SnakeOil-XY Preparations: CANT Board

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Introduction

Many new printer designs include a toolhead board that allows all the electrical parts to be controlled by a bus, mainly CAN. The main advantage is the reduced wire count. Fewer wires are prone to fail due to cable movement and it’s less expensive (especially FEP/PTFE insulated wire). Examples for these boards include:

The Beta 2 version of the SnakeOil-XY 3D-Printer includes a “CANT-Board”. From the name, you may already realise that it is not a CAN-bus powered board, but instead it just adds a new layer of connectors to the toolhead.

By combining ground nets, you save yourself a few wires and maintenance on the extruder is much easier. Additionally, PVC wires are prone to fail after few print hours, so the CANT Board is an easy way to cleanly connect components via FEP-wires.

The board was designed by ChipCE and is released with the SnakeOil-XY files under GNU General Public License v3.0. You can find the files for it on GitHub.

Connection overview

Motor Connector

Attach extruder motor here, 4 pin connection: A1 A2 B1 B2

Fan Connectors

Attach part cooling and Hotend fan here. All three pins are connected individually, to allow for custom voltages and a tacho pin: A B C

Probe

Connection depends heavily on type of probe, but you have two signal lines and a BL-Touch inspired pinout available. Please note there is no BAT85 onboard and you would have to add that on the mainboard side: VP GND S1 S2 GND

X-Endstop

Attach simple 2-pin Endstop towards ground here: X_END GND

Thermistor

Attach a 2-pin Thermistor connected to ground here. Take special care to connect the right pin on the mainboard voltage divider. PT100 and similar can’t really be used here: TEMP GND

Heater

There is no connection for a heater on the CANT board, so you can use a single wire gauge. I will use an external Microfit connector for the heater.

Interactive PCB viewer

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Parts and Assembly

Most of the parts can be purchased from Digikey, including genuine Molex and JST connectors. The 16 Pin Microfit Connector is part number 0449141601 from Molex, and the other connectors are JST-XH.

Don’t be shocked by the high price, at 6€/piece, Molex is always way too expensive in my opinion!

Make sure to order the respective headers and crimp contacts too. C1 is a 100nF capacitor in 0805 size with a minimal voltage rating of your probe voltage plus margin (for example 50V). It acts as a decoupling capacitor to smooth out the voltage on the probe.

Use two M3x6mm and one M3x20mm screw to fasten the PCB to your toolhead.

I ordered the JST XH connectors with boss by accident, which didn’t do much harm after some modifications with a knife.

I highly recommend ordering the PCB from Aisler, because they offer very competitive pricing, local manufacturing and free shipping. You can order the PCB version beta 2 here for 9,07€ including shipping. Alternatively, you may check out ALLPCB, who were active on the SnakeOil-XY Discord server a while ago.

Start by soldering the SMD resistor, then the Microfit connector. Even though the footprint for the connector comes directly from Molex, it was a very tight fit for me. Be very careful while inserting and use as little stress as possible, ideally by pressing it in with a vice and some spacers. Apparently this is on purpose for less expensive machine soldering.

After soldering the JST-XH connectors, I advise you to clean the solder joints to prevent rusting.

It’s now ready to be installed. You could use a second board on the mainboard side, but I chose not to because more connectors mean more resistance and higher failure chance.