The definitions below are typical and found in the laser machined ceramic industry. 

Acceptable Quality Level (AQL):  A statistical evaluation of product lot characteristics when sampled using the plan defined in ANSI/ASQ Z1.4.  Unless otherwise specified, General Inspection Level II is applied.

Alignnment Flat: Machined indentation, located on substrate edges, used for precise mechanical alignment of the substrate in the customer’s process (reference Figure 1 in specifications).  Also called “flats.”

Annealing: Heat treatment of thick and thin film ceramic substrates to thermally modify the heat-affected zone (HAZ) allowing for improved via metal adhesion or, in some cases, to relieve residual stresses. Clean firing is a lower temperature annealing process.

Array:  Final product shipped to customer.

As-fired edge: The edge of a substrate produced by mechanical punching of unfired (green) ceramic tape.

Camber:  Degree of ceramic curvature, expressed in inches per linear inch of ceramic, when measured between two parallel ground plates.  Camber is defined as the gap between the ground plates divided by the longest linear ceramic dimension.

Chamfered corner: A unique reference used to locate the datum point and/or the working surface (“A” side) for substrates (reference Figure 1 in specifications).

Coating: Used to protect substrate surface during laser processing.

Cut Slot: Laser machined feature through thickness of substrate with length greater than width (reference Figure 1 in specifications).

Datum: Reference point (0,0) from which all other ceramic substrate features are measured.

Drilling: Laser machining of round holes through the substrate thickness.

Fiducial: A marking used as a standard reference for substrate orientation and alignment (reference Figure 1 in specifications).

Flaring: A small protrusion left along the edge after breaking. Flares are considered acceptable if within overall specification limits.

Ground edge: The edge of a substrate produced by a mechanical abrasion process on a laser scribed or as-fired edge.

HAZ: Acronym for Heat Affected Zone. Region of material adjacent to the laser scribe or cut.

Hole roll-off: In a cross-sectional view of a laser drilled hole, the radius at the intersection of the hole wall (tangent point) and the face of the substrate, on the beam entry side only (reference Figure 3 in specifications).

Laser: Acronym for light amplification by stimulated emission of radiation.

Locating Hole: Customer-specified optical and/or mechanical feature (reference Figure 3 in specifications).

Machining/Profiling: Cutting through a ceramic substrate with a laser beam to produce a desired shape.

Master: The blank ceramic board with as fired edges from which the array is cut.

Pits: Non-laser related depressions or voids in the ceramic surface only.

Pulse depth: Average penetration distance of a laser pulse measured from the entrance side of the substrate (reference Figure 2b in specifications).

Pulse spacing: Separation distance between two adjacent laser pulses measured from centerline to centerline (reference Figure 2 in specifications).

Scribing: To laser machine a line by perforating the material’s surface. Separation of the material may then be done along the perforated line, thus achieving the desired part dimensions (reference Figure 2 in specifications).

Singulation: Act of separating segments of the scribed substrate into the final part dimensions.

Slag: Re-solidified ceramic material on the substrate’s surface resulting from laser processing.  Also called burrs.

Step and Repeat Design: A single substrate containing multiple laser scribed parts to allow for batch processing in the customer’s process (reference Figure 1 in specifications).

Surface finish:  The relative roughness of the ceramic surface when measured using work instruction QUA-Wxxx.

Tab: Ceramic material intentionally left inside a laser cut feature so as to secure a part to a board. It is a result of the start / stop point of the laser beam.  Alternatives are available should this cause a problem to the function of the part.

Taper: Slope of the wall resulting from laser drilling and machining through the substrate thickness (reference Figure 3 in specifications).