Anatomy of a PCB Design > Parts > Footprints (Land Patterns)

The Placement Point (also known as the Pick-and-Place Point or Component Origin) is a specific reference point on a component’s footprint used for positioning during the PCB assembly process. This point is crucial for aligning and placing components accurately on the PCB using automated machinery, such as pick-and-place machines.

Key Aspects of the Placement Point

•For a surface-mount resistor with a size of 0603 (1.6mm x 0.8mm), the courtyard might be a rectangle that extends 0.5mm beyond each edge of the component body. This ensures that there’s sufficient space around the resistor for placement, soldering, and inspection.

•Component Alignment: The placement point is usually set at a standard location on the component’s footprint, such as its geometric center, center of the pad array, or the center of the first pin. This ensures that the component is correctly oriented and aligned when positioned on the PCB.

•Reference for Automated Placement: Pick-and-place machines use the placement point as a reference to determine where to pick up the component and where to place it on the PCB. The machine’s vision system and software utilize this point to position each component with high precision.

•Consistency Between Design and Assembly: In CAD software, the placement point is defined during the footprint creation. This same point is then used during the generation of pick-and-place files, ensuring consistency between the design and the manufacturing stages.

•Standardized Location: Depending on the component type and its footprint, the placement point might be located at different standard positions, such as:

•The center of the component body (common for ICs, resistors, and capacitors).

•The corner of a component (often used for connectors or large components).

•The center of pin 1 for polarized components like diodes or transistors.

Importance of the Placement Point

•Reduces Misalignment: Properly defining the placement point helps avoid issues like component misalignment, rotation errors, or incorrect placement, which can lead to electrical failures.

•Facilitates Component Orientation: For components with specific orientations (e.g., diodes, ICs), the placement point helps the machine place the component in the correct direction.

•Streamlines Automated Processes: In automated manufacturing, a well-defined placement point helps streamline operations by providing a consistent reference for component handling.

Defining the Placement Point in Design

In PCB design software (such as KiCad, Altium Designer, or Eagle), the placement point is typically defined during the creation of the component footprint. It can be marked as a small cross or dot in the layout editor and is used as the origin for the component’s coordinate system in pick-and-place files.

Overall, the placement point is a critical parameter that ensures accurate, repeatable, and reliable component placement in PCB assembly.