PCB Technology Tutorial
This tutorial explains how the AP 210 application modules ISO/TS 10303-1670 Fabrication_technology and ISO/TS 10303-1716 Part_template_2d_shape are used to document the technology for a Printed Circuit Board (PCB). A particular PCB technology data set may be exchanged together with a particular PCB design in a STEP file. But it is also possible to combine several AP 210 PCB Technology data sets in a library and then used them by any number of PCB designs.
A PCB-Technology data set consists of
- the vertical sequence of materials making up to so called "layer-stack", including mixed PCBs, e.g. flex-rigid, with different layer-stacks in different "regions".
- the vertical passages through the layer stack for the purpose of connecting electrical layers and connecting to wired components but also to define outlines, cutouts and regions boundaries.
- involved tolerances together minimal and maximal size limitations given by the used fabrication process
- typical material characterization
A PCB-Technology data set does not include
- detailed geometry and connectivity information as it is needed for a PCB design
- detailed material definition from a particular vendor
- details of the PCB fabrication process
When generating AP 210 data out of a PCB-CAD system, typically only very rough PCB technology information available. Only with special tools this data can be enriched. On the other hand PCB manufacturer may use the AP 210 capabilities to define the kind of PCB technologies they can produce and publish them on the web so that a PCB designer can select the one which fits to his design. By this the PCB Technology capabilities of AP210 becomes a communication mechanism primarily between PCB designer and PCB manufacturer, but also with PCB assemblers because they have to know the details of the surface finish of a PCB. And because the details of the PCB technology is also relevant for the costs and reliability of a PCB this information is also useful for the overall product planning and simulation.
Please note that throughout AP 210 the generic term stratum is used instead of layer. This is because the term layer is a bit vague and is often used only for the conductive "levels" you see in a PCB-CAD system.
A Stratum_technology is the definition of a prototype of a horizontal level of matter of a single material type. It can be called out several times within a stack model for different vertical positions.
Stratum Stack models
Within the PCB industry the concept of a Layer Stack is well known. It describes the sequence of electrical conductive, dielectric and other "layers" making up a PCB. In addition it includes the possible passages between the layers such as vias and other plated through passages for wired components.
In AP 210 a layer stack is represented by the abstract entity Stratum_stack_model which is a Template_definition with the subtypes Library_stack_model and Design_stack_model. Being a Template_definition a layer stack is treated as a product by its own that can be versioned and related with business data such as approval, certification etc. See the PDM usage guide for more details on this.
The subtype Library_stack_model is a specialization to represent a dynamic capability of PCB-CAD systems to adopt a given footprint and pad-stack library for a chosen number of layers. The details of this capability is documented together with the PCB design tutorial.
The focus of this tutorial is the subtype Design_stack_model because this is what a PCB fabricator can specify or need to know and what is referenced by a particular PCB design.