Progressive Wiring Techniques 手工PCB繞線的先進佈線技術

Progressive Wiring Techniques (手工PCB繞線的先進佈線技術)



To build a circuit board in hobby work, there are some wiring materials. I think many people are using a protobord with PTFE wire to buid a circuit board. However the PTFE wire is not suitable as wiring material for protoboard because there are following problems.

• PTFE wires on the circuit board tends to be bloated due to thickness of the insulator.
• Re-wiring an underlying wire is difficult.
• Efficiency of wiring work is not good, each end of the wire must be stripped to be solderd.

So I recommend to use a UEW for protoboard. The UEW is polyurethane enameled copper wire which is used for small inductors and transformers. This wiring method may be a minor way. However, it solves that problems, so that it is better than PTFE for wiring on the protoboard.

To wire in UEW, a wiring tool that called wiring pen is used. The wiring pen is often sold with PCB kits, however, they are not useful because its tip is dull and weak for heat :-). When you could not satisfy bought wiring pen, it can also be built yourself easy. I built a wiring pen from a cheap drawing pen.

According to some trial, 0.16 or 0.2 dia UEW is the best for the protoboad. This is equivalent to 0.5 or 0.9 mm width printed pattern. Its insuration is sufficient for low voltage circuits such as a logic board below 12 volts.

 
It is very easy to wire in high density layout, even if parts are mounted on the board without free space.

 
Left image shows the solder surface. There is a space on the board cosidering the wiring density, because the polyurethane enamel is very thin. It will become a dish of pasta easy when wire it with PTFE wire :-)


 
This is a wiring pen that I built.

But Recently...

PI(PolyImide),KAPTON® 絕緣膜/膠帶 

In early time, I had wired in avobe method that wire in wind-and-lead like daisy chain. However, it is not suitable for wiring random logic, analog circuit and surface mounted devices. To wire in point-to-point like wiring with PTFE wire is better for them. Now I am working in this method. The polyurethane coat at end of wire is weak in heat so that pre-soldering to the UEW without any stripping process is also easy. 350°C of tip temperture is recommended for UEW.

I am using only through holed protoboard, cut leads at solder surface to zero height, this can wire smoothly and can prevent to damage polyurethane coat by leads edge.

How to mount SMD

To mount SOP or QFP devices, most will use pitch conversion boards. However the conversion board is expensive and require mounting area, it is not smart method. Thus I am mounting that devices on the protoboard directly.

To mount the SMDs without pitch conversion board, put a polyimide (Kapton) tape on the board to insurate, bond the deivce on the tape and wire each lead. The polyimide is heat resistant material which is used for high temperture insurator, film cable and PCB. It can work up to 200°C continuous and resist soldering temperture. To solder wire and lead, pre-solder wire and lead, press wire to the lead with soldering iron, will easy.

Example :