Early 3D printer designs have a print-head or "hotend" that is moved by motors in 3 perpendicular directions, along the x, y, and z axes. A more recent design places the hotend at the end of three arms that are linked to tracks that allow movement in the vertical plane, which translates into movement in the x, y, and z axes based on the coordinated movement of the three arms. This is termed the "Delta" geometry, and robots of this design are called Deltabots. There are several advantages to this design and perhaps a couple of disadvantages.

                                        

This Deltabot is a variant of the Kossel Mini designed by Johann Rocholl, and includes several customizations intended to reduce cost and enhance it's versatility. The original Kossel Mini relies on an aluminum rail and carriage system that is rather costly. The very first deltabots used ball bearings that rode in the grooves of the vertical columns, and while the metal on metal contact was detrimental to the finish on the aluminum, delrin covers have been developed to allow the bearings to ride in the grooves without damage. These have been utilized here. The original Kossel Mini was designed to use timing belts to transfer movement from the motors to the carriages that ride on the vertical columns. This build was altered to use 100 lb test fishing line to reduce cost. This necessitated coming up with a way to tension excess fishing line, so that the line could be installed loosely and wound up to tighten it. A screw tensioning system was devised, similar to a tensioner on a guitar, that reels in the extra line, and final tension is adjusted as one would with the stock Kossel, by the small screw at the top of each column. V-wheel bearings replace timing belt idlers at the tops of the columns. Many people opt for the J-head hotend on their deltabots, but the E3D hotend was incorporated here because of it's all-metal design which provides the potential to use a wider variety of plastics that have higher melting temperatures. Because of an ordering mishap during bill of material changes the PG35l geared stepper motor was purchased while the extruder components were designed to utilize a new motor. This required some jerry-rigging to mesh the two components and yield an operable extruder that would feed the plastic filament off the reel to the hotend. The Kossel Mini was equipped with a deployable probe that allowed for auto-leveling and adapting the print code to the angle of the print surface. Implementing this probe on this machine was problematic so a new "direct probe" was designed to allow for direct probing of the bed surface with the hotend. This probe is based on the design of a touch probe digitizer used to "scan" 3d parts for CNC work. An additional adaptation of the Kossel Mini allowed a dremel flex tool to be mounted in place of the hotend, providing PCB etching, drilling, and light milling capabilities.