Built an Original Prusa i3 MK2.

Now I have two RepRap 3D Printers. The left side is one day old Prusa i3 MK2, the right side is RepRapPro Fisher Beta, which I replaced most acrylic parts with steel and aluminum and named it Steel Fisher.

After upgrading RepRapFirmware v1.12a-dc42, Duet Web Control v1.11, installation of B’struder equipped with geared Nema 17 stepper motor. Steel Fisher has showed impressive performance so far.

It already printed all parts for building Fisher 1 3D Printer, had taken 16 hours of printing. I set the layer height 0.2 mm. The printing quality is better than the kits.

The total weight of Fisher 1’s parts is 184.6 g.

Review of Original Prusa i3 MK2 kit

I bought an Original Prusa i3 MK2 from Prusa Research in Czech Republic. It arrived last weekend. The major reasons I chose is probably the best printing quality among RepRap 3D Printer kits in the market.  This is the first Cartesian 3D Printer and I would use this as benchmark against my Delta 3D Printer development.

The print bed alignment by twisting Y-axis frame is tedious. I spent probably an hour to align the print going through eight adjustments.  The manual says visual inspection of parallelism between the print bed’s grid line and X-axis rods is sufficient.

Here is the measurement of left-most and right-most point I got:

55.0 54.0

55.15 54.25

55.25 53,15

54.15 53.85

53.50 52.70

52.90 52.50

54.70 54.40

54.85 54.70* (I stopped here)

A bag of candy, HARIBO Happy Cola. I considered Coca Cola is toxic black water, and haven’t drank a bottle of coke for decades.  I ate it the candy though.

The packaging was meticulous.

Checklist of main components.

The company should provide the tools as an option that might save $10 to $15 depend on individual buyers. I already had the tools. Except flat head screw driver, the others’ quality is below average.  I had to file one of wrench’s tip.

Some parts had to be cleaned up like this.

Nema 17 stepper motors

BLK GRN RED BLU

1          2        3       4

Measurement of pair of coil resistance:

X-axis motor: 1-2 is 7.8 ohm, 3-4 is 7 ohm

Y-axis motor: 1-2 is 6.8 ohm, 3-4 is 6.8 ohm

Z-axis motor, left: 1-2 is 8.4 ohm, 3-4 is 8.3 ohm

Z-axis motor, right: 1-2 8.3 ohm, 3-4 is 8.4 ohm

It doesn’t have provide adjuster of the belt tension. This is an outstanding design flaw.

Y-axis belt holder.

The print bed frame where the heated bed mounts.

It comes with a pre-built Genuine E3D V6 Hotend. E3D improved thermistor installation. Previous design which I broke the original thermistor, later on I drilled a hole on the heater block to install a diode type thermistor.

Direct drive extruder

The effector assembly has two fans, heat sink and layer (print). The blower acts as a layer fan (print fan according to the assembly instruction).

Joseph Prusa must love zip-ties. The effector assembly has 15+ zip-ties.

The PCB heated bed is the print bed.

I removed extra film on the edge.

M3 nut hole of most black parts were dirty and dimensional inaccuracy.

The image is cover base of Rambo-mini controller.

Genuine Rambo-mini board.

It’s compact version of the RAMPS kit for RepRap 3D Printer:

• Arduino Mega 2560 – 8 bit processor
• RAMPS shield
• Five stepper motor drivers

Mounting the board was inconvenient due to small size of the cover base.

I cut 43 cm length of Hoten’s thermistor wires, and made 2 pin connector.

5A blade fuse.

The dimension matches conventional automotive fuses, which is easy to have spares. The board has two 5A fuses, one 15 A fuse.