Working grids

The working grids are visible or non-visible grids, fixed or non-fixed. An important, passive grid is screen grid or visible grid, which allows the designer to create not only a good-working, but also a good looking PCB design. An important rule of PCB design is to lay out the PCB on a fixed grid, named in literature snap grid, as the cursor, components and tracks will "snap" into fixed grid points (which are usually invisible).Not just any size grid mind you, but a fairly coarse one. 100 mil is a standard placement grid for very basic THT project, with 50 mil being a standard for general tracking work, like running tracks between throughhole pads.

For even finer work you may use a 25 mil snap grid or even lower. Many designers will argue over the merits of a 20 thou grid vs a 25 thou grid for instance. In practice, 25 thou is often more useful as it allows you to go exactly half way between 50 thou spaced pads. Large values snap grids are good because they will keep the components neat, symmetrical and aesthetical. It allows a high performance editing, dragging, movement and alignment of tracks, components and blocks of components easier as the layout grows in size and complexity.

Good PCB layout practice would involve the user starting out with a coarse grid like 50 thou and using a progressively finer snap grid if your design becomes "tight" on space. Drop to 25 thou and 10 thou for finer routing and placement when needed. This will do 99% of boards. Make sure the finer grid you choose is an even division of 100mil (50, 25, 20, 10, or 5 mil). Many designers, even the creator of this couse, prefer a 100 mil visible grid.

Some programs also have what is called an electrical grid. This grid is not visible, but it makes the cursor "snap" onto the center of electrical objects like tracks and pads, when the cursor gets close enough. This is extremely useful for manual routing, editing and moving objects. One other type of grid is the component grid (placement grid). This works the same as the snap grid, but it’s for component movement only. This allows the user to align components up to a different grid. to, and your PCB designs will be one step closer to being neat and professional.

Additionally, there are also details grid, routing grid, via grid, etc., in order to satisfy the design requirements.