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A clean and elegant personal 3D printer built on a delta robot platform.
A clean and elegant personal 3D printer built on a delta robot platform.
231 backers pledged $152,597 to help bring this project to life.

Auto Bed Leveling - Technical Update

Several backers have asked for some more technical details on the DeltaMaker to help them better understand how this printer is different from other printers. Below are some technical details regarding our auto calibration approach, and our Wi-Fi support. 

Auto Calibration 

 In February we announced that every DeltaMaker 3D printer would include auto calibration and bed leveling. In this update, we would like to share more details regarding how our auto calibration is implemented. 

 Consistently printing high-quality 3D objects requires the build platform to be exactly where the printer thinks it is. Automatic bed leveling is the fastest way to calibrate the printer’s build platform. There are several approaches to auto bed leveling; most involve the use of a “touch probe” which is attached near the extruder nozzle. 

 As the touch probe is moved over the build platform, a sensor is used to detect when the probe is in contact with the build surface. 

 DeltaMaker Touch Probe and Sensor 

To allow for a fully automatic bed leveling feature, the touch probe that is used to “feel” the location of the bed must be retractable to permit it to get out of the way while the printer is printing. The are many different ways to build a retractable touch probe; some use springs, some use magnets, and some touch probes do not retract automatically; they must be manually retracted by the user. For the DeltaMaker, we want a fully automatic touch probe that is small enough to mount next to the extruder nozzle. Our probe is constructed from a small solenoid that is mounted in such a way that when that solenoid is not engaged, the probe is higher than the extruder nozzle. The probe is normally in this retracted position, and it does not get in the way while printing. During the auto bed leveling function, the solenoid is engaged, which lowers the probe below the tip of the extruder nozzle. This allows the probe to make contact with the build platform, which allows the DeltaMaker to measure the height of the build platform at various locations around the build surface. 

To measure the height of the build platform at a specific location, a sensor is used to detect when the touch probe is in contact with the build surface. The most common sensor to use with the touch probe is a micro switch (like the end-stop switches used when “homing” the printer). Switches are fine, but for the DeltaMaker we have selected a different sensor for our touch probe. We wanted to select a sensor that would be used for more than just auto calibration. Our sensor is also in use while the DeltaMaker is printing a 3D object. 

 In addition to sensing the location of the build platform, the DeltaMaker can also sense when the extruder printhead is touched or bumped unexpectedly. This allows the DeltaMaker to respond to various situations that may occur while printing an object -- such as, if the extruder head hits something (or someone) while the printer is operating.  

The sensor we used for both the touch probe during auto calibration, and collision detection during printer operation, is a solid-state accelerometer. The accelerometer is mounted on the extruder printhead behind the fan. The accelerometer can detect a variety of events, such as when the touch probe “taps” the build platform, and the extruder collides with something while the DeltaMaker is printing. 

Wi-Fi Connectivity 

The DeltaMaker will ship with built-in Wi-Fi and Ethernet. You may connect your DeltaMaker directly to an Ethernet cable, or add it to your WiFi network. This means that you can send 3D objects to print directly to the DeltaMaker, from any computer on your network. You may also control the printer from your smartphone and other mobile devices. In addition to network support, the DeltaMaker can receive future software upgrades via the Internet. To enable these capabilities, every DeltaMaker includes an embedded Linux computer, such as a Raspberry Pi (raspberrypi.org). The Raspberry Pi may be configured to run a variety of 3D printing apps, such as web-based control panels. 

OctoPrint 

The main app that runs on the embedded Linux computer in the DeltaMaker is the OctoPrint Web-UI app. If you’re not familiar with OctoPrint, please check-out their website (octoprint.org); it is great. We are in contact with the developer of OctoPrint, to discuss adding new features at will be beneficial to the DeltaMaker, and other deltabot 3D printers. Please stay-tuned... Once you begin operating your 3D printer over Wi-Fi, you will not want to go back to the old way of using USB cables and SD cards. Instead of copying 3D objects to print onto an SD card, you simply upload the objects directly to your printer using a web browser.

Comments

    1. Creator Kirk Wong on September 13, 2013

      Anticipation is killing me! Any update on status of the printer?

    2. Creator Nathan Schrenk on August 18, 2013

      Looking amazing! Do you have an updated estimate on when the Early Adopter units will ship?

    3. Creator Jim Mott on August 2, 2013

      Simply amazing! Good job.

    4. Creator Jason Doege on August 1, 2013

      I ought to add, on the topic of calibration, dimensional calibration. Knowing where the platform is, this way, is only in reference to the model of the printer in the software and not in relation to physical position. What is accomplished by this is aligning the plane of the internal model to the platform. What remains, aside from perpendicularity of each leg of the printer to the plane, is positional accuracy. If you ask for a print of a 1x1x1 inch cube then you'd expect to get a 1x1x1 inch cube out the other side.

      This become important when you stop printing vases and start printing things that are meant to fit together, mechanically.

    5. Creator Jason Doege on July 31, 2013

      I'm excited and, like Matt, just working on other things while waiting. I think the use of an accelerometer is a pretty novel way to do this. I have three questions. First, this accounts for bed levelling, but what about the rest of the calibration, i.e. "square-ness" of the printer? You could have a perfectly level bed but still be printing parallelepipeds instead of cubes. Second is, what is the precision and accuracy you obtain using the accelerometer? Finally, once you have this ability, then you can consider using it to scan objects with little to no additional hardware. Do you plan to offer that ability at some point?

    6. Creator Matt Gorton on July 31, 2013

      I'm really excited as well. Just focusing on other things so I don't go crazy from the wait : )

      This update is incredible!

    7. Creator Heri Sim on July 31, 2013

      Am I the only guy around here who is excited for the Deltamaker? So quiet around here. Makes me wonder what kind of vibrant community I will be part of. Just like the PC wars in the early days, the community can be an important element to adoption.

    8. Creator Heri Sim on July 31, 2013

      Wow! Thanks for the update! You guys rock! I hope the Deltabot comes with a webcam as timelapses via OctoPrint and remote monitoring can be really really useful in practice. Who wants a fire brewing in their living rooms? Or to discover a bad print only when they come home. Timelapses by real users are also probably the best way for word-of-mouth marketing. Any attempts on nylon printing yet? The material rocks!