Roller / Tunnel Kiln (ferrite sintering)

Selection criteria

Temperature uniformity across the width, length of the firing zone, throughput, energy use.

Supply chain

Built by Chinese kiln makers, many of them also serving the ceramics industry in Guangdong and Jiangxi. Temperature uniformity controls shrinkage and magnetic properties, so ask magnet suppliers how they monitor kiln profiles.

Buyer FAQ

Roller kiln or tunnel kiln for ferrite sintering?

Roller kilns carry parts directly on ceramic rollers, giving shorter firing cycles and more uniform heating for thin arc segments. Tunnel kilns with kiln cars or pushed plates handle heavier loads and larger parts but have longer cycles and more heat stored in kiln furniture. Both need tight control of the firing zone around 1,180–1,250 °C.

What temperature uniformity should a sintering kiln achieve?

Aim for about ±3–5 °C across the width of the firing zone. Verify it with a travelling data logger or temperature-indicating rings run through the kiln at several positions across the width. Ferrite shrinks substantially during sintering (often 10–20 % linearly), so uneven temperature shows up directly as size spread and warpage.

What defects come from poor sintering?

Under-firing leaves low density and remanence; over-firing causes grain growth that lowers coercivity. Uneven heating or fast cooling causes cracks and warped arc segments that need more grinding. Ask suppliers for their grinding allowance and for Br and Hcj sampling by kiln and lane, not only per lot.

Where it is used