Sawmills and kilns: timber drying runs blind on moisture, species

Wood moisture and species vary within one kiln load

What happens. A kiln is loaded with boards of different species, thickness and starting moisture. The programme follows a schedule or a few probe readings. Nobody knows how wet the boards in the middle of the stack are, so the kiln runs until the slowest board is surely dry.

What it costs. Heat and fan power spent on boards that were ready long before, and kiln time that blocks the next load. If drying goes too fast, boards check, split or warp, and then the margin is raised again.

Why the usual fix fails. A drying schedule per species is a good start, but it assumes an average load. Moisture probes in a few boards show a few spots. Raising the safety margin by hand works against energy cost every time.

How a fixed-price remote diagnosis checks it. From your kiln logs (air temperatures, humidity, fan speeds, probe readings, weights where available, defects after drying) I estimate how the moisture develops in the load and where the schedule is too careful. The fixed-price remote diagnosis tells you whether a computed moisture value can lead the kiln, and what that would take.

Background: Predictive control of process plants

The cutting pattern is not optimised for each scanned log

What happens. The log is scanned before the saw, but the cutting pattern often comes from a table or from the experience of the sawyer. A crooked log or an odd taper gets a standard pattern, because the line must keep moving and there is no time to try variants.

What it costs. Boards that could have been cut from the log end up as chips, and sold products are not the ones that pay best. The yield per log is lower than the scan shows is possible.

Why the usual fix fails. More patterns in the table cover more cases, but never this log. A faster scanner brings more data without a decision behind it. Doing it by hand cannot keep up with the speed of the line.

How a fixed-price remote diagnosis checks it. From scan data, the cutting patterns you run, the product list with prices and the yield you measure, I check how much value is left in the pattern choice. The fixed-price remote diagnosis answers whether an optimisation that picks the pattern for each log in the time of the line is possible, and what it would take.

Background: Optimal paths and setpoint plans

Kilns are the largest energy user and run at the wrong time

What happens. In a sawmill the drying kilns use more energy than the saw itself. Power and heat are often bought at a high price, and the kilns run when loads are ready, not when energy is cheap. Drying runs are rarely recorded in a way that allows a comparison.

What it costs. Energy cost per cubic metre of dried timber, drying defects, and less planning room because nobody can say what a run will cost in heat and time.

Why the usual fix fails. A new burner or better insulation helps once. Moving loads to cheaper hours by hand clashes with the rhythm of the saw and the order list. Logging drying runs is a good start, but the logs alone do not change the programme.

How a fixed-price remote diagnosis checks it. From drying logs, energy meters, the load plan and your energy prices I check how much a change of programme and timing could save and what stops it. The fixed-price remote diagnosis tells you whether a computed moisture value and a schedule against the energy price can work in your kilns, and what that would take.

Background: Economic predictive control