As stated in the Manufacturing Overview and Capabilities chapter, rivets are used to produce a through-hole connection between copper pads on opposite sides of the base material. The list of available rivet dimensions for four different sizes is reproduced in Table 6.3.1.

Table 2.3: Rivet Dimensions
There are four rivet sizes available.
*UPDATE: Due to a recent tool failure, the two smaller rivet sizes are temporarily unavailable.

The rivets used are part of the LPKF EasyContac set, which includes an automatic rivet-punch and an anvil. Instructions to attach the rivets are elegantly provided in the LPKF EasyContac user manual and will not reproduced here. Rather, a set of design guidelines will be provided. A set of successfully formed rivets is shown in Figure 6.3.1.

Figure 6.3.1: Successfully Formed Rivets.
These are to be occupied by female header pins.

After completing the design for a PCB, any holes of diameter 0.6, 0.8, 1.0, or 1.2 mm that require through-hole plating should be increased in diameter to 1.3, 1.6, 2.2, or 2.6 mm respectively, to accomodate a rivet.

Unfortunately, the collar diameter of some rivets limits how closely the rivets may be spaced together. For example, male header pins require a through-hole of approximately 0.9 mm in diamter, which means a 1.0 mm rivet could be used. However, these header pins could not be placed in a row as intended because the pin pitch is 0.1″, which means the collars of the rivets would intersect and short out. This may be overcome by clipping the edges of the rivets before insertion to give them extra clearance. This is a manual process however that takes a very long time for many rivets.

Another unfortunate limitation is an incompatibility with certain solder mask designs. This means that for the 0.6 mm rivets set in a default sized pad, the automatic punch will crush the solder mask surrounding the rivet unless extra solder mask clearance is given. An easy way to achieve this is to increase the pad size of the through-hole so that only bare copper is exposed to the automatic punch. Alternatively, the negative mask can be adjusted to not apply solder mask so close to the rivet.

Figure 6.3.2: Solder Mask Smashed by Auto-Punch
While not technically harming device operation, the crushed solder mask greatly reduces the aesthetic quality of the PCB.