What OpenChip is (and isn't)

OpenChip is a browser tool for designing microfluidic mixing chips and exporting them as STL files for a desktop resin printer.

You draw a 2D channel network, place ports, set channel widths, look at the result as a solid, get told what will probably not print, get an estimate of how the fluid will behave — and then export an STL and print it.

Who it is for

A scientist or engineer who needs a chip and does not want to learn CAD to get one. If you have used a drawing tool, you can use this. Nothing here assumes you know what a boolean difference is or how to set up a sketch plane.

It also assumes you are competent in your own field, so it tells you the real constraint rather than hiding it. Where a number is a rule of thumb, it says so.

What it does

Draws channels. Straight or curved segments, endpoint and angle snapping, widths pinned along a path and lofted between.
Builds the solid. Live, in the browser, through the same geometry kernel modern OpenSCAD uses internally.
Checks manufacturability. Minimum feature size, walls between channels, port clearance, overhangs, build volume, dead ends, trapped cavities, regions that will not drain.
Estimates the flow. Pressure drop, Reynolds number, velocity, wall shear, residence time, and heat exchange between adjacent streams.
Exports. STL, OpenSCAD, SVG, PNG, and a presentation bundle.

What it is not

Not a CFD package. The flow numbers are one-dimensional analytical estimates from a resistor-network model. They will tell you whether your pump can push 10 µL/min through a 0.4 mm channel. They will not give you a concentration field or a velocity profile round a bend. See The limits of analytical estimates.

Not a substitute for a test print. The design checks are geometric rules of thumb against a printer profile you typed in. They know nothing about your resin’s actual cure-through, your exposure settings, or how your machine is behaving today.

Not a general CAD tool. It builds one shape: a rectangular block with a channel network in it, ports, chambers and vents. If you need a mounting boss or an imaging window, export OpenSCAD and add it there.

Not a service. There is no account, no server and no upload. Everything runs in your browser and your files stay on your machine.

The one rule

Nothing OpenChip tells you ever blocks you.

The Design checks panel has no way to express “you may not export this”. Every finding is a warning that says what was measured, what it was compared against, and what tends to go wrong — and then leaves the decision with you.

This is deliberate and it is not going to change. You are the one holding the printer. You know your resin, you know what this chip is for, and you may have excellent reasons to do something the geometry thinks is unwise. A tool that refuses is a tool you work around.

Where your data lives

In your browser, and in files you save.

The app keeps your work in browser storage as you go, so closing the tab does not lose it. Saving writes a .openchip file — plain JSON — to wherever you choose. Nothing is transmitted anywhere. The app works offline once loaded.

Install and run if you want it on your own machine.
Your first chip — twenty minutes, ends in an STL.
The interface, briefly if you would rather look around first.