A complete drawing defines more than the outside envelope
Length, width and height describe the overall shape. On a board-level shielding part, mounting features, PCB datums, lid engagement, openings and component clearances determine whether that shape can actually be installed. Review these relationships as one set of controlled inputs.
STEP/STP, DWG/DXF and PDF files can support the discussion. A 2D drawing communicates dimensions, tolerances and inspection criteria, while a 3D model makes the spatial relationships easier to review. If they disagree, establish the governing revision before quoting or manufacturing.
Check the information that commonly becomes disconnected
Units and dimension definitions
State whether a dimension describes the external body, usable internal cavity or flat blank. For frame-and-lid assemblies, distinguish each part from the assembled envelope.
Datums and mating interfaces
Relate mounting features, holes and frame edges to the PCB or mating part. The inspection reference should make sense for the intended board location.
Openings and formed features
Identify the purpose of each opening and whether its location can change. Review bends, corner transitions and partitions in the installed condition.
Revisions and associated parts
Use matching revision identifiers for the drawing, model, PCB layout and mating samples. A new lid should not be evaluated against an obsolete frame without an explicit compatibility check.
Give critical dimensions an executable inspection method
| Feature | Useful supporting information | Question to resolve |
|---|---|---|
| Height and internal space | Component envelope, keep-outs and local sections | Does the stated height correspond to usable space in the installed condition? |
| Frame and lid | Assembly model, locating datums and removal direction | Is acceptance based on individual dimensions or assembled fit and access? |
| Mounting tabs and holes | PCB datums, lands or mounting-hole positions | Can inspection reproduce the intended locating relationship? |
| Cavity partitions | Circuit areas, component clearance and attachment boundaries | Are partition locations consistent with the board layout? |
| Surface finish | Base metal, treatment areas and final dimensions | Which dimensions and contact areas need checking after treatment? |
Specify the control requirement, measurement method and acceptance condition for critical features. Tolerances, contact forces, coating thicknesses and performance criteria cannot be established from a product photograph.
Keep DFM feedback tied to a defined feature
A manufacturing recommendation may concern a bend sequence, hole position, forming feature, material or locating method. It should identify the feature being changed and the functional or assembly boundaries that must remain intact.
A process suggestion becomes a design input only after approval. Update the revision and carry it into the sample, order and inspection records. Changes affecting a lid, frame, PCB or packaging carrier should also be checked against those associated items.
Locate the change
Use a marked drawing or local view to show what changed in the height, opening, partition, mounting feature or material.
State the retained function
Identify compatibility with an existing PCB, removable access, connector location or assembly supply direction.
Set the revalidation scope
Determine which affected dimensions, manufacturing features and assembly checks need a new sample or inspection record.
Before you submit the review request
Match the file names, part numbers and revisions. Include the units, critical dimensions, sample quantity, forecast batch quantity and the engineering question. If only a sketch or physical sample is available, distinguish confirmed features from those still under review.
Use the contact form for the project brief and email the related drawings with the same project or part reference. Discuss confidentiality arrangements before sending proprietary design details.