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January 1998

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Subject:
From:
"Hamilton, Richard -4454" <[log in to unmask]>
Reply To:
TechNet Mail Forum.
Date:
Tue, 13 Jan 1998 14:22:56 -0700
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text/plain (85 lines)
Chan Chi Man,

I will assume that your assemblies have voltage above what UL specifies
as Class II Circuitry. In other words, above 32VAC. You might see if the
product can be designed so that all voltages on the board are below
32VAC, that way there is no concern for anything.

We have all our board assemblies designed so that no voltage goes
outside the Class II Circuitry. We have never been subjected to any of
that type of testing at UL because of that. We use single layer FR4 with
solder mask.

Just a thought.

Richard Hamilton
Clemar Mfg. / Rain Bird
[log in to unmask]

> -----Original Message-----
> From: Chi-man Chan [SMTP:[log in to unmask]]
> Sent: Monday, January 12, 1998 1:33 AM
> To:   [log in to unmask]
> Subject:      [TN] UL 94V-0 Question
>
> We sent 2 types of samples to UL Lab for 94V-0 Approval. One type
> of samples passed but the other type failed.
>
> The samples which passed the 94V-0 test were 10 pcs of 10-layer FR4
> multilayer boards without solder mask or copper circuit. The
> total Flaming for applications (Set of 5 specimens) are 15 sec
> (23 +/- 2 deg C and 50 +/- 5% RH for 48 hrs) and 12 sec (168 hrs
> air oven at 70 +/- 1 deg C then cooled in a dessicator for at
> least 4 hrs)
>
> The samples which failed the 94V-0 test were 10 pcs of 10-layer
> FR4 multilayer boards coated with solder mask. The total Flaming
> for applications (Set of 5 specimens) are 32 sec (23 +/- 2 deg C
> and 50 +/- 5% RH for 48 hrs) and 48 sec (168 hrs air oven at 70
> +/- 1 deg C then cooled in a dessicator for at least 4 hrs)
>
> The materials we used are :
>  Laminate: Isola E-Cu#104ML
>  Prepreg:  Isola E#104ML
>  Solder Mask: Lea Ronal OPSR 5600 GDA
>
> All the materials are UL 94V-0 approved. I think there could be
> something wrong on our processing, e.g. solder mask over post bake,
> too much thinner, improper thinner, etc.  We use the thinner:
> Butyl Icinol at 3-5%.
>
> What process settings may affect the 94V-0 test result?
> Is there anybody can help ?
>
> Thank you
>
>
> Chan Chi Man
>
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