Week 8 — Electronics production

This week was about electronics production ( Fab Academy — Electronics Production). At Chaihuo Makerspace we could not get the right PCB CNC tooling (the small end mills / drills needed for reliable isolation milling) in time, so I did not mill my individual board in-house this round. Instead I followed the board-house workflow on JLCPCB (嘉立创): exported fabrication data, ordered two PCB revisions, and documented what changed between them. My final project (“birthday spirit”) will need room on the carrier for my planned NanoStat / ESP32 Pico–class MCU module and sensor hardware, so revision 2 adds a clear keep-out area beside the circuit for sticking that module down later. Group milling notes for our lab CNC are on this same page under Group assignment.

Individual assignment — JLCPCB order & two PCB revisions

What constrained my choices

I still wanted to understand fabrication end-to-end, but our lab could not source the right CNC bits for isolation milling in time. Rather than pause layout work, I switched to a board-house order so I could hold real PCBs while iterating the carrier for the final project. The two-revision story below is blunt: rev 1 was electrically fine but had no sensible area to stick the NanoStat-style module; rev 2 is the layout lesson applied after I admitted that integration space is not optional.

Why board-house instead of in-house milling

The weekly goal still includes understanding both milling and sending work to a fabricator. Our space documents the in-house mill workflow in the group section below; for my own board, without suitable CNC bits on hand I chose an outsourced rapid-turn path so I could keep moving on layout and integration for the final project.

Revision 1 — dense layout, no integration margin

I laid out a first PCB that packed the circuit tightly. Electrically it was fine for a first cut, but there was no unused copper area left next to the main circuit where I could later mount a small microcontroller carrier or breakout for sensors. For the birthday-spirit idea I need a predictable place to attach my NanoStat (ESP32 Pico–footprint) board and related sensor hardware without cramming everything into one cluttered copper island.

Revision 2 — reserved side area for the Pico module

On the second spin I kept the same core circuit intent but moved outlines and poured/open regions so there is a dedicated blank panel beside the dense logic. That zone is for mechanically attaching (e.g. adhesive standoffs or double-sided tape, pending mechanical review) the NanoStat module without overlapping traces or interfering with reflow on the main section.

Ordering through the JLCPCB desktop client

I uploaded Gerbers through the 嘉立创 / JLCPCB client, checked layer previews and board thickness, then pushed the job through their quoting flow. Keeping filenames and revision notes aligned between EDA and the upload dialog avoided mixing rev1 and rev2 uploads.

JLCPCB desktop client window showing PCB order and layer preview — JLCPCB client — verifying the upload and order details before fabrication.

Boards arrived

The fabricated panels showed both revisions clearly; handling them highlighted how much easier plated holes and solder mask make bring-up compared to quick milled copper — especially for dense SMT footprints I plan to assemble next.

Received PCBs from JLCPCB showing both design revisions — Boards received from the fab — rev1 vs rev2 visible on the panel/stencil layout.

Fabricated boards — photos after delivery

The close-ups below are physical boards photographed after the JLC shipment arrived — same revisions as above, shown as fabricated copper and solder mask rather than EDA captures.

Fabricated first PCB revision after delivery from JLCPCB — Revision 1 as built — dense routing; little spare area for mounting the MCU / sensor stack.

Fabricated second PCB revision with side keep-out after delivery from JLCPCB — Revision 2 as built — reserved side panel for the NanoStat module.

Alignment with this week’s checklist

This documents the board-house workflow Fab Academy asks for when you outsource PCBs, and shows deliberate iteration driven by system-level packaging (final-project MCU + sensors). Next I need to complete the remaining individual evidence from the module page: stuff, solder, debug, and prove the board runs firmware (e.g. a blink or sensor read), then add source links and a tidy hero shot of the assembled, powered board.

Group assignment

Guangzhou (Chaihuo) — group documentation: in-house PCB fabrication on the lab CNC mill (operating notes and safety).

In-house PCB fabrication, CNC milling: operating notes

Equipment: Lab PCB CNC mill / engraver (single- or double-sided copper-clad stock, isolation routing plus outline cutting; exact model per nameplate and local training).
Use case: Quick-turn prototypes, coursework boards, small batches; not a substitute for a professional fab’s plating, solder mask, or surface finish.

Overview: The process uses a small-diameter end mill to cut isolation channels in copper, defining traces, and can cut the board outline. Design data must match tool diameter, cut depth, and work zero; mismatches often cause opens, shorts, or dimensional errors. Minimum trace width, spacing, and tool specs are defined by your lab’s published rules.

I. Recommended operating sequence (aligned with on-site steps)

Typical lab workflow: secure stock and tool, set zeros, then run the toolpath.

1. Prepare machining data and verify

Finish schematic and PCB layout in an EDA tool (e.g. KiCad, Altium, Eagle), then export Gerber (copper, outline, drill layers as required) and drill files; if the lab uses dedicated CAM software, merge layers and set the origin per its instructions.
In CAM, confirm units (mm), mirroring (top copper on a single-sided board is usually not mirrored; bottom copper per software guidance), and trace-width compensation against the actual tool diameter.
Check that the outline is closed and does not conflict with fixture keep-out zones.

(This step is done at the computer; no floor photo.)

2. Load and secure the copper-clad board

Clean the table and the underside of the stock so chips do not cause warp or uneven thickness.
Place the board within the machine’s usable travel, with clearance for clamps and the toolpath; for double-sided work, plan dowel or optical alignment if the lab provides it.
Clamp with lab-approved fixturing with enough holding force, and ensure clamps / bolts stay outside the toolpath envelope.

Placing and securing the copper-clad board on the PCB mill — Placing and securing the copper-clad board

3. Change the tool (end mill, V-bit)

Install or remove tools only with the spindle fully stopped and the machine in a safe state (per lab procedure).
Seat the tool for the collet type and tighten to the specified torque; check flute length and stick-out for enough reach without excess overhang that causes chatter.
Match the tool diameter to the CAM settings (common isolation milling uses roughly 0.1 mm to 0.2 mm cylindrical end mills; confirm against lab inventory).

Changing the end mill on the PCB CNC — Changing the tool

Installing or removing a tool in the PCB mill spindle with the machine safe — Spindle tool change — follow collet torque and stick-out rules.

Side-by-side comparison of milling and cutting tool heads for PCB work — Milling versus cutting cutter heads — confirm which geometry matches your CAM tool definition.

Close-up of the milling cutter head on the PCB CNC — Milling cutter head (typical isolation routing).

Close-up of the cutting cutter head on the PCB CNC — Cutting cutter head — verify diameter and flute length in CAM.

4. Position the cutter

Jog the tool to a safe height above the board so rapid moves cannot hit the stock or clamps.
Align the tool roughly with the programmed origin (board corner or locating feature) to match the CAM work coordinate system.
Confirm the dust shoe, guards, tool length, and clamps do not interfere.

Adjusting cutter position above the PCB stock — Adjusting cutter position

5. Touch off and set work zero

XY zero is often a board corner or locating feature and must match the CAM origin definition.
Z zero is often on the top of the copper-clad surface or a lab-defined reference; Z error yields shallow cuts (copper not fully cleared) or deep cuts (substrate damage, broken tool).
The two images below show the initial state before touch-off and zero-related steps; the exact method (touch plate, shim, paper drag, etc.) follows on-site training.

Touch-off and zeroing the Z axis — Touch-off / zeroing

6. Test cut and production run

For a new file, use a reduced feed override or single-block mode first and watch whether the first isolation pass fully clears copper and whether the sound is normal.
The operator must stay at the machine; on any fault, hit emergency stop immediately.
After the run, inspect for residual copper and burrs between traces; deburr if needed and spot-check continuity with a multimeter.

PCB outline cutting in progress.

PCB after outline cutting is complete — Board after outline cutting.

II. Safety and precautions

Personnel and motion: Do not clear chips by hand near a running spindle; do not wear gloves on rotating parts; tie back long hair; know where the emergency stop is.
Tool and workholding: A loose tool or loose board can eject; after each load or tool change, push gently to verify the board cannot shift.
Dust and copper swarf: Use dust collection; avoid inhaling copper dust; stop the machine before cleanup.
Electrical: Do not touch electrical parts with wet hands; route cables away from moving parts.
Program and coordinates: Mismatched zero, tool diameter, stock thickness, and CAM data is a common cause of shorts, opens, and crashes; after a board change or tool change, re-touch off or re-verify Z.