"Continuously updating"

It’s summer vacation, let’s open a new pit╮(￣▽￣)╭

Onboard resources:

• Five-way stepper motor drive, among which E1 can be synchronized with the Z-axis through short circuit, quickly realizing dual Z-axis (no need to modify the firmware)
• Two temperature measurement interfaces, pulled up through a 4.7k resistor
• Three-way optocoupler isolation high-power PWM control interface
• Three-way limit switch interface
• USB to serial port and automatic download circuit
• Support WIFI/serial port printing

Version/Update Notes

* Note: All versions with a major version number of 0 are beta versions, and their availability cannot be guaranteed.

Schematic diagram

0.1: Preliminary improvement of the schematic diagram

0.2: Modify the fan output, simplify the mos driver part, and adjust some IO

0.3: Modify all interfaces to plug-in xh2.54 2p, add an inverter to the fan output, simplify the power supply section, adjust the IO again, and add indicator LEDs

0.4: Optimize the power supply section, add more LED indicators, and optimize the inverter of the fan output. Since the IO of ESP32 (34 x GPIOs) is not enough, I am going to consider replacing it with ESP32-S2 (43 x GPIOs). Marlin has written support for S2, waiting for testing.

//Since the power supply chips purchased overseas have not been shipped, the 0.4 PCB will not be updated for the time being.

PCB

V0.1: Initial improvements

T0.1: Simplify the MOS driver part and change the shape to a long shape

V0.2: Re-layout, simplify the board size, optimize power routing, other modifications see 0.2 schematic diagram

V0.3: Re-layout again, add m.3 screw holes at the four corners, and other modifications are as shown in the 0.3 schematic diagram

Production process

In order to build a low-cost 3D printer, after several searches, the open source printers with CoreXY structure that I have found so far are mainly the following two

• Voron series, the open source warehouse is on Github. It looks very fancy and the cost is very high.
• Dayu's CoreXY structure 3D printer, the assembly tutorial video is at Station B, and the information can be found in the comment area of ​​Station B. Because of the lower cost, the structure of this scheme is adopted.

According to the information provided, I tried to modify the outer frame size to match the design of this main control board. The printing stroke was modified to 220mm x 220mm x 370mm, and the height of the frame reached 500mm+. The goal of this project is to print on this half-meter-long The main control board can be placed perfectly on the Z axis. The following is the length of the 2020 aluminum profile required for the frame.

Use M5 hexagon socket screws, 2020 angle steel and T-shaped nuts to fix the aluminum profile, and try to make the frame stable enough (note that the T-shaped nuts need to be buried in the aluminum profile in advance)

According to the height of the frame, the PCB of v0.1 is a 490mm*20mm four-layer board. Two M4 screw holes are reserved in the upper part. The lower part is not fixed and is waiting to be changed.

Install the XY axis and stepper motor (the optical axis is the previous one, the new one has not arrived yet)

2021/7/16

After installing the XY axis and heating head, the new optical axis is very smooth~. At the same time, the first version of the board arrived today and can be tested tomorrow.

2021/7/17

The timing belt and remote extruder have been installed, and the main control board is being verified. . .

2021/7/18

The Z-axis is basically completed, but two optical axes and T-shaped screws are missing. Main control board welding progress is more than half

2021/7/29

After the basic assembly is completed, start redrawing the main control board.

I finally passed some of the summer homework deadlines and can continue to update in the next half month~

2021/8/02

The Marlin code has been modified for several days, but it still cannot drive the motor. I guess there is something that has not been modified. Change the firmware to GRBL and it will drive normally. Once the problem is solved, switch back to Mralin.

2021/8/08

Please be careful when buying printed copies from a certain fish. . .

Also, does any good friend know where I can get 3D printing for free? It’s quite urgent to wait online.