Control method for digital light processing (DLP) printing based on absorbance of photocurable material

A control method for digital light processing (DLP) printing based on an absorbance of a photocurable material, comprising:

• adding a light absorber to the photocurable material, and subjecting the photocurable material with the light absorber to photocuring for DLP printing, wherein a printing process comprises:
• 1) measuring a liquid absorbance Al and a solid absorbance As per unit thickness of the photocurable material with the light absorber under different concentrations of the light absorber;
• 2) calculating a ratio of the liquid absorbance Al to the solid absorbance As per unit thickness that change with the concentrations of the light absorber as an actual solid-liquid absorbance ratio Rsf;
• Rsl=As/Al
• 3) comparing the actual solid-liquid absorbance ratio with a theoretically predicted value of a solid-liquid absorbance ratio:
• when a difference between the actual solid-liquid absorbance ratio and the theoretically predicted value of the solid-liquid absorbance ratio reaches more than 10% of the theoretically predicted value of the solid-liquid absorbance ratio, determining that the actual solid-liquid absorbance ratio deviates from the theoretically predicted value of the solid-liquid absorbance ratio, and taking a concentration range of the light absorber corresponding to the deviating actual solid-liquid absorbance ratio as an actual concentration of the light absorber in the photocurable material;
• 4) determining, by a photorheological test, a curing threshold time tT of the photocurable material under the concentration of the light absorber determined in step 3);
• 5) substituting the solid absorbance per unit thickness, the liquid absorbance per unit thickness and the curing threshold time of the photocurable material into a single-layer curing model as follows to obtain a relationship between an exposure time tH and a curing thickness H:
• t
• H
• =
• t
• T
• ·
• [
• A
• s
• -
• A
• l
• A
• s
• +
• A
• l
• A
• s
• ·
• e
• (
• -
• A
• s
• ·
• H
• )
• ]
• wherein, tT denotes the curing threshold time, H denotes the curing thickness, and e denotes a natural constant;
• 6) substituting, in actual printing, a desired curing thickness H into the single-layer curing model to obtain the exposure time tH, and performing a DLP printing control according to the exposure time tH.