Help Wanted =========== This page collects parts of OpenCAL that we **started but did not finish**: features and add-ons that are not yet fully working. We would love the **community's help** to complete them. Have experience, ideas, or want to take one of these on? Reach out on the `OpenCAL Discord `__; contributions are very welcome. Cheaper Motor Controller (TMC5160T) ----------------------------------- To lower the build cost, we wanted to drive the stepper motor with a **cheaper controller** than the **Pololu Tic T249** used in the current build. We tried the **TMC5160T** as a candidate: * `TMC5160T stepper motor driver (Amazon) `__ We **could not get it working reliably**, so it never made it into the official build. If you can get the TMC5160T (or another low-cost driver) running dependably with OpenCAL, we'd love your help. Large Vial (Screw-On) --------------------- We designed a large, **screw-on glass vial** to print bigger parts, but we **could not get it fully working and reliable**. For now, use the small vial — or the simpler **lid-style large vial** documented in the :doc:`Rotational Element guide <../step_by_step/rotational_element_stepbystep>` — for printing. If you'd like to help finish the screw-on design, we'd welcome it. .. image:: ../static/Step_by_Step/Rotational_Element_Subassemblies/Large_Vial/large_vial_1_CAD.png :align: center :width: 300px .. image:: ../static/Step_by_Step/Rotational_Element_Subassemblies/Large_Vial/large_vial_2_CAD.png :align: center :width: 300px **Parts:** * (QTY 1) Large Glass Vial * (QTY 1) Bottom Glass Vial Attachment * (QTY 1) Bottom Vial Lock * (QTY 1) Top Glass Vial Attachment * (QTY 1) Top Vial Lock * (QTY 1) Bottom Glass Disk * (QTY 2) 1/8'' Soft Silicone O-Ring * (QTY 1) Silicone Caulk **Tools:** Tape We never finalized the screw-on assembly, so step-by-step instructions are not documented — the parts and CAD above are the design as far as we took it. Vial Light-Protection Covers ---------------------------- Photopolymer resin cures on exposure to stray light (see the resin-handling warnings in the :doc:`Materials overview <../materials/overview>`). We started designing **covers for the vials** to shield them from ambient and stray light **when they are not being printed** (protecting the resin between prints and during storage), but we **never settled on a reliable, easy-to-use design**. Ideas and designs from the community are welcome. Centrifugal Spinning (CentrifuCAL) ---------------------------------- We explored a centrifugal spinning add-on, **CentrifuCAL**, to counteract sinking or floating of the part in low-viscosity resin. It is a **hand-cranked, planetary-gear spinner** that holds and rotates the vial. .. figure:: ../static/centrifucal_setup.jpg :align: center :width: 360px An early CentrifuCAL prototype. We built the **early prototype** shown above but **did not fully finish or validate** the design, so it is not part of the official build. Its parts and assembly steps are recorded below to help anyone who wants to pick it up. .. tip:: **Off-the-shelf alternative.** If you don't want to build the CentrifuCAL spinner, a manual **salad spinner** can provide a simple, low-cost way to spin the vial, such as `this salad spinner `__. .. note:: The steps below describe an early prototype. Step images are not yet included; they will be added as the design is finalized. Tools ~~~~~ * Soldering iron (for heat-set inserts) * 3D printer — PETG capable, minimum bed size 256 × 256 mm (prototype printed on a Prusa) * 3 mm hex key * Superglue * Scissors / box cutter Parts ~~~~~ **3D-printed parts** (each links to its Onshape model; print quantity in parentheses): * `Lower Base `__ (3 parts) * `Upper Base `__ (3 parts) * `Lid `__ (3 parts) * `Vial Holder `__ * `Spinner `__ * `Tab `__ * `Sun Gear `__ * `Ring Gear `__ * `Planet Gear `__ (×3) * `Gearbox Crank Top `__ * `Gearbox Crank Cover `__ * `Gearbox Bottom `__ * `Crank Handle `__ * `Door `__ * `Door Handle `__ * `Handle `__ (×2) * `Handle Cap `__ (×4) * `Hinge Bottom `__ * `Hinge Top `__ * `Hinge Pin `__ * `Foot `__ (×4) * `Drain Plug `__ **Other materials:** * 2 × polycarbonate sheets, cut to 145 × 135 mm * 28 mm bearing * M3 heat-set inserts * M3 bolts: M3×6, M3×10, M3×25, M3×40, M3×50 (See the :doc:`BOM <../engineering_documentation/bom>` for quantities and sourcing.) Assembly (prototype) ~~~~~~~~~~~~~~~~~~~~~~ #. 3D print all parts. #. Cut 2 polycarbonate sheets to **145 × 135 mm**. #. Place the polycarbonate sheets into their respective slots in the **Lower Base**. #. Using the soldering iron, place **3× M3 heat-set inserts** into the holes on the top of the Lower Base. #. Place the remaining M3 heat-set inserts: **7 on the Lid** and **4 on the Upper Base**. #. Assemble the Lower and Upper Base in thirds, placing the Upper Base onto the polycarbonate sheets and fastening with an **M3×40 bolt**. #. Fasten the three pieces of the Lower Base, Upper Base, and Lid together with superglue. #. Place the final **3× M3 heat-set inserts** into the holes on the Door. #. On the Lower Base, press-fit a **28 mm bearing** into the middle section. #. Superglue the **Vial Holder** to the **Spinner**. #. Secure the **Tab** to the Vial Holder with an **M3×6 bolt**. #. Place the Vial Holder and Spinner onto the bearing in the Lower Base. #. Affix the Lid and handles with **4× M3×50 bolts**. #. Affix the **Ring Gear** with **4× M3×25 bolts**. #. Assemble the remaining gears (3 planet gears + 1 sun gear), passing the Sun Gear through the hole and fastening it into the slot on the Vial Holder. #. Assemble the gearbox: stack the Gearbox Bottom, Cover, and Top; flip it over and drive **3× M3×10 bolts** into the holes. #. Place the assembled gearbox on top of the gears, fitting its pegs into each planet gear. #. Secure the gearbox to the Lid with **4× M3×25 bolts**. #. Superglue the **4 feet** to the bottom of the assembly. #. Place the handles on top of the box and secure with **4× M3×50 bolts**. #. Place the handle caps on the handles and secure with superglue.