The MakerGear M2 has a build platform design that incorporates a 3.8mm thick borosilicate glass topper (seen below). This type of glass is very resistant to thermal shock unlike common glass which will shatter if used with a heated build platform. A great advantage to having the glass build surface is that it is very flat and easy to clean compared to a fixed build platform which must be cleaned or stripped on the machine itself.
       In a production atmosphere one could use multiple glass plates to quickly swap out a fresh print for cooling and start the next print with alternate glass plate.

       The glass topper plate mounts to the heated bed with four small “binder clips” that hold the plate tight to the aluminum plate.

       With the glass installed my new M2 is ready for power!!!

       Before powering up the printer I needed to download the appropriate drivers and software to run the machine. I studied all of the software options suggested on the MakerGear Wikidot page before committing to a game plan. After reading a few reviews of the suggested software titles I decided I would try using “freeware” before purchasing the $140 Simplify 3D software that is preconfigured to be used with the MakerGear M2.
         I started the software installation process by downloading the necessary RAMBo drivers followed by the Arduino IDE program which allows for the proper communication with the RAMBo board. I then downloaded a free printer interface program called Repetier-Host which can feed the movement instructions (G-code) into the printer directly from your computer.

       I followed the instructions for getting started on the MakerGear Wikidot page by loading the RAMBo and Arduino drivers into my Windows 7 laptop which will be used to control the printer. I then powered up the M2 and plugged in the USB cable to start the port configuration process in Windows Device Manager. Once I got the computer to recognize the RAMBo board as “3D Printer powered by RAMBo (COM7)” I was able to move on to loading the Repetier-Host software.

       I had chosen to load a previous version of Repetier (Ver 0.95F) which seems to work really well with the M2. The program installation was painless and didn’t contain any advertising or bloatware that so many free programs are polluted with these days. Once the program loaded I was able to set my port settings to COM 7 in “Printer Settings > Connection” and test the connection between the machine and my computer. Once I had established communication I was able to test the RAMBo board by commanding the X and Y axis to move with Repetier’s user interface controls.

       The printer responded well to the user interface so I proceeded to set up the other printer settings in Repetier before continuing. Here are a few screen shots of my settings in Repetier for reference...

       The next task was to adjust the Z-axis end stop switch so that the platform can “home” to the correct height before printing.

       With the machine powered and connected to Repetier I tested the “Home Z” button under the Manual Control tab. This was done with the extruder head moved all the way to the right (not shown) to prevent the glass from hitting the nozzle should the adjustment be too high. The machine raised the platform and stopped once it hit the limit switch (seen below). I also tested the X and Y axis end stops to make sure they worked correctly before proceeding.

       Next I adjusted the Z-axis limit switch by raising (and lowering) it’s mounting clamp on the linear rail until the glass platform was about 2mm away from the nozzle (in the center of the glass). I checked this by manually moving the nozzle over to check the distance after each attempt at homing the platform (to prevent a collision).

       Once the Z-axis end stop switch was adjusted I tightened the clamp and tested it a few more times to see if it would reliably stop at the same height. Once I felt comfortable with this adjustment I moved on to leveling the build platform. This was done by homing the Z-axis with Repetier and then manually moving the printer nozzle by hand so that it was at the front edge of the build platform and in line with the front and back bed leveling screws as seen below. I then used a 0.203mm (0.008”) feeler gauge to check the gap between the nozzle and the glass.

       I loosened the front bed leveling screw until the blade of the feeler gauge just began to touch the extruder nozzle as seen below.

       Next I moved the platform so that the nozzle was over the back half of the glass (keeping it centered on the adjustment screws as before). I then loosened the rear bed leveling screw until the correct height was achieved. I moved the platform back and forth several times while adjusting the screws until both ends of the glass were about 0.2mm away from the nozzle.

       Now that the front and back screws were adjusted I could move on to the last leveling screw on the right side of the spider mounting plate. This screw sort of teeters the whole platform from side to side so what you are looking for is an even nozzle gap on both the left and right sides of the platform. I moved the nozzle over to the right side of the platform and loosened the adjustment screw until the feeler gauge indicated that I was close.

       Next I moved the extruder over to the left side of the platform to see if the adjustment was balanced between the left and right sides. Once I was happy with the results I was ready for my first print ;0)

       To prepare the printer for the first attempt I decided to apply some Aqua Net unscented hair spray to the glass topper plate. I removed the glass from the printer and “fogged” the glass with an even coat from the aerosol can. This is a common way to help printed parts adhere to glass build platforms...

       I replaced the glass plate and secured it using the binder clips. I am ready to attempt my first print at this point ;0)

       The MakerGear M2 comes with a 1kg spool of Poly Lactic Acid or PLA filament which is a common filament used in 3D printers. PLA has some good characteristics including it’s resistance to warping and it’s glossy finish. Unfortunately it does not do well with heat (being in direct sunlight) and can be more brittle than other plastics. Regardless of it’s shortcomings PLA is a forgiving material and perfect choice for printing prototypes with minimal warping.

       I loaded up the spool of filament on the printer and fed the filament through the filament guide and guide tube (not shown). I then commanded the extruder heater to warm up to 215° C which is the recommended PLA temperature for this type of extruder (V3b).
       Note: Different type of PLA filaments can take as much as 225°C to properly extrude so experimentation is needed with the different manufacturers of filament.
       Once Repetier showed the extruder was up to temperature I  commanded the extruder motor to advance the filament into the extruder until it flowed out of the brass nozzle. I then set the “pinch roller” adjustment screw (black cap screw seen below) so that it was 3/4 to 1 full turn in from where it just begins to apply pressure on the pinch roller arm.
       Note: Only moderate pinch roller pressure is needed to properly feed the filament through the extruder under normal conditions. If the pinch roller is set too tightly it can jam the extruder “GrooveMount” with the “knurled” filament. Some PLA filaments are harder than others and may require up to 1.5 turns on the tension screw to get the extruder gear to “bite” into the filament without slipping. If you back out the filament from the drive and measure the indentation depth into the filament with a digital caliper you should read .10 to .15 mm in depth which will assure good traction...

       I advanced the extruder motor several times to make sure the filament drive was working properly...

       Once I was happy with the consistency of the plastic flow I turned off the extruder heater and started to warm up the build platform to 60° C. Note: It takes about 4 minutes for the platform to heat up to 60° C so it is a good idea to wait until the platform gets up to full temperature before heating the extruder. You only want the extruder heat on when you are ready to print as to not “cook” the plastic in the nozzle. Most control software will do this automatically so unless you are changing filament color you shouldn’t have to preheat the extruder as you would the heated build platform.

       In order for a 3D printer to print a 3D computer model it needs a set of instructions called a G-code file. This special computer language contains all of the movement instructions that the printer will follow while it is laying down the plastic filament on the platform. In some cases there can be several million individual G-code commands required to create a complex shape. That’s a whole lot of information that needs to be compiled before printing even starts.
       Most 3D models are created in what is called a “polygon mesh” format. This mesh is made up of thousands of two dimensional triangles or squares that are interwoven together to create what seems to be a continuously flowing shape. These mesh files are what G-code instructions are based on although they need to be processed or “sliced” from the original mesh file to become a complete string of G-code.
       The MakerGear M2 comes with three pre-sliced 3D models that have been converted into G-code specifically for the M2. These G-code files have been loaded onto the SD memory card that comes with the M2 and can be accessed in Repetier for easy loading. I decided that I would try the sample prints prepared by MakerGear before attempting to slice my own mesh files. This way I can see how the machine works before moving onto more advanced projects like creating my own designs.
       I started out by loading the “Bracelet” G-code file into Repetier from the memory card and then commanded the M2 to run the job. Immediately my new machine started homing all of the axis and then paused for the extruder to come up to temperature. After a short period the machine started making that crazy harmonic sound with it’s stepper motors and a form started to appear on the platform.

       All of the components of my new machine seemed to work together flawlessly. There were no vibrations or metal to metal sounds coming from the frame just smooth deliberate movements of the table and extruder.

       I was amazed at the precise control executed by the M2 as it laid layer upon layer of the PLA plastic on the bracelet model.

       After about ten minutes the model was complete. I’m not sure what it is but it looks neat ;0)

       At this point I was pretty happy considering only a few days earlier I had a box of parts and now had a working printer. It was only a matter of minutes before I loaded up another sample print and started up the machine again. This time I chose the “Bigfoot” file which was a much more complex file to print. The Bigfoot file contains 188,000 individual lines of G-code of which consist of very short straight lines arranged in a pattern to create the illusion that there are no straight lines at all.
       In fact most 3D printing consists of very short straight lines that are segmented together to form arcs and circles. In the case of the Bigfoot file all of the exterior of this model are indeed very short straight lines stitched together to make this complex shape...

       After the successful print of the Bigfoot head sculpture I had noticed a problem with the heated build platform. The glass topper plate that sits on top of the aluminum heated plate was not resting flat in the HBP mounting pads. This is because the glass is slightly larger than the aluminum plate of which sits slightly down into the rubber pads as seen below. When the glass plate if clamped to the heated plate it slightly raises the assembly which can throw off the platform alignment arbitrarily.

       To solve this alignment issue I decided to add four more pieces of the gasket material on all four corners of the spider assembly so that the whole platform would sit on the gasket pads and not the edges of the rubber pads as before. To do this I cut four 10 x 13mm pieces of the .030” thick gasket material just like the two I made to level out the heated plate earlier...

       Next I used cyanoacrylate glue to glue one square on top of each of the existing back two squares (seen below)...

       Then I glued one pad on each of the two front pads to evenly raise the HBP.

       Now the platform sits firm in the spider and the glass will not askew the alignment when clamped in. This of course will require me to realign the platform although it should keep it’s alignment much longer now.

       The next “issue” that I wanted to correct was one that I noticed during the Bigfoot print. I had observed that the stepper motor driver chips were getting fairly hot as I had measured temperatures as high as 72° C (162° F) through the front grill of the enclosure (with a non-contact thermometer). It seems that the fan on the top of the case really does very little to push cool air over the driver chips in it current configuration.

       The A4982 DMOS microstepping driver chip is designed to be cooled by the circuit board substrate it is soldered to which in turn wicks the heat away from the chip. In most cases this is ample cooling for the A4982 which is capable of withstanding temperatures up to 85° C or 185° F. In the case of the RAMBo motherboard I would suspect that prolonged temperatures of +70° C could shorten the life of the board and so I wanted to pursue a more active cooling method.

       To improve the cooling capacity of the existing fan on the enclosure I would need to make a baffle to install into the laser cut enclosure to force cool air over the driver chips. I did this by cutting out a baffle made from .015” thick clear plastic sheeting (seen below) which can easily be added to the enclosure without any modification to the box.

       I cut out a 40mm x 184mm piece of the plastic and then formed a bend at 106mm measured from one end. I then placed the piece in the corner of the enclosure to measure out where I would need to make a cutout for the power connector (not shown). I then cut a window out for the power connector to form what you see below...

       The fan baffle installed easily in the corner of the enclosure. Notice that it does not go past the row of driver chips but does cover all of the holes on the left side of the photo below.

       I reinstalled the top cover (not shown) and printed another model to see if the baffle changed the driver temperature and from what I see it lowered the temperature by almost 8° C. What is obvious is that airflow is now detectable coming out of the holes on the front and back whereas before there was very little movement. This looks like an easy and effective mod that really helps.

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