1.3 General notes on soldering
Permissible heat exposure loads on film capacitors are primarily characterized by the upper cate-
gory temperature T
max
. Long exposure to temperatures above this type-related temperature limit
can lead to changes in the plastic dielectric and thus change irreversibly a capacitor's electrical
characteristics. For short exposures (as in practical soldering processes) the heat load (and thus
the possible effects on a capacitor) will also depend on other factors like:
Pre-heating temperature and time
Forced cooling immediately after soldering
Terminal characteristics:
diameter, length, thermal resistance, special configurations (e.g. crimping)
Height of capacitor above solder bath
Shadowing by neighboring components
Additional heating due to heat dissipation by neighboring components
Use of solder-resist coatings
The overheating associated with some of these factors can usually be reduced by suitable coun-
termeasures. For example, if a pre-heating step cannot be avoided, an additional or reinforced
cooling process may possibly have to be included.
EPCOS recommends the following conditions:
Pre-heating with a maximum temperature of 110 °C
Temperature inside the capacitor should not exceed the following limits:
MKP/MFP 110 °C
MKT 160 °C
When SMD components are used together with leaded ones, the leaded film capacitors should
not pass into the SMD adhesive curing oven. The leaded components should be assembled af-
ter the SMD curing step.
Leaded film capacitors are not suitable for reflow soldering.
Uncoated capacitors
For uncoated MKT capacitors with lead spacings ≤10 mm (B32560/B32561) the following mea-
sures are recommended:
pre-heating to not more than 110 °C in the preheater phase
rapid cooling after soldering
B32520 ... B32529
General purpose (stacked/wound)
Page 39 of 45Please read Important notes
at the end of this document.
