PCB Manufacturing
-----------------

**Location:** ``TestBenches / AraTestBenches / PCB_Manufacturing``

This test bench automates the generation of files needed for PCB
manufacturing and assembly. Specifically, it can produce:

-  Extended Gerber files and an Excellon drill file,
-  a CSV file giving the location and rotation angle of each component,
   and
-  an Assembly Bill of Materials (BOM).

Configure
~~~~~~~~~

If you are *not* using pre-loaded files supplied in the demo, you'll
need to first run the **PlaceAndRoute** and **CostEstimation** test
benches on your design, and, for now, manually copy their results into
the design subfolder. (The design subfolder is located in the
``designs`` folder, and has a random-looking name. Its name can be
determined by checking the "Path" attribute of the top-level component
assembly.)

For general instructions on running test benches, refer to
:ref:`ara_test_bench_basics`.

You'll also need an Eagle CAM job file for your design. This file
specifies, among other things, which Gerber plot files will be produced
and the mapping of Eagle board layers to Gerber plot files. Eagle comes
with some sample CAM files, and some can be downloaded from PCB
manufacturers, but making custom ones in Eagle CAD is not hard.

The value of the testbench's **CAM file** parameter must be set to the
path of the CAM file. This path can be either absolute or relative to
the project folder.

.. figure:: images/11-08-pcb-mfg-test.png
   :alt: PCB Mfg test bench

   Configured copy of the **PCB manufacturing** testbench with
   **AstableMultivibrator** as the system under test.

Metrics
~~~~~~~

This test bench produces no metrics.

Outputs
~~~~~~~

+---------------------------------------+------------------------------------+
| Filename                              | Description                        |
+=======================================+====================================+
| ``assemblyBom.csv``                   | The generated assembly BOM file.   |
+---------------------------------------+------------------------------------+
| ``schema_centroids.csv``              | The generated centroids file, with |
|                                       | component locations and rotations. |
+---------------------------------------+------------------------------------+
| (names depend on CAM file)            | Gerber plot files. Names as        |
|                                       | specified in the CAM file.         |
+---------------------------------------+------------------------------------+
| (names depend on CAM file)            | Excellon drill file. Name as       |
|                                       | specified in the CAM file.         |
+---------------------------------------+------------------------------------+

Workflow Details
~~~~~~~~~~~~~~~~

In GME, the **PCB\_Mfg** workflow consists of an initial
**MGA.Interpreter.CyPhy2PCBMfg** task, and three execution tasks, named
**CAM Processing**, **Get Centroids**, and **Get Assembly BOM**. Each of
these is explained in more detail below.

.. figure:: images/11-08-pcb-mfg-task.png
   :alt: PCB Mfg Workflow

   The **PCB\_Mfg** test bench.

The **MGA.Interpreter.CyPhy2PCBMfg** task starts when the **CyPhy Master
Interpreter** runs from the **PCB Manufacturing** testbench. This task
copies input files from the design subfolder into the testbench's
results folder, and starts a script to start the three execution tasks.

The **CAM Processing** execution task runs an Eagle CAM job on the
design's board file to produce Gerber files and n Excellon drill files.
The mapping of Eagle board layers to Gerber and Excellon files is
specified via a standard Eagle CAM file. The path to the CAM file is
specified in OpenMETA as the value of a test bench parameter named **CAM
file**. The resulting Gerber and Excellon files will be named as
specified by the CAM job file.

The **Get Centroids** execution task runs an Eagle User-Language Program
(ULP) that creates a CSV file giving the location and rotation angle for
each component on the board. The resulting file is named
``schema_centroids.csv``.

The **Get Assembly BOM** execution task produces a BOM CSV file, called
``assemblyBOM.csv``, based on the EAGLE model's reference designators.
It does this by taking the cost estimation BOM and a cross reference
between OpenMETA components and Eagle CAD component reference designators.

Assumptions
~~~~~~~~~~~

The **PCB manufacturing** test bench is currently experimental. The only
output devices supported by the *CAM Processing* execution task are
extended Gerber and Excellon devices.