Bulbul Junior 3D Printer.

[phpenguin]

It had taken half year to build it, and another half year to trouble shoot and fine tuning.
I'm designing large 3D Printers for my small business and workshop.



It started printing models I've been expecting lately.



In-place printing
What it does is to print all movable parts as a whole model.


I helped two builders last year by printing them plastic parts.


Anybody who really want to experience magic like 3D Printing should consider SLA (Stereolithography )3D Printers that build models out of UV or light reactive resin.  It requires only one or two stepper motors, a high-resolution projector, and special resin. DIY kit starts at at $1,000 plus a projector cost.



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Hi,

I bought a RAMPS (RepRap Arduino Mega Pololu Shield) kit for my Mini Kossel 3D Printer.
I couldn't resist the outrageous price from Aliexpress at $35 for the full kit including LCD module.

4x NEMA 17 Stepper motor: 25.20W (Power rating of the motor is 6.3W - 4.2V, 1.5A)
4x A4988 Stepper motor driver: 96W (Power rating of the driver is 24W - 12V, max 2A)
1x Arduino Mega: 2.7W
2x 12V cooling fan: 3W (Power rating of the fan is around 1W to 1.5W - 12V, 0.08A)
1x Heating Resistor, Welwyn W21 6R8 JI: 3W
1x RepRapDiscount Smart Controller LCD: 2W (estimate)
Total power consumption of RAMPS 1.4 controller and electric parts is between 106.70W and 131.90W.
(I don't quite understand relationship between A4988 stepper motor driver and NEMA 17 motor. Does the stepper motor driver delivers power to the stepper motor? Then I think one pair of A4988 driver and stepper motor should be lower than 96W.)

Source: http://reprap.org/wiki/RAMPS_1.4

Third, the MF-R500 (5A) PTC fuse is rated to 30V and the MF-R1100 (11A) PTC fuse is rated to 16V. They will need to be replaced with real fuses.

Two yellow plates are the MF-R500 PTC fuses on below picture. What kind of real fuses should I use for the replacement?


I plan to use a 450W ATX power supply that has 20A capacity for 12V power line. I can buy a new unit under $25.




Source: http://blomker.com/Kossel_Mini_Assembly_Guide_V1.0.pdf
The building instruction I followed mounts the RAMPS 1.4 board on the aluminium extrusion using two metal bolts like below.
Is it really safe? It's beyond my comprehension honestly.


Temperature of the Hotend, which melts PLA / ABS filament and squeezes out on the printing bed, reaches from 190 to 300 Celsius degrees.
3D Printer can be caught in fire.

Yes, 3D printers can go on fire.http://forums.reprap.org/read.php?392,294850



I have very rough idea about fail-safe features against potential fire of 3D Printer at the moment.

Thanks in advance,
Hughe

[kam]

First, I like your attitude dude! I mean, sharing is the mother of creativity, creativity is the mother of ingenious, ingenious is the mother simplicity and simplicity is the mother of science (and goes the other way as well).

Second

I plan to use a 450W ATX power supply that has 20A capacity for 12V power line. I can buy a new unit under $25.

let me offer you a 300W PSU - brand new. I got 4 of them, i fried one, used one, plan to experiment with the third one, so i have a fourth laying there and i have no idea what to do with this. It can deliver 12A @ 12V, is that ok? Email or PM your address if you're interested.

Third, I can't wait to see this beauty in operation. When this is finished, I will make a page with the worklog under your name. Keep it up!

[phpenguin]

4x NEMA 17 Stepper motor: 25.20W (Power rating of the motor is 6.3W - 4.2V, 1.5A)
4x A4988 Stepper motor driver: 96W (Power rating of the driver is 24W - 12V, max 2A)
1x Arduino Mega: 2.7W
2x 12V cooling fan: 3W (Power rating of the fan is around 1W to 1.5W - 12V, 0.08A)
1x Heating Resistor, Welwyn W21 6R8 JI: 3W
1x RepRapDiscount Smart Controller LCD: 2W (estimate)
Total power consumption of RAMPS 1.4 controller and electric parts is between 106.70W and 131.90W.

Yesterday I checked power consumption of A4988 driver. It turned out it consumes power little more than stepper motor because it controls amount of electricity of the motor like a regulator. Correct me if I'm wrong. I gives 2W per each driver.
So total power consumption of RAMPS 1.4 controller is around 44W.

[phpenguin]

Today was like a sweet dream.

Pilot test of all electronic components of the Kossel Mini 3D Printer except Hotend and Endstop switches went smoothly.
I connected four NEMA 17 stepper motors to the RAMPS 1.4 controller, uploaded test code to Arduino Mega and then performed stepper motor calibration intensively for good three or four hours.

It was first time that I felt limitation of my test equipment, BK Precision 390A. Two SMD resistors on the Stepstick - A4988 chip - motor driver have R100, which means 0.1 ohm.  The multimeter was reading 0.2 ohm and 0.3 ohm of the SMD resistance that gave me little frustration.

S1 and S2 are the sense resistors that dictates motor current.

A = VREF / (8 x RS)

= VREF / (8 x 0.1)

= VREF / 0.8

To set 1A current

VREF = 1.0 x 0.8 = 0.8V (800 mV)

Reprap Wiki recommends 1.0A current for NEMA 17 stepper motors.
I adjusted the trim pot of four motor drivers.

VREF values I set for the four motors:
Extruder - 792 mV
X axis - 783 mV
Y axis - 791 mV
Z axis - 785 mV

Running four motors about sixty minutes gave temperature above 10 Celsius degrees of ambient temperature, which is good.
The stepper driver's temperature went upto 60 Celsius degrees during previous test. I ran a 12V@0.08A fan supplying +5V in the final calibration session. It definitely cooled down the stepper driver - 30 to 35 Celsius degrees during operation.



I think building a Reprap Open Source 3D Printer will provide a lot of learning experiences, improve overall workmanship. I realized that to build decent 3D Printer, the build must have three set of skills - mechanical, electronics, various material handling and problem solving . 

Once I finish building Kossel Mini pretty soon, I plan to write a complete building manual of Kossel Mini from scratch, volume of 500+ pages. I've taken hundreds photos and gathered data over the past six months. I stopped counting number of photos.

Regards,
Hughe

PS: I made two short videos.
http://youtu.be/Tyl60cKShuQ
http://youtu.be/EtkYuU-6HF8

[kam]

Good job mate!
Your next step is to design your own 3D printer, seems a logical step to me.
As of the BK-P, I know that it is not top line but it is good value for money.

[phpenguin]

@kam

When you start building a Reprap 3D Printer?
I'm pretty sure you are interest about it. 

I ran basic functions of the 3D Printer today.


It heats up the Hotend to 230 degrees Celsius within few minutes.

[kam]

When you start building a Reprap 3D Printer?

as a matter of fact, if i ever find enough free time to make such a project, it will be a laser cutter, or a pick'n'place plus solder paste dispenser...