Metalworking & Knife Glossary: Fine Blanking, Vacuum Heat Treatment, Liner Lock, MOQ

Manufacturing processes
Knife construction
Business & quality

Manufacturing processes

Fine blanking: A stamping process that clamps the sheet with a V-ring and counter-pressure while cutting, producing a smooth, fully sheared edge and tight dimensions; used for blades, lock bars and gear-like parts, often removing the need for later milling.
Stamping: Using a press and a die to punch, shear, bend or form sheet metal; fast and low in unit cost, it is the main process for high-volume hardware parts.
CNC machining: Milling, turning or grinding where the tool path is controlled by a computer program; it produces 3D shapes and precise holes that stamping cannot. Three-axis suits flat parts; five-axis machines complex curved handles in one setup.
Vacuum heat treatment: Heating, quenching and tempering inside a vacuum furnace to bring the steel to its designed hardness and toughness; with no air present the surface does not oxidise or decarburise and blade distortion stays low, which suits high-alloy stainless and powder steels.
Tempering: Re-heating the steel at a lower temperature after quenching and holding it there to reduce brittleness and raise toughness, balancing hardness against chipping; usually done twice.
Water grinding: Grinding with coolant flooding the wheel and the workpiece, used to shape a blade's flats, bevels and edge; the water carries heat away so the blade does not overheat locally and lose the hardness gained in heat treatment.
PVD coating: Physical vapour deposition: metal or ceramic material is vaporised in a vacuum chamber and condensed onto the blade as a very thin, hard, wear-resistant film, typically black, grey or gold; DLC (diamond-like carbon) is the PVD variant with the lowest friction.
Electro-deposition coating (EDP): The part is immersed in a water-based paint bath and an electric current makes the paint deposit evenly on every surface, including holes and recesses, before oven curing; uniform thickness, strong adhesion and good corrosion resistance make it common for black tool and defense hardware parts.
Sandblasting: Compressed air fires fine abrasive or glass bead at the surface to create a uniform matte texture and remove burrs and scale; it is also a pre-treatment that improves adhesion before painting or PVD.
Tumbling: Large batches of parts are run in a barrel or vibratory machine with media, water and compound to remove burrs and round off edges; suited to volume finishing of small stamped parts.
Passivation: An acid wash removes free iron from a stainless-steel surface and lets a complete chromium-oxide layer form, improving corrosion resistance; commonly the last step before stainless parts ship.
Tooling: The dies, jigs and fixtures made specifically for stamping or forming a part. Tooling is a one-off cost before mass production and its life is counted in strokes; in OEM projects the customer usually pays for and owns it while the factory stores and maintains it.

Knife construction

Liner lock: The most common folding-knife lock: a spring-steel liner inside the handle snaps behind the blade tang when the knife opens and holds the blade; the thumb pushes the liner aside to close. Simple, low cost and one-handed.
Frame lock: Works like a liner lock, but the locking bar is part of the handle frame itself (usually titanium or stainless plate), thicker and more rigid; common on higher-end folders.
Back lock: A spring-loaded rocker bar along the handle spine drops into a notch on the blade tang to lock; pressing the release on the spine unlocks it. A long-established design, ambidextrous and strong.
Crossbar lock: A steel bar passing through the handle is pushed by springs on both sides into a notch on the tang; pulling it back releases the blade. Ambidextrous, one-handed to open and close, and fingers stay out of the blade path.
Tang: The part of the blade that extends into the handle. On a folder the tang carries the pivot hole, lock notch and stop; on a fixed blade a full tang runs the full length of the handle while a hidden tang is enclosed inside it.
Handle scales: The outer handle material fastened to each side of the tang or liners — commonly G10, Micarta, titanium, aluminium, wood or carbon fibre; they set the feel, weight and look and are usually CNC machined.
Pivot: The axis a folding blade rotates on, made of a pivot screw plus washers or ball bearings; the machining accuracy of the pivot and the washer material determine how smoothly the blade opens and how much side-to-side play it has.
Detent: A small steel ball set into the liner that drops into a dimple on the tang when the knife is closed, so the blade stays shut instead of swinging open; the depth and position of the dimple set how firm the opening action feels.
Blade grind: The cross-section shape from spine to edge: flat is sharp and versatile, hollow is thinnest and sharpest but less robust, convex is the most durable, scandi is easiest to maintain; the application decides, and the drawing must specify it.
Edge bevel: The narrow final bevel at the very edge that does the cutting, specified as an angle per side (for example 15°–20°); a smaller angle cuts better but chips more easily, and in production it is ground with fixed jigs so every knife matches.
Thumb stud / Flipper: Two common one-handed opening features on folders: a thumb stud is a small post fixed to the side of the blade that the thumb pushes; a flipper is a tab extending from the tang that the index finger presses to swing the blade out, usually paired with bearings.

Business & quality

OEM: Original Equipment Manufacturing: the customer supplies drawings and specifications, the factory builds to them, and the design and IP belong to the customer.
ODM: Original Design Manufacturing: the customer states requirements, the factory designs and builds, and the product carries the customer's brand; design ownership is set by contract.
RFQ (Request for Quotation): A customer's request for a price. A complete RFQ includes drawings, material, finish, quantity, annual volume, target price and required delivery; the more complete it is, the more accurate and faster the quotation.
MOQ (Minimum Order Quantity): The smallest quantity a factory will accept per order, driven by tooling amortisation, material purchase lots and changeover time; the MOQ for the same part changes with material and finish.
Lead time: The time from order to shipment, split into sampling lead time and production lead time; the first batch that includes tooling is usually the longest, and repeat orders count only material and production time.
DFM (Design for Manufacturing): The factory's review of a customer drawing before quoting, suggesting changes to material, tolerances, radii, wall thickness and process sequence so that unmakeable or needlessly expensive features are removed before tooling is cut.
FAI (First Article Inspection): After tooling or a process is complete, every dimension on the drawing is measured on the first parts produced and reported; mass production starts only after the customer approves. Usually required by defense and industrial customers.
Tolerance: The permitted deviation on each dimension of a drawing. Tighter tolerances raise process, inspection and scrap cost, so putting tight tolerances only where function needs them (pivot holes, lock faces) and relaxing the rest is key to cost control.
NDA (Non-Disclosure Agreement): A confidentiality contract signed before drawings and business information are exchanged, restricting the data to that project and forbidding disclosure. Choun Yi signs an NDA on request before receiving drawings, which are then held in a PDM system with project-level access.

Metalworking & knife glossary

Manufacturing processes

Knife construction

Business & quality

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