Actions

Air flow switch holder: Difference between revisions

From HacDC Wiki

(updated introductory text to state dimensions match nozzle)
m (adjusted height and position of filler block between switch holder and wafer flanges to unblock hinge pin hole)
 
(6 intermediate revisions by the same user not shown)
Line 1: Line 1:
This is the OpenSCAD code to create a wafer air flow sensor (and backflow preventer) to hold a microswitch to stop the laser from firing if the exhaust flow stops.  Dimensions have been set to match the exhaust nozzle.  The current version of the nacelle doesn't quite match, even though the nozzle was reverse engineered from it.
This is the OpenSCAD code to create a wafer air flow sensor (and backflow preventer) to hold a microswitch to stop the laser from firing if the exhaust flow stops.  Dimensions have been set to match the exhaust nozzle.  The current version of the header doesn't quite match, even though the nozzle was reverse engineered from it.


This was printed on 5/1 and it has some issues. 
#The arms which hold the switch body interfere with the flap plate. 
#The flap plate axis of rotation could be lowered to improve the balance. 
#The thickness of the wafer can be increased to reduce the warpage of the piece.
Model was redesigned on 5/5:
#Switch holder moved to side from top center
#Flap axis of rotation lowered
#Up arrow added
#Thickness increased from 3 to 5 mm
#Wire holes relocated 180°
You can find the stl file here [[File:Airflow-switch.stl]]
<pre>
<nowiki>
<nowiki>
/*
/*
exhaust airflow detector
exhaust airflow detector
safety interlock for cheap Chinese laser at Hac DC
safety interlock for cheap Chinese laser at Hac DC
This switch is a lug style wafer for insertion between the exhaust collector and the exhaust nozzle on the back of the laser chassis. When the exhaust fan is running and air is flowing the switch will operate to allow the laser to fire.  This switch is upstream of the exhaust fan so air will leak into the exhaust stream, not exhaust leaking out into room air.
This switch is a lug style wafer for insertion between the exhaust collector and the exhaust nozzle on the back of the laser chassis.
  When the exhaust fan is running and air is flowing the switch will operate to allow the laser to fire.  This switch is upstream of
  the exhaust fan so air will leak into the exhaust stream, not exhaust leaking out into room air.
James Sullivan
James Sullivan
4-20-17
5-5-17, v2
OpenSCAD version 2015.03-1  
OpenSCAD version 2015.03-1  


Line 24: Line 38:
fod=108;    //foot outside dimension, from outside edge to outside edge
fod=108;    //foot outside dimension, from outside edge to outside edge
fid=(nid+nod)/2;//foot inside dimension, from inside edge to inside edge
fid=(nid+nod)/2;//foot inside dimension, from inside edge to inside edge
*/
*/
fid=60;  //flange inner diameter, same as nid
fid=60;  //flange inner diameter, same as nid
Line 30: Line 43:
bhd=3.6; //bolt hole diameter
bhd=3.6; //bolt hole diameter
bcd=93.6;//bolt circle diameter
bcd=93.6;//bolt circle diameter
hph=10; //hinge pin height above center line, i.e. butterfly offset.  Reduce to make switch more sensitive.  Increse to make switch more stable.
thick=5; //thickness of flange - originally 3, but warped when removing from printer bed
sfw=sqrt(fid*fid-4*hph*hph); //switch flap width
flap=3;  //thickness of flap - originally 3, but warped when removing from printer bed
hph=bhd*2;   //hinge pin height above center line, i.e. butterfly offset.  Reduce to make switch more sensitive.  Increse to make switch more stable. - originally 10
sfw=fid-thick*2; //switch flap width - originally sqrt(fid*fid-4*hph*hph)
shd=2;  //switch hole diameter
shd=2;  //switch hole diameter
shp=10; //switch hole pitch, i.e. center to center spacing of mounting holes on microswitch
shp=10; //switch hole pitch, i.e. center to center spacing of mounting holes on microswitch
srh=8;  //switch roller height, i.e. height above switch hole centerline where switching action occurs
srh=12;  //switch roller height, i.e. height above switch hole centerline where switching action occurs
sbw=6;  //switch body width
sbw=6;  //switch body width
nfw=5;  //nut face width
nfw=5;  //nut face width
nt=1;  //nut thickness
nt=1;  //nut thickness
thick=3;    //thickness of flange
$fn=80;
$fn=80;


difference(){
difference(){ //wafer body
     union(){
     union(){
         cylinder(d=fod,h=thick);    //wafer body
         cylinder(d=fod,h=thick);     
         hull(){ //horizontal lugs
         for(ang=[0,90]){
            translate([bcd/2,0,0]) cylinder(d=3*bhd, h=thick);
            rotate([0,0,ang]) hull(){ //lugs
            translate([-bcd/2,0,0]) cylinder(d=3*bhd, h=thick);
                translate([bcd/2,0,0]) cylinder(d=3*bhd, h=thick);
                translate([-bcd/2,0,0]) cylinder(d=3*bhd, h=thick);
            }
         }
         }
         rotate([0,0,90]) hull(){  //vertical lugs
         translate([sfw/2+thick/2,0,thick]) rotate([-90,0,0]) cylinder(d1=shd*1.6,d2=0,h=shd*2);//up direction arrow head
            translate([bcd/2,0,0]) cylinder(d=3*bhd, h=thick);
        translate([sfw/2+thick/2,0,thick]) rotate([90,0,0]) cylinder(d=shd*0.8,h=shd*2); //up direction arrow shaft
            translate([-bcd/2,0,0]) cylinder(d=3*bhd, h=thick);
        }
     }
     }
     translate([0,0,-thick/2]) intersection(){   //bore
     translate([0,0,-thick/2]) intersection(){ //bore
         cylinder(d=fid, h=2*thick); //circular top and bottom
         cylinder(d=fid, h=2*thick);           //circular top and bottom
         cube([sfw,fod,thick*4],true);   //vertical left and right
         cube([sfw,fod,thick*4],true);         //vertical left and right
     }
     }
     for (angle=[0:90:270]){ //bolt holes in lugs
     for (angle=[0:90:270]){ //bolt holes in lugs
         rotate([0,0,angle]) translate([bcd/2,0,-thick/2]) cylinder(d=bhd,h=thick*2);
         rotate([0,0,angle]) translate([bcd/2,0,-thick/2]) cylinder(d=bhd,h=thick*2);
     }
     }
     for (angle=[55:5:65]){  //wire holes through flange
     for (angle=[235:5:245]){  //wire holes through flange
         translate([0,0,thick/2]) rotate([0,90,angle]) cylinder(d=1,h=bcd/2);
         translate([0,0,thick-flap/2]) rotate([0,90,angle]) cylinder(d=1,h=bcd/2);
     }
     }
     translate([0,hph,thick/2]) rotate([0,90,0]) cylinder(d=1,h=bcd+4*bhd,center=true);  //hinge pin axle hole
     translate([0,hph,flap/2]) rotate([0,90,0]) cylinder(d=1,h=bcd+4*bhd,center=true);  //hinge pin axle hole
}
} //end of wafer body
translate([0,fid/2-shp-3*shd,0]){  //switch holder
translate([-thick/2-sfw/2,0,flap/2+srh]){  //switch holder
     difference(){
     difference(){
         union(){
         union(){
             translate([sbw/2,0,0]) cube([thick,shp+3*shd,3*shd]);   //left mount flange
             cube([thick,shp+3*shd,3*shd],center=true);//mount flange
             translate([-sbw/2-thick,0,0]) cube([thick,shp+3*shd,3*shd]);//right mount flange
            color("blue") translate([0,0,-srh/2-flap/4+thick/2-3*shd/4]) cube([thick,shp+3*shd,srh+flap/2-thick-3*shd/2],center=true); //support for mount flange
             translate([-thick/2,0,-shd*2]) cylinder(d2=shd*1.6,d1=0,h=shd*2.0);//flow direction arrow head
            translate([-thick/2,0,-shd/2]) cylinder(d=shd*0.8,h=shd*2.0); //flow direction arrow shaft
         }
         }
         translate([-sbw/2-3/2*thick,3/2*shd,3/2*shd]) rotate([0,90,0]) cylinder(d=shd,h=sbw+3*thick);  //lower bolt hole
         for (dy=[-shp/2,shp/2]) {
        translate([-sbw/2-3/2*thick,shp+3/2*shd,3/2*shd]) rotate([0,90,0]) cylinder(d=shd,h=sbw+3*thick);//upper bolt hole
            translate([0,dy,0]) rotate([0,90,0]) cylinder(d=shd,h=2*thick,center=true);   //bolt holes
        for (angle=[0:120:240]){
            for (angle=[0:120:240]){
            translate([-sbw/2-thick,3/2*shd,3/2*shd]) rotate([angle,0,0]) cube([nt*2,nfw,nfw/sqrt(3)],center=true); //lower nut socket
                translate([-thick/2,dy,0]) rotate([angle,0,0]) cube([nt*2,nfw,nfw/sqrt(3)],center=true); //nut sockets
             translate([-sbw/2-thick,shp+3/2*shd,3/2*shd]) rotate([angle,0,0]) cube([nt*2,nfw,nfw/sqrt(3)],center=true); //upper nut socket
             }
         }
         }
     }
     }
    translate([sbw/2+thick,shp/2+shd*1.5,shd*1.5]) cylinder(d1=shd*1.2,d2=0,h=shd*1.5); //flow direction arrow head
    translate([sbw/2+thick,shp/2+shd*1.5,0]) cylinder(d=shd*0.6,h=shd*1.5); //flow direction arrow shaft
    translate([-sbw/2-thick,shp/2+shd*1.5,shd*1.5]) cylinder(d1=shd*1.2,d2=0,h=shd*1.5);//flow direction arrow head
    translate([-sbw/2-thick,shp/2+shd*1.5,0]) cylinder(d=shd*0.6,h=shd*1.5); //flow direction arrow shaft
}
}


translate([0,fid/2+bcd/2+bhd*2,0]) difference(){    //flap disk
translate([0,fid/2+bcd/2+bhd*2,0]) difference(){    //flap disk
     intersection(){  //bore
     intersection(){  //bore
         cylinder(d=fid-0.5, h=thick);  //circular top and bottom
         cylinder(d=fid-0.5, h=flap);  //circular top and bottom
         cube([sfw-0.5,fod,thick*2],true);    //vertical left and right
         cube([sfw-0.5,fod,flap*2],true);    //vertical left and right
     }
     }
     translate([0,hph,thick/2]) rotate([0,90,0]) cylinder(d=1,h=bcd+4*bhd,center=true);  //hinge pin axis
     translate([0,hph,flap/2]) rotate([0,90,0]) cylinder(d=1,h=bcd+4*bhd,center=true);  //hinge pin axis
}
}
</nowiki>
</nowiki>
</pre>
[[Category: CheapChineseLaser]]

Latest revision as of 04:22, 7 May 2017

This is the OpenSCAD code to create a wafer air flow sensor (and backflow preventer) to hold a microswitch to stop the laser from firing if the exhaust flow stops. Dimensions have been set to match the exhaust nozzle. The current version of the header doesn't quite match, even though the nozzle was reverse engineered from it.

This was printed on 5/1 and it has some issues.

  1. The arms which hold the switch body interfere with the flap plate.
  2. The flap plate axis of rotation could be lowered to improve the balance.
  3. The thickness of the wafer can be increased to reduce the warpage of the piece.

Model was redesigned on 5/5:

  1. Switch holder moved to side from top center
  2. Flap axis of rotation lowered
  3. Up arrow added
  4. Thickness increased from 3 to 5 mm
  5. Wire holes relocated 180°

You can find the stl file here File:Airflow-switch.stl


/*
exhaust airflow detector
safety interlock for cheap Chinese laser at Hac DC
This switch is a lug style wafer for insertion between the exhaust collector and the exhaust nozzle on the back of the laser chassis.
  When the exhaust fan is running and air is flowing the switch will operate to allow the laser to fire.  This switch is upstream of
  the exhaust fan so air will leak into the exhaust stream, not exhaust leaking out into room air.
James Sullivan
5-5-17, v2
OpenSCAD version 2015.03-1 

--dimensions from mating exhaust nozzle--
nid=60;     //nozzle inner diameter
nod=80;     //nozzle outer diameter
mod=100;    //maximum outer diameter
sh=30;      //step height
sw=5;       //step width
oah=50;     //over-all height
tlw=3;      //top ledge width
bcd=46.8*2; //bolt circle diameter
bhd=3.6;    //bolt hole diameter
fw=12;      //foot width
fh=15;      //foot height
fod=108;    //foot outside dimension, from outside edge to outside edge
fid=(nid+nod)/2;//foot inside dimension, from inside edge to inside edge
*/
fid=60;  //flange inner diameter, same as nid
fod=80;  //flange outer diameter, same as nod
bhd=3.6; //bolt hole diameter
bcd=93.6;//bolt circle diameter
thick=5; //thickness of flange - originally 3, but warped when removing from printer bed
flap=3;  //thickness of flap - originally 3, but warped when removing from printer bed
hph=bhd*2;   //hinge pin height above center line, i.e. butterfly offset.  Reduce to make switch more sensitive.  Increse to make switch more stable. - originally 10
sfw=fid-thick*2; //switch flap width - originally sqrt(fid*fid-4*hph*hph)
shd=2;  //switch hole diameter
shp=10; //switch hole pitch, i.e. center to center spacing of mounting holes on microswitch
srh=12;  //switch roller height, i.e. height above switch hole centerline where switching action occurs
sbw=6;  //switch body width
nfw=5;  //nut face width
nt=1;   //nut thickness
$fn=80;

difference(){ //wafer body
    union(){
        cylinder(d=fod,h=thick);    
        for(ang=[0,90]){
            rotate([0,0,ang]) hull(){  //lugs
                translate([bcd/2,0,0]) cylinder(d=3*bhd, h=thick);
                translate([-bcd/2,0,0]) cylinder(d=3*bhd, h=thick);
            }
        }
        translate([sfw/2+thick/2,0,thick]) rotate([-90,0,0]) cylinder(d1=shd*1.6,d2=0,h=shd*2);//up direction arrow head
        translate([sfw/2+thick/2,0,thick]) rotate([90,0,0]) cylinder(d=shd*0.8,h=shd*2); //up direction arrow shaft
    }
    translate([0,0,-thick/2]) intersection(){ //bore
        cylinder(d=fid, h=2*thick);           //circular top and bottom
        cube([sfw,fod,thick*4],true);         //vertical left and right
    }
    for (angle=[0:90:270]){ //bolt holes in lugs
        rotate([0,0,angle]) translate([bcd/2,0,-thick/2]) cylinder(d=bhd,h=thick*2);
    }
    for (angle=[235:5:245]){  //wire holes through flange
        translate([0,0,thick-flap/2]) rotate([0,90,angle]) cylinder(d=1,h=bcd/2);
    }
    translate([0,hph,flap/2]) rotate([0,90,0]) cylinder(d=1,h=bcd+4*bhd,center=true);  //hinge pin axle hole
} //end of wafer body
translate([-thick/2-sfw/2,0,flap/2+srh]){   //switch holder
    difference(){
        union(){
            cube([thick,shp+3*shd,3*shd],center=true);//mount flange
            color("blue") translate([0,0,-srh/2-flap/4+thick/2-3*shd/4]) cube([thick,shp+3*shd,srh+flap/2-thick-3*shd/2],center=true); //support for mount flange
            translate([-thick/2,0,-shd*2]) cylinder(d2=shd*1.6,d1=0,h=shd*2.0);//flow direction arrow head
            translate([-thick/2,0,-shd/2]) cylinder(d=shd*0.8,h=shd*2.0); //flow direction arrow shaft
        }
        for (dy=[-shp/2,shp/2]) {
            translate([0,dy,0]) rotate([0,90,0]) cylinder(d=shd,h=2*thick,center=true);   //bolt holes
            for (angle=[0:120:240]){
                translate([-thick/2,dy,0]) rotate([angle,0,0]) cube([nt*2,nfw,nfw/sqrt(3)],center=true); //nut sockets
            }
        }
    }
}

translate([0,fid/2+bcd/2+bhd*2,0]) difference(){    //flap disk
    intersection(){   //bore
        cylinder(d=fid-0.5, h=flap);  //circular top and bottom
        cube([sfw-0.5,fod,flap*2],true);    //vertical left and right
    }
    translate([0,hph,flap/2]) rotate([0,90,0]) cylinder(d=1,h=bcd+4*bhd,center=true);  //hinge pin axis
}