Material yield, furnace utilization, inspection margin, coating first pass yield, scrap recovery and supplier concentration: how to measure each KPI for a sintered NdFeB plant and which figures have a cited source.
Six KPIs tell you whether a sintered NdFeB magnet plant is healthy, and the gap between typical and world class is usually worth 8 to 15 points of gross margin no cited source. Use the ranges below as reference points for spotting a gap, not as targets; your own mass balance and cycle logs say more than any published figure.
Every figure shows its basis. A superscript number links to a public source in the Sources list, and the sentence gives that source's scope and year. A figure marked no cited source is kept exactly as originally published because it has not been matched to a public source that states it, so treat it as illustrative.
Ranges are as originally published, with the original's wording kept in the cell. The cited Department of Energy figure behind the supplier row is China's share of global sintered NdFeB magnet manufacturing, approximately 92 percent in its 2022 assessment1. Not stated means the original gave no figure for that column.
Method: How the figures in this guide are sourced
A figure with a superscript number is stated by the cited source, listed under Sources with its publisher, date and access date. Most cited figures come from a Department of Energy supply chain assessment and the United States Geological Survey's commodity summary; they describe the industry, not one plant's performance. A figure marked no cited source is kept exactly as originally published because no public source stating it was found. It is illustrative, not measured industry data. Worked examples are arithmetic, not benchmarks.
Overall material yield
Overall material yield, finished mass shipped divided by alloy mass charged, is the headline KPI. Typical plants run 60 to 70 percent on mixed product, and world class block producers reach 78 to 85 percent no cited source. Shops heavy in thin arcs and small discs cap near 55 to 65 percent because geometry sets the machining floor no cited source.
The United States Department of Energy (DOE) shows where the loss sits. In its 2022 supply chain assessment, the largest material losses occur in the machining step, depending on the final size and shape of the magnet2.
Typical yield at each process step
Typical first-time process yield by mass for sintered NdFeB magnets
Furnace utilization is loaded kilograms times cycles actually run, divided by rated capacity over the same calendar hours. Typical plants sit at 55 to 65 percent, while world class runs 80 to 88 percent no cited source.
World class plants treat the 14 to 18 hour sinter cycle as the drumbeat of the whole plant no cited source. The DOE describes sintering at 1,000 to 1,100 degrees C, after the powder is aligned and pressed in a magnetic field4.
Fill density comes first in payback order, because it adds capacity for zero capital.
For example, moving from 350 to 450 kg per load is a 29 percent capacity gain.
Next come fixed preventive maintenance windows, then batching grades to cut atmosphere changeovers that cost 2 to 4 hours each no cited source.
How to measure
Multiply loaded kilograms by cycles run, then divide by rated capacity over the same calendar hours.
Log loads per week, kilograms per load and downtime hours from cycle logs.
Review it weekly.
What moves it
Fill density per load.
Fixed preventive maintenance windows.
Batching grades to cut atmosphere changeovers.
Inspection throughput margin
Inspection throughput margin is inspection capacity divided by production rate, and it should sit at 120 percent or better no cited source. Magnet plants run 100 percent flux and dimensional checks, and a Helmholtz coil measurement takes 3 to 6 seconds per part with handling no cited source.
For example, at 4.5 seconds per part one station caps at 800 parts per hour. When production runs 900 parts per hour, work in process piles up in front of quality control within a single shift.
How to measure
Divide inspection capacity per hour by production per hour.
Time the full measurement cycle, including handling.
Review it weekly, alongside production plans.
What moves it
Multi-part fixtures.
Camera-based dimensional gauging at 1 to 2 seconds per part no cited source.
Sampling plans on stable dimensions, while flux checks stay on every part.
Coating first pass yield separates disciplined plants from the rest. Typical nickel-copper-nickel (NiCuNi) lines accept 92 to 95 percent on the first pass no cited source. World class exceeds 98 percent, with salt spray survival of 48 to 96 hours per ASTM B117 no cited source.
The DOE describes the coating as a metal film of nickel, 5 to 10 microns thick, applied after machining4. One magnet maker, Arnold Magnetic Technologies, runs salt spray to ASTM B-117 as an attribute test reported as days to failure5.
For uncoated magnets, the same lab runs an autoclave weight-loss test at 2 atmospheres, 130 degrees C and 100 percent relative humidity, for a duration of 96 hours6.
Measure per rack or barrel lot and Pareto the rejects. Edge chips from handling usually lead, then thin coating at contact points, then blisters from poor pretreatment.
Each recovered point of coating yield returns roughly 1 percent of combined material and conversion cost, because rejected parts already carry both.
How to measure
Divide parts accepted by parts loaded, per rack or barrel lot.
Pareto the rejects by cause.
What moves it
Tumble deburring edges to a 0.1 to 0.2 mm radius before plating no cited source.
Scrap recovery rate measures what fraction of process loss actually reaches a recycler instead of the floor or the general waste stream. Typical plants capture 60 to 80 percent of swarf and solid scrap no cited source. World class exceeds 95 percent using segregated, labeled, oxidation-protected containers at every slicing and grinding station no cited source.
Swarf matters at industry scale. The DOE estimates the 2020 swarf recycling stream at 9 percent of the NdFeB magnets produced globally7.
Weigh scrap shipments monthly and reconcile them against the loss implied by your mass balance. A gap above 5 percent means material is leaking somewhere unpaid no cited source.
The lever is mostly housekeeping plus contract terms: consolidated shipments and clean segregation by grade can lift recycler payment by 5 to 10 points of contained value no cited source.
How to measure
Divide scrap mass shipped to recyclers by process loss from the mass balance.
Reconcile shipments against the mass balance every month.
What moves it
Segregated, labeled, oxidation-protected containers at each station.
Supplier concentration is the strategic KPI. Many western buyers still source 80 to 100 percent of sintered NdFeB or its feedstock from a single country; at the global level, China accounted for approximately 92 percent of sintered NdFeB magnet manufacturing, according to the DOE1.
The DOE's 2020 figures put China at 89 percent of rare earth separation, 90 percent of metal refining and 92 percent of magnet alloy manufacturing8. Upstream, China supplied 71 percent of United States imports of rare-earth compounds and metals from 2021 to 2024, according to the United States Geological Survey (USGS)9.
Prices swing hard, so single sourcing converts price volatility straight into margin volatility. The USGS reports that the annual average price of NdPr oxide fell 40 percent from 2022 to 2023, from $124 to $75 per kilogram10. It averaged $92 in 2021, $55 in 2024 and an estimated $69 in 202510.
Score each input on share of spend, qualified alternates and requalification lead time, which runs 9 to 18 months for a new magnet source on automotive programs no cited source. A workable target is no supplier above 60 percent of spend on any critical grade within two years, with one alternate fully qualified rather than merely sampled no cited source.
How to measure
Record each supplier's share of spend on every critical grade.
Count qualified alternates per grade, not sampled ones.
Review it quarterly with purchasing at the table.
What moves it
Qualifying a second source before you need it.
Splitting spend on critical grades across qualified suppliers.
Mineral Commodity Summaries 2026: Rare Earths. U.S. Geological Survey. published February 2026. Salient Statistics, 'Price, average, dollars per kilogram' (footnote 6: free on board, Argus Media). Accessed September 30, 2026.