Air flow switch holder: Difference between revisions
From HacDC Wiki
(adjusted dimensions to match exhaust nozzle, added clearance to flap) |
m (adjusted height and position of filler block between switch holder and wafer flanges to unblock hinge pin hole) |
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This is the OpenSCAD code to create a | 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. | 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 | ||
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= | thick=5; //thickness of flange - originally 3, but warped when removing from printer bed | ||
sfw=sqrt(fid*fid-4*hph*hph) | 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= | 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 | ||
$fn=80; | $fn=80; | ||
difference(){ | difference(){ //wafer body | ||
union(){ | union(){ | ||
cylinder(d=fod,h=thick); | cylinder(d=fod,h=thick); | ||
hull(){ // | 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(){ | translate([0,0,-thick/2]) intersection(){ //bore | ||
cylinder(d=fid, h=2*thick); | cylinder(d=fid, h=2*thick); //circular top and bottom | ||
cube([sfw,fod,thick*4],true); | 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=[ | 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, | 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([ | translate([-thick/2-sfw/2,0,flap/2+srh]){ //switch holder | ||
difference(){ | difference(){ | ||
union(){ | union(){ | ||
translate([ | cube([thick,shp+3*shd,3*shd],center=true);//mount flange | ||
translate([- | 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 | translate([0,fid/2+bcd/2+bhd*2,0]) difference(){ //flap disk | ||
intersection(){ //bore | intersection(){ //bore | ||
cylinder(d=fid-0.5, h= | cylinder(d=fid-0.5, h=flap); //circular top and bottom | ||
cube([sfw-0.5,fod, | cube([sfw-0.5,fod,flap*2],true); //vertical left and right | ||
} | } | ||
translate([0,hph, | 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.
- 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
/* 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 }