3d printer

Abstract

A 3D printer incorporating two angular axes as an inverted SCARA arm and a vertical, linear Z-axis, is described. A platter on which a 3D object is built is rotated around lambda axis and revolved around a lambda axis. Embodiments are described that: (i) are free of belts, pulleys, cables and other soft drive mechanisms; (ii) are free of any lead-screw compensating devices; (iii) are free of rectangular box frame; (iv) translate X-Y-Z voxel coordinates into an angular coordinate system, optionally in real-time; (v) optimize non-sinusoidal drive waveforms for stepping motors; (vi) deal with special cases at or near the lambda axis; (vii) measure and compensate for non-orthogonal platter skew. Both device and method embodiments are claimed.

1 . A 3D machine tool for the purpose of manufacturing a part comprising: a minimum of two controllable motions: a first motion and a second motion; a build surface to which the part is directly or indirectly affixed; and a machine tool head; wherein the improvement comprises:
 the first motion is a rotary motion around a first axis;   the second motion is a rotary motion around a second axis, wherein the second axis is parallel to and offset from the first axis; wherein the first axis revolves around the second axis;   the build surface is driven in the direction of the first motion and the build surface is normal to the first axis; and   the build surface is rotated about the axis of the second motion;   such that, responsive to the first and second motions, the machine tool head is positionable relative to the build surface over a continuous planar tool range area of the build surface, at a machine tool head distance from the build surface wherein the machine tool head distance is measured normal to the build surface.   
     
     
         2 . The 3D machine tool of  claim 1  wherein:
 the first motion is driven by a first rotary motor, the “lambda motor;” 
 the second motion is driven by a second rotary motor, the “theta motor;” 
 the mechanical components of the 3D machine tool between the first and second motors and the build surface, inclusively, are free of any mechanical conversion of motor-generated rotary motion to linear motion. 
 
     
     
         3 . The 3D machine tool of  claim 2  wherein:
 the mechanical portions of the 3D machine tool that implement the first and second motions, including the first and second rotary motors and all mechanical interconnections between the first and second motors and the build surface, and the build surface, are free of belts, pulleys, chains, wires, gears, screw drives and hydraulics. 
 
     
     
         4 . The 3D machine tool of  claim 2  wherein:
 the second motion moves the mechanical components of the first motion, including the first motor. 
 
     
     
         5 . The 3D machine tool of  claim 2  wherein:
 the first motor connects to the build surface such that the angular position of the build surface is equal to the angular position of the first motor shaft. 
 
     
     
         6 . The 3D machine tool of  claim 2  wherein:
 the second motor connects to the first motor such that the angle of revolution of the first axis around the second axis is equal to the angular position of the second motor shaft. 
 
     
     
         7 . The 3D machine tool of  claim 6  further comprising:
 a first rotational angle sensor and a second rotational angle sensor wherein the two angle sensors measure, in real time, the rotational angle of the first and second motors, respectively; 
 wherein a machine tool controller is configured to provide motor control outputs to the first and second motors such that the planar tool range area may be moved relative to the tool head; and 
 the motor control outputs for at least the first and second motors are responsive to the real time angular measurements of the two rotational angle sensors. 
 
     
     
         8 . The 3D machine tool of  claim 7  wherein:
 the first and second rotational angle sensors are mounted on the motor shafts of the first and second motors, respectively. 
 
     
     
         9 . The 3D machine tool of  claim 2  additionally comprising:
 a third motion driven by a third motor wherein the third motion is linear. 
 
     
     
         10 . The 3D machine tool of  claim 9  wherein:
 the third motion drives the machine tool head in a linear motion on a Z-axis that is normal to the planar tool range area. 
 
     
     
         11 . The 3D machine tool of  claim 10  additionally comprising:
 a base plate; 
 a boom driven by the linear motion of the Z-axis, wherein the boom comprises the machine tool head; 
 a personal electronic device mount on a mechanical element of the invention, and wherein the mount is adapted to accept a personal electronic device that comprises a wireless data interface and a camera; and 
 a machine tool controller with a wireless data interface configured to communicate with the personal electronic device; 
 wherein the controller is adapted to drive at least the first and second motions and configured to provide commands over its wireless interface to the personal electronic device, timed such that consecutive camera images, taken responsively to the commands and used as input to a 3D model reconstruction program, will generate from the 3D model reconstruction program a complete, accurate 3D model of a part on the planar tool range area; and 
 wherein the 3D machine tool is free of any additional controllable motions; 
 
     
     
         12 . The 3D machine tool of  claim 11  wherein:
 the controller comprises the 3D model reconstruction program. 
 
     
     
         13 . The 3D machine tool of  claim 10  wherein:
 the third motor connects to the machine tool head at least in part via a threaded rod functioning as a drive screw; and 
 the 3D machine tool is free of any drive screw-compensating device. 
 
     
     
         14 . The 3D machine tool of  claim 10  wherein:
 the 3D machine tool is an additive-material manufacturing tool, and the machine tool head provides the additive material used to manufacture the part. 
 
     
     
         15 . The 3D machine tool of  claim 10  additionally comprising:
 a build surface skew measuring sensor configured such that an offset of the plane of the planar tool range area from the plane normal to the Z-axis is measurable by the sensor; and 
 wherein the build surface skew measuring sensor is functional for this purpose during the manufacturing of the part. 
 
     
     
         16 . The 3D machine tool of  claim 15  additionally comprising:
 a machine tool controller configured to accept input source data comprising a set of voxels described in an X-Y-Z Cartesian coordinate system; 
 wherein the controller is configured to provide coordinate translation from the X-Y-Z Cartesian coordinate system to the coordinate system of the 3D machine tool comprising: two rotational axes corresponding to the first and second motions, and the third, linear motion; 
 wherein the controller is configured to provide motor control outputs to the first, second and third motors such that the tool head may be moved, relative to the build surface, within a continuous cylindrical manufacturing volume with one planar end of the cylindrical manufacturing volume coincident with the planar tool range area; 
 wherein the controller's motor control outputs are responsive to the measurements provided by the build surface skew measuring sensor; and 
 wherein the measurement of the build surface skew measuring sensor may change during the manufacture of a part. 
 
     
     
         17 . The 3D machine tool of  claim 9  wherein:
 the 3D machine tool is free of a rectangular box frame, encompassing the planar tool range area and extending upwards along the direction of the third motion, wherein the rectangular box frame provides required mechanical support for any 3D machine tool components that provide any of the three motions. 
 
     
     
         18 . The 3D machine tool of  claim 1  additionally comprising:
 a base plate comprising a curved base plate slot through which the rotary motion of the lambda motor connects directly or indirectly to the build surface; and 
 a first friction element configured to provide damping of the first motion; and 
 wherein the first friction element is located, at least in part, inside the base plate slot. 
 
     
     
         19 . The 3D machine tool of  claim 1  additionally comprising:
 a base plate comprising a curved base plate slot through which the first rotary motion connects directly or indirectly to the build surface; and 
 a second element configured to provide damping of the second motion; 
 wherein the second element is located, at least in part, inside the base plate slot. 
 
     
     
         20 . The 3D machine tool of  claim 1  additionally comprising:
 a base plate comprising a curved base plate slot through which the rotary motion of the lambda motor connects directly or indirectly to the build surface; 
 a first friction element configured to provide damping of the first motion; and 
 a first second element configured to provide damping of the second motion; 
 wherein the first and second friction elements share at least one common element and wherein the common element is located within the slot. 
 
     
     
         21 . The 3D machine tool of  claim 1  additionally comprising:
 a base plate comprising a curved base plate slot through which the rotary motion of the lambda motor connects directly or indirectly to the build surface; 
 a first friction element configured to provide damping of the first motion; and 
 a first second element configured to provide damping of the second motion; 
 wherein either or both of the first and second friction elements are monolithic and wherein the first and second friction elements may be the same element. 
 
     
     
         22 . The 3D machine tool of  claim 1  additionally comprising:
 a mount, on a mechanical element of the 3D machine tool, for a personal electronic device wherein the personal electronic devices comprises a wireless data interface and a camera; and 
 a machine tool controller with a wireless data interface configured to communicate with the personal electronic device; 
 wherein the machine tool controller is configured to provide commands over its wireless interface to the personal electronic device, timed so that consecutive camera images taken by the personal electronic device responsive to the commands, when presented as a time-series of images, show the part being manufactured with a fixed part orientation relative to the personal electronic device; 
 and wherein the 3D machine tool, when providing such commands via the machine tool controller, is adapted to manufacture a part in at least 90% of the time it would take the 3D machine tool to manufacture the part if it were not providing such commands. 
 
     
     
         23 . The 3D machine tool of  claim 1  additionally comprising:
 a machine tool controller configured to drive the first and second motors with motor drive signals; 
 wherein the first and second motors are stepper motors; and 
 wherein the drive signals for the first and second motors are each dual phase waveforms with each phase comprising additively both a square wave component and a sine wave component. 
 
     
     
         24 . A method of manufacturing a part using the 3D machine tool of  claim 1 . 
     
     
         25 . A method of manufacturing a part using the 3D machine tool of  claim 8 .