Twist Snap

Overview

The twist_snap module provides two Part objects for generating twist-snap connectors, useful for connections that are meant to be opened repeatedly.

All linear dimensions are in millimeters.

Clearance

TwistSnapConnector is built at nominal size. All fit clearance lives on the socket, which opens its bore and snapfit recess by its own tolerance. That is why the connector takes no tolerance argument: applying it to both halves would double the gap.

Pass the same connector_radius, snapfit_radius_extension, snapfit_height, arc_percentage and snapfit_count to both halves so they mate; only the socket takes tolerance and wall_width.

TwistSnapConnector

arguments

• connector_radius: the base radius of the connector mechanism
• arc_percentage: the percentage of the arc that the snapfit will cover
• snapfit_count: how many snapfit mechanisms to add
• snapfit_radius_extension: how far beyond the connector the snapfit extends
• wall_depth: the depth of the wall mechanism
• snapfit_height: the height of the snapfit mechanism

TwistSnapSocket

arguments

• connector_radius: the base radius of the connector mechanism
• tolerance: the clearance between the connector and the socket
• arc_percentage: the percentage of the arc that the snapfit will cover
• snapfit_count: how many snapfit mechanisms to add
• snapfit_radius_extension: how far beyond the connector the snapfit extends
• wall_width: the thickness of the wall mechanism
• wall_depth: the depth of the wall mechanism
• snapfit_height: the height of the snapfit mechanism

Example

from build123d import Axis, Location
from b3dkit import TwistSnapConnector, TwistSnapSocket

connector = (
    TwistSnapConnector(
        connector_radius=4.5,
        snapfit_height=2,
        snapfit_radius_extension=2 * (2 / 3),
        wall_depth=2,
    )
    .rotate(Axis.X, 180)
    .move(Location((0, 0, 15)))
)

socket = TwistSnapSocket(
    connector_radius=4.5,
    tolerance=0.12,
    snapfit_height=2,
    snapfit_radius_extension=2 * (2 / 3),
    wall_width=2,
    wall_depth=2,
)