This spectrometer has been designed to be created without glue or scotch tape for the main structure.
All the files can be printed without support to improve the print quality.
The use of tape or glue is strongly suggested for attaching the spectrometer to your camera, to improve the quality of the image and the calibration.
Insert the fragment of DVD between the roof and the mask, force the two parts to stick together, then stick the base with the roof and the job is done.
Hope this could be helpful!