initial import from sources

Bearing_6807-2RS.scad

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+// Values from http://www.astbearings.com/product.html?product=6807-2RS
+bearing6807_2RS_rs = 1.2;	// lip width
+bearing6807_2RS_d = 35;		// ID
+bearing6807_2RS_D = 47;		// OD
+bearing6807_2RS_B = 7;		// width
+
+module bearing6807_2RS() {
+    rs = bearing6807_2RS_rs;
+    d = bearing6807_2RS_d;
+    D = bearing6807_2RS_D;
+    B = bearing6807_2RS_B;
+	//render(convexity = 3)
+    translate([0, 0, B / 2])
+	union() {
+        // outer lip
+        difference() {
+            cylinder(h = B, d = D, center = true);
+            cylinder(h = B, d = D - rs, center = true);
+        }
+        // inner lip
+        difference() {
+            cylinder(h = B, d = d + rs, center = true);
+            cylinder(h = B, d = d, center = true);
+        }
+        // race
+            difference() {
+                cylinder(h = B - (rs * 2), d = D, center = true);
+                cylinder(h = B - (rs * 2), d = d, center = true);
+            };
+    }
+}

Hub_28BYJ-48.scad

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+// Hub for 28BYJ-48 stepper motor w/ set screw
+// Example for 3mm set screw:
+//stepperHub(10, 7, 6, 3.1, 1.5, 2.75);
+module stepperHub(height, radius, shaftHeight, shaftRadius, setScrewRadius, setScrewHeight) {
+    //render(convexity = 3)
+    difference() {
+        // hub
+        cylinder(h = height, r = radius, center = false);
+        // shaft
+        intersection() {
+            cylinder(h = shaftHeight, r = shaftRadius, center = false);
+            translate([-shaftRadius, -shaftRadius/2, 0])
+                cube(size = [shaftRadius * 2., shaftRadius, shaftHeight], center = false);
+        }
+        // set screw hole
+        translate([0, 0, setScrewHeight])
+            rotate([90, 0, 0]) 
+                cylinder(h = (radius * 2) + radius, r = setScrewRadius, center = true);
+    }
+}

LICENSE

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+Copyright (c) 2014, beckdac
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+

README.md

@@ -1 +1,3 @@
 # SCARA
+====
+Ultra low cost 3D printable SCARA arm

SCARA.scad

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+use <StepMotor_28BYJ-48.scad>;
+use <Hub_28BYJ-48.scad>;
+include <Bearing_6807-2RS.scad>;
+
+// global rendering parameters
+$fn = 24;
+
+// library examples
+// translate([100, 100, 10]) { StepMotor28BYJ(); }
+// stepperHub(10, 7, 6, 3.1, 1.5, 2.75);
+//translate([0, 0, 8]) bearing6807_2RS();
+// bearingInnerStep(bearing6807_2RS_d - iFitAdjust, 2, 2);
+//shoulderBase(2, 55, 9.1, 3.1);
+
+// interference fit adjustment for 3D printer
+iFitAdjust = .6;
+
+// size in mm of bearing interface step
+bearingStep = 2;
+
+// shoulder base parameters
+shoulderBaseHeight = 3;
+shoulderBaseDiameter = 55;
+shaftBossDiameter = 9.1;
+mountScrewDiameter = 3.1;
+bearingStep = 2;
+// joint parameters
+hubHeight = 10;
+hubRadius = 7;
+shaftHeight = 6;
+shaftRadius = 3.1;
+setScrewRadius = 1.5;
+setScrewHeight = 2.75;
+spokeWidth = 3;
+spokes = 6;
+screwTabs = 4;
+screwTabHeight = 4;
+armLength = 200;
+
+/* Pieces in this model
+** Shoulder:
+*** Base plate
+*** Top plate
+*** Lower arm
+*** Upper arm
+** Forearm:
+*** ?
+** Hand:
+*** ?
+*/
+
+// shoulder base
+color([.7, .7, 1]) shoulderBase(shoulderBaseHeight, shoulderBaseDiameter, shaftBossDiameter, mountScrewDiameter);
+// shoulder stepper
+rotate([0, 180, 0]) translate([-8, 0, 10]) StepMotor28BYJ();
+// lower shoulder bearing
+translate([0, 0, shoulderBaseHeight + bearingStep]) %bearing6807_2RS();
+// shoulder - arm joint 
+color([1, .7, .7]) translate([0, 0, shoulderBaseHeight + 7]) armLower(bearing6807_2RS_D + iFitAdjust, bearingStep, bearingStep, hubHeight, hubRadius, shaftHeight, shaftRadius, setScrewRadius, setScrewHeight, spokeWidth, spokes, screwTabs, screwTabHeight, armLength);
+
+//bearingInnerStep(bearing6807_2RS_d - iFitAdjust, 2, 2);
+module bearingInnerStep(bearingID, stepHeight, stepWidth) {
+    difference() {
+        union() {
+            // this fits inside of the bearing
+            cylinder(h = stepHeight * 2, d = bearingID);
+            // this rests on the bearing inner lip
+            cylinder(h = stepHeight, d = bearingID + stepWidth);
+        }
+        // remove center
+        cylinder(h = stepHeight * 2, d = bearingID - (stepWidth * 2));
+    }
+}
+
+//translate([0, 0, 12]) bearingOuterStep(bearing6807_2RS_D + iFitAdjust, 2, 2);
+module bearingOuterStep(bearingOD, stepHeight, stepWidth) {
+    //render(convexivity = 3)
+    difference() {
+        cylinder(h = stepHeight * 2, d = bearingOD + stepWidth);
+        cylinder(h = stepHeight * 2, d = bearingOD - stepWidth);
+        cylinder(h = stepHeight, d = bearingOD);
+    }
+}
+
+//shoulderBase(2, 55, 9.1, 3.1);
+// WARNING: has some hard-coded non-parametric values in here!
+module shoulderBase(shoulderBaseHeight, shoulderBaseDiameter, shaftBossDiameter, mountScrewDiameter) {
+    mountHoleDepth = shoulderBaseHeight;
+    // hardcoded values should be moved out
+    baseDeckExtension = 50;
+    // 8 is distance from shaft center to screw center on x axis
+    // 35 is screw center to screw center on y axis
+    shaftCenterToMountHoldCenterXAxis = 8;
+    mountHoleCenterToMountHoleCenter = 35;
+    leadScrewDiameter = 8;
+    // end
+    //render(convexivity = 3)
+    difference() {
+        union () {
+            cylinder(h = shoulderBaseHeight, d = shoulderBaseDiameter);
+            translate([0, 0, shoulderBaseHeight])
+                bearingInnerStep(bearing6807_2RS_d - iFitAdjust, bearingStep, bearingStep);
+            // 40 is the length of deck extension from the baseplate in x
+            translate([0, -shoulderBaseDiameter / 2, 0])
+                cube([baseDeckExtension, shoulderBaseDiameter, shoulderBaseHeight], center = false);
+        }
+        // motor shaft hole
+        cylinder(h = shoulderBaseHeight + (bearingStep * 2), d = shaftBossDiameter);
+        // mounting holes
+
+        translate([shaftCenterToMountHoldCenterXAxis, mountHoleCenterToMountHoleCenter/2, 0]) 
+            cylinder(h = mountHoleDepth, d = mountScrewDiameter);
+        translate([shaftCenterToMountHoldCenterXAxis, -mountHoleCenterToMountHoleCenter/2, 0]) 
+            cylinder(h = mountHoleDepth, d = mountScrewDiameter);
+        // lead screw hole
+        translate([baseDeckExtension - (leadScrewDiameter * 1.5), 0, 0])
+            cylinder(h = shoulderBaseHeight, d = leadScrewDiameter + (leadScrewDiameter / 2));
+    }
+    // NOTE: need to add LM8UU mounts
+}
+
+
+
+module armLower(bearingOD, stepHeight, stepWidth, hubHeight, hubRadius, shaftHeight, shaftRadius, setScrewRadius, setScrewHeight, spokeWidth, spokes, screwTabs, screwTabHeight, armLength) {
+    boundingBox = 12;
+    boundingBoxHalf = boundingBox / 2;
+    //
+    armWidth = bearingOD + bearingStep;
+    //render(convexivity = 3)
+    union() {
+        armInnerJoint(bearingOD, bearingStep, bearingStep, hubHeight, hubRadius, shaftHeight, shaftRadius, setScrewRadius, setScrewHeight, spokeWidth, spokes, screwTabs, screwTabHeight);
+        //translate([-armLength, 0, 2 * bearingStep])
+        //    rotate([180, 0, 0])
+        //        armInnerJoint(bearingOD, bearingStep, bearingStep, hubHeight, hubRadius, shaftHeight, shaftRadius, setScrewRadius, setScrewHeight, spokeWidth, spokes, screwTabs, screwTabHeight);
+        difference() {
+            translate([-armLength, -armWidth / 2, 0])
+                cube([armLength, armWidth, bearingStep * 2], center=false);
+            cylinder(h = bearingStep * 2, d = bearingOD);
+            translate([-armLength, 0, 0])
+                cylinder(h = bearingStep * 2, d = bearingOD);
+            translate([-armLength + (bearingOD / 2) + (boundingBox / 2), -(armWidth / 2) + boundingBoxHalf, 0])
+                cube([armLength - bearingOD - boundingBox, armWidth - boundingBox, bearingStep * 2], center = false);
+        }
+        difference() {
+            intersection() {
+
+            translate([-armLength + (bearingOD / 2) + (boundingBox / 2), -(armWidth / 2) + boundingBoxHalf, 0])
+                cube([armLength - bearingOD - boundingBox, armWidth - boundingBox, bearingStep * 2], center = false);
+            for (i = [ bearingOD / 2 : armWidth / 2 : armLength]) {
+                translate([ -i, 0, bearingStep])
+                    rotate([0, 0, 45])
+                        cube([spokeWidth, armWidth + boundingBoxHalf, bearingStep * 2], center = true);
+                translate([ -i, 0, bearingStep])
+                    rotate([0, 0, -45])
+                        cube([spokeWidth, armWidth + boundingBoxHalf, bearingStep * 2], center = true);
+            }
+        }
+    }
+/*    
+            difference() {
+            
+                linear_extrude(height = bearingStep * 2, center = false, convexivity = 10, twist = 0)
+                    polygon(points = [ [0, -armWidth/2], [0, armWidth/2], [-armLength, armWidth/2], [-armLength, -armWidth/2] ]);
+                cylinder(h = bearingStep * 2, d = bearingOD);
+                translate([-armLength + boundingBox, -(armWidth / 2) + boundingBoxHalf, 0])
+                    cube([armLength - boundingBox, armWidth - boundingBox, bearingStep * 2], center = false);
+                translate([-armLength, 0, 0])
+                    cylinder(h = bearingStep * 2, d = bearingOD);
+            }
+            intersection() {
+            
+                translate([-armLength + bearingOD / 2, -(armWidth / 2) + boundingBoxHalf, 0])
+                    cube([armLength - bearingOD - boundingBox, armWidth - boundingBox, bearingStep * 2], center = false);
+                for (i = [ bearingOD / 2 : armWidth / 2 : armLength]) {
+                    translate([ -i, 0, bearingStep])
+                        rotate([0, 0, 45])
+                            cube([spokeWidth, armWidth + boundingBoxHalf, bearingStep * 2], center = true);
+                    translate([ -i, 0, bearingStep])
+                        rotate([0, 0, -45])
+                            cube([spokeWidth, armWidth + boundingBoxHalf, bearingStep * 2], center = true);
+                }
+            }
+            */
+
+   }
+}
+
+//armInnerJoint(bearing6807_2RS_D + iFitAdjust, bearingStep, bearingStep, hubHeight, hubRadius, shaftHeight, shaftRadius, setScrewRadius, setScrewHeight, spokeWidth, spokes, screwTabs, screwTabHeight);
+module armInnerJoint(bearingOD, stepHeight, stepWidth, hubHeight, hubRadius, shaftHeight, shaftRadius, setScrewRadius, setScrewHeight, spokeWidth, spokes, screwTabs, screwTabHeight) {
+    //translate([0, 0, hubHeight - (2 * stepHeight)])
+    union() {
+        bearingOuterStep(bearingOD, stepHeight, stepWidth);
+        // hub
+        translate([0, 0, -(hubHeight - (2 * stepHeight))])
+            stepperHub(hubHeight, hubRadius, shaftHeight, shaftRadius, setScrewRadius, setScrewHeight);
+        // spokes
+        radial_array(vec=[0, 0, 1], n = spokes)
+                translate([hubRadius - (stepWidth / 2), -(spokeWidth / 2), stepHeight]) 
+                    cube([(bearingOD / 2) - hubRadius, spokeWidth, stepHeight], center = false);
+        // screw holes for joining to upper
+        radial_array(vec = [0, 0, 1], n = screwTabs)
+                translate([bearingOD / 2 + (setScrewRadius * 2), 0, (2 * stepHeight) - screwTabHeight])
+                    difference() {
+                        union () {
+                            cylinder(h = screwTabHeight, r = setScrewRadius * 2);
+                            translate([-2 * setScrewRadius, - 2 * setScrewRadius, 0])
+                                cube([setScrewRadius * 2, 4 * setScrewRadius, screwTabHeight], center = false);
+                        }
+                        cylinder(h = screwTabHeight, r = setScrewRadius);
+                    }
+    }
+}
+
+
+module copy_mirror(vec=[0,1,0]) { 
+    children(); 
+    mirror(vec)
+        children(); 
+} 
+
+module radial_array(vec = [0,0,1], n = 4) {
+    for ( i = [0 : n - 1] )
+    {
+        rotate( i * 360 / n, vec)
+            children();
+    }   
+}