D-Sub Connector Hood – DE9 / DA15 / DB25, closed with cable ties, no screws

What it is

A two-part printable hood (backshell) for D-Sub connectors with solder cups, in three sizes: DE9 (often called DB9), DA15 and DB25. It fits on a connector you have already soldered. The two shells are held together by cable ties instead of screws: one tie around each ear and one around the neck at the cable exit. A fourth tie inside the hood acts as strain relief. The ties sit in grooves just below the surface, so nothing sticks out except the tie heads, which rest in pockets.

The flange of the connector sits in a slot, the D stays free at the front, and both mounting holes stay usable (room for 4.8 mm hex standoffs / jack screws of the mating connector). It works with plugs (male) and sockets (female).

What you need per hood

• 2 printed shells (top and bottom)

• 4 cable ties, 2.5 mm wide, 100 to 200 mm long (3 to close the hood, 1 inside as strain relief)

• optional: heat shrink tubing for the solder cups

No screws, nuts or glue.

Sizes

For a different cable, change the channel diameter in the CadQuery source (see below).

Print settings

• Material: PETG (PLA should work too, but is untested)

• Nozzle 0.4 mm, layer height 0.15 mm

• No supports. Print each shell with its outer face on the bed and the parting face up, exactly as oriented in the STL files.

• Printed with the stock PrusaSlicer profile "0.15mm SPEED" for the Prusa CORE One (2 perimeters, 15 % infill). The 3MF files contain this profile and both shells of one size on a single plate.

• Estimated time and filament for both shells (PrusaSlicer 2.9.6): DE9 25 min / 7.0 g, DA15 27 min / 8.3 g, DB25 33 min / 10.8 g

Tip: print one bottom shell first and lay the connector flange into the slot. It should sit without clamping and without rattling.

Assembly

1. Insulate the solder cups (heat shrink), bundle the wires.

2. Lay the connector with its flange into the slot of the bottom shell and lead the wires through the cable channel.

3. Close the strain-relief tie around the bundle inside the chamber in front of the rear wall, then cut it short. If you pull the cable, this tie stops against the wall.

4. Put the top shell on. The small collars on the top shell fit into pockets in the bottom shell and align both halves.

5. On each side, push a tie from the top through the slot in the ear, lead it out underneath, up along the narrow side, and into its head. Put the head into the pocket of the top shell, pull tight and cut flush.

6. Put the third tie around the neck, head in the pocket on top, pull tight and cut flush.

Opening

Cut the three outer ties at the head with side cutters, not at the hood. Use new ties to close it again, or releasable ties of the same width if their head fits the pocket.

Notes and assumptions

• Designed for standard 2.5 mm cable ties: band about 1.05 mm thick, head about 5.0 x 4.2 x 3.4 mm. If your ties are thicker than 1.2 mm or the head is wider than 4.6 mm, adjust the parameters in the source and regenerate.

• Connector geometry follows the standard dimensions of MIL-DTL-24308. The fit was checked in CAD for plug and socket, each with the mating connector fully inserted and 4.8 mm standoffs. Solder-cup length varies between makers; the hood leaves room for cups up to about 10 mm behind the front of the flange.

• The cable ties are what hold the hood together. It is meant for cables at a desk or inside equipment, not as a load-bearing part.

Print status (honest)

• All three sizes were printed in Prusament PETG on a Prusa CORE One, 0.15 mm SPEED profile, without supports.

• DB25: assembled with a soldered socket, wires and cable ties (photos 1, 2 and 4).

• DE9: shells printed and fitted together (photo 3). An earlier DE9 test print confirmed that the flange fits the slot.

• DA15: printed, not yet assembled.

• Not tested yet: long-term use, pull force on the strain relief, printing in PLA.

The photos show the real prints; the other images are renders of the CAD model.

Files

• <size>_hood_top.stl, <size>_hood_bottom.stl: shells in print orientation

• <size>_hood_plate_PETG_CoreOne.3mf: both shells on one plate, with print profile

• <size>_hood_assembly.step: both shells in assembled position, for your own CAD work

• create_hood.py, create_subd_step.py: the parametric CadQuery source

• <size>_hood_plate_PETG_CoreOne.bgcode: ready-to-print G-code for the Prusa CORE One (PETG, 0.15 mm, both shells on one plate)

Source

The model is parametric and written in CadQuery (Python). The source is included as two Python files, so you can change cable diameter, clearances or tie size and generate your own version. Put both files into one folder, install CadQuery 2.8 (pip install cadquery==2.8.0) and run python create_hood.py de9 da15 db25 --kabelbinder. The shells are written to <size>_kabelbinder/ (*_haube_oben.stl = top, *_haube_unten.stl = bottom, plus a STEP assembly). All parameters are in the HoodParams dataclass at the top of create_hood.py (comments in German), for example kabel_d and klemm_d (cable channel, clamp ribs), schlitz_spiel (flange slot clearance), binder_b, binder_t and binder_kopf_* (cable tie size).

How it was made

The model was designed with AI coding agents; I set the requirements and checked the prints.

License

Creative Commons Attribution 4.0 (CC BY 4.0): anyone may use, change and also sell it, as long as the author is credited.

Kurz auf Deutsch

Zweiteilige Haube zum Drucken für Sub-D-Stecker und -Buchsen mit Lötkelchen, in drei Größen: DE9 (oft DB9 genannt), DA15 und DB25. Die Schalen halten ohne Schrauben: Je ein Kabelbinder läuft um die beiden Ohren, ein dritter um den Hals am Kabelausgang. Ein vierter Binder innen dient als Zugentlastung.

• Du brauchst je Haube 4 Kabelbinder 2,5 mm (100 bis 200 mm lang), optional Schrumpfschlauch für die Lötkelche.

• Druck: PETG, 0,15 mm Schicht, ohne Stützen, Außenfläche aufs Bett, Trennfläche oben wie in den STL.

• Montage: Stecker mit dem Flansch in den Schlitz der unteren Schale legen, Zugentlastungs-Binder innen schließen, obere Schale aufsetzen, die zwei Ohr-Binder und den Hals-Binder einfädeln, festziehen, bündig abschneiden.

• Öffnen: die drei äußeren Binder am Kopf durchtrennen, zum Schließen neue nehmen.

• Gedruckt sind alle drei Größen. Die DB25 ist mit Buchse, Litzen und Kabelbindern montiert, die DE9-Schalen sind zusammengesetzt, die DA15 ist noch nicht montiert. Langzeitgebrauch und Zugkraft sind noch nicht erprobt.

• Der Quelltext liegt als parametrisches CadQuery-Modell bei (zwei Python-Dateien). Lizenz CC BY 4.0: Jeder darf es nutzen, ändern und auch verkaufen, wenn er den Urheber nennt.