Noupoi.nethttps://www.noupoi.net/2020-07-11T10:20:00+01:00Bottle cap thread calculator2020-07-11T10:20:00+01:002020-07-11T10:20:00+01:00Noupoitag:www.noupoi.net,2020-07-11:/bottle-cap-thread-calculator.html<p>Specification calculator for plastic bottle cap threads for use in CAD modelling</p><p>This tool calculates the thread specifications of bottle caps for modelling in CAD programs such as Fusion 360. </p>
<p>This is intended for use with bottles that conform to <a href="https://www.astm.org/Standards/D2911.htm">ASTM D2911</a>,
also known as "GPI" or "SPI" thread finishes. </p>
<p>(While ASTM charges $60 for the spec, the important parts can be found <a href="https://www.sanleplastics.com/solution/plastic-bottle-cap-threads-specifications/">freely online</a>.)</p>
<p>This assumes that you are modelling the thread by creating a coil with a triangular cross section, then
cutting the tip of the triangle off with a cylindrical hole. </p>
<h3>Calculator</h3>
<script type="text/javascript">
var decimals = 3;
var presets = {
'': null,
'13 - SP415': {tMax: 13.06, eMax: 11.53, threadWidth: 1.14, angleDeg: 3, angleArcmin: 11, tolerance: 0.2},
'15 - SP415': {tMax: 14.76, eMax: 13.23, threadWidth: 1.14, angleDeg: 2, angleArcmin: 48, tolerance: 0.2},
'18 - SP400, SP410, SP415': {tMax: 17.88, eMax: 15.75, threadWidth: 2.13, angleDeg: 3, angleArcmin: 30, tolerance: 0.2},
'20 - SP400, SP410, SP415': {tMax: 19.89, eMax: 17.75, threadWidth: 2.13, angleDeg: 3, angleArcmin: 7, tolerance: 0.2},
'22 - SP400, SP410, SP415': {tMax: 21.89, eMax: 19.76, threadWidth: 2.13, angleDeg: 2, angleArcmin: 49, tolerance: 0.2},
'24 - SP400, SP410, SP415': {tMax: 23.87, eMax: 21.74, threadWidth: 2.13, angleDeg: 2, angleArcmin: 34, tolerance: 0.2},
'28 - SP400, SP410, SP415': {tMax: 27.64, eMax: 25.25, threadWidth: 2.39, angleDeg: 2, angleArcmin: 57, tolerance: 0.2},
'30 - SP400': {tMax: 28.62, eMax: 26.23, threadWidth: 2.39, angleDeg: 2, angleArcmin: 51, tolerance: 0.2},
'33 - SP400, SP415': {tMax: 32.14, eMax: 29.74, threadWidth: 2.39, angleDeg: 2, angleArcmin: 31, tolerance: 0.2},
'35 - SP400': {tMax: 34.64, eMax: 32.25, threadWidth: 2.39, angleDeg: 2, angleArcmin: 21, tolerance: 0.2},
'38 - SP400': {tMax: 37.5, eMax: 35.1, threadWidth: 2.39, angleDeg: 2, angleArcmin: 9, tolerance: 0.2},
'40 - SP400': {tMax: 40.13, eMax: 37.75, threadWidth: 2.39, angleDeg: 2, angleArcmin: 0, tolerance: 0.2},
'43 - SP400': {tMax: 42, eMax: 39.62, threadWidth: 2.39, angleDeg: 1, angleArcmin: 55, tolerance: 0.2},
'45 - SP400': {tMax: 44.2, eMax: 41.81, threadWidth: 2.39, angleDeg: 1, angleArcmin: 49, tolerance: 0.2},
'48 - SP400': {tMax: 47.5, eMax: 45.11, threadWidth: 2.39, angleDeg: 1, angleArcmin: 41, tolerance: 0.2},
'51 - SP400': {tMax: 50, eMax: 47.6, threadWidth: 2.39, angleDeg: 1, angleArcmin: 36, tolerance: 0.2},
'53 - SP400': {tMax: 52.5, eMax: 50.11, threadWidth: 2.39, angleDeg: 1, angleArcmin: 31, tolerance: 0.2},
'58 - SP400': {tMax: 56.5, eMax: 54.1, threadWidth: 2.39, angleDeg: 1, angleArcmin: 25, tolerance: 0.2},
'60 - SP400': {tMax: 59.5, eMax: 57.1, threadWidth: 2.39, angleDeg: 1, angleArcmin: 20, tolerance: 0.2},
'63 - SP400': {tMax: 62.51, eMax: 60.12, threadWidth: 2.39, angleDeg: 1, angleArcmin: 16, tolerance: 0.2},
'66 - SP400': {tMax: 65.5, eMax: 63.12, threadWidth: 2.39, angleDeg: 1, angleArcmin: 13, tolerance: 0.2},
'70 - SP400': {tMax: 69.5, eMax: 67, threadWidth: 2.39, angleDeg: 1, angleArcmin: 8, tolerance: 0.2},
'75 - SP400': {tMax: 74, eMax: 71.6, threadWidth: 2.39, angleDeg: 1, angleArcmin: 4, tolerance: 0.2},
'77 - SP400': {tMax: 77.1, eMax: 74.7, threadWidth: 2.39, angleDeg: 1, angleArcmin: 1, tolerance: 0.2},
'83 - SP400': {tMax: 83, eMax: 80, threadWidth: 3.05, angleDeg: 1, angleArcmin: 9, tolerance: 0.2},
'89 - SP400': {tMax: 89.18, eMax: 86.12, threadWidth: 3.05, angleDeg: 1, angleArcmin: 4, tolerance: 0.2},
'100 - SP400': {tMax: 100, eMax: 96.95, threadWidth: 3.05, angleDeg: 0, angleArcmin: 59, tolerance: 0.2},
'110 - SP400': {tMax: 110, eMax: 107, threadWidth: 3.05, angleDeg: 0, angleArcmin: 51, tolerance: 0.2},
'120 - SP400': {tMax: 120, eMax: 117, threadWidth: 3.05, angleDeg: 0, angleArcmin: 47, tolerance: 0.2},
};
function populatePresets() {
$.each(presets, function (name) {
var option = new Option(name);
$("#threadPreset").append(option);
});
}
function loadPreset() {
var selection = $("#threadPreset").val();
var config = presets[selection];
if (config) {
$("#tMax").val(config.tMax);
$("#eMax").val(config.eMax);
$("#threadWidth").val(config.threadWidth);
$("#angleDegrees").val(config.angleDeg);
$("#angleArcmins").val(config.angleArcmin);
$("#tolerance").val(config.tolerance);
}
calculate();
}
function getFloatById(id) {
return parseFloat($("#" + id).val());
}
function getTanDeg(deg) {
var rad = deg * Math.PI / 180;
return Math.tan(rad);
}
function calculate() {
var tMax = getFloatById("tMax");
var eMax = getFloatById("eMax");
var threadWidth = getFloatById("threadWidth");
var angleDegrees = getFloatById("angleDegrees");
var angleArcmins = getFloatById("angleArcmins");
var tolerance = getFloatById("tolerance");
var threadDiameter = tMax + tolerance;
var pitch = getTanDeg(angleDegrees + angleArcmins / 60) * Math.PI * threadDiameter;
var sectionHeight = getTanDeg(60) * threadWidth / 2;
var holeDiameter = eMax + tolerance;
$("#threadDiameter").val(threadDiameter.toFixed(decimals));
$("#pitch").val(pitch.toFixed(decimals));
$("#height").val(sectionHeight.toFixed(decimals));
$("#holeDiameter").val(holeDiameter.toFixed(decimals));
}
window.onload = populatePresets;
</script>
<form class="pure-form pure-form-aligned">
<fieldset>
<div class="pure-control-group">
<label for="threadPreset">Preset</label>
<select id="threadPreset" onchange="loadPreset()"></select>
</div>
</fieldset>
</form>
<form class="pure-form pure-form-aligned">
<fieldset>
<legend>Neck finish specifications</legend>
<div class="pure-control-group">
<label for="tMax">T<sub>max</sub></label>
<input type="text" id="tMax" placeholder="thread outside diameter"/>
<!-- <span class="pure-form-message-inline">This is a required field.</span>-->
</div>
<div class="pure-control-group">
<label for="eMax">E<sub>max</sub></label>
<input type="text" id="eMax" placeholder="neck outside diameter"/>
</div>
<div class="pure-control-group">
<label for="threadWidth">Thread width (<i>a</i>)</label>
<input type="text" id="threadWidth" placeholder="thread width"/>
</div>
<div class="pure-control-group">
<label for="aligned_angle">Helix angle β</label>
<span id="aligned_angle">
<input type="number" id="angleDegrees" placeholder="degrees"/>
<span class="pure-form-message-inline">°</span>
<input type="number" id="angleArcmins" placeholder="arcminutes"/>
<span class="pure-form-message-inline">′</span>
</span>
</div>
<div class="pure-control-group">
<label for="tolerance">Tolerance</label>
<input type="text" id="tolerance" placeholder="tolerance"/>
<span class="pure-form-message-inline">0.2 mm is suggested</span>
</div>
<div class="pure-controls">
<button type="button" class="pure-button pure-button-primary" onclick="calculate()">Calculate</button>
</div>
</fieldset>
</form>
<form class="pure-form pure-form-aligned">
<fieldset>
<legend>Cap thread parameters</legend>
<div class="pure-control-group">
<label for="threadDiameter">Diameter</label>
<input type="text" id="threadDiameter" value="" readonly=""/>
</div>
<div class="pure-control-group">
<label for="pitch">Pitch</label>
<input type="text" id="pitch" value="" readonly=""/>
</div>
<div class="pure-control-group">
<label for="height">Section height</label>
<input type="text" id="height" value="" readonly=""/>
</div>
<div class="pure-control-group">
<label for="holeDiameter">Hole diameter</label>
<input type="text" id="holeDiameter" value="" readonly=""/>
<span class="pure-form-message-inline">Used to flatten the tip of the thread</span>
</div>
</fieldset>
</form>
<h3>References</h3>
<p><a href="https://www.mjspackaging.com/resources/training-technical-specs/neck-finish-information">How to identify the neck finish on a bottle</a></p>
<p><a href="https://www.youtube.com/watch?v=-BS9KR-B9U4">How to model a threaded cap in Fusion 360</a></p>
<p><a href="https://www.premierformtools.co.uk/assets/pdf/DC18.pdf">Helix angle calcuation</a></p>
<p><a href="/static/thread_specs.xlsx">Preset calculation spreadsheet</a></p>Test post2020-07-08T10:20:00+01:002020-07-08T10:20:00+01:00Noupoitag:www.noupoi.net,2020-07-08:/test-post.html<p>This is a test post.</p>