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Explore what
controls the fit.

Size, alignment and positioning all affect the space between parts. Follow two illustrative USB-C studies, then explore how tolerance changes a simple block-and-pocket fit.

The parts can meet their size limits and still clash when they’re misaligned. See how a locating change recovers clearance.

Initial alignment−10 µm

Local interference

Refined alignment+15 µm

Local clearance

Same size limits. Offset reduced from 30 to 5 µm.
Illustrative rigid-shell fit study.

What’s your assembly’s fit question?
From the whole connector to the interface that decides the fit.Silent film · On-screen explanationsDownload illustrated study (PDF)

USB-C / Before & after

USB-C fit comparison: reducing the prescribed alignment offset from 30 to 5 micrometres changes local clearance from minus 10 to plus 15 micrometres

The fit goes deeper.

Give every contact room. Follow the clearance between two neighboring contacts, then see how a positioning change recovers 40 µm of space.

Adverse position152.5 µm
Refined position192.5 µm

Same maximum contact widths. Both gaps stay positive.
175 µm is the minimum chosen for this illustrative study.

Explore the contact study
From the product to the contact that controls the gap.Silent film · Illustrated geometry and actual StackUp 3D captures

The CAD model fits.
Will the real parts fit?

Manufactured parts vary in size. Tolerance analysis shows how that variation affects their fit.

Pocket specification
20.00 ±0.20 mm
Block specification
19.70 ±0.20 mm
A purple block seated against the left side of a gray pocket, with a positive nominal gap at the right wall
Illustrative model · Purple block, gray pocket. The cyan strip marks the 0.30 mm nominal gap at the right wall.

Nominal gap / Nominal sizes

20.00 − 19.70 = +0.30 mm

The intended sizes leave a 0.30 mm gap.

Check the fit in your assembly.

Import STEP geometry, set tolerances and inspect the gaps that matter.

Actual StackUp 3D · 0.300 mm nominal gapNominal app measurement; size-limit comparison calculated separately.
See more assembly stories

Actual StackUp 3D · 0.300 mm nominal gap

Enlarged StackUp 3D interface measuring the block and pocket’s 0.300 mm nominal gap

Nominal app measurement; size-limit comparison calculated separately.

What’s your assembly’s
fit question?

Bring one assembly and a decision that matters. We’ll help define a hands-on evaluation around it.

Book a demo Plan your assembly review