Engineered Quartz : A Guided Tour

Visiting an engineered quartz plant, will help you understand some particular things that relate to the product. Not so long ago I posted a guided tour of an engineered marble (cultured marble) plant, today I will guide you through a engineered quartz slab plant, what I have described in these two posts are in general the way things still work today, many brand names which you may know use similar methods.

So we'll start off with raw material ... engineered quartz and engineered marble have more or less the same type of composition, although, engineered marble normally is made from natural stone with less that 4 Mohs hardness. Engineered quartz technology is based on a slab production plant, which avoids the stressful sawing. Just to add, that you can make engineered quartz using the marble block technology (in theory) although you'd have several problems afterwards, mainly regarding to sawing and polishing. You'd need to use granite cutting and polishing technology to actually have any positive results. So to make really hard materials like quartz slabs, it's has been made in a slab by slab processing units.

The guided tour through a engineered quartz plant starts here:

• Raw materials: the components necessary to make an engineered quartz slab are quartz grit (which may vary in size, it basically defines the texture of the final product), quartz dust (main filler component), unsaturated polyester resin and coloring pigments.

• Raw material feeding system: the feeding system is divided into several types, as the polyester resin is used in a liquid state, all other materials are either dust or chips. So you may have screw conveyors for the dust and normal conveyor belt systems for the grit. The pigments are used in such small doses that it has a separate feeding system for them.
• Making the engineered quartz slab - Mixing: the first phase in the slab production line is the mixing of the components. A engineered quartz slab production line may have 2 to 3 mixers in some cases even more. The multiple mixers are used due to two reasons: to maintain and guarantee production flow, while one is discharging the content to the slab moulds the other one will be loading another batch; the second reason is to do special effects on the slab texture, namely bi-colours and tri-colours, the mixtures  (2or 3 colours can be used) are mixed separately in specific vertical mixers, before going into the mould they are slightly mixed in one final vertical mixer, the final effect on the slab is a unique texture filled with colour nuances.
• Filling the moulds with the mixture: In the photo position D is the transport conveyor that brings the mixture from the mixer to the mould filling unit. At point E the mould is filled with the mixture, due to the gas emitted by resin in the composition of the engineered quartz slab the whole mould filling sector is protected. The mixture is evenly spread on the mould.
• Vacuum & Vibro Compressing Unit: at point A we have a small vacuum chamber and a vibro compressing unit. This is the main secret of engineered stone, this procedure is of the utmost importance in the production of high quality engineered stone.

•  Staging Hub: at point B, we will find a staging hub. The chemical reaction has started before the mould filling so by the time it reaches the staging hub, although it is still not solid., it has hardened significantly The staging hub is a giant oven where the slabs accelerate and stabilize the curing. These staging hub are one of the greatest limitations to a production plant so the bigger the better, you'll have several slabs in this position, constantly one going in and one coming out on the other end.

•  Slab and mould separating unit (F): at this point the slab just left the staging hub, it's very warm, a little too warm to put your hand on. It's time to separate the slab from the mould. In the photo underneath you may see the moulds G, which are separate from the engineered quartz slab (H).

•  Mould cleaning line (C): I guess by now, most of you have questioned about C, as it has appeared on the last few photos. Well C is the mould cleaning line, the first models of engineered quartz production lines used paper base moulds, which would only be used once in most cases, the waste was too much, associated with the waste treatment cost and the cost of the paper moulds, not very long after appeared the first rubber mould cleaning line. A recycling line with a water treatment plant for the waste.
• Slab calibrating and polishing: The final phase: the slab surface finishing unit. One particular thing about the quartz slab, it's calibrated on both surfaces, before it gets polished. So the finishing line starts off with a JOT robot loading the slab, followed by a first calibration of the non finished side. Then comes one of the coolest devices I have seen, it's an inline flipping unit for slabs. After this stage the rest of the line is very similar to granite surface finishing line, with the required inspection at the end.