CORE One INDX Filament Sensor Top with PC4-M10 Connectors on Input

When printing in a relatively humid location, it is preferable to print directly from filament dryers or dry boxes, keeping the filament enclosed in PTFE tubing all the way to the printer.  This filament sensor top for the CoreOne INDX was designed because the standard sensor top has no facility for attaching PTFE tubing to the input side.

This model is based on the R1 version from Prusa, redrawn in CAD, then modified to add PC4-M10 connectors on the input side.  If you prefer to have collets on the input side rather than PC4-M10 connectors, please see my other sensor top design: CORE One INDX Filament Sensor Top with PTFE Collets on Input.

It is easier to load filament without tubing on the input side, and both collets and PC4-M10 connectors make it more difficult to disconnect the input tubing.  For quick disconnect, you may want to add an in-line magnetic coupler close to the filament sensor top (the “collet” model linked above has a picture showing this solution).

This model is optimized for 2.5mm ID tubing to provide a smooth transition to the internal structure of the sensor.  If you are still using 2mm ID tubing in your setup, consider upgrading it all to 2.5mm ID since it also reduces friction.  Since the input tubing provides a direct interface within the sensor, the input sleeves provided in the kit from Prusa are not used with this model.

There are two different sets of models with numbers, plus one that has a blank surface (no numbers):

1. Embossed:  The numbers are recessed; perfect for single color prints.

2. Multi-part:  The numbers are separate parts in the model, allowing them to be assigned different colors in the slicer.  Either load the .STL file into your slicer and split it into separate parts, or load the .3mf project (which is already split up), then change the printer and filament to match your setup.

3. Blank:  No numbers; perfect for adding your own embossed text, labels, laser etching, etc.

Design Features:

• No supports required

• Drop-in replacement for the original sensor top

• Allows using PTFE tubes on the input side to isolate filament from the environment between a dry box and the printer.

• Optimized for 2.5mm ID x 4mm OD PTFE tubing for smooth transitions between the tube and the sensor (2mm ID tubing not recommended).

Parts Required:

• 4 PC4-M10 connectors per sensor block. I used these from Amazon: PC4-M10 Male Straight Pneumatic PEFE Tube Connector.

Printing Notes:

• Print using a 0.4mm nozzle, 0.2mm layer height, structural, 15% infill.

• Since the connector threads are printed on the side, 0.15mm layer height will produce cleaner threads (particularly at the top and bottom of the holes).  However, I didn’t find this necessary.

• PETG is recommended, but PLA should also work since the sensor assembly is mounted outside the enclosure.

• Please DO NOT use the .bgcode files that have been provided (always slice your own files for your specific printer, filament, environment, etc.).  The files were only included to provide a reference for approximate print time.

Assembly Instructions:

1. Follow the instructions from Prusa for the assembling the filament sensor top, except for inserting the input sleeves since they are not used with this design.

2. Screw the PC4-M10 connectors into the sensor top.  Be very careful when threading the connectors (at least for the first couple turns); ensure that the connectors are straight to prevent cross-threading.  If you notice that there is excessive resistance or the connector is not straight, then stop, unscrew it, and start again.

3. Cut the ends of the input tubes straight.

4. Push the input tubes all the way through the connectors until the end of each tube is flush against the inner surface.