Sizing a retreading line: start with the curing chamber

Most people start planning a retreading line from the buffing machine. That is the wrong end. Your daily output is set by the curing chamber; every step before it only has to keep up.

**Step 1 — size the chamber.** Curing chambers are chosen by how many tyres they hold: commonly 4 to 24 per cycle. A φ1.5 × 6.5 m chamber, for example, holds 16 tyres and takes tyres up to 1.2 m in outer diameter. How many cycles you get per day depends on tread thickness, curing temperature and how fast tyres are loaded and unloaded — that has to be worked out for your own tyre sizes, not guessed. Tyres per cycle × cycles per day gives the ceiling for the whole line.

**Step 2 — match the upstream machines.** A gantry buffing machine takes about 3 minutes per tyre; a building (pressing) machine about the same. Over a 9-hour shift, one machine of each handles well over ten tyres an hour — comfortably more than a 60-tyre day needs, with room for changeovers and breaks. Add stations only when you run two shifts or a much higher target.

**Step 3 — do not forget the support machines.** Inspection (pressure testing, casing spreader), crown cutting, cement mixing, gum extrusion, envelope and rim mounting, tyre racks and conveyor rails. None of them is expensive on its own, but a missing one stalls the whole line.

**Two common mistakes:**

Buying the chamber too small. You have already paid for the building, the labour and the power supply, and then the most expensive machine caps your output. Expanding later means buying a second chamber.

Buying it too big. A half-empty chamber still burns close to a full cycle of energy; the empty positions are wasted electricity.

Send us your tyre sizes, target tyres per day and shift hours, and we will put together an equipment list and a workshop layout drawing with electrical and air-piping plans.