Insulating Shim for DIO_SMA and TTL_SMA

This repository contains the designs of the electrical insulation shim for sinara-hw DIO_SMA and SMA_IDC_Adapter. This can prevent an electrical short between the front panel and the SMA connectors' ground. The design can be 3D printed or manufactured with a Mylar/PET electrical insulation sheet.

Note: SMA_IDC_Adapter rev v1.0 and DIO_SMA rev < 1.4.3 shares the same insulating shim design.

3D Printing Instructions

The shims are best printed on a FDM 3D printer, with nylon filament.

Use 0.15 mm layer height, and the shim should be printed with 2 layers.

To ensure success when printing nylon, it is strongly advised to bake dry the nylon filament in 80 °C for 4-6 hours before printing. Keep the filament in a dry environment when printing, and re-bake the filament if the extruded plastic contains bubbles.

As the shim design contains fine details that need to be adhered well to the print surface, a print surface adhesion solution is highly recommended. A mixture of 70 g of Polyvinylpyrrolidone (PVP) K-30 and 30 g of Polyvinyl alcohol (PVA) dissolved in 500 ml of 50% isopropyl alcohol makes for a good print surface adhesive. Apply the adhesive to a Polyetherimide (PEI) print surface before each print to maximize the yield of the printed shims.

Mylar/PET Electrical Insulation Sheet

Alternatively, an insulation sheet with hole cutouts can be manufactured. The insulation materials should be bendable, non-flammable and non-conductive. Materials like Mylar / PET are suitable for this application. Recommended thickness for the insulation sheet is < 0.15 mm.