PCB Express Tips (PCB Express doesn't suck)

[George Giblet]

The motivation for this post stems from the "small pad" problem with the PCB Express libraries.

This posts shows how to fix this problem by making your own libraries.

PCB and schematic programs come with supplied with part libraries.  For the beginner this is great because it gets you up and running relatively quickly.  However what beginners might not know is you can create your own schematic and PCB parts.  In fact some supplied libraries are often so crap you *have to* make your own.  Moreover, the supplied libraries cannot possibly cover all the parts in the world, this is particulary true for PCB mounted connectors and switches, so there's cases where you will need to create a custom part.

Many schematic and PCB packages provide library editors, which are another layer of junk you have to learn.  PCB Express doesn't have a library editor as such, it uses the normal PCB app. to create library parts.

I often create special PCB libraries for hand made boards which have larger pads.   Professionally made PCBs are have different constraints to the handmade ones.

OK that's enough background.

As far as increasing the pad size goes the idea is this:  you edit the existing parts, make the pads bigger then save them to your own custom PCB library.  PCB Express has support for custom libraries.

Here's the steps:
1) Select a component: Component Menu -> Component Manager, Select the part (make sure Library Components is ticked), click the "Insert into PCB" button.
2) Select the component, then Component Menu -> Ungroup
3) Double click on the pad, select a new pad size from the list
4) Component Menu -> Group
5)  Component Menu -> Save Custom Component, choose a name
     I recommend using the same name as the existing part with "Large Pad" appendend to the end.
     Probably the easiest way to do this is to have a Windows Explorer menu open
     at C:\Program Files\ExpressPCB\PCBComponents_Library then select rename, control C to steal the
     component text, then past it back into the save custom component textbox and type Large Pad at the end.

Note in (3) you can change individual pad by removing the selection on the component.  However you have to select the component again when you do the grouping in (4) before you can save a valid library part (in 5).

I suggest play around with a few test parts to get the hang of it before you do the whole library, just in case you haven't go things right.

Repeat for all the components you use.

When you make a PCB choose components from your custom library instead of the standard libary.  You do this by selecting "Custom Component" after doing Component Menu -> Component Manager.  You will get a new list of your parts.

The custom PCB libraries are stored in the folder:
C:\Program Files\ExpressPCB\PCBComponents_Custom

I suggest you back this up once you create the parts.  If you have to install PCBExpress on a new machine just copy your custom PCB library  files back into the folder C:\Program Files\ExpressPCB\PCBComponents_Custom and they will be there ready for use.

Good Luck.

[gak]

thanks a lot man! i've never knew how to create custom components 
i think now i'm gonna be a little less lazy when i need to make a layout 

[Satch12879]

Or you could just have ExpressPCB make the boards for you, then no pad hole drilling problems!

[moosapotamus]

I just refreshed the links in this thread that I posted a while back...
http://www.diystompboxes.com/smfforum/index.php?topic=33026

You'll find a *.zip file that contains a bunch of custom components I created, with bigger pads. 

~ Charlie

[Peter Snowberg]

Excellent thread!

Thanks George and Charlie!

And to repeat Satch12879's comment....

     Or you could just have ExpressPCB make the boards for you, then no pad hole drilling problems! 

[no one ever]

 

[LyleCaldwell]

My recent ExpressPCB board:



Aside from some caps and the TO-220s, I think every component and wire pad I made myself based on manufacturers' datasheets.  The power jacks and the pushbutton switches were the trickiest, but no more than 5 minutes each.

[no one ever]

so the stock pads are too small even when ExpressPCB does the board for you?

[LyleCaldwell]

No, they can drill any hole size you specify.  But I was using many components that aren't in the library, and I was using some components that differ from those in the library.  On those, I got the manufacturer's specified hole sizes and distance between holes and made components.

For example, the two pushbutton switches and the two power jacks were both things I made to fit specific parts.

At the other end, the resistors in the library were apparently done for larger carbon resistors.  I didn't need all that room for the 1/4W metal films I use, so I made new "small resistor" components.  Same for the diodes.  I could have used the stock components for those but I was better able to use the PCB space (and use a smaller board) by making my own custom versions.

[bwanasonic]

so the stock pads are too small even when ExpressPCB does the board for you?

The stock pad (.056" / .029" hole) is fine for most component leads, but can be a little tight for off-board wiring if you use heavier than 24 gauge wire. I bump the pad size up to .065 / .035" for most components, and a slightly larger pad for off-board wiring.

Kerry M

[no one ever]

No, they can drill any hole size you specify.  But I was using many components that aren't in the library, and I was using some components that differ from those in the library.  On those, I got the manufacturer's specified hole sizes and distance between holes and made components.

For example, the two pushbutton switches and the two power jacks were both things I made to fit specific parts.

At the other end, the resistors in the library were apparently done for larger carbon resistors.  I didn't need all that room for the 1/4W metal films I use, so I made new "small resistor" components.  Same for the diodes.  I could have used the stock components for those but I was better able to use the PCB space (and use a smaller board) by making my own custom versions.

Ah. well at any rate, great job. From the looks of it, you'll have a small following soon! Good Luck with that.