IEC 60393-6 pdf download – Potentiometers for use in electronic equipment – Part 6: Sectional specification: Surface mount preset potentiometers

IEC 60393-6 pdf download – Potentiometers for use in electronic equipment – Part 6: Sectional specification: Surface mount preset potentiometers
IEc Qc 001001:2000,IEC Quality Assessment System for Electronic Components (IEcQ) -Basic rules
lEc Qc 001002-3:1998,IEC Quality Assessment System for Electronic Components (IECQ) -Rules of procedure – Part 3: Approval procedures
1.4Information to be given in a Detail Specification
Detail Specifications shall be derived from the relevant Blank Detail Specification.
Detail Specifications shall not specify requirements inferior to those of the generic, sectionalor Blank Detail Specification.
When more severe requirements are included，they shall be listed in 1.8 of the DetailSpecification and indicated in the test schedules, for example by an asterisk.
NOTE The information given in 1.4.1 and 1.,4.3 may, for convenience, be presented in tabular form.
The following information shall be given in each Detail Specification and the values quotedshall preferably be selected from those given in the appropriate Clause of this SectionalSpecification.
1.4.1outline drawing and dimensions
The Detail Specification shall incorporate an illustration of the surface mount preset poten-tiometer as aid to easy recognition and for comparison of the surface mount potentiometerwith others.
Dimensions and their associated tolerances,which affect interchangeability and mounting.shall be given in the Detail Specification. All dimensions shall be stated in millimetres.
Normally the numerical values shall be given for the length，width and thickness of the body.
Where space is insufficient to show the detail dimensions required for inspection purposes,such dimensions shall appear on the drawing forming an annex to the Detail Specification.
Recommended land patterns shall be given in Detail Specification.
When the outline drawing is other than described above, the Detail Specification shall statesuch dimensional information as will adequately describe the surface mount potentiometer.
1.4.2Mounting
The Detail Specification shall give guidance on methods of mounting for normal use.
Mounting for test and measurement purposes (when required) shall be in accordance with thefollowing Subclauses1, unless otherwise specified.
1.4.2.1 Surface mount potentiometers shall be mounted on a suitable substrate; the methodof mounting will depend on the potentiometer construction.The Detail Specification shallindicate which maferial is to be used for electrical measurements.
The substrate shall have metallized land areas of proper spacing to permit mounting ofsurface mount potentiometers,and it shall provide electrical connection to the surface mountpotentiometer terminals. The details shall be specified in the Detail Specification.
Examples of test substrates for mechanical and electrical tests are shown in Figures 1 and 2respectively. lf another mounting method applies, the method should be clearly described inthe Detail Specification.
1.4.2.2 When the Detail Specification specifies wave soldering,a suitable glue,details ofwhich may be specified in the Detail Specification,shall be used to fasten the component tothe substrate before soldering is performed.
Small dots of glue shall be applied between the conductors of the substrate by means of asuitable device securing repeatable results.
The surface mount potentiometers shall be placed on the dots using tweezers. ln order toensure that no glue is applied to the conductors, the surface mount potentiometers shall notbe moved about.
The substrate with the surface mount potentiometers shall be heat-treated in an oven at100 -C for 15 min.
The substrate shall be soldered in a wave soldering apparatus. The apparatus shall beadjusted to have a pre-heating temperature of 80 ℃ to 100 C， a solder bath at 260 °℃主5°C, and a soldering time of 5 s t 0.5 s.
The soldering operation shall be repeated a second time (two cycles in total).
The substrate shall be cleaned for 3 min in a suitable solvent (see 3.1.2 of IEC 60068-2-45).
1.4.2.3 When the Detail Specification specifies reflow soldering, the following mountingprocedure applies:
a) The solder used, in preform or paste form, shall be silver bearing (2 % minimum) eutectic
Sn/Pb solder together with a non-activated flux，as stated in test T of lEC 60068-2-20.Alternative solders，such as 60/40 or 63/37 may be used on surface mounts whoseconstruction includes solder leach barriers.
b) The surface mount potentiometer shall then be placed across the metallized land areas of
the test substrate so as to make contact between surface mount and substrate land areas.c)The substrate shall then be placed in or on a suitable heating system (molten solder,hot
plate,tunnel oven,etc.). The temperature of the unit shall be maintained between 215 Cand 260 °C, until the solder melts and reflows forming a homogeneous solder bond, but fornot longer than 10 s.
NOTE 1The flux is removed by a suitable solvent (see 3.1.2 of IEC 60068-2-45)，All subsequent handling issuch as to avoid contamination. care is taken to maintain cleanliness in test chambers and during post tiestmeasurements.
NOTE 2 The Detail Specification may require a more restricted temperature range.
NOTE 3 lf vapour phase soldering is applied, the same method may be used with the temperatures adapted.