# Customizable flexible name bracelet

## by bmcage, published

## Description

A flexible bracelet you can adapt to your liking, and add your name, or another text, on.

For a two color version, see: http://www.thingiverse.com/thing:56257

For a full inside version, see http://www.thingiverse.com/thing:319183

Update 3.5.2014: fixed the issue with the excessive material in the inner circle

## Recent Comments

view allOn the outer rim, the "Spikes" come all the way out to the edge, and they are off to either side of letter faces. Ideally, you want the "Spikes" to come up behind the letter faces, the same way they (almost) do on the inner rim. This will leave that essential bit of extra room between the letter faces that will always work.

Since I mentioned the back faces, I may as well address the orther problem. The "SPikes" there push way into the inner faces, and this leaves a little bit of dangling face edges. It's probably too small to show up in most prints, but if you want to tidy things up, that's the place you want to look.

As I'm typing this, I'm noticing that the text also protrudes out the back of the letter face. I'm sure this is intentional, so that the letters can be printed as holes, but when not printing as holes, you should puch the letters outward a bit, so that they only print on the front. This makes for a cleaner print when using zero infill. Be sure to compensate for letter thickness. It would also be a nice addition to allow the adjustment of the letters to fill up more of the letter face.

If I have more time, I can feed you some snippets, but I'm still trying to wrap my head around the code to figure out what's what :)

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## Instructions

Open it in the customizer. As bracelet stretches, give inner radius so as to sit nicely on your wrist. Set outer radius, set height, and set the text you want on the bracelet, eg a telephone number where you can be reached!.

The text can be in relief, or as holes. When printing relief, make sure you print with 100% infill. Holes still must be tested on a printer, I assume you should print thick and slow so as to not jump over the holes too fast.

It is important that you give the nozzle diameter of your 3D printer, as this is what will make sure your bracelet does not break easily. The thickness is one nozzle diameter, if you want the bracelet thicker, set nozzle to 2 or 3 times your real nozzle diameter

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On the outer rim, the "Spikes" come all the way out to the edge, and they are off to either side of letter faces. Ideally, you want the "Spikes" to come up behind the letter faces, the same way they (almost) do on the inner rim. This will leave that essential bit of extra room between the letter faces that will always work.

Since I mentioned the back faces, I may as well address the orther problem. The "SPikes" there push way into the inner faces, and this leaves a little bit of dangling face edges. It's probably too small to show up in most prints, but if you want to tidy things up, that's the place you want to look.

As I'm typing this, I'm noticing that the text also protrudes out the back of the letter face. I'm sure this is intentional, so that the letters can be printed as holes, but when not printing as holes, you should puch the letters outward a bit, so that they only print on the front. This makes for a cleaner print when using zero infill. Be sure to compensate for letter thickness. It would also be a nice addition to allow the adjustment of the letters to fill up more of the letter face.

If I have more time, I can feed you some snippets, but I'm still trying to wrap my head around the code to figure out what's what :)

With what variables are your running customizer? Perhaps big difference between inner and outer radius? I suppose this could end up with closed triangles.

inner_radius = 28; //[15:150]

//outer radius of the bracelet in mm

outer_radius = 33; //[15:150]

//length of the bracelet in mm

length = 15; // [5:60]

//diameter of your 3d printer nozzle in mm

nozzle = 0.5;

//number of sections on bracelets

sections = 17; //[15:60]

//text to put on bracelet

text = "";

//view text as holes?

holes = "no"; // [yes, no]

//text thickness as amount of nozzle

text_thickness = 3; //[2:6]

use <mcad fonts.scad="">

module test(){

echo("test");

}

baseheight = 0.8;

r1 = inner_radius;

r1a = r1*1.01; //I added this

r2 = outer_radius;

r2a = r2*0.99; //I added this

n = sections;

gapin = 3*nozzle; //I changed this

gapout = 5*nozzle; //I changed this

alpha = 2*PI/sections;

alpha_1 = alpha - gapin/r1a; //I changed this

beta = 2*PI/sections;

beta_1 = alpha - gapout/r2a; //I changed this

alpha_2 = gapin/r1a; //I changed this

beta_2 = gapout/r2a; //I changed this

alpha_3 = nozzle/r1a; //I changed this

beta_3 = nozzle/r2a; //I changed this

fudge = 0.01;

//process the text, we have beta_1 for the symbol, use beta_2 for border!

thisFont=8bit_polyfont();

x_shift=thisFont[0][0];

y_shift=thisFont[0][1];

theseIndicies=search(text,thisFont[2],1,1);

wordlength = (len(theseIndicies));

factorygap = 1;

scale_x = (beta_1-beta_2) * r2 / x_shift;

scale_y = (length - factorygap*gapout) / y_shift;

thicknessword = text_thickness * nozzle;

// Create the Text

module alltext() {

for( j=[0:(len(theseIndicies)-1)] )

rotate([0, 0, (3/2*beta_2 + (beta_1-beta_2)/2 + j* beta)*180/PI])

translate([r2 -1.5* nozzle, -(beta_1-beta_2) * r2 /2 , factorygap/2*gapout])

rotate([90,0,90])

{

scale([scale_x,scale_y,1]){

linear_extrude(height=thicknessword)

polygon(points=thisFont[2][theseIndicies[j]][6][0],paths=thisFont[2][theseIndicies[j]][6][1]);

}

}

}

module innerholes() {

union() {

for (i = [0:n-1]){

rotate([0,0,(-alpha_1/2 + i* alpha)*180/PI])

translate([r1,0,0])

cube(size=[3*nozzle,gapin, 3*length], center=true);

}

}

}

module spikes() {

linear_extrude(height=length) { union(){

for (i = [0:n-1]){

polygon(points = [ [r1a*cos((-alpha_1/2 + i* alpha-alpha_2/2)*180/PI),

r1a*sin((-alpha_1/2 + i* alpha-alpha_2/2)*180/PI)],

[r2a*cos((2*beta_2/2 + (i-1)* beta)*180/PI),

r2a*sin((2*beta_2/2 + (i-1)* beta)*180/PI)],

[r2a*cos((2*beta_2/2 + (i-1)* beta-beta_3)*180/PI),

r2a*sin((2*beta_2/2 + (i-1)* beta-beta_3)*180/PI)],

[r1a*cos((-alpha_1/2 + i* alpha-alpha_2/2-alpha_3)*180/PI),

r1a*sin((-alpha_1/2 + i* alpha-alpha_2/2-alpha_3)*180/PI)]

],

paths = [ [0,1,2,3]]);

}

}}

linear_extrude(height=length) { union(){

for (i = [0:n-1]){

polygon(points = [ [r1a*cos((-alpha_1/2 + i* alpha+alpha_2/2+alpha_3)*180/PI),

r1a*sin((-alpha_1/2 + i* alpha+alpha_2/2+alpha_3)*180/PI)],

[r2a*cos(((i)* beta+beta_3)*180/PI),

r2a*sin(( (i)* beta+beta_3)*180/PI)],

[r2a*cos(( (i)* beta)*180/PI),

r2a*sin(( (i)* beta)*180/PI)],

[r1a*cos((-alpha_1/2 + i* alpha+alpha_2/2)*180/PI),

r1a*sin((-alpha_1/2 + i* alpha+alpha_2/2)*180/PI)]

],

paths = [ [0,1,2,3]]);

}

}}

}

module outerholes() {

union() {

for (i = [0:n-1]){

rotate([0,0,(beta_2/2 + i* beta)*180/PI])

translate([r2-nozzle,0,0])

cube(size=[3*nozzle, gapout, 3*length], center=true);

}

}

}

module outercirc(){

difference(){

cylinder(h=length, r=r2, $fn=100);

translate([0,0,-fudge]) cylinder(h=length+2*fudge, r=r2-nozzle, $fn=100);

outerholes();

}

}

module innercirc(){

difference(){

cylinder(h=length, r=r1+nozzle, $fn=100);

translate([0,0,-fudge]) cylinder(h=length+2*fudge, r=r1, $fn=100);

innerholes();

}

}

module baseform(){

union(){

outercirc();

innercirc();

spikes();

}

}

rotate([0,0,-90])

if (holes == "yes") {

difference(){

baseform();

alltext();

}

} else {

union(){

baseform();

alltext();

}

}</mcad>

I also notice that with some settings, the letters protrude out the back, and in other cases, they produce an indentation. I'll have a look at the code, and see if anything yells out at me, and get back to you.

I don't know of a way to make the letters actually go round, so they are flat, what causes the issues with the letters you see. I suppose using the base letter polygon, and projecting on a cylinder would be nicer and fix that, but a bit more code needed. MCAD I used here does not provide that as far as I know.

I now discovered another bracelet like this exist, which is based on cutting out pieces in scad, see thingiverse.com/thing:13505

Perhaps I should add the letter adding code to that, as cutting out wedges will scale better perhaps.