how to assemble examples mec industriparken 23 p .o. box 26 dk-2750 baller up denmark t el.: +45 44 97 33 66 fax: +45 44 68 15 14 w eb: http://www .mec.dk e-mail: danmec@vip.cyber city .dk mec general infor mation how to get the best r esults with mec switches usage guidelines these guidelines ar e of fer ed to users of mec switches as an aid to ensur e successful and r eliable switch operation. temperatur e both unimec and mul timec switches ar e pr oduced in standar d and high temperatur e materials. please see the technical specifications for details on operating and storage temperatur es and soldering guidelines to make sur e you select the switch best suited to your application. when flow soldering, mec str ongly r ecommend that the temperatur e pr ofile is analysed and compar ed with the temperatur e rating of the switch. in case of doubt always select the high temperatur e version 3xxh9. all accessories for both unimec and mul timec switches ar e made fr om abs plastic with a maximum operating temperatur e of 65 c. car e must be taken not to over heat the accessories during the soldering pr ocess. in soldering pr ocesses exposing the switch to high temperatur es it is str ongly r ecommended that accessories ar e mounted after soldering. led s have their own temperatur e specifications. when fitted in a high temperatur e switch the led will deter mine the max. operating temperatur e, i.e. 3fth922 has an upper temperatur e limit of 85 c - not 160 c! when infrar ed r eflow soldering is used, it is ver y impor tant to monitor the sur face temperatur e of the switch during the pr e-heat stage to pr event excessive heat buildup and over heating during soldering. mounting if switches ar e to be mounted in r ows it is critical that the r ecommendations regar ding spacing ar e followed. pc boar d thickness should be 1.2 to 1.6mm and ter minal hole diameters should be 0.9mm. all unimec and mul timec caps and bezels ar e easily snapped onto the switch modules and can be changed at a later time with the exception of the unimec 16.700 cap. once this cap is installed it is not designed to be removed. t o do so may cause damage to the switch and the pc boar d if not done with extr eme car e. if the 16.300 or 16.700 cap must be r emoved fr om an alter nate action switch, make sur e that the switch actuator is in the r eleased, upper position befor e attempting to r emove the cap. this will pr event possible damage to the inter nal latching pin. car e must be taken when inser ting the 3ft switch and led assembly into the pc boar d. do not pr ess dir ect on the led. this will for ce the led down into the actuator and cause the switch contacts to r emain in the closed posi - tion. t o cor r ect the fault, the led must be raised slightly and center ed in the actuator to assur e unr estricted movement of the actuator . soldering and cleaning unimec most assembly and field pr oblems experienced by users of unsealed switches ar e caused by the contamination of the contacts during soldering and cleaning. contact contamination may be r ecognized by an incr ease in contact r esistance and possible inter mittent operation of the switch, especially in low power applications. car e must be taken not to submer ge the switch in the solder bath or spray the switch during cleaning. the switch must be pr otected at all times to pr event contamination by flux or cleaning fluids. soldering and cleaning mul timec mul timec switches ar e fully sealed to ip-67m specifications to pr event solder flux and aqueous or solvent cleaning solutions fr om entering the switch and contaminating the contacts. the switches can be placed on the pc boar d with other components and wave solder ed. no special handling of mul timec switches is r equir ed, but notice the guidelines mentioned under temperatur e. unimec 15___ + 16300 + 16310 unimec 15___ + 16270 + 16300 + 16324 multimec ? 3a t + 1a/h + 2a/b multimec ? 3a t + 1b/c + 2a/b soldering multimec thr ough hole versions hand soldering: max 350 c for max. 3 s., this applies for both low tempera - tur e and high temp. versions. w ave soldering: heat built up in the switch during pr e-heating and soldering must not exceed the maximum operating temperatur e of the switch. if, for some r eason, a high pr e-heating temperatur e is r equir ed, mec str ongly r e- commend using high temperatur e switches. in any cases peak temperatur e must not exceed 260 c, and soldering time is max. 10 s. sur face mount versions for all methods - infrar ed, convection and vapour phase - the upper limit 260 c/30 s. must be obser ved. the soldering temperatur e pr ofile must have moderate temperatur e gradients r t/t. general t emperatur e limitations low temperatur e 65 c high temperatur e 160 c led s 85/100 c accessories 65 c mec r ecommend that accessories ar e mounted after soldering, unless the pr ocess allows the heat exposur e to be kept within the limits of 65 c. combinations of high temperatur e switches with led s will be limited by the temperatur e capability of the led. packaging unimec and mul timec switches ar e packed in rigid tubes of 50 pieces each.
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