Hot-bar Software Board Design notes

Hot-bar reflow (molten Siena heat welding), the most common function is to use the heat of the melt has been printed on the electronic printing circuit (PCB) on the Siena paste, in order to connect two separate parts of the electronic components, the most commonly seen is the software line (FPB) welding on the electronic printing circuit (PCB).

Since the heat of the Hot-bar is the only source of heat, when the heat pressure is in the soft line (FPC) , it is necessary to transmit heat downward to the printed circuit board (PCB)in order to melt the Siena paste printed on the electronic printed circuit board, so the line There must be a heat-guided functional design.

Generally speaking, the welding Siena mattress on the plated hole (plating holes) or referred to as the guide Hole (Vias) for the most popular thermal function design, the following structure. Recommend that you have three vias on each FPC solder mattress, or 2.5 vias. The plated hole also has a good, in the melt Siena hot welding industry, can let the surplus Siena by the plated hole overflow, not to cause the weld mattress the short circuit.

The software line should be labeled with a double- sided adhesive, which is used to fix the wires on the printed circuit board , since it is unlikely that the operator will hold the FPC until the Hot-bar reflow is finished. In addition, it will produce a problem of unstable quality.

The design requirements for the FPC are summarized as follows (there is also a need for the design of the plated hole and the through hole, which will be discussed separately)

• Each FPC welding mattress preferably have three electrical plated hole or guide through hole, at least two + half electrical plated hole or guide through hole.
• In the software Line (FPB) stickers on the printed circuit board on the side of the adhesive, the thickness of the double surface should be less than 0.15mm, from the solder mattress of the FPC to the surface of the adhesive to the double-sided plastic distance to maintain a distance of 0.20mm.

The proposed Hot-bar board size is as follows:

• The hole diameter of the through hole is 0.4mm
• Guide through Hole Center to center for 1.2mm
• Solder Mattress Center to center distance 1.8mm
• Solder Mattress width of 0.9mm

In order to avoid focusing the power of the broken line, strongly recommend the wrong line of the Edge (cover film, Polymide) edge, refer to the following software line of the structure.

To work with Hot-bar to avoid pressure or damaged parts, here are the suggested parts location limits:

• The minimum size of the front edge of the part to the FPC is 2.0mm.
• The minimum size of the part to the left and right edges of the FPC is 3.0mm.
• When the FPC is extended outward, the minimum space of 5.0mm should be retained so that the FPC can be glued to the printed circuit board. You can also consider making a locating hole on the FPC and locating it on a thermal fixture with a locating column (Alignment Pins), which saves space on both the surface of the adhesive and on the printed circuit board, but it is necessary to consider the accuracy.
• The parts below the FPC have a minimum size of 10.0mm for the rear edge of the FPC (to ensure that the adhesive is glued to the printed circuit board).

Hot-bar Software Board Design notes