DDPrint on Ender-5

Mount Flowrate sensor

Print sensor housing and mount incremental sensor.

Todo: Upload and link Sensor housing stl.

Mainboard

Creality3d V1.1.4 CPU: Atmega 1284p Clock: 16 Mhz

Flowrate sensor connection

Board schematic: https://raw.githubusercontent.com/RudolphRiedel/CR-10_wiring/master/Ender3_schematic.PDF

FRS is connected tho the SPI bus using 6-pin ISP header and one pin of the EXP1 header:

Connector ISP:

1: MISO        --> FRS MISO
2: +5V VCC     --> FRS +5V
3: SCLK        --> FRS SCLK
4: MOSI
5: Reset
6: GND         --> FRS GND

Connector EXP1:

1: Beeper      --> FRS ChipSelect

Note:

Achtung EXP1 ist falsch herum bestückt/bezeichnet (ist um 180 grad gedreht, die nase ist also auf der falschen seite, pin1 <-> pin10).

Damit ist EXP1/pin1 (also unser FRS CS signal) der beeper anschluss welcher mit CPU-pin 33 ADC4/PCINT4/PA4 verbunden ist. --> OK, nachgemessen.

Had to remove the connector housing of the EXP1 header to make room for the ISP connector:

FRS connected to mainboard headers ISP and EXP1:

Level converter/driver mod

• Questionable: floating unused inputs?
• Questionable: miso goes through level converter but output enable pins (OE1/OE2) are always enabled -> bus conflict if other devices on SPI bus (including ISP programmer)?
• No pullup on sd card chip select (SS)?

Did a hardware modification on the mainboard to allow other devices on the CPU SPI bus. This includes the disconnection of the MISO line after the buffer and connecting it directly to the SPI bus.

Mods

Thermistor types

Heated bed and hotend both have a EPCOS 100k termistor in series with a 4.7k pullup resistor, Thermistor type choosen is B57560G104F.

R25 = 100k
R150 = 1.6419k
R250 = 0.2261k

Generate thermistor table with:

python scripts/thermistor_table.py > /tmp/tt.c

Firmware

Install atmega1284p arduino core from https://github.com/Lauszus/Sanguino.

Feeder

Feeder is MK8 style, feeder wheel diameter is 10.95mm, assumed circumfence:

(10.95-0.1) * pi = 34.1mm

Feeder spring set to it's lowest/weakest setting and removed the threaded rivet to lower the spring force even more.

Stepper current

VREF = 8 * Imot * 0.1ohm

Increased stepper motor vref/current to:

X: 0.65V -> 0.81A Y,E: 0.75V -> 0.94A Z: 0.60V -> 0.75A

Bill of materials

FRS:

• EMS Sensor
• FRS housing
• 6mm stahl heatbreak mit teflon inliner (aus 30mm heatbreak können 2*15mm gemacht werden).
• 4mm pneumatic coupler (M6)
• 3/2mm ptfe liner
• Ribbon cable and connectors

Hotend:

• 0.8-er nozzle
• O-ring 4.5 x 2 mm

Misc

For better support of the wobbly printbed i printed and installed the Ender 5 bed support_flat by freudi85 (http://www.thingiverse.com/thing:3447280).

Notes

Mainboard power supply per USB, that means it is always running if USB is connected, even if main power supply is switched off. Printer state gets out of sync if power is switched off, no reset of printer without disconnecting USB and powering off.

Todo: improvements

• Bowden tube pops out of hotend after some time. Bowden tube moves inside pneumatic coupler and develops a grove. Check how we can improve this (perhaps some clamping of the ptfe tube).
• Z-Endstop seems to be not very reliable/repeatable.

Nice to have

• Ventilator feeder da direktantrieb (spannung bereits am frs-kabel vorhanden).
• Stronger heater (50W)

First prints

Some prints done with the Ender5 ddPrinter (more here):

XCat remote control housing, printed with Herz Petg filament, sliced with 0.8 mm nozzle, 0.25 mm layerheight and 65 mm/s printing speed (this is a max flowrate of 13 mm³/s). Weight of the printed part is 524 g, this is 95 % of the slicer-estimated weight (550 g, density 1.29 g/cm³).

More XCat parts.