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F3107_R79 • 4/7/2016

9

Film Capacitors – Polypropylene Pulse/High Frequency Capacitors

R79 Series Single Metallized Polypropylene Film, Radial, 5 mm Lead Spacing, Multipurpose Applications

Manual Soldering Recommendations

Following is the recommendation for manual

soldering with a soldering iron.

The soldering iron tip temperature should be set

at350°C(+10°Cmaximum)withthesoldering

duration not to exceed more than 3 seconds.

Recommended Soldering Temperature

0

50

100

150

200

250

300

350

400

0

1

2

3

4

5

6

7

8

Soldering time (sec)

Soldering Process

The implementation of the RoHS directive has resulted in the selection of SnAgCu (SAC) alloys or SnCu alloys as primary solder. This has

increased the liquidus temperature from that of 183ºC for SnPb eutectic alloy to 217 – 221ºC for the new alloys. As a result, the heat stress

to the components, even in wave soldering, has increased considerably due to higher pre-heat and wave temperatures. Polypropylene

capacitors are especially sensitive to heat (the melting point of polypropylene is 160 – 170ºC). Wave soldering can be destructive, especially

for mechanically small polypropylene capacitors (with lead spacing of 5 mm to 15 mm), and great care has to be taken during soldering. The

recommendedsolderprofilesfromKEMETshouldbeused.PleaseconsultKEMETwithanyquestions.Ingeneral,thewavesolderingcurve

from IEC Publication 61760-1 Edition 2 serves as a solid guideline for successful soldering. Please see Figure 1.

Reflowsolderingisnotrecommendedforthrough-holefilmcapacitors.Exposingcapacitorstoasolderingprofileinexcessoftheabovethe

recommended limits may result to degradation or permanent damage to the capacitors.

Do not place the polypropylene capacitor through an adhesive curing oven to cure resin for surface mount components. Insert through-

holepartsafterthecuringofsurfacemountparts.ConsultKEMETtodiscusstheactualtemperatureprofileintheoven,ifthrough-hole

components must pass through the adhesive curing process. A maximum two soldering cycles is recommended. Please allow time for the

capacitor surface temperature to return to a normal temperature before the second soldering cycle.

Wave Soldering Recommendations

0

50

100

150

200

250

300

0

40

80

120

160

200

240

Time (s)

ca 2°C/s

ca 3.5°C/s typical

ca 5°C/s

Cooling

2+3s max

115°C max

ΔT <150°C

100°C

Preheating

Typical

First wave

Second wave

260°C