No I haven't heard of it. I would think it would get under the body alittle, harden and not come off.
The second problem is that it would be dedicated for that board or part only.
The third problem is you may block too much heat and prevent even heating down at the PCB, its layers and cause a soldering problem or cracked vias from improper thermal expansion. As you know the thermal expansion in the Z direction is the biggest thermal risk and having the bottom touching a 500-515F solder pot and the top at some delta T depending on what your planning could create a big problem.
With a good proifle there are only a few conditions where you need to cover low temp parts like plastic encapsulated relays or critical parts like BGAs or Micro BGAs, digital readout displays, verticle mounted LEDs.
What I've always had where a few ESD bins each filled with a quantity of 2 sided component covers. I have to go by memory here since I'm not working there now.
- U shaped blocks: about 2.5" long 1.5" wide and 1" high from the inside are used for a variety of situations (lifting , leaning etc.
- The comb type blocks were made to keep a block of Sim (single inline Memory) memories from leaning over.
Some were made to keep LEDs lined up andseated flush while blocking direct exposure of IR to the lense.
- BGA covers: a bin of squares about 1/4" thick, milled out in the center to prevent top preheat from reheating BGAs is a very good safeguard.
As mentioned the square black plastic relay blocks have a very thin top layer that bows from the top preheaters if not covered by a 2 sided block to prevent direct exposure to IR preheaters without blocking the convection preheat needed to achieve a good solder fillet.
These blocks are used over and over on any assembly and is the cleanest and simplest solution for:
To prevent heat damage, tilted parts, or lifted connectors/headers.
Recommended materials are: ESD wave solder pallet materal like Durastone or Durapol.
You can have them made or if you have a machine shop, then you can make them from obsolete wave pallets.
John Goulet
MFG/Process Engineer
----- Original Message -----
From: "Torsten Hagge" <[log in to unmask]>
To: [log in to unmask]
Sent: Wednesday, November 24, 2010 8:42:02 AM
Subject: [TN] modelling material/dough for wave soldering
Hi technetters,
has somebody knowledge about a modelling material/dough which can be used to build up fixtures for wave soldering process?
We have heard that it gives a material which can be placed over the components and which is hardened by the first solder process to be used for many cycles, any idea about type/vendor?
Thanks and best regards,
Torsten
i.A. Dipl.Ing.(FH)Torsten Hagge
tech. projectmanager
Kristronics GmbH
Gewerbegrund 5 - 9
24955 Harrislee
Tel.: +49 461 7741 624
Fax: +49 461 7741 642
[log in to unmask]
www.kristronics.de
Gerichtsstand Flensburg, Handelsregister: HRB 1433 FL
Geschäftsführer Dipl.-Ing. oec. Thormod Ohm
Ust-Id-Nr. DE 811182059
Bankverbindung: Deutsche Bank AG Flensburg, Konto-Nr. 4216610, BLZ 21570011
IBAN: DE32 2157 0011 0421 6610 00, BIC: DEUT DE HH 215
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