My first print, my first desappointment

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My first print, my first desappointment

stressless
The code below is a basic housing for an LED and an LDR. I sent it out to print and was expecting to receive a solid object as this one (central cut) :


Instead, I got almost 2 separate pieces. The plate was lightly stuck to the cube (due to printing heat) and it came off immediately...


Could you tell me what's wrong with my design or is it my printing service who screwed up ?

//Couple LED/LDR (gray levels detector)
$fn=50;
difference() {
    union() {
        cube([8,15,10.5],center=true); // body lodging
        // fastening plate
        translate([0,0,-5.25]) {
            hull() {
                translate([-6,-9.5, 0]) // top left
                    cylinder(h=1,r=4);
                translate([-6, 9.5, 0]) // top right
                    cylinder(h=1,r=4);
                translate([ 6, 9.5, 0]) // bottom right
                    cylinder(h=1,r=4);
                translate([ 6,-9.5, 0]) // bottom left
                    cylinder(h=1,r=4);
            } // hull
        } // translate
    } // union
   
    translate([0,3.5,1])
        cylinder(10.5,r=3,center=true); // LED lodging
    translate([0,-3.5,1])
        cylinder(10.5,r=3,center=true); // LDR lodging

union() {
    // inner holes
    translate([0,-5,-5])
        cylinder(3,r=0.5,center=true);
    translate([0,-2,-5])
        cylinder(3,r=0.5,center=true);
    translate([0,4.5,-5])
        cylinder(3,r=0.5,center=true);
    translate([0,2.5,-5])
        cylinder(3,r=0.5,center=true);
    // fastening holes
    translate([7,0,-5])
        cylinder(4,r=1.6,center=true);
    translate([-7,0,-5])
        cylinder(3,r=1.6,center=true);
    translate([0,10.5,-5])
        cylinder(3,r=1.6,center=true);
    translate([0,-10.5,-5])
        cylinder(3,r=1.6,center=true);
} // union
} // difference()

Thanks for any input. Dan

* * * * * * * * * * * * * * * *
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Re: My first print, my first desappointment

Ronaldo
I don't see any issue with your OpenSCAD model. The walls arround the LED and LDR lodging seems a bit scarce. The joint between the block and the plate is certainly the area of greatest stress. You might add some fillet there.

2016-03-12 15:50 GMT-03:00 stressless <[hidden email]>:
The code below is a basic housing for an LED and an LDR. I sent it out to
print and was expecting to receive a solid object as this one (central cut)
:
<http://forum.openscad.org/file/n16449/LED_LDR_solid.jpg>

Instead, I got almost 2 separate pieces. The plate was lightly stuck to the
cube (due to printing heat) and it came off immediately...
<http://forum.openscad.org/file/n16449/LED_LDR_not.jpg>

Could you tell me what's wrong with my design or is it my printing service
who screwed up ?

//Couple LED/LDR (gray levels detector)
$fn=50;
difference() {
    union() {
        cube([8,15,10.5],center=true); // body lodging
        // fastening plate
        translate([0,0,-5.25]) {
            hull() {
                translate([-6,-9.5, 0]) // top left
                    cylinder(h=1,r=4);
                translate([-6, 9.5, 0]) // top right
                    cylinder(h=1,r=4);
                translate([ 6, 9.5, 0]) // bottom right
                    cylinder(h=1,r=4);
                translate([ 6,-9.5, 0]) // bottom left
                    cylinder(h=1,r=4);
            } // hull
        } // translate
    } // union

    translate([0,3.5,1])
        cylinder(10.5,r=3,center=true); // LED lodging
    translate([0,-3.5,1])
        cylinder(10.5,r=3,center=true); // LDR lodging

union() {
    // inner holes
    translate([0,-5,-5])
        cylinder(3,r=0.5,center=true);
    translate([0,-2,-5])
        cylinder(3,r=0.5,center=true);
    translate([0,4.5,-5])
        cylinder(3,r=0.5,center=true);
    translate([0,2.5,-5])
        cylinder(3,r=0.5,center=true);
    // fastening holes
    translate([7,0,-5])
        cylinder(4,r=1.6,center=true);
    translate([-7,0,-5])
        cylinder(3,r=1.6,center=true);
    translate([0,10.5,-5])
        cylinder(3,r=1.6,center=true);
    translate([0,-10.5,-5])
        cylinder(3,r=1.6,center=true);
} // union
} // difference()

Thanks for any input. Dan

* * * * * * * * * * * * * * * *




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Re: My first print, my first desappointment

jon_bondy
In reply to this post by stressless
I printed it using PLA filament, and it was reasonably strong.  Such a
small part might be stronger if printed on a resin printer; and a
fillet, as was previously suggested, would also be helpful.  With walls
so thin, and with printed PLA beads around 0.35 mm, you might only have
3-4 beads of filament used to make each wall.  Still, the part should
not have come apart easily.  What did you pay for the print? I would
have charged $0.25

Jon

On 3/12/2016 1:50 PM, stressless wrote:

> The code below is a basic housing for an LED and an LDR. I sent it out to
> print and was expecting to receive a solid object as this one (central cut)
> :
> <http://forum.openscad.org/file/n16449/LED_LDR_solid.jpg>
>
> Instead, I got almost 2 separate pieces. The plate was lightly stuck to the
> cube (due to printing heat) and it came off immediately...
> <http://forum.openscad.org/file/n16449/LED_LDR_not.jpg>
>
> Could you tell me what's wrong with my design or is it my printing service
> who screwed up ?
>
> //Couple LED/LDR (gray levels detector)
> $fn=50;
> difference() {
>      union() {
>          cube([8,15,10.5],center=true); // body lodging
>          // fastening plate
>          translate([0,0,-5.25]) {
>              hull() {
>                  translate([-6,-9.5, 0]) // top left
>                      cylinder(h=1,r=4);
>                  translate([-6, 9.5, 0]) // top right
>                      cylinder(h=1,r=4);
>                  translate([ 6, 9.5, 0]) // bottom right
>                      cylinder(h=1,r=4);
>                  translate([ 6,-9.5, 0]) // bottom left
>                      cylinder(h=1,r=4);
>              } // hull
>          } // translate
>      } // union
>      
>      translate([0,3.5,1])
>          cylinder(10.5,r=3,center=true); // LED lodging
>      translate([0,-3.5,1])
>          cylinder(10.5,r=3,center=true); // LDR lodging
>
> union() {
>      // inner holes
>      translate([0,-5,-5])
>          cylinder(3,r=0.5,center=true);
>      translate([0,-2,-5])
>          cylinder(3,r=0.5,center=true);
>      translate([0,4.5,-5])
>          cylinder(3,r=0.5,center=true);
>      translate([0,2.5,-5])
>          cylinder(3,r=0.5,center=true);
>      // fastening holes
>      translate([7,0,-5])
>          cylinder(4,r=1.6,center=true);
>      translate([-7,0,-5])
>          cylinder(3,r=1.6,center=true);
>      translate([0,10.5,-5])
>          cylinder(3,r=1.6,center=true);
>      translate([0,-10.5,-5])
>          cylinder(3,r=1.6,center=true);
> } // union
> } // difference()
>
> Thanks for any input. Dan
>
> * * * * * * * * * * * * * * * *
>
>
>
>
> --
> View this message in context: http://forum.openscad.org/My-first-print-my-first-desappointment-tp16449.html
> Sent from the OpenSCAD mailing list archive at Nabble.com.
>
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tp3
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Re: My first print, my first desappointment

tp3
In reply to this post by stressless
On 03/12/2016 07:50 PM, stressless wrote:
> Could you tell me what's wrong with my design or is it my printing
> service who screwed up ?
>
Looking at the STL files created from both 2015.03 release version and
the nightly builds, I can see no issues at all in Blender.

For double checking, you could share the actual STL file that was
sent out and maybe have a look at which version of OpenSCAD you are
using.

As already said, the contact area between the block and the bottom
plate is very small, so that might be a reason for breaking at this
point.

ciao,
  Torsten.


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Re: My first print, my first desappointment

MichaelAtOz
Administrator
In reply to this post by stressless
If it was a home style FDM printer (perhaps via 3DHubs etc) and they didn't have the temperatures dialed-in, layer separation could easily occur. If it was in ABS a dip in acetone can help a bit with bonding.
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Re: My first print, my first desappointment

arhi
In reply to this post by stressless
On 3/12/2016 7:50 PM, stressless wrote:
> The code below is a basic housing for an LED and an LDR. I sent it out to
>

This prints without a problem in ABS, fairly strong.. I would design it
bit differently (to increase part strength) but on the other note (as
none of these anyhow is related to openscad) are you sure you want this
"as is" ? most plastic using for 3d print (including black abs) are
fairly transparent to light, especially to IR so burring leds deep into
the plastic ain't really helping you. I'm using similar setup but I push
a piece of alu tubing and then I have leds inside those (ir led and ir
diode I assume you are using here?) .. with 3d printed part, what you
can easily do is just make a slit between the two holes and use alu
tape, push trough slit to have alu barrier between the two and then wrap
the alu around the plastic to keep anything entering from the sides .
adding fillets on the Z axis edges would make that tape adhere better

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Re: My first print, my first desappointment

stressless
This post was updated on .
In reply to this post by stressless
Thanks to all for the generous comments. This picture clearly shows that there is no binding at all between the plate and the block. These parts are totally useless.


I answer separately to each of your comments

Ronaldo: You are right. Too thin and no filet. My problem is that I don't know anything about printers capabilities and properties and don't know what to avoid when constructing. Everything looks so good on Openscad. Next time, before printing, I will share my project on this list for the community's comments.

jon_bondy : I printed through "3D Hub" and the printer advertises an "UP mini" (?), black ABS. I paid $4.80 for 10 units, plus $5 setup (printed in Switzerland. As I am learning, I selected the cheapest(...), nearest printer).

tp3 : Thanks for the thorough testing. I use OpenScad v.2015.03-2. Here is the *.stl : couple_LED_LDR_2_f.stl
(previous upload was the wrong project file. Sorry).

MichaelAtOz : FDM printer ? I don't know. Yes, "3D Hub". Thanks for the acetone tip.

arhi : Fairly strong ? You must have a better printer than the "UP mini" used.
(Off subject. Sorry) Thanks for the tips in building the sensor. I use a white LED and a flat Light Dependent Resistor. The latter is buried deep to avoid catching stray light. Not being able to use my print, I came up with this. The two var. res. allow me to adjust the brightness and the divider, to adapt the readings to various ambiant lightings. I'll try your solution using IR though.


Lastly, if anyone knows of a good resource for a newbie to learn about 3D printer capabilities and materials, I'd appreciate the link. Also, I find filleting difficult to do. Any recommendation/tip or good lib. on the subject ?

Thanks again to all.
Dan

* * * * * * * * * * * * * *
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Re: My first print, my first desappointment

arhi
On 3/13/2016 11:56 AM, stressless wrote:
> These picture clearly shows that there is no binding at all between the plate and the block.

the UP! slicer has some issues with infills of small areas like these if
you print with higher layer and it's what was done here most probably
(I'd say from the pic they went to 0.25 or even 0.3mm layer) but what is
more important issue here is I'd say they are not using original UP!
filament and in order to use "custom" filament they had to modify the
UP! to tweak temperature manually (either by hacking libusb.dll or by
hacking the PT100 sensor by adding a resistor in series) as original UP!
filament is extruded at some insane temperatures - 265-275C and normal
ABS burns and drips at those temps so you have to lover the temp down
... they either poorly tweaked the temp or they are doing the "bad
tweaking" by telling the UP! slicer it's printing PLA while printing ABS
... in any case - *they printed too cold* hence the result. It is not
your design error, it's purely fault of the print house.

you could (and should) add some fillets to make the part stronger but
this is totally acceptable design


> /arhi/ : Fairly strong ? You must have a better printer than the "UP mini"
> used.

I actually printed it on UP! 2 Plus :D that's the one running behind my
back so was fastest to test on :D


> (Off subject. Sorry) Thanks for the tips in building the sensor. I use a
> white LED and a flat Light Dependent Resistor. The latter is buried deep to
> avoid catching stray light. Not being able to use my print, I came up with
> this. The two var. res. allow me to adjust the brightness and the divider,
> to adapt the readings to various ambiant lightings. I'll try your solution
> using IR though.
> <http://forum.openscad.org/file/n16457/gray_reader.jpg>

For white light it's pretty non-transparent so it should work, I never
tried, I try to use IR led + IR diode or IR transistor, apart from not
being visible I kinda have better control over it.. this flat LDR's like
you have on the pic I have serious issues with and stopped using them
ages ago, they are different, every single one has it's own curve so for
anything but "is there light" with a custom level adjustment they are
useless :( ... for any "measurements" in robotics I use IR.... and very
similar housing like yours just with a slit between the two so I can fit
aluminium tape.


> Lastly, if anyone knows of a good resource for a newbie to learn about 3D
> printer capabilities and materials, I'd appreciate the link.

best way to learn is get one yourself and play with it :D
other then that, when you have a design, before giving the printer a
final design you ask him how "printable" it is and what would (s)he
change to make it more printable/durable/strong ... other then that -
looking at "who made what" (not who design, but who made what) on sites
like youmagine, thingiverse... can give you some insight in what's
difficult (looks like crap) and what's easy (lot of ppl printed it)


>  Also, I find
> filleting difficult to do. Any recommendation/tip or good lib. on the
> subject ?

would be a good feature in openscad - select edge, add fillet :D .. attm
the best I know how to do is add a (cube minus cylinder) but it works
only for straight edges (like for your object) .. but I'm not openscad
master (solidWorks is still my poison)



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Re: My first print, my first desappointment

arhi
In reply to this post by stressless
just to show what I'm talking about, without any tweaking (this I would
generally call non-successful print because it is bit overextruded but
it's hard to control this cheap filament, not very consistent in size)
but .. out of the printer (as I said UP! 2 Plus, that's the small one
near me, easiest to test these small things, chinese el cheapo filament):
http://elco.crsndoo.com/phone_uploads/DSC_1649-1.jpg

and this is me trying to break the top part off the bottom plate
(delamination you experienced with your parts):
http://elco.crsndoo.com/phone_uploads/DSC_1650-1.jpg

as you can see the part broke but it didn't want to delaminate ... so
while this print is not beautiful it would work 100% and not break in usage

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Re: My first print, my first desappointment

osj1961
This post has NOT been accepted by the mailing list yet.
In reply to this post by arhi
Several people have suggested filleting between the body and base plate.  A while ago I wrote
a module I call "weld" which joins two parts but with a fillet (so it looks like they were welded).

fillet-demo.scad

This version of your housing uses the weld() function:

led-ldr-housing.scad

I also wonder if it might be a good idea to adjust your design a little so the bottom of the holes for the
led and ldr aren't coplanar with the top of the base plate (maybe the slicer gets confused by that coincidence...)

Cheers,
Joe
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Re: My first print, my first desappointment

stressless
In reply to this post by arhi
Thanks or all the trouble making these test parts arhi.
It's surprising that you could break the plate without the block coming apart !

Besides the fact that my design is flawed (no fillet, too thin walls, etc.), your prints demonstrate (I think) that my printer did not set the right temperature. I'll submit my new design to him before printing. I'll order one only test unit before printing a bunch.

I will redesign my housing using the weld() module submitted by osj1961 (see his post in this thread).

As for the off-topic subject on the use of LED/LDR for my sensor, I agree with you a 100% on the flat LDR subject. I'll go infrared as you suggested.

Thanks for all that.

Dan
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Re: My first print, my first desappointment

stressless
This post was updated on .
In reply to this post by osj1961
MAGICAL ! Thanks for this osj1961 !

I was working on the tedious task of filleting by differencing cylinders from cubes when you wrote.
At present I am far from understanding the mechanics of your module but will chew on it soon. To quicken generation, I change union() to weld() at the end of designing stage. Wonderful.

 <<... so the bottom of the holes for the led and ldr aren't coplanar with the top of the base plate >>
- You are absolutely right. Impemented ! Here is the revised version of my housing, all recommendations taken into account except the block's wall thickness (has to fit onto my perf board) :
* * * * * * * * *
use <fillet-demo.scad> // by osj1961-openscad forum member

//Couple LED/LDR housing (detects gray intensity)
$fn=50;
difference() {
    //union() {
    weld(2) {
        cube([8,15,11.5],center=true); // body lodging
        // fastening plate
        translate([0,0,-6.25]) {
            hull() {
                translate([-6,-9.5, 0]) // bottom left
                    cylinder(h=2,r=4);
                translate([-6, 9.5, 0]) // top left
                    cylinder(h=2,r=4);
                translate([ 6, 9.5, 0]) // top right
                    cylinder(h=2,r=4);
                translate([ 6,-9.5, 0]) // bottom right
                    cylinder(h=2,r=4);
            } // hull
        } // translate
    } // union
   
    translate([0,3.5,2])
        cylinder(10.5,r=3,center=true); // LED lodging
    translate([0,-3.5,2])
        cylinder(10.5,r=3,center=true); // LDR lodging

union() {
    // components leads holes
    translate([0,-5,-5])
        cylinder(5,r=0.5,center=true); // LED left
    translate([0,-2,-5])
        cylinder(5,r=0.5,center=true); // LED right
    translate([0,2.5,-5])
        cylinder(5,r=0.5,center=true); // LDR left
    translate([0,4.5,-5])
        cylinder(5,r=0.5,center=true); // LDR left

     // fastening holes
    translate([7,0,-5])
        cylinder(3,r=1.6,center=true); // long side right
    translate([-7,0,-5])
        cylinder(3,r=1.6,center=true); // long side left
    translate([0,10.5,-5])
        cylinder(3,r=1.6,center=true); // short side top
    translate([0,-10.5,-5])
        cylinder(3,r=1.6,center=true); // short side bottom
} // union

    // clear fillet around fastening holes
    // top
    translate([0,10,-4.2]) cylinder(h=5,r=2.5);
    // bottom
    translate([0,-10,-4.2]) cylinder(h=5,r=2.5);
    // right
    translate([6.5,0,-4.2]) cylinder(h=5,r=2.5);
    // left
    translate([-6.5,0,-4.2]) cylinder(h=5,r=2.5);

} // difference()
* * * * * * * * * * *
I think I am good to go but comments are welcome. Thanks again to all.
Dan