Altium Mechanical 15

[Eryn]

Iam trying to grasp the purpose of Mechanical layers in Altium Designer. I have seen a tutorial on youtube where the presenter created one new mechanical layer and put information onto it that he said will go into the draft documents.

In any case, since there can be so many mechanical layers in Altium designer and the Mechanical 1 layer is there by default, what is the purpose of Mechanical 1 layer and the remaining possible mechanical layers besides creating outline for draft documents?

It's a give-and-take relationship, but as a PCB designer I'm mostly given mechanical constraints to work with from mechanical engineers as they stake their claim to available space. I might will definitely argue about the board outline, screw-holes, general space etc, and as such I need dedicated places to convey this information to my colleagues, my suppliers, but also myself.

I use Mech 1 for 3D component bodies - both simple extruded primitives for things like passives, but also more detailed, manufacturer-provided step models. It's worthwhile being accurate here. Component-housing collisions and interferences are not fun.

Depending on the manufacturer and the board, I have a specific layer for the cutting outline, ie the path the 2mm routing tool should take. Sometimes I let the manufacturer decide what's best, but other times I might want a specific clean edge in a certain location.

When designing flexirigid PCBs, I use separate mechanical layers for outlining the flexible and rigid regions (top FR4, polyimide...) This is also useful when conforming to IPC-2223, such as keeping a minimum distance between plated holes from rigid to flex, as I can clearly identify where the overlaps are.

They can be for whatever you need them to be ultimately. Experience will dictate what is useful to you, and creating PCB templates with expectant usage of these layers will likely prove to be valuable.

I use Mechanical 1 for bodies and Mechanical 5 for PCB outline, for example, and the built-in IPC-compliant wizard puts elements on Mechanical 13 (body) and Mechanical 15 (location cross and outline).

Put whatever you want on that layer that is non-electrical. I normally don't put anything on Mechanical 1 since sometimes imported entities (e.g., DXF files) end up on that layer, or, I'll force imported entities to end up on Mechanical 1.

Send an enclosure from MCAD to ECAD seamlessly. PCBs often contain restrictions based on the mechanical enclosure, MCAD CoDesigner makes it easy to transfer a 3D enclosure model from your MCAD to Altium Designer.

The Altium MCAD CoDesigner panel displays the full history of accepted and rejected changes from both the electrical and mechanical sides. As soon as changes are applied or rejected by the electrical engineer, you will see a notification in your MCAD application.

Even the simplest board needs design detail beyond the tracks and pads that implement the circuit. It might be the board dimensions or the fabrication detail, it might be the component courtyards, or it might be the 3D component models.

Mechanical layers are added, edited and removed in the View Configuration panel. Their display state is also configured in the panel. Use the button at the bottom-right of the workspace, or press the L shortcut key, to display the panel.

There are several layer types that can be specified when adding a mechanical layer. Right-click in the Mechanical Layers region of the View Configuration panel then select the Add Component Layer Pair command or the Add Mechanical Layer command from the context menu. In the Edit Layer dialog that opens, use the Layer Type drop-down to select the required layer type. Available layer types are defined below.

Component Layer Pairs are used to define component detail in the PCB library editor. They are a pair so that there is one layer for top side components, and the partner layer for bottom side components. Detail is only placed on the top Component Layer Pair in the library editor, that detail is automatically moved to the bottom layer in the pair when the component is placed on the bottom side of the board.

Single Layer Mode is a handy display control feature, where all other layers are hidden apart from the active (current) layer. Press Shift+S to cycle through the enabled Single Layer Modes, then back to the previous layer display state. When the display is in single layer mode the non-active layers can be: completely hidden; set to gray; or set to monochrome. The Available Single Layer Modes options are configured in the PCB Editor - Board Insight Display page of the Preferences dialog.

In some situations the extra detail included on a mechanical layer is only needed once, for example assembly notes that detail the component load order and important assembly instructions. In this situation a standard mechanical layer is added, named, and where possible, has its Layer Type assigned (more on this below).

If the extra detail is required for a component, for example component courtyard outlines, there needs to be two mechanical layers assigned, one layer holding the courtyard detail when the component is placed on the Top side of the board, the other mechanical layer holding that same courtyard detail if the component is flipped to the bottom side of the board.

In this situation a pair of mechanical layers is added, as a Component Layer Pair. When mechanical layers are added as a Component Layer Pair, they are displayed in the Component Layer Pairs section of the View Configuration panel, as shown below.

A common approach to managing mechanical layer usage is to assign a dedicated layer number for each required mechanical layer function. This approach requires all designers to adhere to the same layer assignment & numbering scheme. It can also create difficulties when components are obtained from other sources that do not follow the same assignment & numbering scheme. If a different scheme has been used, the design objects must be moved from their current mechanical layer, to the mechanical layer assigned for that function.

This issue is resolved with the introduction of the Layer Type property. When a component is placed from a library into the PCB editor, or copied from one library to another, or created by the IPC Footprint Wizard, existing Layer Type assignments are automatically matched, regardless of the mechanical layer number(s) assigned to those Layer Types. The objects are relocated on the correct layer(s), according to their Layer Type. If the software is unable to match by Layer Type, it will fall back to matching by Layer Number.

When a Layer Type is assigned, the layer automatically has its Layer Name property changed to be the same as the Layer Type. This can be overridden if required, by typing in a user-defined name. When a layer has a user-defined name and a Layer Type assigned then both are displayed, with the Layer Type shown in brackets, as shown below for the Layer Pair GP (Gold Plating).

If an individual mechanical layer or a Component Layer Pair have a Layer Type assigned then the mechanical layer number is no longer displayed, reflecting that the software will manage and map the layer by Type instead of number.

There is one exception to the naming behavior just described when a Layer Type is assigned, a user-defined name is not permitted when the Layer Type is set to Route Tool Path. The reason for this is that older versions of the software use the name of the Route Tool Path layer to identify the layer that contains the route information (also referred to as rout information). Fixing the naming of this layer insures that the design will continue to function correctly in an older version.

The Route Tool Path Layer Type is used to indicate the layer that contains the mechanical routing information. A typical approach to using this layer is to place tracks and arcs around the outer edge of the board shape to define the machining path and width. Solid sections are left to hold the board within the panel, and then a series of small holes is placed across each solid section to create perforations (often referred to as mouse-bites), allowing the board to be snapped out of the panel once the assembly process is complete.

Use the Line/Arc Primitives from Board Shape dialog to trace the outside of the board shape with tracks and arcs. Enable the Route Tool Outline option in the dialog to have the objects placed outside the board shape, rather than centered along its edge. Some designers prefer to add the fabrication information when they use the Embedded Board Array feature to create an assembly panel, rather than including this detail in the actual board file.

Where possible, it is recommended to edit the source library and assign Layer Types. When a component footprint is placed (or copied) from a library, mechanical layers and Component Layer Pairs of those Layer Types are automatically created in the target board (or library) if they do not exist. If those Layer Types already exist in the target board (or library), the layer contents are automatically mapped to the correct layer.

Mechanical layers are used for a broad variety of tasks, detailing information used during: board design, fabrication, assembly, and product documentation. To support all of these requirements, mechanical layers can be excluded or included in all forms of layer-based output generation, including printing and output file generation.

Any of the layers that are present in the design can be included in the specification of a PCB Printout, including mechanical layers. Printouts are configured by adding the required layers and setting their order, in the PCB Printouts dialog.

The software also includes an advanced, yet flexible graphical editing environment for creating board design production documents, called Draftsman. Complete with a dedicated set of drawing tools, the Draftsman drawing system provides an interactive approach to bringing together fabrication and assembly drawings with custom templates, annotations, dimensions, callouts, and notes.

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