WIP - magnetic TitanClone, LJ12A3, RJ45 quickchange printhead

• WIP

• I saw that people were actually using my prior quickfit carriage, and figured they might be more interested in what i see as a better quickfit design, which am currently working on, and is essentially the reason I stopped... or moved on from.. working on the original levered quickfit style.

• The box that all of the wires connect to fits on top of and replaces the connectors on the side of the mega. (That's not obvious from the photos, so I'm just saying...)

• The magnetic attachment is extremely strong, but a little weird to insert initially, as it repels until the smaller magnets are at least slightly inside the larger ring magnet. I may tinker with a Halbach array (directed magnetic field) at a later time to mitigate/reduce this initial repulsion... but I suspect there isn't enough room between the belts and bearings to do that properly.

• I have printed and wired this for the most part, but installing and testing it hasn't happened yet due to the fact that I need to be relatively sure i wont need to disassemble and revert my printer to the prior version if I find out I forgot to include something which needs printing/fixing. So right now it's sitting on my desk while I tidy up design and think about it in general.

• AWG on all wires seems to be within spec for CAT6 and ~3.5A heaters. But I have been looking at this for a little too long now that there's a good change of serious oversight that something will get warm and drop volts/amps on it's way to it's target. So like I say: I'm still kicking this design around and haven't actually run it to print at all. There's probably something I intended but forgot to design around still lurking.

• I would prefer to use piezo as Z probe, but it seemed easier and an interesting variation to use an LJ12A3 inductive sensor initially.

  • This may also become relevant if i need to add another pair of channels for transferring sufficient power to the heater. ie: Piezo needs 2 conduits, inductive needs 3, plus the one spare means I could remove the inductive, add a piezo somehow, and use four channels/wires to power the heater.

• The inductive sensor requires a power supply larger than the board logic voltage, and is therefore hazardous to the sensor inputs. So you need to make a resistor voltage divider of sufficient wattage, or use a regulator. I plan to use a 7805 and see how hot it gets (still on order) [edit] NOPE: so will use a zener instead.

• Stuff I used/designed around

magnet-N35_8x3_3mmHole

magnet-N35_16x6_8mmHole

A10 1m CAT6 cables
https://www.aliexpress.com/item/1m-2m-3M-5m-40m-CAT5-100M-RJ45-Ethernet-Cables-8Pin-Connector-Ethernet-Internet-Network-Cable/32859856818.html

RJ45-quickConnector
https://www.aliexpress.com/item/RJ45-Cat5e-Cat6-UTP-Keystone-Female-Jack-Connector-Adapter-for-Wall-Platet-Wisted-Pair-RJ-45/32814933677.html

connector-RJ45_2X1_PCBmount
https://www.aliexpress.com/item/5PCS-1-2-RJ45-Metal-16-Pin-Female-PCB-Right-Angle-Board-Jack-Connector-8P8C-Crystal/32870301039.html

fan-4010_blower_12v_0.09a_tronxy-MASTER
https://www.aliexpress.com/item/TRONXY-3D-Printer-part-Fan-4010-Blower-40x40x10mm-12V-DC-Cooler-Small-Cooling-Fan-free-shipping/32847286624.html

fan_3015_sunon-Maglev
https://www.aliexpress.com/item/Original-SUNON-3015-0-4W-GM1203PHV2-8-30-30-15mm-12V-2-wire-3CM-cooling-fan/32743033877.html

voltageRegulator_L7805_7to25Vto5V1.5A
https://www.aliexpress.com/item/10pcs-lot-L7805CV-TO220-L7805-TO-220-7805-LM7805-MC7805-stabilivolt-voltage-regulator-tube-New-original/32922555790.html

inductiveProximitySensor_LJ12A3-4-Z-BX_NPN-DC6-36V_4mmNomDia
https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20190420222335&SearchText=LJ12A3

• Uses a bunch of M3 cap head bolts found in the usual assortments, ie: <30mm
  • All nuts are SQUARE