DRAWING DETAILS / CNC MACHINING INSIGHTS
Slots and open pockets often look self-explanatory in a model, yet a reviewer still needs to know the functional width, depth, end geometry and access condition. Good drawing notes turn an outline in CAD into a feature that can be clearly reviewed with its mating parts.
Define the feature before naming it
A slot can provide clearance, guide a tab, receive a rail, or locate another component. An open pocket may create access, reduce mass or form a seating interface. Start by describing the functional relationship in the drawing package, especially if a mating part depends on the feature.
When a slot controls how components assemble, include the relevant mating geometry. Our guide to assembly fit and mating-part information explains which context helps an RFQ review without adding unnecessary files.
Show the complete feature geometry
| Feature detail | Why it matters | Useful drawing note |
|---|---|---|
| Width and length | They establish the functional envelope. | Dimension from defined references, particularly when the slot locates another part. |
| Depth or through condition | It defines the floor or open path through the part. | Use a section view where the depth is not obvious. |
| End geometry | Internal ends naturally relate to cutter geometry. | State the required radius or relief when it affects mating. |
| Open side | It changes access and functional containment. | Show which side is open and identify any critical adjacent wall. |
A shaded image is helpful for orientation, but a controlled model and PDF drawing should carry the released dimensions and notes.
Make end conditions explicit
Two slots with the same width can have different functional needs. One may accept a rounded tab; another may need a square mating corner with a defined relief. If the end geometry affects assembly, show it and explain the interface instead of using an ambiguous request for a sharp corner.
For pocket corners and tool access, see our guide to internal corner radii and pocket design. It explains why corner intent should be tied to the mating condition.
Connect dimensions to function
Not every slot dimension has the same importance. Mark the dimensions that control fit, movement or alignment, and avoid blanket requirements on unrelated surfaces. If the slot is only a clearance feature, say so. If it locates a part, show the locating references and the mating relationship.
Our CNC drawing datums guide can help buyers choose measurement references that reflect the part’s assembly function.
Questions to answer before release
- Does the slot provide clearance, location, guidance or seating?
- Which side is open, and does that opening matter to the assembly?
- Is the bottom a functional floor or simply an internal clearance surface?
- Do the ends need a stated radius or relief for a mating component?
- Which width, depth or position dimensions need inspection attention?
Keep the review focused
ExactMach coordinates drawing-defined CNC milling, CNC turning, prototypes and custom parts around Shenzhen and Dongguan for international orders. Clear slot and open-pocket notes help establish the intended feature before production is released.