Altium Slots
Altium’s native Slot callout is supported. See our slots slots guide for limitations and DRC requirements of slots. Drill slots are used when you want to drill straight slots in the board. This command is accessed from the CAMtastic Editor by choosing the Place » Drill » Drill Slot (G85) command from the main menus. First, ensure that the layer you wish to place a drill slot on, is the active layer.
I’ve been working recently on a new top secret project that used multiple slots in the board. Normally I just define them as slotted pads in Altium and the board house deals with it.
Usually I just add a pad that’s defined as a slot with a very small pad in the middle
This time I was using OSH Park, and as it turned out things were not that easy. Their process does not support milled slots in the drill file. Instead slot outlines need to be on the board outline layer, and at least 100 mills wide. After a bit of fiddling, here is how I got there (This assumes you have the part footprint open for editing in PCB Library editor) :
- Draw a closed outline of the slot on the keepout layer, making sure it’s 100mil or wider. This also helps making sure polygon pours stay away.
- Go to Tools> Convert>Create Region from Selected Primitives
- Click on the newly created region and check “Board Cutout” box
Making region a board cutout
- Add “CUTOUT” text inside the cutout on the keepout layer
- Update your parts from the library or place your new parts
- Do placement/routing/design rule checks
- When generating Gerbers, go under Gerber Setup>Layers and make sure to check Plot box near Keep-Out-Layer GKO. This will be your board outline/slots drawing for Oshpark
- Check Gerbers and confirm that GKO layer now contains outlines for the slots:
Section of Keepout layer showing board outline, slots and the text for the fab
- Submit files as usually
Big Disclaimer(s)- I am yet to receive my boards back, so while it appears everything satisfies the specs, I may be completely wrong and the boards will be ruined. I’ll post an update once they come in. The directions are for Altium 13, so if you use 14, some menus may look different. My keepout layer contains board outline as I generate that from board shape by default.
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Design Rule Setup
Downloadable Files
Kind customers have provided loadable DRC rule and Stackup files for our 2 and 4 layer services.
Note, these files are not exhaustively validated or guaranteed by OSHPark, and may contain errors. Use your judgment and always verify your designs meet our service specs to prevent design defects that could affect your boards. If you have corrections or find errors, please email support.
known issues: Current minimum 2 layer specs are 10 mil drill hits, with 5 mil annular rings. The RUL file currently shows the older 13mil drill and 6mil ring
Generating Manufacturing Files
For accessing the various menus and output screens, see Altium’s Gerber Setup
Disabling “ Mechanical Layers to Add to All Gerber Plots”
Altium tools have the option Mechanical Layers to Add to All Gerber Plots, which must have all layers unchecked. Many footprints contain mechanical “courtyard” or “pick and place” data on these layers. When these footprints are added to copper layers, it can create gerbers that will be fabricated with shorts. See Altium’s Gerber Setup for information on how to access this setting.
Internal Plane Polarity
We recommend submitting planes with a Positive polarity. See our Positive vs Negative Gerbers page for additional information.
Board Outline
We need a watertight board outline on its own layer with no extra text or measurements. This tells us where the fab should mill the edges of the board. This layer can also contain board cutouts.
For best results, place the outline by itself on the Keep Out, or on a Mechanical Layer (normally 1 or 2). This will generate the outline on .GKO or a .GM<number> file.
Drills
Drill files should work without issues for most export options. If the drill files do not appear correct, check out our Drill File CAM configuration page for settings that we know will work correctly.
Slots
Altium’s native Slot callout is supported. See our [slots][slots] guide for limitations and DRC requirements of slots.
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Common Issues
Missing Drill File
Altium keeps the drill data in the project-name.TXT file. Make sure any uploaded zip files include this file.
Drill file not being read correctly
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Try exporting the drill file with the INCH units. Some format issues in METRIC are more difficult to reliably correct.
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Internal Layer names
If you’re using a 4 layer stackup with both “power” and “signal” internal layers, Altium will generate the internal layers as GP1 and G1. Unfortunately, this makes it impossible for us to determine the correct layer order, since multiple layers identify themselves as “Internal Layer 1”.
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To correct this, simply rename the layers using the G2L and G3L extensions. The G2L will be near the Top Copper Layer, and G3L will be near the bottom layer.