn of HBP
G28 X0 ; home X axis
G1 Y110 ; center Y axis
G1 Z195 ; drop Z
M107 ; turn off the bedfan
M84 ; disable motors
; end custom G-code

       Note: Custom G-code settings aren’t necessary for printing although they seem to make the process easier for the user.

       Lastly under “Printer Settings > Extruder 1” I set the nozzle diameter (seen below) to 0.35mm which is the stock M2 nozzle size. Nothing else was modified on this tab.

       Using the settings discussed above I sliced an STL file I found on Thingiverse which is a M2 tool holder as seen below. Once complete I loaded the sliced G-code into Repetier in preparation for my next print...

       I fired up the M2 and started the 65 minute PLA print...

       Watching the M2 print is so mesmerizing ;0)

       One of the neat functions of Repetier is the ability to see a computer simulation of the filament being laid down simultaneously as the printer is printing. You can also see the filament change color as it cools in the animation (seen below)...

       My new tool holder was now complete!! I waited for the HBP to cool down a minute or two and than popped off the print for inspection.

       I pulled out a M3 x 16mm cap screw from my spare parts bag to install the new tool holder on my M2...

       The new tool holder bolted right up to the frame without issue. This technology is so cool considering that this part was born from a string of code that was downloaded from a server hundreds of miles away. Isn’t this a form of teleportation ;0)

       I loaded up my new tool holder with the tools provided with my M2. It looks good to me ;0>

       The next upgrade part I downloaded and printed was a new filament guide I got from Thingiverse. I had to ream out the filament holes a little to fit the stock guide tube (not shown). Other than that it works great!!!

       The next modification I wanted to work on was installing a work light on my machine. I have seen other users adding LED strip lights to their machines so I wanted to do the same for my M2. Luckily I had a 12 volt strip of white LED lights (from my arsenal of RC airplane stuff) that was ready for installation. I also pulled a 36” long servo lead extension out of my RC stuff to be used as a way to connect the lights to the power connector.
       Note: This mod may or may not void your MakerGear warranty!!! You may choose to power your LEDs with a separate power supply which should have no effect on the machine whatsoever.

       The LED lights I used can only be cut at intervals of three lamps so I cut two strips so that there were 15 LED lamps per strip which came out to about 245mm long each. I then removed the white “signal” wire from the servo lead extension to make a two-lead power cable for my lights.

       Next I cut the servo extension at 2’ from the male connector so that the female had about 1’ left on it (not shown). I then soldered on the 2’ piece to the LED lights in series so that the two 12 volt strips will run together at 24 volts (the voltage that the M2 runs on). You will notice that the scrap white wire was used as a jumper from one strip to another (+ to -).

       Unfortunately there is no easy way to tap 24 volts out of the RAMBo board for accessories unless you want to use the secondary extruder heater port (Heat 1) to power your lights (requiring a sortware/firmware mod). Or you could parallel them off of the “Fan 1” port which runs all the time (controlled by the M2 firmware). I personally don’t want to mess at all with the RAMBo board when adding my lights.
       I decided I would install my lights into the power connector on the outside the RAMBo enclosure which shouldn’t effect the operation of the machine at all. To do this I located the power wires for the HBP connection which are the right two wires of the power connector seen below. I removed the hot glue sealant from the wires to expose the wire terminals in the connector. 

       Next I confirmed the polarity of the wires with a multimeter (not shown) and then loosened the screws holding in the power wires so that the female end of the servo extension could be “piggybacked” into the connector for testing. Once attached I plugged in the servo connector and voila!!!

       Unfortunately left as-is the servo lead could cause a fire should the wires be shorted out. This is because the power supply is capable of producing 18.8 amps at 24 volts which is much more than the 3 amp rated servo wire can handle if it were shorted. That is why I decided to add a fuse into the circuit to prevent that from happening. Seen below is an automotive fuse holder with a 1/2 amp fuse which will protect the circuit conductors from an overcurrent condition.

       I installed the fuse so that it was in series with the servo lead extension as seen below. Now there is very little danger that the servo wires can be damaged with a short.

         Note: The positive terminal of the RAMBo connector is the left one in the photo below. The negative terminal is the right one. The added LED wires are just “stacked” with the existing HBP wires and clamped down with the terminal screws...

       Once the wires were secure I used some hot glue to seal them in as the manufacturer had.

       Next I tucked the fuse wires into the wireloom material and used cable ties to secure the bundle. Now the servo connector is at the end where it can easily be disconnected along with the controller.

       I plugged in the power connector and ran my servo lead extension wires up the existing wireloom material for the end stop switches.

       To make the LED strips stick to the bridge of the machine I added some strips of double sided tape (not shown) underneath the LEDs. They were then arranged on either side of the Nylock nuts (seen below) and secured into place.

       I flipped on the power supply and wow!!! There is plenty of light to see what I are doing now ;0) Unfortunately if you print in a garage it will inevitably attract insects so don’t be surprised if a moth gets into your next print job with these lights ;0P

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