I've developed a 3D-printable spring-loaded backing plate to provide support for the pins which are pressed inwards by the PLCC socket.
The logic behind this is to reduce the tolerance required in the 3D printing process.
A solid plug would probably be more stable in the long term, but 3D printer accuracy has to be high of the order of a tenth of a millimetre in the X and Y directions. My 3D printer isn't up to that.
The principle of operation is you print this slightly longer (say about 1-2mm) than it needs to be and it has enough flex to allow it to clip into place providing outward pressure to opposite edges of the PLCC plug.
A second version fits across the remaining axis. The pressure plates are the full height of the pins and the spring mechanism is half height, to allow crossing.
This model is configured for PLCC68 specifically, but if you have Fusion 360, the parameters may be changed for any size PLCC.
- Set the pressure pad width to be very slightly greater than the length of one row of pins (say pin strip length + 0.5mm). This cannot be too large otherwise it will clash with its neighbours.
- Set the length (distance pad to pad) to be 1-2mm longer than the distance between opposite pin strips. This means you have to compress the spring to fit and and this is what applies the pressure. If you need more pressure, make this distance longer.
- Set the height to be just shy or equal to the pin height, excluding the black plastic depth-control sheath.
- 3D print two copies.
- Load the bottom spring into your PLCC 'plug' first, making sure the pad applies pressure to the pins, no the plastic sheath. Pinch the middle of the spring or insert one pad and apply even force to the other to make a fit. The first spring should lie with the spring furthest down to allow room for the second.
- Repeat this procedure in the other axis, with the spring inverted this time.