One of the core challenges of our automated 3D printing system is successfully clearing the print bed without human intervention. Over the past months, we have discussed many mechanical solutions to this problem, one of them being the 3D modelling of custom bases (feet) for the printer that tilt the entire machine.
Why tilt the printer?
In a standard setup, removing a finished part requires manually flexing the build plate or using a scraper. For a fully autonomous continuous printing loop, the printer needs to eject the part itself.
By designing new feet that incline the printer at a specific angle, we introduce a powerful ally into our automated system: gravity. The tilt is carefully calculated to facilitate the sliding of the piece off the bed once it is detached.
The Automated Removal Mechanism
To ensure 100% reliability, we developed a three-stage removal process that combines mechanical force with gravity.
Once a print is completed and the bed cools down, the following sequence occurs:
- A dedicated linear actuator is triggered. This mechanism applies controlled force to flex the build plate. This is the most critical step, as it breaks the initial adhesion and “pops” the part loose from the surface.
- Thanks to the 10-degree tilt provided by our custom 3D-printed bases, many parts will naturally start to slide off the bed the moment the actuator flexes the plate.
- As a final redundancy, the toolhead (nozzle assembly) performs a sweeping motion across the entire bed. Since the part has already been loosened by the actuator, the nozzle only needs to provide a gentle nudge to ensure the piece clears the bed and falls into the collection area.
The 3D Modelling Process
Designing these bases required careful engineering over several weeks to ensure the printer’s stability wasn’t compromised. Shifting the center of gravity of a heavy, vibrating machine required more than just a simple wedge.
During the CAD modelling phase, several iterations were made:
- Stability Extensions: To prevent the printer from tipping over in the direction of the incline, an extended front base was added to counterbalance the weight.
- Structural Optimization: Instead of printing a massive solid block of plastic, the design was refined using structural engineering principles. We implemented triangular gussets (ribs) and internal support pillars directly beneath the printer’s original feet to create a clear load path to the ground.
- Design for Additive Manufacturing: The models were optimized for FDM printing by using fillets on internal corners to reduce stress concentrations and designing cavities that don’t require internal supports, saving significant material and print time.
- Interlocking modularity: I designed custom keyhole-style connections that allow multiple base components to slide and lock together securely. This ensures that the assembly acts as a single, rigid unit, preventing any shifting during high-speed printing.
Advantages for the automated system
The integration of these custom tilted bases brings several crucial benefits to our project:
- Reduces motor strain: The nozzle doesn’t have to “fight” a stuck part; it only guides a part that is already loose and gravity assists this.
- Prevents mechanical tipping: The engineered extensions ensure the machine remains perfectly stable during high-speed printing.
Conclusion
Hardware modifications are just as vital as software for full automation. By combining a physical tilt, a linear actuator for bed flexing, and smart sweeping routines, we have established a robust method for continuous part ejection. Our system is now one step closer to being a truly autonomous 3D printing factory.