Production and manufacturing

So far, the postmarketOS team has only used JLCPCB for the manufacturing of the phone harness, due to the tight budget constraints of being a donations-funded organization.

PSU

We have validated multiple PSUs. Initially, we went for the high-end Anker 313 https://www.anker.com/eu-en/products/a2677 model, as we could not find models which promised PPS down to 3.3V and 5A. Futher testing has showed that cheaper models, even when they don’t advertise 5A, they can do 5A on those lower-volage modes, even if potentially not at higher voltages (11+A). Therefore, further batches have been accompanied with the cheaper Anker A2653 https://www.ankeritaly.com/products/b2653.

Additional components

In addition to the phone harness PCB, a functional hardware-CI setup requires other components to be functional. Orders by the postmarketOS team have included the following parts, although others might be needed depending on the needs:

PCBA Manufacturing guide

Export the production files

  • Install JLCPCB Tools Kicad plugin

  • Open the Layout editor

  • Open JLCPCB Tools (blue J@LC logo)

  • Press the “Corrections” button in the top right

  • Import the rotations DB usign the “Import” button in the bottom right

  • Close the Corrections Manager window

  • Press the Generate button

  • Click through the following warnings

There are items with identical LCSC number but different values in the list: C720477:

  • SW1 -> BOOT

  • SW3 -> BTN_A

  • SW4 -> BTN_B

  • SW2 -> RESET Continue?

JLC order/serial number placeholder not present! Continue?

DRC found 16 error violation(s).

Resolve or exclude DRC errors before manufacturing whenever possible.

Check for components availability

Quote or order the PCBA

Instant Quote

The process to get a quote or order is the same. After completing this step you will get a quote and the job will be added to your cart. If you go ahead, pay for it and add the shipping details, your quote will become an actual order. If you don’t want to order you can just remove the job from the cart.

  • Go to https://cart.jlcpcb.com/quote

  • Load the gerber file you generated with JLCPCB Tools phone-harness/hardware/jlcpcb/production_files/GERBER-phone-harness.zip

  • Select the [Custom options] and double check the [Default options]

  • Enable PCB Assembly and select the related options

  • Activate any Coupons you might find on the side bar

  • Press “NEXT” on the sidebar to proceed

PCB preview

  • Confirm that the PCB is looking good We noticed the back silkscreen is flipped while it’s correct on Kicad and the component placement preview. This seems to be a bug on JLCPCB website.

  • Press “Process BOM & CPL” to proceed

Bill of Materials

  • Upload the BOM and CPL production files you generated with JLCPCB Tools

  • Make sure all parts are selected

  • Usually the buttons are unselected because of the following warning, select them. “Multiple lines in the BOM have been matched to the same part. Please check if the matching is correct.”

  • Press “NEXT” to proceed

Component Placements

  • Make sure that the component rotations (purple dots or symbols) match the silkscreen indicators (white) If the rotations do not match you need to make sure you imported the Rotations DB in JLCPCB Tools as explained in [Export the production files].

  • Press “NEXT” to proceed

Quote & Order

  • Double check the Total Price and the cost breakdown For smaller batches, the “Extended components fee:” will weigh on the total cost. JLCPCB charges 3$ for every non “Basic” SMD part. This is the cost for loading custom components on the Pick ‘n place machines.

  • Product Description: Research\Education\DIY\Entertainment -> DIY - HS Code 847330

  • Press “SAVE TO CART”

Shopping Cart

  • Select all the checkboxes on the left

  • Click on “Shipping Estimated” to select the shipping method

  • Press “Check out”

Checkout

  • Input shipping and billing address

  • Choose DHL Express (DDP) The DDP shipping type means that JLCPCB will pay the vat and customs taxes for you. This is preferred as everything is paid while placing the order, and you don’t need to pay anything when receiving the package. In our experience this also means faster shipments, as the parcel won’t be held in the customs office.

  • Press “Continue”

  • Select the biggest coupon among the available ones

  • Add the payment details

  • Pay

Custom options

Select these options instead of the default ones:

PCB:

  • PCB Qty: your desired batch size, you should have enough components if JLC has no stock for them.

  • Surface Finish: LeadFree HASL

  • Specify Stackup: Yes

    • Layer Stackup: No requirement

Layer

Material Type

Thickness

Top Layer

Copper

0.035mm

Prepreg

7628*1

0.21040mm

Inner Layer L2

Copper

0.0152mm

1.1mm H/HOZ with copper

Core

Core

1.065mm

1.1mm H/HOZ with copper

Inner Layer L3

Copper

0.0152m

1.1mm H/HOZ with copper

Prepreg

7628*1

0.21040mm

Bottom Layer

Copper

0.035mm

PCB Assembly

  • Board Cleaning: Dry-ice cleaning

Order

  • PCB Build Time: 2-3 days (The 55€ charge makes sense for large batches)

Default options

These are the default options we use, listed for completeness:

PCB

  • Base Material: FR-4

  • Layers: 4

  • Dimensions: 80 * 50 mm

  • Product Type: Industrial/Customer electronics

  • Different Design: 1

  • Delivery Format: Single PCB

  • PCB Thickness: 1.6mm

  • PCB Color: Green

  • Silkscreen: White

  • Material Type: FR4 TG135

  • Outer Copper Weight: 1 oz

  • Inner Copper Weight: 0.5 oz

  • Specify Layer Sequence: No

  • Impedance Control: No requirement

  • Via Covering: Plugged

  • Via Plating Method: Not Specified

  • Min via hole size/diameter: 0.3mm/(0.4/0.45mm)

  • Board Outline Tolerance: +- 0.2mm(Regular)

  • Confirm Production File: No

  • Mark on PCB: Remove Mark

  • Electrical Test: Flying Probe Fully Test

  • Gold Fingers: No

  • Castellated Holes: No

  • Press-Fit Hole: No

  • Edge Plating: No

  • Blind Slots: No

  • UL Marking: No

  • Backdrill: No

  • Humidity Indicator Card: No

PCB Assembly

  • PCBA Type: Economic

  • Assembly Side: Top Side

  • PCBA Qty: same as PCB Qty

  • Tooling holes: Added by JLCPCB

  • Confirm Parts Placement: No

  • Stencil Storage: No

  • Fixture Storage: No

  • Parts Selection: By Customer (Self-Service)

  • Special stencil: No

  • Depanel boards & edge rail before delivery: No

  • Flying Probe Test: No

  • Function test: No

  • Photo Confirmation: No

  • Conformal Coating (cleaning included): No

  • Packaging: Antistatic bubble film

  • Solder Paste: High temp.

  • Nitrogen reflow soldering: Yes (for Economic)

  • Assembly remark: No