How can I do a working curve?

To create a photopolymer “working curve,” which establishes the relationship between the depth of a photocured resin and the corresponding light dose, you can follow these general steps:

  1. Gather the necessary materials:

    • Photopolymer resin
    • Light source (e.g., projector, laser)
    • Power meter (to measure light intensity)
    • Thickness measurement tool (e.g., micrometer, caliper)

  2. Prepare the resin:

    • Ensure the resin is properly mixed and free from any contaminants.

  3. Set up the experiment:

    • Place a layer of the resin on a substrate or in a container.
    • Position the light source at a fixed distance from the resin surface.
    • Adjust the light intensity and exposure duration to achieve different light doses.

  4. Measure the thickness:

    • After each exposure, measure the thickness of the cured resin using the thickness measurement tool.
    • Record the corresponding light dose for each thickness measurement.

  5. Plot the working curve:

    • Create a graph with the light dose (x-axis) plotted on a logarithmic scale and the cured resin thickness (y-axis) plotted on a linear scale.
    • Plot the data points obtained from the measurements on the graph.

  6. Analyze the working curve:

    • Examine the shape of the curve. Ideally, it should be linear when plotted with a logarithmic dose axis and a linear depth axis.
    • Determine the slope of the curve, which represents the depth of light penetration (Dp).
    • Identify the critical dose for gelation (Ecrit), which is the x-intercept of the working curve.

  7. Use the working curve for exposure settings:

    • With the working curve, you can interpolate the dose required to cure a layer of a specific thickness.
    • Use the working curve to determine the optimal exposure settings for your desired resin thickness.

Remember that the specific process and parameters may vary depending on the type of photopolymer resin and equipment you are using. It is also important to note that standardization efforts are underway to establish best practices for working curve measurements.

Learn more:

  1. How to Take a Working Curve Measurement and Create Exposure Settings From It : 9 Steps (with Pictures) - Instructables
  2. Making the Working Curve Work for You - UV+EB Technology
  3. Resin 3D-printing: Ec, Dp, cure depth & more explained

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