▁add itive ▁processes ▁are ▁now ▁available . ▁The ▁main ▁differences ▁between ▁processes ▁are ▁in ▁the ▁way ▁layers ▁are ▁depos ited ▁to ▁create ▁parts ▁and ▁in ▁the ▁materials ▁that ▁are ▁used . ▁Some ▁methods ▁m elt ▁or ▁soft en ▁the ▁material ▁to ▁produce ▁the ▁layers , ▁for ▁example . ▁select ive ▁las er ▁mel ting ▁( SL M ) ▁or ▁direct ▁metal ▁las er ▁s inter ing ▁( D ML S ), ▁select ive ▁las er ▁s inter ing ▁( S LS ), ▁f used ▁de position ▁model ing ▁( F DM ), ▁or ▁f used ▁fil ament ▁fabric ation ▁( FF F ), ▁while ▁others ▁c ure ▁liquid ▁materials ▁using ▁different ▁s oph istic ated ▁techn ologies , ▁such ▁as ▁s tere ol ith ography ▁( S LA ). ▁With ▁l amin ated ▁object ▁manufact uring ▁( LO M ), ▁thin ▁layers ▁are ▁cut ▁to ▁shape ▁and ▁joined ▁together ▁( e . g ., ▁paper , ▁polym er , ▁metal ). ▁Each ▁method ▁has ▁its ▁own ▁advantages ▁and ▁draw back s , ▁which ▁is ▁why ▁some ▁companies ▁offer ▁a ▁choice ▁of ▁pow der ▁and ▁polym er ▁for ▁the ▁material ▁used ▁to ▁build ▁the ▁object . ▁O thers ▁sometimes ▁use ▁standard , ▁off - the - sh elf ▁business ▁paper ▁as ▁the ▁build ▁material ▁to ▁produce ▁a ▁dur able ▁prototype . ▁The ▁main ▁consider ations ▁in ▁choosing ▁a ▁machine ▁are ▁generally ▁speed , ▁costs ▁of ▁the ▁ 3 D ▁printer , ▁of ▁the ▁printed ▁prototype , ▁choice ▁and ▁cost ▁of ▁the ▁materials , ▁and