Help needed finding right connector type to use

Thread Starter

DaveWW00

Joined Aug 6, 2021
1
I am working on building a new 3D printer (RatRig VCore 3) and would like to improve wiring on it. One of the things i am thinking about is creating a small breakout board that takes one cable/connection coming in from control board/power and splits it into connectors going to all the fans, sensors, etc on the hotend. Will be my first try at pcb design but i think i can figure that out. I quickly sketched up what i was thinking below for board. White plugs would be jst connectors or terminal blocks going to the fans, sensors, etc. Blue one is what i could use some help on. I was looking on Mouser and other places and there is just so many options and i just dont know enough to weed through them all to find what would work best for me.
Hoping somebody can point me in the right direction with specific type to look into. Here are my requirements for it.
  • 20 Pins
  • Connection needs to stay secure with movement (this will be on print head whizzing back and forth). If connection gets loose just for second on some of the sensors the controller would stop print.
  • As small as possible to eliminate bulk that would get in way of other things and dont want it too heavy.
  • Would prefer its connection to board would be thru hole pins that i can solder on.
  • Does not need to be waterproof or anything crazy like that.
  • Dont care if connector is round or flat, guessing round would be less bulky though.
  • Was looking at using this cable to connect to blue connector since i read it was good for repeated movement (https://www.igus.com/product/1074?artNr=CF211-PUR-05-14-02)

breakout board.png

Thanks!
 

strantor

Joined Oct 3, 2010
5,667
20-pin D-sub? Basically same connector as RS232 serial (9-pin) or a VGA monitor (15-pin) connector, but with 20 pins. It's a good solid connector (captive with screws) and about as small you probably want to go; Anything with more contact density is very challenging to solder.
 

ErnieM

Joined Apr 24, 2011
8,183
I make the count 6 low current (HE fan, Part fan, HE thermocouple), and 2 power pins for the HE heater. The heater has the only significant current, or about 2 amps for a 50W heater on a 24V system. Double that for a 12V system

Most garden variety DSUB connectors can handle 3A per pin so a 9 pin conn should be fine on a 24V system.

dsub9.jpg
 

MisterBill2

Joined Jan 23, 2018
9,463
There are a lot of connectors available that mount thru-hole on a circuit board. The challenge then being to produce the board with the correct hole positions.
An alternative is connectors with pin spacings of 0.100 inch, in which case you get to use standard perf board and wire the connections. The other challenge is the wire side of those connectors, either crimp or solder, and the wire support beyond the connection. If the assembly needs to be reliable then the wires need support separate from the actual connection point. Chek out the Digikey catalog for connector information.
 

MrSalts

Joined Apr 2, 2020
617
There are a lot of connectors available that mount thru-hole on a circuit board. The challenge then being to produce the board with the correct hole positions.
An alternative is connectors with pin spacings of 0.100 inch, in which case you get to use standard perf board and wire the connections. The other challenge is the wire side of those connectors, either crimp or solder, and the wire support beyond the connection. If the assembly needs to be reliable then the wires need support separate from the actual connection point. Chek out the Digikey catalog for connector information.
PCB Footprints for many connectors are available on Mouser.com and, it they are not available, you can request one and it magically appears within 24 hours. I don't know how they do it but I started buying parts from Mouser just because of this service.
 

MrSalts

Joined Apr 2, 2020
617
If it is all signal wires, no high current over 500mA, then you can use Flat Flexible Cables (FFC).
1628341200677.png1628341247956.png
Connectors are available in through-hole layout. Look specifically for brands (model numbers) that can withstand a high number of flex cycles. These are the types of cables commonly used in inject printers. Make sure you have some type of cable restraint in your equipment design so the flex is not at the connector. The ribbon should come straight out of the connector snd then be fixed for the next 5 to 10mm so there is no strain to pop the cable out of the connector.
Some cables can handle over 1 amp but I generally stick to 500mA. Also, if you need more power you can use a cable/connector set with more "channels" (eg 24 instead of 20). Then you can parallel several together to get clean power out. If, however, you need 2 amps, you parallel 4 power channels together but you'll need 4 channels on ground (or power return if you switching is done at the supply board).

cables are available with a wide range of pitches (distance between individual "wires". Hand soldering of 1mm pitch is fairly easy with the right tools. That means a 20 channel cable is only 20mm wide and very easy to work with in 3D printer space.
 

MrChips

Joined Oct 2, 2009
24,398
The first thing that comes to mind is a 2x10 IDC connector.

1628344034992.png

For signal integrity I would put GND on one side which would place GND on ever other wire.
For higher power I would choose a different type of connector such as Molex.

1628344217499.png
 

MaxHeadRoom

Joined Jul 18, 2013
23,779
PCB Footprints for many connectors are available on Mouser.com and, it they are not available, you can request one and it magically appears within 24 hours. I don't know how they do it but I started buying parts from Mouser just because of this service.
Digikey also offer schematic component and footprints for their inventory.
They are supplied by SnapEDA.
 

MrSalts

Joined Apr 2, 2020
617
The cable is #28 wire, or thinner, so current must be considered.
Current must be considered for ALL wire.
Ribbon cables as shown in post #7 are typically 28-gauge but available in 24-gauge. They are also available in thinner. Before going ribbon cable, check the durability for flexing. Typically stranded wires form stress points and crack after many repetitions. The foil that is either laminated and etched or slotted snd laminated to the Teflon, poly-imide or other durable film substrate use rolled foils with metal grain oriented correctly to maximize flexibility and endurance.
 

MrSalts

Joined Apr 2, 2020
617
Digikey also offer schematic component and footprints for their inventory.
They are supplied by SnapEDA.
They are available for some parts - missing on MANY parts. Digikey has no way to request a footprint if one is not provided and the turnaround time from the Mouser service is amazing - I don't know who programmed the AI that makes the footprints from the datasheets or if they have the children from some fairly tale locked in a cabinet making PCB footprints. Really a great service.
 
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