Capitalizing on any new or unfamiliar manufacturing technology requires an ability to look beyond the manufacturing limitations that have constrained one's design ideas in the past. For advanced manufacturing technology with unique capabilities such as additive manufacturing, this becomes critical for designing effective geometric features and parts. However, cognitive bias or fixation on familiar manufacturing processes may make it challenging for designers to determine how to take advantage of new manufacturing technology. For example, a person that is used to generating design ideas for subtractive manufacturing may struggle when asked to use additive manufacturing. This research is the first to provide evidence that fixation on certain manufacturing types can impact designers’ ability to utilize new, and less familiar, technologies during idea generation. We call this new form of design fixation Manufacturing Fixation in Design (MFD), which we define as unconscious and often unintentional adherence to a limited set of manufacturing processes and/or constraints and capabilities during the design ideation process. A workshop-based study with industry practitioners confirms that MFD exists and introduces a method to assess its impact. Specifically, a Design for Additive Manufacturing workshop given at an aerospace technology company with professional engineering designers explores how MFD manifests and how it can be measured. Implications of the results on practice and education are discussed along with future studies to delineate the drivers of MFD in design professionals.