Overview
=========

The OpenCAL resin is a UDMA-based photopolymer tuned for Computed Axial Lithography. For most
users, there is no need to mix the resin yourself; it is being produced and distributed
commercially so you can buy it ready to print.

- **Formlabs** mixes and manufactures the resin to the OpenCAL formulation.
- **MatterHackers** distributes the finished resin, making it easy to purchase.

This means you can get consistent, professionally produced resin without handling the raw
chemistry. Buying the pre-mixed resin is strongly recommended.

.. warning::

   **Resin handling — important.** Photopolymer resin cures when exposed to light:

   * Always wear **nitrile gloves** when handling resin or uncured (wet) parts.
   * **Never expose the resin to natural sunlight.** Sunlight (and other strong UV / blue
     light) causes **rapid, uncontrolled curing** that will ruin the resin and can solidify it
     in its container. Keep it away from windows, work under subdued ambient room light, and keep
     containers **capped** whenever they are not in use.
   * Store the resin in a cool, dark place, and follow its Safety Data Sheet (SDS).

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    <div style="text-align: center; margin: 1.5em 0;">
        <a href="https://formlabs.com" target="_blank"
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            <img src="../../_static/formlabs_logo.png" alt="" style="height: 1.6em; border-radius: 6px; border: 2px solid #b0b0b0; background: #ffffff; padding: 3px;">
            Visit Formlabs
        </a>
    </div>

.. note::

   Mixing the resin from raw chemicals is **only** for trained professionals working in a
   laboratory. If that applies to you, see the :doc:`lab_directions` page for the full recipe
   and procedure.