Darmawan's high level of business performance has won the confidence from a wide variety of industrial clients to reliably support their operational needs. Among the major companies using Darmawan's product and services are:
- PT Nestle Indonesia
- Indofood Group
- Sinar Mas Group
- PT Indocement Tunggal Prakarsa Tbk.
- Semen Indonesia Group
- PT Cabot Indonesia
- PT Krakatau Posco
- PT Nsk Bearings Manufacturing (Indonesia)
- PT Sanbe Farma
- PT Angkasa Pura
- PT Argha Karya Prima Industry Tbk.
- PT Kahatex
- PT Freeport Indonesia
- PT Gudang Garam Tbk.
- PT Frisian Flag Indonesia
- PT Aneka Coffee Industry
- PT Indonesia Fibreboard Industry
- PT Krones Machinery Indonesia
- And many more.