Machines and Appliances: The "-arka" Suffix
Polish frequently creates nouns for tools and machines by adding suffixes to verbs. The feminine suffix -arka is very common for household appliances and automated machines.
For example, the verb zmywać (to wash) becomes zmywarka (dishwasher).
Since they end in -a, these nouns decline exactly like standard feminine nouns. Notice how they take -i or -y in the Genitive case.
Fixtures and Containers: The "-nik" Suffix
The masculine inanimate suffix -nik is widely used for household fixtures, containers, and appliances. For instance, the verb piec (to bake) forms piekarnik (oven).
For smaller tools or devices designed for a specific action, Polish typically uses the masculine inanimate suffix -acz.
It attaches directly to a verb: otwierać (to open) gives us otwieracz (opener), and dziurkować (to punch holes) forms dziurkacz (hole puncher).
Because words ending in -nik and -acz are masculine inanimate, their Accusative form is identical to their Nominative form. In the Genitive case (such as to express need), they usually take -a or -u.
They decline normally in all other cases, such as taking -u or -e in the Locative case when describing where something is located.