Ray: Thanks for both this and your lengthier post later on Saturday evening. I'm
back on the case today. But I'm postponing getting into geo-code and Marlin
stuff. I'm on a deadline because the labeled panel is envisaged as part of a an
Arduino project I dreamt up a few days ago. If successful it will be a sort of
music-come-trinket box, a change from the too frequent  'earrings and necklace'
Christmas gift for my wife.

Status report:

Spent most of Sunday so far experimenting further. Concluded with regret that
filling hollow text with the likes of 'Hard As Nails' is unsatisfactory at these
small sizes. Messy and aesthetically unsatisfying too!

So for now I'm focusing on OpenSCAD/Cura solutions.

With the code shown I can print this hollow example in size 7 text.

It looks fine previewed in Cura.
https://www.dropbox.com/s/tdk9rw3u35ss4un/ArilalNB7Cura.jpg?raw=1

difference()
{
translate([0, 8, 0])
cube([28, 12, 3]); //
translate([0, 11, -0.5])
color("red")
linear_extrude(5)
text(" Off-On ", 7, font="Arial:style=Narrow Bold"); // Size 7 text, empty
}

But I'd like to try my 'push in' idea next.  So I'm about to add code that will
print the solid text itself, in the same run. Before I do...

Q1: I assume I should make it a tad smaller? Say 6.9?

Q2: I'll obviously soon find out, but will it print isolated letters
successfully, or must I add support?

Q3: If so, would others recommend I keep that to a minimum by coding it myself
rather than using Cura's support options?

Terry

On Sat, 27 Nov 2021 16:18:01 +0000, you wrote:

David,

As you may have seen from my recent pots I'm leaning towards that method -
push fit. Could you expand a bit on the details please? As I understand it
you do two prints. One for the 'hollow/' text in the base. The other for
the text itself, which is the part I need more details about.

Do you make it smaller than the cavities into which it will be pushed, and
if so how much?

Do you get your slicer to support the individual characters of the string?

What font do you recommend?

What is the smallest text size you use?

Any other tips/pitfalls?

On Fri, 26 Nov 2021 at 18:39, David Schooley dcschooley@gmail.com wrote:

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Terry,

You started with:

You are starting to stray into another wider OT.

There are better places for 3D printing techniques.

Can we wind-up this topic soon.

From: Terry Pinnell [mailto:terrypingm@gmail.com]
Sent: Mon, 29 Nov 2021 09:56
To: OpenSCAD general discussion
Subject: [OpenSCAD] Re: Printing text flush to a flat surface

David,

As you may have seen from my recent pots I'm leaning towards that method - push fit. Could you expand a bit on the details please? As I understand it you do two prints. One for the 'hollow/' text in the base. The other for the text itself, which is the part I need more details about.

Do you make it smaller than the cavities into which it will be pushed, and if so how much?

Do you get your slicer to support the individual characters of the string?

What font do you recommend?

What is the smallest text size you use?

Any other tips/pitfalls?

On Fri, 26 Nov 2021 at 18:39, David Schooley dcschooley@gmail.com wrote:

I would print them separately and push them into place. Starting and stopping the printer while reloading filament might end up being a horror show.

This is easy if you have a dual nozzle, but I don’t know if that is possible with your Ender. I do this stuff all of the time with OpenSCAD by extruding text and then subtracting to get the models.

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You are going to have to experiment.

You must make the cavities slightly larger than whatever you put into them.

My rule of thumb is that things inserted into other things need 0.25mm of clearance for a tight fit that could end up being permanent. A loose fit is 0.5mm. These numbers are based on regular shapes like cylinders and cubes. Text could be another ball game. It also sounds like your text is quite small.

I would start with the text the size you think you need for the solid text. Then subtract larger versions of that text to make the hollow portion until you get something that fits. I don’t have a clue how OpenSCAD will do scaling in this case or what will happen with the inner parts the lettering. Maybe start by making the text bold when you subtract it. After that, either scale with OpenSCAD scaling or by making the text larger. I really don’t know. This is doable but you will have to experiment.

I’ve only done this with text using dual extrusion, which makes it easy. I’ve made press fit parts but not with text.

Use simple font with lots of vertical and horizontal lines.

Sorry, youre right of course, Michael. Pity though, with such a lot of 3D printing know-how here!

Thanks to all for the help.

I think my email address is already public. Either tdotpinnellatbtinternetdotcom or terrypingmatgmaildotcom will deliver any outstanding replies or further advice anyone wishes to offer please.

--
Terry

On 11/28/2021 4:39 PM, David Schooley wrote:

You don't want scaling.  You want offset().

Consider a capital O.  You want the outer edge of the O to get larger,
and that sounds like scaling.  But you want the inner edge to get
smaller, and that's not like scaling at all.

Consider "A VERY LONG STRING".  For any single letter, you want the
letter to get (say) 0.4mm wider.  That sounds like scaling.  But you
don't want the overall length of the string to increase by 0.4mm per
letter.  You want the letters to stay in the same place, and get
larger, with the spacing between them getting smaller.

You want something sort of like this:

// Text to create
str = "Hello";

// Size of block
w = 32;
d = 12;
h = 10;

// Thickness of letters to be pushed into place
t = 1;

// Gap around letter (exaggerated for visibility).
// Used for both X-Y and Z; should perhaps have a
// separate Z value.
gap = 0.6;

// Extend the difference this far above the surface
// to avoid Z-fighting.

epsilon = 1;

difference() {
    cube([w,d,h]);
    translate([0,1,h-t-gap])
        linear_extrude(height=t+gap+epsilon, convexity=10)
        offset(gap)
        text(str);
}
color("black")
    translate([0,1,h-t])
    linear_extrude(height=t, convexity=10)
    text(str);

which will yield something like this:

On Mon, 29 Nov 2021 18:40:35 +0000, you wrote:

Fortuitous timing, Jordan! I started reading your post while printing the
following 9-minute test. As you see, my tentative ‘solution’ to my sizing
dilemma was different.

// Solid text size 8.0 to fit hollow size 8.2
// Will push in this solid character by character, after removing the
// thin 'support'.

$fn=99;
cube([44, 12, 0.8], true); // Support
color("red")
translate([0, 0, 0.2]) // So text 1mm above bottom of panel
//mirror([0, 1, 0])
linear_extrude(2)
text("OFF-ON", 8.2, font = "Arial:style=Bold", halign = "center", valign =
"center");

I’d previously printed the ‘hollow’ equivalent. Will now study your post in
detail.

// Hollow to within 1mm of panel bottom, size 8.2
// Will push solid text size 8.0 in from front
$fn=99;
difference()
{
cube([44, 12, 3], true); //
color("red")
translate([0, 0, -0.5]) // So text 1mm above bottom of panel
linear_extrude(5)
text("OFF-ON", 8.2, font = "Arial:style=Bold", halign = "center", valign =
"center");
}

Michael: I accepted your justified rap of the knuckles yesterday for straying
too far towards the printing aspect. But trust you agree that we are now back on
topic and that the thread should remain open?

I think it’s arguable where the boundary comes, as 3D printing is presumably one
of the major uses of OpenSCAD. Discussions about code is therefore often bound
to include its practical application.

But it would probably be OT to debate that further ;-)

Terry

This is great. I will keep it for future reference. You answered my uncertainty about what will happen with the interior of the lettering. You could accomplish this to some extent by making the letters bold, but there is less control doing that, and it wouldn’t work at all for some fonts.

Thanks.