) ▁Be am ▁power ▁– ▁The ▁power ▁of ▁the ▁beam ▁[ W ] ▁is ▁the ▁product ▁of ▁the ▁acceler ating ▁voltage ▁[ k V ] ▁and ▁beam ▁current ▁[ m A ], ▁parameters ▁easily ▁meas urable ▁and ▁precisely ▁cont roll able . ▁The ▁power ▁is ▁controlled ▁by ▁the ▁beam ▁current ▁at ▁constant ▁acceler ating ▁voltage , ▁usually ▁the ▁highest ▁accessible . ▁ ▁( 2 ) ▁Power ▁density ▁( f oc using ▁of ▁the ▁beam ) ▁– ▁The ▁power ▁density ▁at ▁the ▁spot ▁of ▁inc idence ▁of ▁the ▁beam ▁with ▁the ▁work pie ce ▁depends ▁on ▁factors ▁like ▁the ▁size ▁of ▁the ▁electron ▁source ▁on ▁the ▁c ath ode , ▁the ▁optical ▁quality ▁of ▁the ▁acceler ating ▁electric ▁l ens ▁and ▁the ▁foc using ▁magnetic ▁l ens , ▁alignment ▁of ▁the ▁beam , ▁the ▁value ▁of ▁the ▁acceler ating ▁voltage , ▁and ▁the ▁foc al ▁length . ▁All ▁these ▁factors ▁( except ▁the ▁foc al ▁length ) ▁depend ▁on ▁the ▁design ▁of ▁the ▁machine . ▁ ▁( 3 ) ▁W eld ing ▁speed ▁– ▁The ▁construction ▁of ▁the ▁w eld ing ▁equipment ▁should ▁enable ▁adjust ment ▁of ▁the ▁relative ▁speed ▁of ▁motion ▁of ▁the ▁work pie ce ▁with ▁respect ▁to ▁the ▁beam ▁in ▁wide ▁enough ▁limits , ▁e . g ., ▁between ▁ 2 ▁and ▁ 5 0   mm / s . ▁ ▁( 4 ) ▁Material ▁properties , ▁and ▁in ▁some ▁cases ▁also ▁on ▁ ▁( 5 ) ▁Ge ometry ▁( shape ▁and ▁dimensions ) ▁of ▁the ▁joint . ▁ ▁The ▁final