# Housing for the HCW-M421, XY-LJ02 module, snap-on without screws, with 4 buttons

- Page: https://sigmanortec.ro/en/housing-for-the-hcw-m421-xy-lj02-module-snap-on-without-screws-with-4-buttons
- Price: 24.37 RON
- Availability: In stock; 1-2 zile
- Reference: 5007 · EAN: 5947632421931
- Category: Mechatronics and IoT > The Box
- Specifications: Dimensions: 45 x 70 x 26.5 mm; Material: PLA, 3D printed; Weight: aprox. 40 g; Compatibility: HCW-M421 / XY-LJ02
- Package (shipping data): 0.034 kg
- Updated: 2026-10-22
- Shop: [Sigmanortec.ro](https://sigmanortec.ro/en/llms.txt)
- Prices: RON, VAT included; prices and stock as of 2026-11-11 01:49 (Europe/Bucharest)

## Description

3D-printed enclosure, snap-fit without screws, specially designed for the HCW-M421 / XY-LJ02 timer relay module, with four dedicated 9 mm buttons for STOP, SET, UP, and DOWN, a tapered window for the display, a hole for the status LED, and cutouts for both terminal blocks and the micro-USB connector, ideal for panel mounting or use on a workbench without looking like a prototype.
The enclosure is a 3D-printed mechanical part, specially designed for the HCW-M421 timer relay module, also known as XY-LJ02, which normally reaches the buyer as a bare board, with exposed terminals, small hard-to-press buttons, and an unprotected display. Mounted over the board, the enclosure turns the module into a finished device that can be placed on a table, mounted in an electrical panel, or handed on to a customer without looking like a prototype.
The assembly is done without any screws and without any metal inserts. The module board sits on four bosses with centering pins in the base, and four columns in the lid press on it and hold it firmly in place. The lid is pushed in by hand and is retained by six clips hidden inside the walls, so that on the outside no joint is visible other than the fine line between base and lid. The walls are 2.5 mm thick, sufficient for a rigid clip fit and for protecting the board inside.
Among the main features are four dedicated 9 mm buttons, aligned over the module tact switches and marked STOP, SET, UP and DOWN, which remain captive in the lid and do not fall out when the enclosure is turned over, a funnel-shaped window for the display that keeps the digits visible while hiding the board behind, a 3 mm hole for the status LED, embossed terminal labels on the bottom of the enclosure (6-30V, GND, TRIGGER, GND-T for the 4-pole block and NO, COM, NC for the 3-pole block), and cutouts for both screw terminal blocks and for the micro-USB connector. Through these cutouts, both power supply options of the housed module remain accessible, either through the terminal block at 6 - 30 VDC or through the micro-USB connector at 5 VDC, without needing to remove the board from the enclosure to change the power source.
Specifications:
Compatibility: HCW-M421 / XY-LJ02 timer relay module, 38 x 63 mm board, mounting holes at 31.8 x 57.2 mm pitch
Overall dimensions: 45 x 70 x 26.5 mm
Weight: approx. 40 g
Material: PLA, 3D printed, 2.5 mm walls
Components: base, lid and 4 buttons
Lid attachment: 6 internal clips, no screws
Board mounting: 4 bosses with centering pins and 4 pressing columns in the lid
Cutouts: 4-pole terminal block, 3-pole terminal block, micro-USB, display window, 4 buttons, status LED
Markings: button labels and logo on the lid, terminal legend on the bottom of the enclosure
Use:
Push the 4 buttons into the lid from the outside until you hear the retaining clip click; the buttons remain captive but slide freely in the pressing direction.
Place the HCW-M421 / XY-LJ02 module board in the base, with the display facing the window; the centering pins of the bosses fit into the board mounting holes and hold it in position.
Check that the 4-pole terminal block, the 3-pole terminal block and the micro-USB connector align exactly with the cutouts in the base wall.
Press the lid evenly along the full length of the board until the six internal clips fully engage and the lid no longer has play.
To disassemble, insert a wide screwdriver into the gripping slot in the base frame and gently lift one end of the lid, then continue along the length until the clips release.
Power the module either through the 4-pole terminal block at 6 - 30 VDC or through the micro-USB connector at 5 VDC, both directly accessible through the enclosure cutouts, without removing the lid.
Connect the load to the 3-pole terminal block, on the NO, COM and NC relay contacts, depending on the desired operating mode.
If the load controlled by the relay operates at dangerous voltages, for example 220 VAC, wiring to the terminal block must be carried out only by a qualified person, with the equipment disconnected from the mains, and the enclosure must be installed in a suitable electrical panel.
The enclosure is a 3D-printed PLA part, functional but not sealed; fine layer lines specific to 3D printing may be visible on the surfaces, therefore installation outdoors or in humid environments is not recommended.