The KM datasheet maximum is Dia 800 × 30 mm T. That is the CVD envelope. It is not a finished window sitting on a Florida shelf. Area is the reason this process exists.
Why CVD plates are large
Melt-grown ZnSe does not make 800 mm windows. CVD does, because the deposit is a sheet on a mandrel. The 1977–79 production paper (DTIC ADA083005) already talked about furnaces capable of inch-class thickness over thousands of square inches; a 17 × 60 inch plate shows up in that report. Harris (SPIE, 1999, ch. 6) treats area as the industrial point of CVD ZnS and ZnSe. KM’s 2023.06 introduction specifies Dia 800 × 30 mm T (45 mm T is also noted). You nest cores and SMTY out of that envelope. Capacity on the same intro is up to 1,000 kg/month. Density 5.27 g/cm³: a 30 mm plate 800 mm in diameter is on the order of 80 kg before you cut it. That is a crane, not a tote.
Published quality rates put 30 mm in weeks of furnace-on time if the rate holds: ~25 days at 50 µm/h and ~21 days at 60 µm/h (RU2253705C1 50–70 µm/h quality window); ~10 days at 127 µm/h (ADA042147 laser-quality, 0.005 in/h). The fast 0.010 in/h end of ADA083005 is not the quality default on this site. Heat-up, cool-down, grind and inspect are extra. That arithmetic is not a KM lead time. Thickness near 45 mm is a special conversation; it is not the datasheet default.
Size on the quotation
Round: Dia × T in millimetres. Rectangular: L × W × T. If the part is SMTY, state whether the min. +1.5 mm oversize is already in the CAD. Core-drilled stock on this desk uses +2.032 mm (0.080") on diameter and ±0.254 mm (0.010") on thickness; edge chip < 0.762 mm. A drawing beats a verbal diameter. Domes and non-plano shapes need STEP or DXF. Polishing in the South Korea machine shop is listed to Dia 300 mm; larger finished optics are a quote, not an assumption.
What Dia 800 does not mean
It does not mean every line is an 800 mm window, and it does not mean Florida holds that diameter as finished stock. It means the South Korea CVD process is specified to that envelope. A clear aperture near the top of that range needs grade, quantity and ship-to country on the quotation request. The quote states what we can cut and when.
References. KM Innovation ZnSe datasheet (Dia 800 × 30 mm T) and 2023.06 plant introduction (capacity, 45 mm T note, polish to Dia 300 mm). Miles et al., DTIC ADA042147 (1977). DTIC ADA083005 (production area / thickness). Harris, D.C., SPIE (1999), ch. 6, CVD ZnS/ZnSe.