# mixerchip_f658 — reference chip (mixer-chip family)

A monolithic resin-SLA design of the microfluidic ChipShop *Fluidic 658* pearl-chain
mixer, drawn from measurements of the vendor's technical datasheet (drawing
MV-FO 003/1_A3, 27.10.2015). It is not a vendor part.

Two inlets, joined by a Y-junction → viewing stadium → 7-pass pearl-chain
serpentine → viewing stadium → two outlets, joined by a Y-junction. Channels are
0.20 mm deep; the stadiums and the round chamber 0.60 mm.

## Ports

Seen from the top, with the round chamber at the right-hand end. Positions are in
mm from the chip's centre, x along its length toward the round chamber. Every hole
is a straight Ø1.5 mm bore from the top face.

| port | position (x, y) | connects to |
|---|---|---|
| inlets (2) | (+29.25, +6.75), (+29.25, +2.25) | a Y-junction, then the first viewing stadium |
| outlets (2) | (−29.25, −6.75), (−29.25, −2.25) | a Y-junction, from the second viewing stadium |
| bare holes (4) | (−29.25, +2.25), (−29.25, +6.75), (+29.25, −6.75), (+29.25, −2.25) | **nothing** — as on the datasheet. Do not push tubing into them. They are blind, stopping 0.10 mm below the channel floor. |
| round-chamber holes (2) | (+34.30, +1.80), (+34.30, −1.80) | the round chamber only |

## From the datasheet, and ours

- **From the datasheet:** channel depth 0.20 mm, stadium depth 0.60 mm, pearl Ø0.9 mm
  on 0.3 mm necks, 7 passes, the 8-port grid and which four ports the channels
  reach, the two stadiums (ca. 40 µl each), the serpentine (ca. 35 µl), and the
  75.5 × 25.5 mm outline.
- **Ours:** the connector channels are 0.30 mm wide where the drawing shows
  0.5 × 0.2 mm; the exact curves of the connectors; the round chamber's depth and its
  two holes; the 2.4 mm block and its four mounting holes. Ports are straight
  bores; standing in for the vendor's MFCS Mini Luer sockets.
- **Round chamber:** an empty open well, Ø6.22 × 0.60 mm, copying an
  unlabelled circle on the datasheet drawing. Nothing flows through it. Its two holes
  let uncured resin drain. Its wall to the end face is only 0.34 mm.
- **The .scad's original header is older than its geometry.** A dated correction
  note at the top of the file lists what it gets wrong (one outlet, the unused ports
  joined to the stadiums, and the printer's pixel pitch, which the header now gives as
  the lab's Phrozen Sonic Mighty 12K: 19 µm in X, 24 µm in Y), and says the code
  builds what this file describes.

## Measured from the files in this folder

The chip and void STLs, and fresh renders of the .scad for the serpentine, stadium
and chamber volumes. Mesh checks use trimesh with merged vertices.

| metric | value |
|---|---|
| serpentine | 7 passes, 39 pearls each on a 1.05 mm pitch |
| pearl Ø / neck | 0.90 / 0.30 mm |
| channel / chamber depth | 0.20 / 0.60 mm |
| connector channels (W × H) | 0.30 × 0.20 mm (datasheet drawing: 0.5 × 0.2) |
| viewing stadiums, each | 39.99 µl (datasheet: ca. 40) |
| serpentine volume | 37.94 µl (datasheet: ca. 35; +8.4 %) |
| round chamber | Ø6.22 × 0.60 mm, 18.18 µl |
| mixer network, inlets to outlets, with its 4 port holes | 131.57 µl inside the block |
| void | watertight, 6 bodies: the mixer network, the round chamber, 4 bare holes |
| chip | watertight, Euler -14 (genus 8: 4 mounting holes, 3 from the mixer's 4 open ports, 1 from the chamber's 2 holes; the bare holes are blind) |
| round chamber's wall to the end face | 0.34 mm |
| footprint | 75.5 × 25.5 × 2.4 mm |

## Files

| file | what it is |
|---|---|
| `mixerchip_f658.scad` | the design source, self-contained OpenSCAD; its geometry last changed 2026-07-14, and a dated correction note (comments only) was added on 2026-09-23 |
| `mixerchip_f658.stl` | the chip, rendered from the .scad on 2026-07-14 with OpenSCAD 2021.01 |
| `void_mixerchip_f658.stl` | the fluid void — channels, stadiums, round chamber and bores — from the same render |
| `renders/` | pictures of this design, made on 2026-07-14: the x-ray and section from these STLs, the top and iso views by OpenSCAD from the .scad |

A fresh render of the .scad on 2026-09-23 reproduced both STLs facet for facet.

## Print note

Flush uncured resin from the inlets to the outlets before any UV
post-cure. The round chamber drains through its own two holes; the four bare holes
are open, blind pockets.