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From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-1856240@logan.com>
Subject: Re: [FlyRotary] Re: Cooked Board - Really!IV
Date: Thu, 22 Feb 2007 17:30:40 -0500
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Thanks, Bob.

It turns out a fairly light pressure is apparently required.  Too much and 
the squeegee scopes paste out of the pad area and too little pressure and it 
leaves too much for the finer pitch components.  I don't think board 
thickness is going to matter.  What I intend to do if that happens is simply 
use a different thickness acrylic sheet to hold the board and stand-off the 
stencil.

I'll gain some experience with the other two PC boards.  I find that my 
scheme for placing the components - all capacitors, all resistors, all 
diodes, etc.  does not work well.  Need a scheme that starts from the bottom 
and works up, top and works down or center and works out regardless of 
component type - otherwise your tweezers knocks previously place components 
out of place.  Also you do need those tweezers that have a dip in the end so 
you can clear closely place components.

Old shaky hands can really shove a tiny component all over the place, wiping 
the paste off the pad, etc.  So a good arm brace would help.

I decided its doable, but I think I will design the board to use only 1206 
size and not the smaller 0805 I was trying to use.  Will make life easier. 
In fact, I sat down in a hour or less and redid the board design- now I have 
to find all new components in the catalogs.

Ed

----- Original Message ----- 
From: "Bob White" <rlwhite@comcast.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Thursday, February 22, 2007 3:56 PM
Subject: [FlyRotary] Re: Cooked Board - Really!IV


> That's really looking good Ed.  I hope that pressure adjustment isn't
> so critical that you have a hard time getting good repeatability.  Will
> slight variations in board thickness be a problem?
>
> Bob W.
>
>
> On Thu, 22 Feb 2007 15:40:18 -0500
> "Ed Anderson" <eanderson@carolina.rr.com> wrote:
>
>> On the first solder run, I had too much pressure and while the area of 
>> the solder paste deposit was excellent (even on the 0.25mm socket lands), 
>> there was too little quantity of solder to hold the hold the components 
>> in position.
>>
>> The second solder run I used less squeegee pressure and it left (did not 
>> scope it out) a large volume of solder (too much in the case of the 
>> 0.25mm socket lands and they bridged).  Solder wick may be able to get 
>> the excess solder out.
>>
>> I have two more boards to experiment with - hopefully by the end I will 
>> have it down.
>>
>> Ed
>>
>> Ed Anderson
>> Rv-6A N494BW Rotary Powered
>> Matthews, NC
>> eanderson@carolina.rr.com
>> http://members.cox.net/rogersda/rotary/configs.htm#N494BW
>> http://www.dmack.net/mazda/index.html
>
>
> -- 
> N93BD - Rotary Powered BD-4 - http://www.bob-white.com
> First Flight:  11/23/2006 7:50AM - 3.3 Hours Total Time
> Cables for your rotary installation - http://www.roblinphoto.com/shop/
>
> --
> Homepage:  http://www.flyrotary.com/
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