home Hart Plastics is a custom thermoformer located in the industrial heart of northern Indiana. We are family owned and have been in business since 1984. With our additional capabilities from Hart Enginee Hart Plastics is a custom thermoformer located in the industrial heart of northern Indiana. We are family owned and have been in business since 1984. With our additional capabilities from Hart Engineering, we can help you design, and tool your project and then produce parts that meet your requirements. We are truly a one stop destination for all of your thermoforming needs.