A few weeks ago, an Italian rare-earth recycling company shipped us a single trapezoidal NdFeB blank — top edge 24 mm, bottom edge 38 mm, height 48 mm, thickness 3 mm — and asked whether we could cut three different test specimens out of it. The blank wasn’t from a freshly produced magnet. It came from end-of-life motor scrap that the customer had reclaimed and re-sintered into a recycled NdFeB block. Recycled NdFeB cutting is exactly the kind of small-batch sample prep our SGR 20 was built for, so we agreed to do the cut for free and report back with parameters, results, and a few opinions.
This article walks through the brief, the cutting setup, and what fell out the other side. If you’re working with reclaimed magnet material — or you’re a magnet OEM evaluating recycled feedstock — the same workflow applies.
Who the Customer Is and Why This Test Mattered
The customer is one of a new wave of European rare-earth recyclers operating on a circular-economy thesis: dismantle end-of-life motors and electronics, recover NdFeB permanent magnets, purify them through a mechanochemical process, and re-sinter them into industrial-grade magnets for the electric motor and sensor industries. According to [CEPS analysis of the EU recycled magnet supply chain], European NdFeB demand is projected to triple by 2030 — from 12,000 to 36,000 tonnes per year— and most of that supply still comes from outside the EU, so any operator who can produce recycled magnet material to spec inside Europe has a clear runway.
The commercial obstacle is the same for every magnet recycler: motor and sensor customers don’t buy on a story. They buy after they’ve measured the magnetic properties and confirmed the recycled material matches virgin sintered NdFeB. That means every batch needs B-H curve testing, microstructure analysis, and dimensional verification. The cut samples we made were not end-use parts — they were test specimens for QC validation. This is where sample prep turns from a peripheral step into a recurring production cost.
The Sample and the Three Target Cuts
The trapezoidal shape of the input blank is itself a recycling artifact. Many EV traction motors and industrial servo motors use wedge-shaped rotor magnets, so when you reclaim and re-sinter, you often end up with the original geometry. From the 24 × 38 × 48 mm trapezoid, the customer wanted three things:
- Target 1: Two paired 22 × 18.6 mm rectangles (Part A + Part B), sharing one 0.4 mm kerf. These sit in the wider lower half of the trapezoid. Likely use: paired specimens for B-H curve testing on a permeameter.
- Target 2: One 26 × 30 mm rectangle. The original spec was 26 × 41.5 mm, but 41.5 mm doesn’t fit anywhere in a 38 mm-wide trapezoid — we flagged this back and they shortened the long dimension to 30 mm.
- Target 3: One 26 × 30 × 1.5 mm thin slice. The 1.5 mm thickness was the giveaway: this one is for microstructure analysis (SEM, EBSD, or magnetic-domain observation), not B-H testing.
We also pushed back on the thickness spec. They asked for 3 mm-thick parts, but anyone running a finished-magnet workflow knows the cutting surface needs roughly 0.5 mm per side as grinding allowance to land on final dimension. Cutting net to 3 mm means you grind below spec. We told them to send 4 mm-thick blanks instead, so the 1 mm allowance gets removed at the grinder, not the wire saw. That single conversation probably saved them a wasted batch.
Setting Up the Cuts on the SGR 20
We ran this job on the SGR 20 — gantry structure with a rotary axis, max cut envelope Ø200 × 200 mm, table-top footprint. For one-off lab specimens at this size, the SGR 20 is the right tool: small enough to live in a QC lab, and the rotary axis lets you reposition the workpiece between cuts without re-fixturing every time.
One thing that simplified the job: the samples arrived demagnetized. Cutting magnetized NdFeB is its own problem — the ferromagnetic dust clings to guide wheels, motor housings, and anywhere there’s steel, and you spend half the day cleaning the machine. With demag’d material, the dust still gets generated but it doesn’t stick. We’ve cut both states. Demagnetized is always easier. If you’re prepping QC samples, demag before cutting.
Final cutting parameters:
| Параметр | Значение |
| Диаметр проволоки | 0,35 мм |
| Натяжение проволоки | 100 N |
| Линейная скорость проволоки | 40 m/s |
| Скорость подачи | 0.03 mm/min |
| Охлаждающая жидкость | Белое минеральное масло |
| Ширина пропила | ~0,4 мм |
A note on the coolant choice. Our magnet cutting reference page lists either water-based coolant or white mineral oil for NdFeB. For test specimens going straight to a permeameter or SEM, we picked mineral oil. NdFeB rusts fast in water — the rare-earth phase oxidizes within hours, and a rusted surface throws off both magnetic measurement and microstructure imaging. Oil keeps the sample clean. Slightly messier to handle, but worth it for QC work.
Results
All three targets came off the wire with flat parallel faces, no visible edge chipping, and dimensional deviation within 0.03 mm of spec. The shared 0.4 mm kerf between Part A and Part B held — both parts came out at 22.0 × 18.6 mm without overcutting either side. The 1.5 mm thin slice was the riskiest cut because thin sections are prone to thickness drift as the wire bows late in the kerf; slowing the feed to 1.5 mm/min and keeping wire tension at the upper end of the working range (140 N for that cut) kept it within tolerance.
Surface finish was sand-textured, typical of 0.35 mm diamond wire on sintered NdFeB. The customer will surface-grind to final dimension before measuring — the wire-cut surface is the input to the grinder, not the finished face.
What Recycled NdFeB Cutting Means for Magnet Recyclers
For recyclers ramping into industrial production, the takeaway isn’t about a single test cut — it’s that sample prep is a recurring cost line you have to budget for. Every batch of recycled NdFeB needs cut specimens for magnetic testing and microstructure validation, every customer qualification cycle needs more, and any QC failure means going back to the wire saw. Endless diamond wire handles this cleanly because the cutting force stays low, heat input is minimal (no thermal demagnetization risk after re-magnetization), and the 0.4 mm kerf is narrow enough that even a small recycled blank yields multiple specimens.
If you’re processing NdFeB, send us a small sample and we’ll run a free test cut on the matching machine and ship the parts back with parameters and photos. Email levy@endlesswiresaw.com to set one up.
