当你刚开始使用PCB编辑器进行一个新的项目设计的时候，系统只有一种默认的线宽 - 0.25mm(9.84mils)， 如果你想改变走线的宽度，你需要创建一个定制化的线宽。例如我们要让一个电源走线能够在30mm的长度传输1A的电流，最高温升不超过10摄氏度，使用KiCad自带的计算器计算得到走向的线宽为大约0.3mm，我们可手工设定这个电源网络对应的走线宽度。
The Track drop-down menu; there is only one width available by default.
By default, this drop-down offer a single track width option: 0.250 mm. In this recipe, you will learn how to add '0.30 mm' as a track width option in the top toolbar drop-down menu. You can also use the exact same way to add custom Via sizes.
我们也可以用这种方式来添加定制化的过孔尺寸。 在PCB编辑器中，启动电路板设置按钮，我们可以使用下面的三种形式之一:
无论任何方式，都会得到下面的结果:
电路板设置窗口，选中的走线和过孔
Select the Tracks & Vias pane, under Design Rules. There, you will see three columns: Tracks, Via and Differential Pairs. There’s a “+” button at the bottom of each column.
来添加几个定制的宽度和过孔尺寸。每增添一个，点击”+“按钮，在相应的框里输入你要的数值，
在这个图中你可以看到我定制的走线和过孔
图: 电路板设置窗口， 选中的走线和过孔以及增加的定制化线宽和过孔
点击”OK“确认改变，线宽和过孔的下拉菜单变成下面的新值
图: 线宽下拉菜单包含了定制的值
Let’s test that you can create a trace with the custom with. First, select the '0.30 mm' option from the track width drop-down menu. Then, use the 'X' shortcut or click on the Route Tracks button from the right toolbar to enter the track drawing mode. Draw a new track in the Page. Type 'Esc' to end the drawing, and choose the '0.25 mm' option from the track width menu. Draw another trace and compare its width to the first. I have also added a third trace, with 0.40 mm width. Notice that the traces have a different width?
Figure 26.5: Three traces with different widths.
You can change the width of a track at any time by using the trace’s properties window. Place your mouse on the trace, type the 'E' shortcut (for 'Edit') and select the desired width from the Width drop-down menu (see Figure 26.6).
Figure 26.6: How to change the width of a track via the Properties window. Click OK to make the change effective.