From 04f03386761d24bf28759d2dbefa7c9bd10a3726 Mon Sep 17 00:00:00 2001
From: Michael Krelin <hacker@klever.net>
Date: Tue, 31 Jul 2018 19:31:44 +0000
Subject: mixer: committing narrow-channel version

but basically I abandon this design
---
diff --git a/mixer.scad b/mixer.scad
index 3740ae5..c298482 100644
--- a/mixer.scad
+++ b/mixer.scad
@@ -24,22 +24,54 @@ module the_mixer(
  liner_d = 4, liner_id = 2, // ptfe liner inner and outer diameters
  filament_d = 1.75,
  join_angle = 30,
+ joint = "wide", // wide|narrow
 
  interpushfit = 2*extrusion_width, // space between two pushfit holes
  pushfit_s = 2, // shell around pushfit holes
- output_l = 4, // length of output after before pushfit
+ output_l = 4, // length of output liner after before pushfit
  outer_r = 3, // outer radius
 
  liner_d_tolerance = .2,
+ filament_d_tolerance = .25
 ) {
  fnd = PI*2*2; fnr = fnd*2;
- module liner(l,in) {
-  inh=ld-liner_id;
-  union() {
-   translate([0,0,inh])
-   cylinder(d=ld,h=l-inh,$fn=ld*fnd);
-   translate([0,0,-epsilon])
-   cylinder(d1=ld+epsilon,d2=liner_id-epsilon,h=inh+2*epsilon,$fn=ld*fnd);
+
+ ld = liner_d+liner_d_tolerance;
+ fd = filament_d+filament_d_tolerance;
+ linero = ld/2/tan(join_angle/2); // liner offset
+
+ jd = (joint=="narrow") ? fd : ld; // joint diameter
+ jo = (joint=="narrow") ? jd/2/tan(join_angle/2) : linero; // joint offset
+
+ pfrx = interpushfit/2/cos(join_angle/2); // radial margin
+ pfR = pushfit_d/2+pfrx;      // radius of pushfit with margin
+ // offset of pushfit offset
+ pfoo = (pushfit_type=="threaded") ? 0 :
+        (pushfit_type=="embedded") ? (pushfit_h-pushfit_ring_h) :
+        (pushfit_type=="embeddest") ? 0 : undef;
+ pfo = pfR/tan(join_angle/2)-pfoo; // pushfit thread ofset
+
+ h = pushfit_d+pushfit_s*2;
+ 
+ module liner(l,in,offset=0,linero) {
+  lo = linero==undef ? l/2 : linero;
+  translate([0,0,offset])
+  if(joint=="narrow") {
+   $fn = max(fd,ld,jd)*fnd;
+   cylinder(d=fd,h=l);
+   //if(in=="top") cylinder(d1=jd,d2=fd,h=(jd-fd)/2);
+   translate([0,0,lo])
+   cylinder(d=ld,h=l-lo);
+   if(in=="bottom") translate([0,0,lo+epsilon]) mirror([0,0,1])
+    cylinder(d1=(liner_id+ld)/2,d2=fd,h=(liner_id+ld-fd)/2);
+  }else{
+   inh=ld-liner_id;
+   union() {
+    translate([0,0,inh])
+    cylinder(d=ld,h=l-inh,$fn=ld*fnd);
+    translate([0,0,-epsilon])
+    cylinder(d1=ld+epsilon,d2=liner_id-epsilon,h=inh+2*epsilon,$fn=ld*fnd);
+   }
   }
  }
  module pushfit() {
@@ -52,7 +84,7 @@ module the_mixer(
   }else if(pushfit_type=="embeddest") {
    cylinder(d=pushfit_id,h=pushfit_h+1,$fn=pushfit_insert_d*fnd);
    cylinder(d=pushfit_d,h=pushfit_legspace_h,$fn=pushfit_d*fnd);
-   dd = pushfit_d-pushfit_id;
+   dd = (pushfit_d-pushfit_id)/2;
    translate([0,0,pushfit_legspace_h-epsilon])
    cylinder(d1=pushfit_d,d2=pushfit_id-2*epsilon,h=dd+epsilon,$fn=pushfit_d*fnd);
    translate([0,0,pushfit_h-pushfit_inlet_ch-epsilon])
@@ -60,17 +92,6 @@ module the_mixer(
   }
  }
  
- ld = liner_d+liner_d_tolerance;
- linero = ld/2/tan(join_angle/2); // liner offset
- pfrx = interpushfit/2/cos(join_angle/2); // radial margin
- pfR = pushfit_d/2+pfrx;      // radius of pushfit with margin
- // offset of pushfit offset
- pfoo = (pushfit_type=="threaded") ? 0 :
-        (pushfit_type=="embedded") ? (pushfit_h-pushfit_ring_h) :
-        (pushfit_type=="embeddest") ? 0 : undef;
- pfo = pfR/tan(join_angle/2)-pfoo; // pushfit thread ofset
-
- h = pushfit_d+pushfit_s*2;
  difference() {
   hull() {
    for(s=[-1,1]) {
@@ -83,14 +104,13 @@ module the_mixer(
    }
   }
   for(s=[-1,1]) rotate([0,0,s*join_angle/2]) {
-   translate([0,linero,0]) rotate([-90,0,0])
-   liner(l=pfo-linero+epsilon,in="bottom");
-   //cylinder(d=ld,h=pfo-linero+1,$fn=ld*fnd);
+   rotate([-90,0,0])
+   liner(l=pfo-jo+epsilon,in="bottom",offset=jo);
    translate([0,pfo,0]) rotate([-90,0,0])
    pushfit();
   }
   rotate([90,0,0]) {
-   liner(l=output_l+epsilon,in="top");
+   liner(l=output_l+epsilon,in="top",linero=0);
    //cylinder(d=ld,h=output_l+1,$fn=ld*fnd);
    translate([0,0,output_l])
    pushfit();
@@ -98,11 +118,11 @@ module the_mixer(
   hull() {
    for(s=[-1,1]) rotate([0,0,s*join_angle/2]) {
     rotate([-90,0,0])
-    translate([0,0,linero])
-    cylinder(d=ld,h=epsilon,$fn=ld*fnd);
+    translate([0,0,jo])
+    cylinder(d=jd,h=epsilon,$fn=jd*fnd);
    }
    rotate([90,0,0])
-   cylinder(d=ld,h=epsilon,$fn=ld*fnd);
+   cylinder(d=jd,h=epsilon,$fn=jd*fnd);
   }
  }
 }
@@ -112,7 +132,8 @@ module this() {
   pushfit_type="embeddest",
   pushfit_d = 8,
   pushfit_h = 7,
-  interpushfit = extrusion_width
+  interpushfit = extrusion_width,
+  joint = "narrow"
  );
 }
 
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