AVR-Chat

Hi guys,
 
More in response to Graham, but have you considered some of the low cost
prototype stencil offers that are now being made if you are considering
doing such small SMD devices?
 
I recently did a board (2 off as it happens) for a customer and I ordered a
stencil at the same time. I had used 0.5mm pitch FPC connectors and a number
of QFN devices on the board which are a nightmare to hand solder (they also
have GND pads on the underside). Using the stencil and a cheap Chinese
stencil machine from eBay, both boards came out of the oven and worked first
time. I was converted there and then to the use of a stencil and my air
dispensing kit now sits and gathers dust (unless I do some simple SMD board
that is)
 
 
PS.. I have kicked ezPCB's butt for the response Mile received. I don't work
for them but I am a happy customer and I basically told them to change their
tactics as regards getting new customers. Let's see if this makes a
change!!!
 
Dave...
---
Very funny Scotty, now beam down my clothes!!!
---


 
From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf
Of Mike Payson
Sent: 27 May 2011 01:15
To: AVR-Chat@yahoogroups.com
Subject: Re: [AVR-Chat] 0402 parts (was: Cheap 2 layer prototype PCB boards
..)
 
  
On the particular board I am designing there are probably a dozen places
where using 0402 would be beneficial, and in these cases, I don't need to
run traces underneath them. In general, I use 0805 or above, but for this
particular board the extra density would be nice.

On Thu, May 26, 2011 at 3:54 AM, ecros_technology
<Yahoo37849@ecrostech.com <mailto:Yahoo37849%40ecrostech.com> >wrote:

> --- In AVR-Chat@yahoogroups.com <mailto:AVR-Chat%40yahoogroups.com> , Mike
Payson <mike@...> wrote:
>
> > ... interested in EzPCB ... offer to populate 0402
> > resistors and capacitors for free ... asked support representative ...
> transcript of the live chat:
>
> Thank you very much for going to this trouble and posting the results of
> your investigation.
>
> I don't want to warp this thread off its topic, but if I correctly read
> between the lines that you don't like populating 0402 components, I have
to
> agree with you. Everything down to 0603 is fine, but with 0402 I have
> trouble getting the right amount of solder paste without a stencil (i.e.
for
> prototypes). As a result, about 10% of the parts "tombstone" (stand up on
> end) and I have to laboriously reposition them after reflow.
>
> I have decided not to use 0402 parts. Unless I omit the silkscreen marking
> of the ref. des., they don't really save that much space. Also, I can get
a
> trace under an 0603 part, which helps routing and can save vias so, again,
> I'm not convinced that an 0402 saves space. If the customer requires 0402,
> of course, them I'm OK with that.
>
> We should also be clear that the EzPCB offer applies only to "parts in
> stock". It's not at all clear how to find out what that means.
>
> Graham.




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