Manufacturing Glossary

This glossary defines the manufacturing terms that come up when sourcing custom parts — each in a single, self-contained sentence you can quote directly. It is written for buyers and engineers specifying parts, not for the shop floor: the emphasis is on what a term means for your cost, lead time, and quality.

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Die casting terms

High-pressure die casting (HPDC)

High-pressure die casting (HPDC) is a process that forces molten metal — usually aluminum, zinc, or magnesium — into a reusable hardened steel mould at high pressure and speed, producing strong, thin-walled, complex net-shape parts at high volume with excellent repeatability. It is the dominant form of die casting. See our die casting services and HPDC overview.

Cold-chamber die casting

Cold-chamber die casting ladles molten metal into an unheated injection chamber for each shot, and is used for higher-melting-point metals such as aluminum and magnesium that would attack a submerged injection system. It has a longer cycle than hot-chamber casting because the chamber is refilled every shot.

Hot-chamber die casting

Hot-chamber die casting keeps the injection system submerged in the molten metal bath, giving fast cycle times, and is used for low-melting-point alloys — in practice, zinc. See aluminum vs zinc die casting for which one your part wants.

Porosity

Porosity is void space inside a casting, occurring either as gas porosity (trapped air or hydrogen, leaving round smooth-walled pores) or shrinkage porosity (metal contracting during solidification, leaving jagged angular pores). It is the defining constraint of die casting: it limits welding and heat treatment, and it is graded against ASTM E505 reference radiographs. See die casting defects.

Flash

Flash is a thin fin of excess metal that escapes the die at the parting line or around ejector pins, caused by insufficient clamp force, a worn die, or excessive injection pressure, and trimmed off after casting. Light flash is normal and trimmed; heavy or persistent flash signals a machine, die-condition, or pressure problem.

Draft angle

Draft angle is the slight taper applied to a part's vertical faces — typically 1–3° for die casting, more on interior surfaces — so the part releases from the mould cleanly instead of dragging or soldering. Too little draft is one of the most common and most avoidable causes of surface damage on cast and moulded parts.

Parting line

The parting line is the seam where the two halves of a die or mould meet, visible on the finished part, and the place where flash forms if the halves do not stay tightly closed. Where the parting line falls is a design decision worth making deliberately — it affects appearance, flash trimming, and draft direction.

Net shape / near-net shape

A net-shape part comes out of the process at its final dimensions with no further machining, while a near-net-shape part is close to final but needs machining on selected critical features. Most production die castings are near-net shape: cast for the geometry, CNC machined for the features that must hold tight tolerance.

NADCA

NADCA (the North American Die Casting Association) publishes the product specification standards that define achievable tolerances, and acceptable porosity levels, for die castings. Specifying "no porosity" on a drawing is not achievable; specifying a NADCA grade in the critical region is.

Sheet metal terms

Press brake

A press brake is the machine that bends sheet metal, pressing a punch into a V-shaped die with the sheet between them to form a straight bend. See sheet metal bending.

K-factor

The K-factor is the ratio locating the neutral axis inside a bend — the layer that is neither stretched nor compressed — expressed as a fraction of material thickness, and it is what makes a flat pattern come out the right size. Typically 0.3–0.5 depending on material and radius. See the bend allowance guide.

Bend allowance

Bend allowance is the length of material consumed by a bend, measured along the neutral axis, and it is added to the flat legs to calculate the flat blank size. Get it wrong and the finished part is the wrong size even though every bend is correct.

Springback

Springback is the elastic recovery that makes a bend open up slightly after the punch lifts, and it increases with harder material, thicker material, and larger bend radii. Press brakes compensate by overbending so the part relaxes into the specified angle.

Air bending

Air bending forms a part without the punch reaching the bottom of the die, so the angle is set by how far the punch descends — which means one tool set can produce any angle. It is the default bending method because it needs no tool change between angles.

Deburring

Deburring removes the sharp raised edges left by cutting, punching, or machining, both for safety in handling and so that coatings adhere and parts assemble properly. See the deburring guide.

Heat-affected zone (HAZ)

The heat-affected zone is the narrow band beside a thermal cut or weld where the metal's structure has been changed by heat without melting, which can leave it harder, softer, or more brittle than the parent material. Laser and plasma cutting leave a HAZ; waterjet cuts cold and leaves none. See laser vs punching vs waterjet.

Sheet metal gauge

Gauge is a traditional numbering system for sheet thickness in which a higher number means thinner metal, and the actual thickness differs between steel, aluminum, and stainless for the same gauge number. Always confirm thickness in millimetres. See the gauge chart.

Tooling and volume terms

Rapid tooling

Rapid tooling is the use of faster, cheaper moulds — often aluminum rather than hardened steel — to bridge the gap between prototypes and full production tooling, trading die life for lead time and cost. Use it when the design is not yet frozen. See rapid tooling.

DFM (Design for Manufacturing)

Design for Manufacturing (DFM) is the practice of designing a part so it is easy, fast, and cheap to make — simplifying geometry, using standard tolerances and materials, and avoiding hard-to-manufacture features — so cost and quality problems are caught in design rather than on the shop floor. Sendot includes a free DFM review with every quote. See the DFM guide.

MOQ (minimum order quantity)

MOQ is the smallest number of parts a supplier will accept for an order, driven by whether the setup or tooling cost can be recovered across the run. Sendot has no MOQ for CNC machining — a single prototype is a valid order. Die casting is different: it needs a steel die, so the MOQ is 1,000–3,000 pieces, depending on tooling cost. Below that, machining is usually the cheaper answer.

Vacuum die casting

Vacuum die casting evacuates the air from the die cavity before the metal is injected, sharply reducing gas porosity and producing castings that can be welded, heat treated, or used as pressure-tight parts. Standard high-pressure die castings usually cannot be heat treated without blistering. Sendot offers vacuum die casting — specify it up front if your part needs it.

Quality terms

CMM (coordinate measuring machine)

A coordinate measuring machine (CMM) is a precision instrument that measures a part's actual geometry by probing points on its surfaces, and is the standard way to verify critical dimensions against a drawing. Sendot provides CMM reports on request.

FAI (First Article Inspection)

A First Article Inspection (FAI) is a full dimensional report on the first part produced from a new process or tool, verifying every drawing dimension before the rest of the run is committed. Ask for it when a new tool or a new supplier is involved — it is the cheapest place to catch a problem.

ISO 9001

ISO 9001 is the international standard for quality management systems, certifying that a supplier has documented, audited processes for controlling quality — not that any individual part meets a specification. Sendot Technology operates an ISO 9001-certified quality system.

Tolerance

A tolerance is the permitted deviation from a nominal dimension, and it is the single specification with the largest effect on machining cost — every tightening step costs slower machining and more inspection. Sendot machines to ±0.05 mm where required. Only tighten what the application truly needs. See CNC machining tolerances.

Overseas sourcing terms

Total landed cost

Total landed cost is the ex-works unit price plus every cost that gets a part onto your shelf: tooling amortised over the run, freight, insurance, import duty and VAT/GST, customs brokerage, inland freight, and inventory carrying cost. It is the only number worth comparing between suppliers or between domestic and overseas sourcing, because a low unit price can land high once freight and duty are added. Freight and tooling amortise as quantity rises; duty does not. See our full landed-cost formula with a worked example.

Incoterms

Incoterms are the standardised trade terms — such as EXW, FOB, CIF and DDP — that define exactly where the seller's responsibility for a shipment ends and the buyer's begins, covering who pays freight, insurance, export and import clearance. They decide which landed-cost lines are already in the quoted price and which you pay separately, so a quote is not comparable until you know its Incoterm. The rules are published by the International Chamber of Commerce; how they apply to a specific shipment should be confirmed with your freight forwarder.

NRE (non-recurring engineering)

NRE is the one-time cost of setting a part up for production — programming, fixtures, first-article inspection and any tooling — charged once rather than per part. Spread across the run it falls as quantity rises, which is why a small batch carries a higher cost per part than a large one for the same design. On a quote it may appear as a separate line or be built into the unit price; ask which, so you can compare suppliers on the same basis.

HTS / commodity code

An HTS (Harmonized Tariff Schedule) or commodity code is the classification number that determines the import duty rate on a part in a given country. To estimate duty, find the code for your part in the importing country's official tariff schedule, look up the rate there, and confirm it with a customs broker — rates change and classification can be genuinely ambiguous. This is not tax advice, and no supplier can tell you your duty owed. Duty is one line in the total landed cost of an imported part. See import duties on machined parts for the official tools by country.

Section 301

Section 301 is a US trade measure that can add extra import duties on certain goods of Chinese origin, on top of the base HTS rate. Whether it applies depends on the part's classification, and product exclusions are sometimes available through the USTR process. Check the current status for your code in the HTS and confirm the all-in rate with a customs broker.

de minimis

De minimis is the value threshold below which imports could enter duty-free without formal customs entry. The US $800 de minimis exemption has ended, so even low-value sample and prototype shipments are now dutiable and need formal entry. Budget duty and clearance into prototype cost and consolidate small shipments where you can.

EORI number

An EORI (Economic Operators Registration and Identification) number is the registration an importer needs to bring goods into the EU (and, separately, into Great Britain). It identifies the importer of record to customs. You obtain it from your national customs authority before your first import; your supplier does not provide it.

Milestone payment

A milestone payment splits the price into instalments tied to stages of the job — for example a deposit to start, a payment when the first article is approved, and the balance before or after shipment — rather than paying all of it up front or all on delivery. It shares risk between buyer and supplier: the supplier needs a deposit because material and machine time are committed before you have parts, while later instalments keep leverage with the buyer. How to structure the split, and how it varies by transaction size, should be confirmed with your own bank or a trade-finance professional. See our guide on payment terms for overseas manufacturing.

Escrow

Escrow is an arrangement where a neutral third party holds the buyer's payment and releases it to the supplier only when agreed conditions are met — typically inspection or shipment of the parts. It is designed to reduce the risk of paying before parts exist, but it adds fees and friction and its protections vary by provider and jurisdiction. It is not a substitute for legal advice — confirm what any escrow service actually guarantees before relying on it.

On-time delivery (OTD)

On-time delivery rate is the share of orders a supplier delivers by the promised date, usually tracked as a rolling percentage — a core metric on any supplier scorecard. A single late shipment is noise; a trend below, say, 90% is a signal worth a conversation. Measure it against the date confirmed at order, not a date renegotiated later, or the number flatters the supplier. See how to measure a machine shop with a scorecard.

First-pass yield

First-pass yield is the share of parts that pass inspection the first time, without rework or scrap — a direct read on a shop's process control. It is often expressed as a percentage or, for tight-tolerance work, as defects per million (PPM). Low first-pass yield shows up as delays and cost even when the parts eventually ship, because rework consumes the time and margin that were quoted against a clean run.

Landed cost

Landed cost is the total cost of getting a part to your door, not the price on the quotation — unit price plus tooling, freight, insurance, import duty and customs fees, inspection, and the inventory you must hold to cover the transit time. It is the only number worth comparing between a domestic and an overseas supplier, because a lower unit price can arrive at a higher landed cost once freight and duty are added. See our domestic vs overseas cost comparison for the full model.

Due diligence

Due diligence is verifying a supplier's claims with evidence before you place an order — checking the certificate scope and issuing body, reading a real FAI report and CMM data, confirming material certificates, and running a paid first-article order before committing to volume. The distinction that matters is between what a supplier says and what it can show: a certificate logo is a claim, a scope statement naming manufacturing at the address that will machine your parts is evidence. See our 12-point supplier vetting checklist.

NDA (non-disclosure agreement)

An NDA is a contract in which a supplier agrees to keep your designs, files and project details confidential and not to use them for any purpose other than making your parts. A mutual manufacturing NDA also covers what happens to your files after the job, subcontractor obligations, and how long confidentiality lasts. An NDA is one layer of protection, not a guarantee — enforceability varies by jurisdiction, and any binding agreement should be reviewed by a qualified lawyer. See our guide on protecting your IP when outsourcing abroad. Sendot signs NDAs on request and handles all uploaded files confidentially.

Lead time

Lead time is the elapsed time from a confirmed order to parts ready to ship — distinct from the quote turnaround, which is how fast you get a price. For machined parts it is driven by material availability, machine queue, the number of setups, finishing and inspection. At Sendot, CNC samples run 3–5 working days and a quote comes back within 12 hours of receiving CAD; production lead time is confirmed per project. When comparing suppliers, ask whether a quoted lead time counts from order confirmation or from receipt of your files.

Get a part quoted

Upload your CAD (STEP, IGES, X_T, DWG, PDF or STL) on our Request a Quote page with your material, tolerance, and quantity. Every quote includes a free DFM review, and we respond within 12 hours.