parylene to be transparent several coats of pva solution may be required to achieve the desired shine on the wax molds the smoothing process may also be used for extra dimensional control of the wax molds when once again the required dimensions or tolerances cannot be created or maintained by the wax printer itself allowing the su 8 photoresist to remain on the surface of the mold before baking for a longer time period will reduce the size of the mold features this facilitates incorporation of features that are smaller than the minimum size achievable using available 3d printing technology increasing the time the su 8 photoresist remains on the mold during spinning from 10 up to 20 seconds decreases the feature size by 10 15 from the 3d printed dimension by adjusting this spin time very accurate dimensional changes and control can be achieved once the mold is smoothed it is placed in a parylene deposition chamber in which a controlled thickness e g 20 u03bcm of a polymer e g parylene c is deposited on the surface after parylene deposition the ends of the resulting tubular structure are clipped to expose the wax on each end to the outside environment a fixture may be used for accurate trimming the structure is then placed in acetone or another other suitable solvent to dissolve away the wax mold from the inside after 24 48 hours of soak time in acetone only the parylene outer layer remains unlike other tube manufacturing methods 3d printing as described herein easily allows for production of tubes of virtually any shape diameter and routing fig1.