spyghost

hi,

homemade double sided pcb's suffer the scenario of sodering when it comes to dealing with tight areas... samples of these tight areas are dip socket pins and various connectors (db connectors in particular)

is there a good way of soldering the top part of such components? in the case of a db connector, the soldering iron tip is too big to fit between the terminals attached to the pcb, thereby soldering cannot be made properly on top.

hot air soldering can reach tight areas, however there are risks melting the plastic casing of such components...

| *Component obscuring top layer
|___________
==|==|==|== A -> how can this layer be soldered?
==|==|==|== B -> can be soldered easily
\------ Pins------/

If A is obscured because of the physical construction of the component, then soldering the top layer would be quite a headache... B won't have problems since its the bottom and everthing is "clear" on that layer.

is there a way of soldering the top part of the pcb for the tight areas mentioned - particularly, w/o using vias for the attachement?

fat-tony

I'm not sure i'm quite following your diagram, but basically that's part of the design process. You make sure that it is in fact possible to solder all components on the board. . Sometimes you have a specific ordering that will allow you to do it, but it should be doable. If not, you probably want to redesign the board, since it'll be a pain in the ass to troubleshoot if it ever fails.

Exo

Use SMD components...
I didn't want to use them at first, and now... now i hate it whan i have to use a normal trough-hole device :lol:

Normal SMD-IC's (SO) are easy to hand solder with some practice (i even have some QSOP's hand soldered!) and you can always reach the legs.

Save's you a lot of that damn drilling too.

spyghost

yup, smd components would really solve the problem plus possibly eliminating the tediuos drilling process.

however, there are some components that are not surface mount - like the dsub connectors...

ok, i may not have explained it well... some through hole components obscure the pads of the top layer, thus those top pads cannot be soldered with ordinary soldering iron. a case would be the dsub connectors... how would you be able to solder the top pads of this connector when the whole connector itself covers the pads?

motion

Home-made PCBs without plated-thru connections should have artwork made with this problem considered. That is, avoid connections to the component side solder pads underneath an IC socket.

One other solution is to pre-solder a thin wire through the hole to connect the top pad to the bottom, before the IC socket is inserted.

__________________
"Having to do with Motion Control"

scottraynor

Good suggestions!

spyghost

hmmm... so there would really be lots of vias there... worst case would be 1:1 pin-via ratio for ic's

this sounds good... 8) it looks like i have to make the pads a bit more wider to accomodate a tiny wire together with the component terminals...

fat-tony

Ahh gotcha. Well, what you can do is put a pad on both sides of the board, and use a bit of flux. When you solder, the solder should suck through the hole and get both pads. If you have plated through-hole boards, this works quite well. I've never tried it on non-plated through boards, although I suspect it would work ok.

spyghost

isn't it that solder won't stick to the "board" even though there is flux?