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.

Chinese quartz - Importing quartz slabs from China

Today's topic is Chinese quartz, if you are already importing quartz slabs from China, maybe some of the things I'm going to mention on this post is just a confirmation of your reality. Or maybe you have had a good experience with Chinese quartz imports. I must say that not everyone has had good experiences with quartz slab imported from China.

I figure that most of you are unaware of the size the Chinese manufacturers have currently in the engineered stone business. Their internal market is huge, their exports of quartz slabs and other engineered stone are still very little compared to their great potential. Currently there are more than 100 manufacturers in China alone, few use Breton Technology and most use Chinese Keda technology.

As I have mentioned a few times before, Chinese engineered stone  is unavoidable to the International markets. However, the main problem with Chinese engineered stone is quality.

You may find great pricing, excellent colours, but I advise you to be very careful, choose wisely your supplier and make sure you personally inspect the quality of your shipments prior to loading.

What may you encounter in quartz engineered stone from China?

•  Excess resin: while Breton plants have been using less than 10% of unsaturated polyester resin, Chinese manufacturers tend to use bigger quantities of resin.

• Raw materials: some Chinese manufacturers either use inadequate raw materials, or low quality materials, which have caused some International incidents with some customs

•  Inefficient Compaction: the Italian production lines does a better compaction, this means the product is more resistant and has a better performance.

•  Claims: you might have problems for your Chinese supplier to accept claims due to poor quality

• Delivery delay: most common in Chinese manufacturers, they either receive pre-payment or by L/C and delivery may take a while, emending L/Cs is common.

• CE Marking Compliance: most of the manufacturers are not complying with these terms yet;

•  Health and Safety Issues: while European and other Worldwide manufacturers are looking at these issues seriously due to local and regional legislation, namely they are far from VOC (Volatile Organic Compounds) certification of their products and production facilities.

Personally I have bought from China engineered stone, and I did have some of the above mentioned problems, namely:

• They didn’t comply with the last shipping date on my L/C, which I had to exchange, actually looking back this happened a few times.

• Due to the fact that I did not trust their quality, I had the slabs come in sawn, I did the final surface finish at my local factory, my quality index for first choice material was far from 100%, I actually had a lot or two which barely did 75%, so I ended up buying 75% first choice and 25% of problematic material;

• My claim was initially treated professionally, until they figured out that it was totally their poor quality that caused the whole mess, after that they didn’t actually give me a direct response on how I would be compensated, so time passed and until this day no compensation was given for those quality claims, nevertheless we did not import anymore from that supplier

• Non-existent CE Markings or even knowledge of the regulatory status

•  Laboratory testing, I asked them for their laboratory testing and they sent me a few pdf files in Chinese for me to translate, I ended up doing my own testing locally.

•  Price: I was importing a pure white fine grain which is very difficult to make, the price was good on a few thicknesses, although some thicknesses had an awkward pricing … a very non-proportional price, so I just avoided that thickness, although I did have a common and constant question coming from my clients: Why don’t you have 30mm slabs in this colour?

With this post I'm not saying you can't find good quality engineered stone in China, to find it you have to really look around and personally judge your supplier. But in time, I think it will be much easier to source engineered stone in China, but currently, be careful.

CE Markings for Engineered Stone ( Agglomerate Stone )

The CE markings for engineered stone (agglomerate stone) as of the begining of 2010 are mandatory for modular tiles sold in the European Union.  The JWG (Joint Working Group) n. 229/246 is responsible for setting standards for the agglomerate stone. The official designation of agglomerate stone represents all products which are manufactured by mixing mainly natural stone grit with a bonding agent. The natural stone grit may be of several sorts, marble, granite or other. The binder is said to be made of artificial components like unsaturated polyester resin or cement. The product group includes artificial stone and compacted marble.

The standards are not all complete, as the JWG is still working actively, however some standards have been approved and are actually already in use. The standards mentioned in the table relate to testing methods that are required for agglomerate stones. So basically when dealing with agglomerate stones, every laboratory should follow these procedures to guarantee comparability between agglomerate stones and the tolerance levels defined in the approved standards.

Until the end of 2010, 2 product standards have been approved and published, namely the UNI EN 15388 (voluntary standard) which specifies the requirements for kitchen and bathroom countertops, the other approved and mandatory standard is the UNI EN 15285 which defines the requirements for modular composite tiles. The UNI EN 15285 is effectively mandatory as of the 1^st of January 2010, and includes tiles size up to 600 mm x 600 mm and with a maximum thickness of 20 mm destined to be applied on flooring and stares.

Currently the JWG (Joint Work Group) is working on two standards: one for agglomerate stone slabs and the other one for agglomerate stone tiles used as interior or exterior wall cladding.

So currently if you are selling agglomerate stone modular tiles for flooring and stairs in Europe, you must comply with the European standard EN 15285. Besides complying with specification in the factories at shop floor level and labeling, your product (agglomerate stone) must be tested by a certified laboratory according to the standard EN 14617. And of course, the labeling with the CE mark means that your product is within the tolerance levels defined by the standard, if not you should not label it as CE, which in the future may mean that you may not sell it in Europe.

What is ASTA Europe?

I guess ASTA Europe has not had enough spotlight to be recognized Internationally by the industry, not only the agglomerate manufacturers, but by everyone in general. ASTA Europe is a European association of agglomerate stone manufacturers. It has currently 15 members, mostly Italian producers, but all the major European agglomerate manufacturers are already members.
This association aims to promote and protect it's members interest, and I figure that more than ever they'll need it. Personally, it sounds like a European Breton family meeting, but who am I to say such a thing. Truth is that they all have common interests, and the main one is protecting their product and their markets.
ASTA Europe was created in 2010, the members meet several times a year, the Marmomacc fair has been a traditional meeting ground for the members, it represents more than 80% of total European production. ASTA Europe has it's origins in the Italian association ANPLA, created about 10 years ago to establish and define standards for the agglomerate stone. ANPLA has been playing an important part in the CE marking for the agglomerate stone industry in Europe. So the Italian association, has overcome their national borders and is now named ASTA Europe, they've expanded membership to all European countries that obide by the references of the European Committee for Standardisation (or the Comité Européen de Normalisation (CEN)). So currently they've got members from Italy, Spain, Romania, Germany, Belgium, Turkey and the Czech Republic.
ASTA Europe wants to continue to play the main part in establishing European standards for the agglomerate stone industry. There are many hidden interests at stake, and most of the European manufacturers have many in common.
So basically I see three things that unite this very restricted group of companies:

• European standards : Participating actively in setting European standards that will protect their product against competition (Chinese mainly)
• Environmental issues: face the environmental issue regarding their industry
• Health and safety issues: face the health issues regarding their production, namely the usage of some health hazard products like resin, quartz, cristobalite and others.

Granite Countertops : Is radon testing necessary?

Are granite countertops radon free? Can granite countertops be a health risk to you and your family? Back in 2008 granite countertops radon emission hit the news headlines, potential health hazards and other issues arose ... an International discussion of the matter helped shed some light on the risks involved.
The New York Times and The Houston Chronicle news article about the potential health hazard in our homes, put  radon emission from granite in the spotlight. Back then we had the granite fabricators on one side saying that the granite radiation was not dangerous, which means it does have radiation. The question was if the granite emission was acceptable as per health standards.

What is radon?

Scientifically Radon was discovered in 1899, it's a gas an is highly radioactive, you can't see it as it has no color, you can't smell it as it's odorless. Radon gas is a serious cause of cancer, it's said to be the second cause of lung cancer in the US.
Radon gas has it's origin in uranium's natural breakdown, it's not manufactured nor sold, you can find radon gas, almost everywhere (normally in small non harmful amounts).

So is it really a threat? Can my granite countertops be a health threat?

Radon gas level is measured in PCi/l (Picocuries Per Liter) action should be taken is the level is above 4 Pci/L. In theory small levels of Radon gas can be found in several places in your home, it's highly soluble in water and is air born, your granite countertop, your granite tile, or any other granite used in construction may not be the only materials you have that emit this gas.
In truth granite countertops may emit radon gas, however the levels are significantly low to actually pose as a health hazard. The current level of radon gas that exists in buildings is most likely greater than the single emission of your granite countertop.Their are many other sources of radon gas in your home, most of it comes in through the soil or rock base of your home. You can also find traces in some construction materials used to build your home, besides granite as we have already mentioned, you may find it in bricks, cement, etc.

One thing that has been proven is that each type of granite has a radon emission level, and it varies significantly, although scientists are unable to actually attach numbers to specific types of granite, which means that the existing level in a specific granite countertop is not easily accessed, the only way to be certain is to measure it.


I guess it safe to say that granite has been around for ages, and it's still not proven that it's hazardous to our health.

How to cut a countertop : Quartz Worktop

How to cut a countertop, a quartz worktop, from a full size quartz slab using a CNC? On this post I’m going to add additional information to a post I did a while ago.

Cutting a quartz worktop on a Numeric Control machine without breaking the quartz slab has its secrets. It’ll be quite a waste if anything goes wrong while working on your expensive quartz slab, you might just end up with a giant loss. This post will contain important information which you should read carefully, it may save you money.

The engineered quartz slab is a man made stone, which basically is formed with quartz grit and polyester resin. The chemical reaction of the hardening process may cause tensions in the slab, which may crack the slab while cutting it.

There are a few simple tips I can give you, although every brand and colour is very specific regarding this type of problems. Anyway cracking may occur if you do not do the first few cuts correctly, the breakage risk decreases significantly after the first few cuts.

•  As I mentioned in a prior post, the cut-outs are one of the most risky parts of the engineered quartz countertops cutting procedure do not do square corners. The corners are considered stress points, engineered quartz tends to release tensions, to overcome this problem, drilling a 5mm or bigger hole in each corner, before cutting the cut out with a diamond disk, will reduce all risks of cracking.

• Cutting diagonally should be done with a blunt disk, a used disk, will be less aggressive during cutting as the diamonds will more effective for cutting at this point.

• The cut should start from the outside of the slab inwards, don’t try to plunge cut.

• The cut should go all the way through right off the slab, truly cutting the slab.

• Make sure the diamond disk is in good condition, the diamonds should be cutting effectively and perfectly, if not use cement block or other type of stone to help improve the disks cutting ability

• Cutting diagonally often may affect the diamond disks ability to cut perfectly, as it works uneven, if this happens you can improve your disks cutting ability the same way I mentioned before

And one more thing the CAM software used in Numeric Control machines may not have been properly built considering the specific information regarding engineered quartz. Although some have already been adapted for these types of cutting, make sure your CAM software is capable of dealing with engineered quartz, if not contact your local dealer and see if an upgrade is available.

Basically I hope you avoid problems like the one in the photo below.