Deliver the DWG and identify the controlling revision
Provide the CAD drawing in DWG format. Use a file name containing the part number and revision, and identify the matching pattern layer or mask-set sheet. A PDF or screenshot may be supplied for visual cross-checking; manufacturing geometry and editable drawing data must be present in the DWG.
- Include all referenced geometry in the supplied package; unresolved external references can leave the pattern incomplete.
- Use one released revision for quotation or production review. Mark superseded files explicitly.
- If a DWG compatibility version is needed, agree it before re-saving and recheck the exported geometry.
Use 1:1 model geometry and a declared unit
A dimension label does not prove that the underlying geometry has the same size. Draw the actual component at 1:1 in model space, state the drawing unit and include at least one known overall dimension for checking. Paper-space viewport scale is a presentation setting, not the manufacturing scale.
Give layers a physical meaning
Separate the mechanical outline, clear regions, opaque regions, alignment marks and annotations. A layer legend must explain which geometry defines film and which defines glass. Do not rely on a black screen background, line colour or a plot-style setting to communicate polarity.
| Layer example | Meaning | Review point |
|---|---|---|
| MECH_OUTLINE | Glass perimeter, holes and cut-outs | Not automatically a chromium boundary |
| PATTERN_OPAQUE | Regions intended to retain opaque film | Confirm nested islands and openings |
| PATTERN_CLEAR | Regions intended to transmit light | A clear film window is not a hole through glass |
| ALIGNMENT | Manufactured registration marks | Identify coordinate origin and common mask-set marks |
| ANNOTATION | Dimensions and instructions | Exclude from functional pattern unless explicitly intended |
Define feature boundaries rather than display line weight
A CAD centreline with a display line weight is not necessarily a bounded manufacturable stripe. Prefer closed boundaries for filled features, or explicitly define how a centreline and width are to be interpreted. Review duplicate entities, gaps, self-intersections and overlapping regions before release.
For circles, arcs and imported curves, inspect the smallest repeated feature as well as the whole view. Excessive faceting or an open endpoint can be invisible at full-plate zoom. Block insertion scale and non-uniform scaling must also be checked when geometry is reused.
Define film side, viewing side and mirroring
State whether the DWG is viewed from the coated side or through the substrate. Add an asymmetric orientation mark and dimension its relationship to the pattern. For a photomask, also state how the film side faces the workpiece during exposure. A symmetrical grid cannot reveal an accidental mirror reversal.
Do not mirror the production data merely to make a preview resemble a photograph. Confirm the required reading side and transfer direction first, then approve a labelled orientation view alongside the DWG.
Tie the pattern to the mounting datum
Define the centre, origin and angular zero used for inspection and assembly. On a rotary disc, identify whether the bore, outer diameter or a specified construction centre establishes the datum. On a scale, identify the reference end and which direction increases the reading.
- Show active pattern limits and the clamp or bonding area independently.
- For a mask set, use common coordinates and list which marks are shared or layer-specific.
- State whether a tolerance applies to a local feature, a pattern group or the whole active area.
Resolve tolerance and document conflicts before release
Put functional tolerances on the features to which they apply, with units and measurement references. If a general tolerance differs from a local callout, make the intended precedence explicit. When the DWG, a PDF and a specification sheet disagree, flag the conflict for confirmation rather than expecting manufacturing to choose one silently.
- DWG file, part number, revision and layer list match.
- Known dimensions, units, orientation and polarity have been checked.
- Critical feature limits and inspection conditions are written down.
- The editable inquiry form identifies quantity, application and attached file names.