SinapTec

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SinapTec AT328.02 is a 3D FDM printer controller board of very low cost, its operation is based on an Arduino Nano running a version of Teacup_Firmware. The board layout is designed so that it can be manufactured by any hobbyist, it is a simple face plate with through-hole components.

Crystal Clear action run.png
SinapTec AT328.02

Release status: Working

SinapTec AT328.02 - Foto.jpg
Description
SinapTec AT328.02 3d printer controller board based on Arduino Nano.
License
Author
Contributors
Based-on
Categories
CAD Models
External Link


Summary

  • 1 Arduino Nano socket.
  • 4 Pololus sockets (X,Y,Z y E)
  • 3 Line in for X_MIN, Y_MIN and Z_MIN endstops.
  • 2 Line in for Hotend and heated bed sensors.
  • 3 Mosfets outputs for Heater, Fan and Bed (this last with independent power supply).

Image Gallery

Bill of Materials (BOM)

Amount Code Description
3 IRFZ44N-IR TR. MOS-FET N-CH 50A 60V .028 E TO-220
3 CR25M-10E CARBON RESISTOR 1/4W 5% 10E
3 CR25M-100K CARBON RESISTOR 1/4W 5% 100K
4 CR25M-1K8 CARBON RESISTOR 1/4W 5% 1K8
2 CR25M-4K7 CARBON RESISTOR 1/4W 5% 4K7
3 L3R LED 3MM STANDARD RED 8MCD 60°
1 L3G LED 3MM STANDARD GREEn 8MCD 60
1 1N4007 DIODE RECTIFIER 1A 1000V
2 10X50SR CAP. ELECTROLITIC 10 X 50V RADIAL (5 X 11 MM)
4 470X16SR CAP. ELECTROLITIC 470 X 16V RADIAL (8 X 14MM)
1 LM7805 REG. POSITIVO 5V 1.5A (10-220)
2 CER.1 DISC CERAMIC CAPACITOR 100NF X 50V Y5V (P=2.5mm)
5 B2P BORNE 2 POLOS APIL. 8A 300VAC AZUL
12 MJ2C MINI JUMPER CORTO 6.5MM (CERRADO)
1 TP 1X40 TIRA DE POSTES RECTA SIMPLE (1X40) .1"
3 TPHS1X40 TIRA HEMBRA P/POSTE P/C.I. (1X40) .1" STANDARD


Board Connection Diagram Pin Out

SinapTec vAT328-02 Connection Diagram.png

Warnings

Reversing +/- or otherwise incorrectly connecting power can destroy your electronics and cause fire hazard.

Incorrectly inserting stepper drivers will destroy your electronics and cause a fire risk. Always make sure power and USB is disconnected when removing or adjusting stepper drivers. Always make sure to insert drivers in correct orientation and in the socket correctly.

The endstop pins are Signal - GND - VCC, instead of the VCC - Sig - GND like the rest of RepRaps boards. Make sure to wire them correctly. This is done to allow squeezing fatter traces on the printable board.

DON'T secure SinapTec AT328.02 with conductive screws through both mounting holes. The screw may cut into the positive trace creating a HIGH current short.


Best Practices

A best practice is a technique or methodology that, through experience and research, has proven to reliably lead to a desired result.
  • It higly recommended to place a fuse on power input of 5A and 10A for the bed.
ATO / ATC Fuse Cartridge Fuse
Fusible1.jpg
Fusible2.jpg



  • Active cooling over the electronics with a 80mm cooler is recommended.


12v 80mm Cooler
80mm Cooler.jpg



Stepper Jumpers Configuration

The following table compares Made in China A4988 Stepper driver boards vs DRV8825 ones, for RepRap use:

A4988 DRV8825
Availability very widely available widely available
Approx. price $6.80 / 5 pieces $10 / 5 pieces
Max. theoretical current 2A 2.5A
Max. microsteps 16 32
PCB color Green / Red Purple
Stepper current adjust. trimpot Yes, near Dir pin Yes, near En pin
Typical Rs value 0.05 Ohm or
0.1 Ohm or
0.2 Ohm
0.1 Ohm
Vref formula (*) I_TripMax= Vref/(8*Rs) I_TripMax= Vref/(5*Rs)
Thermal Overload Protection (**) Yes Yes
PCB layers 2 4
Small heatsink included (***) Almost always Sometimes not
Active cooling required? Recommended Recommended
IC packaging 5x5mm 28-lead QFN 9.7x6.4mm 28HTSSOP

Note that some important technical characteristics from the respective datasheets of the ICs are not directly comparable. For example, the DRV8825 is fully specified in terms of thermal characteristics, the A4988 is not. Another important characteristic that unfortunately is not directly comparable is RDSon, which is specified at different current levels in the respective IC datasheets.


(*) Adjusting the stepper driver current

See these instructions: Pololu_stepper_driver_board#Tuning_motor_current.

(**) Temperature Overload Protection

It is very important to keep the stepper driver ICs below a certain temperature during printing, since both ICs feature thermal overload protection that when triggered (typically when the die reaches a temperature of around 150~160 C), shuts down the output stages i.e. halts all commands to the affected stepper and in doing so, ruins the part being printed.

(***) Heatsinks

It is not yet determined how much of a real impact the small aluminum heatsinks shown in the pictures above have on cooling the ICs, as both stepper driver ICs depend much more on proper PCB layout and solder pad contact (as well as proper airflow, remember!) for heat dissipation, rather than on dissipation through the top of the IC package. This is because both stepper driver ICs have an exposed metal pad under the chip that contacts the PCB and this is the "path of least resistance" for heat dissipation. The secondary path for heat dissipation is through the package leads and in this aspect the DRV8825 provides for possibly slightly better power dissipation compared to the leadless A4988. It is my understanding that dissipation through the top of the ICs is almost irrelevant here.


Jumpers Configuration

  • Jumpers need to be installed under each stepper driver:
Jumper 1 Jumper 2 Jumper 3 Step Size
No No No Full Step
Yes No No Half Step
No Yes No 1/4 Step
Yes Yes No 1/8 Step
Yes Yes Yes 1/16 Step

For now the default is 1/16 micro stepping (all jumpers installed under drivers)

Datasheets

Extra Files

Firmware TeaCup_-_CoreXY:

PBC (Eagle)

PCB diagram for transfer toner

Gcode for drilling CNC:

Gcode for PCB CNC Milling:

External Links

Development forum

WIKI Firmware page