Hi James,
To me cost factors would run something like this:
1. Layer count
2. Material type and end thickness spec.
3. Copper thickness of inner and outer layers
4. Width of lines/spaces
5. Smallest hole size
6. Final finish (all or selective Ni/Au)
7. Drill time (number of holes and hole types)
8. Special route/score or other machining that could add cost/time
As to your second question, yes, those are all important factors to consider
in design. Some things you may want to look into opening up:
1. Minimum plating thickness has been relaxed by many users to be .0008".
Many users
require .001 average rather than minimum.
2. Base copper thickness of core material and outer layers are often 1/2
ounce. This is
expecially true when running fine lines and spaces.
I don't think it's unfair to request a quote using an estimation of hole
count. So long as you know the minimum hole size. Other things I'd not
like to have come up after a quote using estimated data:
1. Non-standard or multiple final finishes
2. Special machining requirements
3. Special material requirements or non-standard thickness tolerences
4. Fine lines/spaces
But I think you'll find most shops give quotes using "best estimate"
information to facilitate a timely response.
Good luck.
Mark Mazzoli
Eng. Mgr.
Circuit Technologies, Inc.
3622 Clearview Pkwy.
Atlanta, GA 30340
770-458-1700
[log in to unmask]
----- Original Message -----
From: James Patten <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, September 28, 1999 12:29 PM
Subject: [TN] Quick Prototype
> Is it possible to give me a better feel for what the biggest cost-saving
> factors for a quick-turn (5 days is good enough) pwb. In general, the
board
> types would be Class1 end-use, smt using FR4, 8-10 lyrs, 1500 drills of 3
> types. If you were to rate the following, what would be the greatest
> factor?:
>
> 1. Layer count
> 2. Number of hole types
> 3. Number of holes
> 4. Standard material, standard thickness
> 5. All 1oz.
> 6. Stacking 2-3 drilling
> 7. Other
>
> What would the order of importance be: (1,2,etc.)________________________.
>
> And are these reasonable things to consider/require for design?:
>
> 1. Use standard materials - FR4 Cu clad 1oz.
> 2. Standard thickness - .062 (.057-.067)
> 3. Min PTH thk - .001
> 4. Plating of all holes, func and non-func?
> 5. Dimensioned holes within (.xxx true-pos)?
> 6. Silk is white epoxy ink - 75mils min height.
> 7. LPI mask
> 8. No internal plane donuts - clearance pads only.
> 9. All 1oz.
> 10. Vias .050 pad w/ .025 finished PTH.
> 11. 8/7 trace-space
> 12. 274X
> 13. Other______________.
>
> Again these are bench test-set end-use. This is sort of a long list, but
if
> I can get the following one question answered I'd appreciate immensily:
> During the quote process, there are some issues of internal
> paperwork/protocol that can facilitate quicker time to fab. Is it
reasonable
> to quote a design near completion, by giving a PTHV 'range' (say, between
> 1200-1500 vias)? Is there a safe number that wouldn't affect a quote?
This
> would be for ONE size only (the vias). Is this an unreasonable request for
a
> quote?
>
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