ABOUT OUR THERMOFORMING & CLAMSHELL PACKAGING DM Sales and Engineering, which was founded in 1967, has been a leader in the development of thermoformed plastic packaging. From concept and design to production DM has the ability to perform and meet all expectations in thermoformed plastics. We offer computer aided design capabilities, prototyping, in house tool facilities and production equipment to meet all quantity requirements. DM can provide blister packaging and clamshell packaging for any consumer packaging to medical requirements needing the utmost care and quality. The philosophy at DM Sales and Engineering is put our customer desires into reality with cost effective and quality thermoformed plastic packaging.