3D Printing File Checklist: Units, Models and Critical Fits

Prepare a clearer 3D printing enquiry by checking model scale, revisions, design-to-file mapping and the drawings needed for critical fits.

Release one intended model for each design

Start with a named part and a controlled revision. Export the model you want quoted, then reopen the exported file rather than relying only on the native CAD view. Check that it contains the intended component and that its overall shape matches the released design.

The DIYIPCB print enquiry accepts model formats including STL, OBJ, 3MF and STEP/STP, as well as ZIP packages. Select a format that communicates the geometry needed for the review, and keep reference documents clearly identified.

A file that uploads successfully has passed an upload step. It has not automatically been checked for printable geometry, suitable features or a valid manufacturing plan. Treat those as review questions.

Check units against a known dimension

State the model units in the request and verify an overall dimension in the exported model. Use a known feature such as enclosure width or mounting-hole spacing as a cross-check. This is particularly useful when files move between CAD and mesh applications.

Do not rely on a filename such as “millimeters-final” to carry the entire scale requirement. Put the units in the configuration and show important dimensions in a reference drawing. If a model is deliberately scaled for a display piece, record both the scale and the intended finished size.

A quick scale check before upload can prevent an otherwise complete enquiry from describing a different physical object than the one you intended.

Inspect the exported geometry

For mesh files, inspect the surface for unintended gaps, missing regions and stray objects. Where possible, export a closed, watertight model. Keep the version being reviewed distinct from a visualization mesh or an unfinished modeling intermediate.

If the design contains separate components, explain whether they should be printed separately, assembled later or reviewed as a connected design. A model viewer screenshot can clarify intent, but it does not replace the manufacturing geometry.

Identify any intentionally open areas, internal passages or moving interfaces that need review. Do not silently fill or merge features just to remove a software warning if the change would alter the product’s function.

Add drawings for the features that control fit

Attach a PDF drawing when dimensional requirements are important. Mark mounting interfaces, mating features and the reference surfaces used to measure them. State which dimensions are mandatory and which are informational.

For a lid-and-base assembly, show which revision of each component is being checked. For a fixture, identify the mating component or provide its relevant interface. This gives the reviewer context for deciding whether the proposed print and finishing approach can serve the test.

If a feature needs secondary machining or a drawing-specific tolerance, request that operation explicitly. Avoid using a layer-height setting as evidence that the finished feature will meet a tolerance; the accepted requirement needs separate confirmation.

Map files, quantities and alternatives before submission

• Give each design a unique name and revision.
• Attach the model and its own reference drawing to the correct design.
• Set quantity and units for every design rather than assuming they are inherited.
• Label duplicated configurations as alternatives when only one will be selected.
• Identify orientation, important surfaces and any inspection requests in the part notes.
• Keep the submitted package free of obsolete exports that could be mistaken for the release.

The service combines the configured designs into one quotation request. Its summary is a useful final cross-check, especially when one model is being quoted at several quantities or in different materials.

Use a short handoff note

Part/revision: [reference]. Model units and checked overall size: [details]. Quantity: [number]. Purpose of the print: [fit, appearance or function]. Critical interfaces: [drawing callouts]. Process/material: [requested or advise]. Orientation/finish: [notes]. Required documents: [scope]. Delivery target: [date and destination].

Keep a copy of that note with the submitted files and the resulting quote. If a requirement changes during review, resolve it in the same record. For a repeat print, identify the previously accepted configuration and describe changes explicitly rather than submitting an unmarked replacement file.