Earlier this month, we were invited by Vida, one of Sweden's largest timber suppliers (and our timber supplier for a number of years) to visit their sawmills in Sweden. This blog is a short summary of that trip, along with some interesting statistics and a range of images inside the mills.
We landed in Gothenburg early on Monday morning and were promptly picked up in the national car of Sweden, the Volvo (no complaints). From then, it was on to Borgstena, around an hour from the airport. Upon arrival, we were greeted with what can only be described as an ocean of logs. Seriously, look as far away as you want, you'll only see logs or trees! Despite this enormous quantity of timber, we were surprised at how streamlined the whole place was. Everything was neatly segmented into piles of different diameters, with separate piles almost autonomously created for logs that didn't meet the cut (pun not intended).
There were a few lorries driving in and out, but it was remarkably quiet given the mill churns out almost 80 full loads per day, or 1,380,000 cubic metres of product per year (split between timber and wood chips). To put this into perspective, the images below are just a few days worth.
Inside, we visited this 'command centre', where each log is visually graded and assessed for defects. On a screen to the left, the log is scanned and displays a graphic to represent how many pieces of timber it will provide
Next, we ventured into the rest of the mill where the timber is automatically rotated by the machines to achieve the highest quantity of timber per log, reducing the waste as much as possible. After this, it's rolled by this big spiky wheel thing, planed, and eventually comes out looking like a finished product.
Despite what looks like a usable piece of timber popping out, it's still far from being ready to sell. They're cut to the correct length, then passed through to be stress tested and checked for defects. We were surprised to find a little piece of the UK in the factory in the form of this 'computermatic' stress testing machine (wonder how old this thing is!). As lengths of wood feed through the machine at high speeds, they are subjected to a non-destructive bending load; the resulting deflection is measured to calculate the material's Modulus of Elasticity. By using the scientific correlation between stiffness and strength, the machine's computer predicts the wood's load-bearing capacity and automatically applies a standardised stress grade stamp, such as C16 or C24.
Or, depending on which sawmill you visit, it can be graded with microphones. The timber is prodded with these silicone cylinders which contains a microphone—this listens for vibrations and grades the timber's modus of elasticity via response. A stiffer, higher quality piece of timber will reverberate the sound back almost instantly, whereas a softer piece of timber with cracks, knots and other defects will slow down the acoustic response. Using this information, it can grade the timber accordingly, with the stuff we purchase being TR26 graded.
Finally, the timber is placed into packs, wrapped, loaded onto a lorry or train (the train track runs right next to the mill) and shipped off to one of five continents that Vida exports to.
