棚板怎么选：厚度、翘曲与叠放层数｜Kiln Shelf Selection: Thickness, Warping and Stacking

摘要：棚板一加厚，单窑装载量立刻缩水。讲跨度与厚度匹配、三点翘曲对叠放的影响、堇青莫来石与碳化硅棚板的成本分界线。
Abstract: Thicker shelves shrink your payload faster than a smaller kiln does. Matching thickness to span, what warp does to stacks, and the cost crossover between cordierite-mullite and SiC shelves.

正文： 窑膛尺寸定死之后，能装多少制品其实由棚板决定。板厚加两毫米，同一窑少装一层制品的案例比比皆是。棚板选型选的是跨度、厚度、材质三者的平衡，不是越厚越保险。
Main text: Once the kiln chamber is fixed, payload is decided by the shelves. Add two millimetres of thickness and lose a product layer — it happens constantly. Shelf selection balances span, thickness and material; thicker is not safer.

一、厚度跟着跨度走
1. Thickness follows span

同样材质下，跨中挠度与跨度三次方成正比。300 毫米跨用 12 到 15 毫米板够用，400 毫米跨就要 20 毫米往上。想减厚度先减跨度：加一根支柱比换厚板便宜得多。
At equal material, mid-span deflection scales with the cube of span. A 300 mm span runs fine on 12 to 15 mm; at 400 mm you need 20-plus. To cut thickness, cut span first — one extra pillar costs far less than thicker plate.

二、翘曲对叠放的杀伤
2. What warping does to stacks

棚板翘曲超过千分之五，叠放到第四五层就应力集中，上层板压在凸点上，轻则码不稳重则压裂制品。进厂抽检翘曲度，码放超过三层的产品线尤其要抓这项。
Warp beyond five per mille concentrates stress by the fourth or fifth layer: the upper plate rides on the bump, unbalancing stacks or crushing product. Inspect warp on incoming lots — mandatory where stacks run three or more.

三、材质分界线
3. The material crossover

• 1300 摄氏度以下、中轻载：堇青莫来石棚板综合成本最低。
  Below 1300 C at moderate loads, cordierite-mullite wins on total cost.
• 重载、大跨、1400 摄氏度以上：碳化硅棚板，贵但薄。
  Heavy loads, wide spans, above 1400 C: SiC — costly but thinner for the same duty.
• 同跨度下碳化硅板可薄三分之一，装载量能补回不少价差。
  At equal span SiC runs about a third thinner, recovering much of the price gap.

把棚板当承载结构件来算，而不是当耗材来买，装载量和成本两头都会好看。
Treat shelves as structural members, not consumables, and both payload and cost improve.