Engineering Query Reference

Stack-up not specified

Layer order and finished thickness given; dielectric thickness and copper weight missing

You confirmConfirm the proposed stack-up, or supply the complete stack-up table

Stack-up does not add up to the stated thickness

Layer-by-layer total differs from the drawing's nominal thickness by more than ±10%

Options — confirm one

• Option A: keep the specified stack-up, accept the computed thickness
• Option B: modify the stack-up to hold the stated nominal thickness

You confirmName Option A or B, and state the governing finished-thickness value

Thickness tolerance tighter than standard

Drawing thickness tolerance is tighter than the ±10% standard

Options — confirm one

• Option A: relax to the ±10% standard
• Option B: proceed on non-standard material to hold the tight tolerance

You confirmName Option A or B; Option B also requires the cost change confirmed

Impedance target not achievable with the given stack-up

The trace width required to hit the impedance target is outside the workable range

Options — confirm one

• Option A: adopt the fab's adjusted dielectric thicknesses
• Option B: keep the stack-up and relax the impedance target

You confirmName Option A or B, and confirm the impedance target and tolerance class

Undefined label on the drawing

A drawing marking matches no Gerber feature and no note on the drawing explains it

You confirmState what the marking means: reference, requirement to execute, or to be deleted

No dimensioned drawing supplied

Gerber and drill files only; no dimensioned drawing supplied

You confirmSign off our measured draft, or supply a formal drawing with tolerances and critical dimensions

Unit too small, panel array proposed

Unit too small to clamp and register economically at drill, mask, test and packing

You confirmConfirm the panel proposal, and state the maximum X-out units acceptable per panel

Breakaway tab set back from the unit edge

Breakaway tabs set back from the unit edge, not flush with it

You confirmApprove moving the tabs flush to the unit edge, or state the constrained positions

CAD/CAM data and drawing disagree on a dimension

CAD/CAM data and drawing give different values for the same dimension

Options — confirm one

• Option A: the CAD/CAM data governs
• Option B: the drawing governs; we revise the data and resubmit

You confirmName Option A or B, stating whether the data or the drawing governs

Blind or buried hole purpose not stated

Blind or buried hole present; interconnect or mounting purpose not stated

You confirmState the hole purpose; if mounting, give barrel plating, thickness and bottom flatness

Breakaway hole sits partially over copper on all layers

Breakaway holes sit partially over copper on every layer

You confirmApprove the 0.50 mm clearance on all layers, or state the current or shielding constraint

Hole centres so close that the drills overlap

Plated and non-plated holes of equal diameter overlap at their centre distance

Options — confirm one

• Option A: convert to a single slot
• Option B: increase the centre distance so both holes drill cleanly

You confirmName Option A or B; for A, confirm the plating requirement for the slot

No solder-mask bridge between adjacent SMT pads

Adjacent SMT pads share one mask opening with no dam between them

You confirmApprove adding the mask dam, or require the original opening and accept the bridging risk

Via plugged on one side, open on the other

Vias specified plugged on one face and open on the other, with HASL finish

Options — confirm one

• Option A: keep the single-sided plug and accept the solder balls
• Option B: give the plugged side a small opening of about 3 mil to vent

You confirmName Option A or B, and state the final mask condition on that face

Hole specified for plugging is larger than about 30 mil

Hole specified for plugging exceeds about 30 mil, beyond reliable mask fill

Options — confirm one

• Option A: reduce the finished hole diameter and plug it
• Option B: change the requirement to a covered (tented) hole

You confirmName Option A (with the acceptable finished diameter) or Option B

Hole specified for covering is smaller than about 10 mil

Hole specified for tenting is under about 10 mil; mask is wicked into the barrel

Options — confirm one

• Option A: change the requirement to a plugged hole
• Option B: open the mask larger than the finished hole by about 5 mil per side

You confirmName Option A (change to plugged) or Option B (mask opening +5 mil per side)

Legend printed over a pad or exposed copper

Characters sit on pads or exposed copper with no process clearance

Options — confirm one

• Option A: clip the legend clear of the pad, accepting partially cut characters
• Option B: relocate the affected text to nearby clear space so it stays complete and legible

You confirmName Option A or B, and list the designators that must stay fully legible

Legend line width or character height below printable resolution

Some legend line widths and character heights fall below printable resolution

Options — confirm one

• Option A: scale the legend up to the published minimum so every character prints cleanly
• Option B: print as supplied, accepting reduced legibility on the characters below the limit

You confirmName Option A (scale up to the published minimum) or Option B (print as supplied)

Legend crosses a hole, the board edge or a routing path

Strings run across holes, past the finished outline or onto a cutter path

You confirmApprove relocating each string as a whole, or specify a target position for each