For manufacturability, we recommend that the connector housings match the pin number of the headers that they plug into. This makes it less likely that a mistake will be made during assembly, since there are fewer possible ways to plug it in.
I think for the servo signal we could even get away with an 8 pin double stack filled with dummies. The servo signals are on the 3rd pinset from the left of the board on the 24 pin header, and an 8 pin would go one row past that position.
We have seen a couple instances so far (2 through email, and 1 over phone) of the 10 pin header coming loose from the Archim board during shipping. This is leading to false errors from the filament sensor and their second extruder not lowering right out of the box. When I mentioned this in MER meeting it was suggested that adding additional pins to the blank pin slots would help to improve the fit of this connection and hopefully help prevent this issue in the future. Could we reconsider adding pins to the blank slots on this ten pin header to stabilize it?
Ticket ID's related to this issue:
I looked at the drawing and it's not clear that there should be blank pins there, not only that, but it not particularly efficient for production to build them that way. Probably best would be to have a latching connector that only plugs in one way like the motors or thermistors. This would also solve this issue: https://code.alephobjects.com/T3426. That fix is a little harder though because it would require an Archim rev. Another thing we could try is using a little hot glue on the connector housing where it touches the board. If done right, this will hold it in place without being too difficult to remove. @mjpelletier I'm interested in any suggestions you have to mitigate this issue.
Hot glue is something that is frequently used for this purpose, but would be very tedious in this case given the size of the header being attached to and close proximity of other board mounted components.
If we find a location suitable for this, it may be better to attach and glue this connector prior to placing the Archim in the box in order to prevent other wires from being burnt by the glue gun tip.
Would a glob just to the right of this connector, placed on the exposed pins/against the connector be an acceptable option?
I agree that adding dummy pins is not a very efficient way to build these for production, however we have done dummy pins in the past, and i think this is a better option than hot glue.
The connector will only require 4 dummy pins. which are the EL-MS0059 (female molex) pins. These are not hard to install or remove if need be. The most time consuming part will be pre crimping the pins
And overall I think that dummy pins will be less time consuming that dealing with hot glue
btw, I'm confident that a design like this https://code.alephobjects.com/T3306#64439 would prevented issues like https://code.alephobjects.com/T3307#140910 due to the fact that the wires with latching connectors are attached to and supported by the wires without latching connectors so they are held in place better. This is essentially the same fix that Mark is suggesting now for https://code.alephobjects.com/T7785, just for all the wires instead of just two.
I just encountered a client who is having a issue with his actuators not moving when he is doing a dual print. Still waiting to get pics of the Archim but I was able to recreate the issue in house.
I removed the cable connection for Servo 1 and Servo 2 (The cable below the LCD cable on the Archim board) Then I powered on the printer and tried to do a filament change and just switch between the two extruders. Extruder 1 remained in the lowered position and when I would select extruder 2 it would not raise and extruder 2 would not lower.