The basis of modern non-stick coatings is the polymer polytetrafluoroethylene (or PTFE). In its properties, the compound approaches noble metals; those. does not react with most aggressive environments. Moreover, PTFE is non-toxic. Today there are two main methods of applying non-stick layers.
Roller roll
This method is characterized by a short production cycle time. The thickness of the applied layer is adjusted to 25 microns. Roller rolling is considered an economical method; Products processed in this way belong to the economy class and are available to most consumers. How does the process happen?
First, blanks are prepared in the form of aluminum disks up to 2.7 mm thick. The production line is a mechanism with a length of up to 50 meters. This includes coating rollers, pre-drying oven and final drying oven. First, the discs (3 in a row) are fed into a pre-firing and drying oven. Here, the remaining technical oil remaining during the stamping of discs is burned off; Along the way, the workpieces are heated to the required temperature. Next, the first layer of non-stick coating is applied using rollers. The discs then go into a pre-drying oven. Thus, up to 5 layers can be applied. Sometimes a coating is applied over the latter.
According to technology, the number of layers cannot be less than three. The first layer makes it easier to apply subsequent ones; the second, thickest, is the main one, the third – secures the previous ones and carries out a protective function. At the end of the line, a product is obtained with a layer thickness of up to 25 microns, which is sufficient to maintain non-stick properties during the service life declared by the manufacturer (usually 1 year).
Sputtering
The main advantage of this method is obtaining a thicker non-stick layer (up to 60 microns), which increases the service life and increases the strength of the coating. Dishes processed by spraying are considered elite, their service life is 3-4 years. How does spraying occur?
The stamped discs are fed into a tunnel, where residual oil and other contaminants are removed from them using special detergents; at the same time roughness is added (for better adhesion). After the washing procedure, the workpieces must not be touched so as not to leave traces of fat. Next, the discs are installed in a rotating holder (120 rpm), and PTFE is supplied to them from nozzles under pressure. As in the roller rolling method, each layer is dried and finally heated up. If necessary, a drawing or pattern is applied to the last layer using silk-screen printing.
A new frying pan is comfortable to use, but after prolonged or improper use its non-stick coating loses its properties. As a result of its damage, food burns and sticks to the bottom.
Today there are different coatings which prevent food from burning. These are Teflon, marble, ceramics and titanium. They make cooking quick and hassle-free.
When using cookware with a non-stick top layer, it is necessary to take into account the recommendations for caring for the product so that it lasts longer and does not harm the health of family members.
Teflon pans are easy to use. There is no need to oil them while cooking. But when heated, they can release harmful substances. Caring for a frying pan non-stick coating made of Teflon must be careful:
- Avoid using iron devices. It is better to give preference to wooden, rubber or silicone.
- Wash dishes only with a soft sponge. Do not use metal brushes. They create microscopic cracks that destroy the coating of the pan.
- Do not hold hot cookware without food long time on fire.
- Eliminate friction. It is better to soak the container for a while.
Ceramic products are considered environmentally friendly, but also have their own characteristics. It is not recommended to heat them. Too high temperatures are contraindicated for the ceramic layer. If such a surface has deteriorated and food begins to burn, it is impossible to correct the situation at home.
What you need to do to prevent a non-stick frying pan from burning
To prevent any pan from burning, you must adhere to the following rules:
- Cook food only on clean and washed dishes. Layering of contaminants must be avoided.
- Avoid temperature changes. It is not recommended to lower a hot frying pan into cold water.
- Frozen food should not be placed on a heated surface. It’s better to take the time to defrost them and then start cooking.
- Gentle ones should be used detergents and devices.
If a frying pan burns, you need to pay attention to its material. Aluminum or cast iron can be revived without special costs. They have a porous surface that wears off over time.
First, the dishes need to be washed well. This will help baking soda. It is poured into a container with water and the pan is boiled in the solution for some time. Afterwards, the liquid is drained and its remains are disposed of.
After thoroughly rinsing off the soda solution, sprinkle coarse kitchen salt onto the bottom of the dish and place on the fire. You can use the oven. The frying pan is heated for 20-30 minutes, after which it is set aside to cool. When all the salt has been removed, the surface is greased with vegetable oil.
Another simple method is to fry the bread on the surface that has become unusable. The bread absorbs food residues and dirt that have formed during the operation of the product.
Enameled cookware should not be heated. It needs to be cleaned, dried with a towel, and generously rubbed with lard or other fat. For a high-quality result, the procedure is repeated before each use of the dishes.
To prevent food from burning in a frying pan with a ceramic top layer, it is recommended to follow the operating instructions for such products:
- Don't rush to use new dishes. First, it should be washed, dried and rubbed with oil.
- After long-term use, it is necessary to carry out a special treatment that will extend the service life of the ceramic layer for another year.
- Contrasting temperatures must be avoided.
- Avoid using metal spatulas and utensils. It is better to replace them with wood or silicone.
- Ceramics need careful care after cooking. It is better to wash the coating by gentle means and devices. Do not use soda or other powders that scratch the surface.
- It is advisable to lightly oil clean and dry utensils before each use.
To avoid premature destruction of a non-stick frying pan, as a preventative measure, it is recommended to pour water into the container, completely filling the space, and boil for 10-12 minutes. After this, get rid of the liquid, grease the bottom and walls of the frying pan or saucepan with oil. This will help extend shelf life and avoid damage.
There are times when food only burns in the middle. The reason is uneven distribution of fire and, accordingly, non-uniform heating of the bottom.
An excellent coating for cooking pancakes is Teflon. Food in such a frying pan does not burn and quickly lags behind the surface. If there is no Teflon layer or it needs to be replaced on the dishes, you can apply the coating yourself.
Cast iron frying pans are still found in homes. Their main drawback is weight. They are too heavy, so they are inconvenient when preparing pancakes and omelettes.
Aluminum containers with ceramic coating are lighter. They have protective layer, which prevents food from burning. For a frying pan to work for a long time, it needs proper and careful care. If damage occurs, then restoring the non-stick ceramic coating is impossible and you need to look for a new option.
Steel cookware with a non-stick coating is practical. It is durable and does not react chemically with food, so it does not affect the taste of the food. To prevent pancakes from sticking, the product must be clean and have a thick bottom.
Making a Teflon coating for a frying pan with your own hands
If teflon frying pan began to burn, this indicates damage to the protective layer or its poor quality. It is impossible to completely restore the original properties of the coating, but you can try to correct the situation at home. To do this, boil a mixture of water in a frying pan for 15 minutes, laundry soap and a small amount of vinegar.
After draining the solution, the dishes should be rinsed, gently rubbed with a soft sponge and dried. Grease the prepared surface with oil and start frying. If the procedure does not work, it is worth applying a Teflon coating, which will be done efficiently and quickly by specialists.
Non-stick coating restoration workshops
Restoring Teflon coatings has recently become possible. Workshops are opening that specialize in high-quality replacement of non-stick coatings. They have special equipment, with which a new layer of polymer is applied. The companies guarantee that the dishes will be returned to their original appearance and functionality. The service is not cheap, so sometimes it is more profitable to buy a new frying pan.
It does not matter what material the kitchen products are made of if care is neglected. It is necessary to use the utensils correctly and carefully and periodically carry out preventive measures to extend its shelf life.
It is in great demand among buyers: this particular kitchen utensil is purchased more often than any other. It is easy and convenient to cook in, and quite easy to clean after use.
Exists two main types of non-stick coatings:
- Silicone and silicone polyester. These organic resins, as a rule, rarely become the basis for non-stick coatings. They were not designed to withstand high heat on the stove, but so that they could be used to cook a variety of sweet baked goods, and also be safe to wash these dishes in dishwasher. In general, silicone nonstick coatings are less expensive than fluoropolymer-based coatings.
- PTFE or fluoropolymer compounds. These nonstick coatings are only used in cookware intended for stovetop cooking. The active component of these coatings is a compound known as polytetrafluoroethylene PTFE - a hard, waxy substance that is considered the world's slipperiest - even slipperier than wet ice. It is thanks to the presence of this compound that products do not stick at all to fluoropolymer non-stick coatings.
Non-stick coating components.
Both silicone and fluoropolymer nonstick coatings contain at least four and sometimes five main components:
Resin or other viscous substance that provides reliable adhesion to the surface of the pan.
The pigment that colors the coating.
Free agent (providing non-stick properties) - either PTFE or silicone compound.
- “Carrier” - an organic solvent or water - which “carries” the components, but evaporates when the coating cures at high temperature.
Additional reinforcing compounds to increase wear resistance.
Layers
Coatings can have from one to three layers. Most coatings also have a reinforcement layer for added wear protection. Obviously, multi-layer coatings are more expensive than single- or double-layer coatings.
Single layer coating resin, pigment, free agent and solvent are a single mixture that is used to treat the surface of the cookware and then cure it at high temperature.
In dishes with a two-layer coating The first layer is made as a primer, and a second layer of composition with a higher percentage of free agent is applied to it.
Three-layer coating contains a primer, then a middle layer with an increased content of fluoropolymer, which improves adhesion, and a base layer. The layers are successively fused onto each other and dried, and then the piece of cookware is sent to the final stage of production, where the coating is completely hardened.
To improve performance, three-layer coatings are strengthened in one of the following ways:
External reinforcement: a layer of stainless steel is sprayed onto a specially prepared surface of the cookware, thanks to which subsequent layers of non-stick coating are very securely fixed.
Internal reinforcement: solid particles (titanium, ceramic) are added to the composition for the primer and middle layers. The top or base layer is usually not reinforced. This treatment significantly increases the wear resistance and non-stick properties of the coating.
Non-stick coating for cookware made from different materials
Most modern ones have a non-stick coating. Aluminum is easy to prepare for processing, and its thermal conductivity makes the curing process quite fast and inexpensive. Stainless steel is more difficult to coat with any kind of non-stick coating. Indeed, in this case, the surface must be carefully prepared for application, so the hardening operation of the coating is longer and, therefore, more expensive. In addition, many consumers choose it for its radiant shine, so the demand for steel non-stick cookware is not as great as for aluminum. It is even rarer to find cookware made of cast iron or glass equipped with a non-stick coating.
Coating Methods
There are three main methods used to apply non-stick coating:
Spraying. A sprayed non-stick coating is applied to the surface of the cookware automatically or manually. Advantages: denser coverage. Disadvantages: Lower productivity than other methods, loss of expensive coating material due to spraying (splashes that fall past the product).
Covering under the veil: Blanks (round or square pieces of material from which the dishes will later be made) pass through a curtain of non-stick coating along a conveyor belt (Figure 1). Advantages: high performance with virtually no loss of non-stick composition. Disadvantages: Flat workpieces are required; finished cookware cannot be processed using this method.
Coating using rollers (roller rolling): blanks (round or square pieces of material from which dishes will later be made) pass through rollers coated with a liquid coating. Applying the coating with rollers is carried out in the same way as painting walls using a roller. Advantages: high performance with low cost of non-stick material. Disadvantages: on finished products Uneven grooves are formed; finished dishes cannot be processed using this method.
Of the three methods described above, the most expensive is spraying, followed by the curtain method and roller rolling.
Application of non-stick anti-adhesive teflon coating(Teflon coating, or as it is scientifically called " PTFE" – polytetrafluoroethylene or fluoroplastic) on almost any materials and surfaces of products made of aluminum and its alloys, steel, cast iron, etc. (imported raw materials are used).
Applications of Teflon coatings (PTFE)
Application of Teflon (Teflonization) can be performed for the following parts and equipment:
- baking and confectionery industry: molds, baking sheets, baking sheets for buns, cookies, baguettes, croissants, making pizza; molds for making chocolate, sweets, kozinaki, etc.;
- meat and dairy industry: thermal plates and thermal knives;
- refrigeration industry: anti-adhesive materials in low temperature zones (semi-finished products, fresh frozen dough, dumplings, pizza, etc.);
- medical equipment: containers for transportation and storage of frozen organs and blood plasma;
- duplicating, flexographic and office equipment: shafts and rollers of duplicating machines;
- packaging equipment: knives for welding thermoplastic plastics;
- molds for forming products from thermoplastic plastics, foamed polystyrene and rubber;
- textile industry: on shafts;
- woodworking industry: end surfaces of cutters and circular saws;
- welding mirrors for welding polyethylene and polypropylene pipes.
Teflon coating is carried out using an industrial method, which includes several step-by-step technological processes. The selection of the type of Teflon coating and the mode of its application is carried out taking into account the functional purpose of the product (part) and its operating conditions.
Main types of coatings:
- two-layer PTFE coating;
- PFA powder coating;
- ceramic coating "CERAM".
The main advantages of Tefloncoatings(PTFE):
- heat resistance from -150°С to +300°С (short-term up to +350°С);
- high anti-friction, anti-adhesive and dielectric properties;
- high chemical and biochemical resistance;
- biological inertness (Teflon is harmless to the body).
It is possible to restore used Teflon coating, including on products with complex geometric shapes.
The cost and lead time of the order depends on the area of application of the product, its geometry, weight and material. Agreed upon at the ordering stage.
Non-stick Teflon coating (PTFE) –
We apply and restore Teflon on parts and products
As a rule, during the operation of parts and products coated with a non-stick layer, important role plays its integrity. With intensive use, wear of this layer occurs, and the part begins to lose its functional properties (adhesion increases - “sticking”). It is necessary to replace the part with a new one, investing in its cost. An alternative to this investment is to replace the non-stick layer (reconditioning the Teflon) instead of replacing the part. If you simply re-coat the surface of the part with Teflon (using a special restoration technology), then the original properties and functions of the part will be significantly restored.
Our company will help you restore the non-stick Teflon coating (PTFE - polytetrafluoroethylene or fluoroplastic) on the metal surface of various parts and products (heating elements, welding knives, molds, stamps, etc.) in order to reduce the cost of repairs and modernization of your production , and also coat new parts and products with Teflon (non-stick Teflon coating) to give them anti-adhesive and non-stick properties.
Baking trays
cheesecakes - "CERAM" coating
Main properties of Teflon coating:
Heat resistance from -150°C to +300°C (short-term up to +350°C);
- high antifriction, antiadhesive and dielectric properties;
- high chemical and biochemical resistance;
- biological inertness (contact with food products).
Non-stick coating
Non-stick coating - developed on the basis of polytetrafluoroethylene (PTFE) polymer, this is an inert material with properties close to those of noble metals and the ability not to enter into chemical reactions with a large number aggressive environments, non-toxic.
Main characteristics of non-stick coatings:
Heat resistance (non-stick surfaces retain their integrity when heated to 300°C);
-high resistance to abrasion;
- ease of cleaning.
The non-stick coating does not have high surface strength and is susceptible to mechanical damage, so it is not recommended to use metal objects when cleaning the surface with a non-stick coating.
D In order to have a good understanding of the quality of cookware, you need to understand how it is made. Unfortunately, not many cookware manufacturers are ready to open their production process for various reasons. The Scovo company, which owns the largest and most modern plant in Russia for the production of non-stick cookware, abandoned prejudices and spoke in great detail about how the products of the brand of the same name are made.
Production aluminum cookware with non-stick coating is a high-tech event. Despite its apparent simplicity, the process of making frying pans is a rather complex process, which has its own “secrets”. And who can reveal them if not experts?
Let's omit the huge preparatory work in the form of product drawings, marketing elaboration of the assortment, selection of accessories, color, coating, writing and approval technological maps, calculating the cost and its assessment in relation to market expectations... We will not dwell on the intricacies of planning promotion and support events, commercial policy and logistics features. Our story is only about the production of cookware with non-stick coating from extruded aluminum.
Scovo cookware is manufactured in two factories. One of them is the oldest enterprise in Russia for the production of aluminum cookware, located in the Urals, in the city of Kamensk-Uralsky, the second, the largest plant in Europe for the production of non-stick cookware, is in the town of Stupino near Moscow.
Frying pan device
The frying pan consists on average of 11 parts (parts).
Metal preparation
Aluminum comes to the plant in large coils, 3-6 tons each. This is a specially processed strip of food-grade aluminum, certified for the production of cookware.
Reference
Aluminum tape with a thickness of 0.8mm to 2.7mm is traditionally used for the manufacture of economy-class cookware and is suitable for applying non-stick coating using the roller rolling method.
The service life of a product with such a coating is 1-1.5 years.
Aluminum strip with a thickness of 2.7 mm is used for the production of medium and premium class cookware. The non-stick coating is applied exclusively by spraying.
The service life when using this coating is 3-4 years. Regardless of the type of coating, according to hygienic recommendations, pans should be changed every 3 years.
To make frying pans, you need to cut aluminum circles from tape in order to stamp the necessary products from them, having previously applied a non-stick coating (or after stamping, depending on the type of coating).
The coil with the tape is installed in the cutting machine. At Skovo, high-performance Italian machines cope with this task. This device allows, depending on the diameter of the circle, to select the most economical metal “cut” patterns to reduce the amount of cutting residues. Each diameter has its own program.
Finished discs are cleaned in a special apparatus, where burrs are mechanically removed and creating an easy roughness to improve the adhesion of metal to coatings.
IN future fate discs of the economy segment and the middle (premium) segment differ, since the technology for applying non-stick and decorative (external) coatings on different metal thicknesses differs.
Discs intended for the production of tableware in the economy segment are first painted, and then products are stamped from them; in the middle and premium segments, blanks are first stamped, which are then sent for painting. Again, the products will only be found on the assembly and packaging line.
Coating of economy class dishes.
Painting of discs up to 2.7 mm thick occurs on the line for applying non-stick and decorative coatings using the roller rolling method. The line is a mechanism up to 50 meters long with several coating rollers, pre-drying ovens and a final drying oven.
Reference
Application by roller rolling is carried out in 3-5 layers, resulting in a final coating thickness of 20-25 microns, which is optimal for maintaining the non-stick properties of the product during its intended service life.
The discs (3 pieces in a row) first go into the oven for pre-firing and drying the disc. The remaining oil from stamping is burned off from them, and the discs are then heated to apply the first layer of coating. The roller, impregnated with the required layer of non-stick, evenly applies it to a number of disks, after which they enter the preliminary drying of the first layer. Next, apply the second layer and the third in the same way. There can be up to 5 layers in one line, plus an additional decorative layer can be applied on top of the resulting layer.
Reference
The number of layers is established by the specifications of the coating manufacturers. It affects the durability and strength of the coating. The first layer is intended to facilitate the application of other layers, as it serves as the “glue” between the aluminum and the non-stick or decorative layers. The second layer, the thickest, serves as the main one in the coating, carries out the main function of the coating, the last layer (finish) secures the middle layers and provides the protective and strengthening function of the coating.
There is a myth that ceramic coating lasts longer than PTFE based coating. This is incorrect, since in the second case the entire layer of coating has non-stick properties, which will serve until it is rubbed down to the metal. In the case of ceramic coatings Only the top film has non-stick properties, after abrasion of which the coating loses its non-stick properties, despite the fact that external changes are not visible.
During the process of annealing the non-stick coating in ovens at a temperature of 450° C, all chemical compounds necessary for “sticking” the coating to aluminum evaporate, which makes them safe for home use and environmentally friendly.
After coating one side of the discs, they are returned to the beginning of the conveyor, all shafts are washed and the second side of the discs is coated. As a rule, the non-stick coating is applied first, and then the decorative layer. After painting both sides, the discs go to the assembly line.
At this point, let’s take a break and consider a similar process, but on mid- and premium-class products, with spray coating.
Coating of medium and premium class dishes.
Coatings applied by spraying are sprayed from nozzles under high pressure onto specially prepared fezzes.
Discs for these classes of cookware are initially stamped with powerful presses, acquiring the required shape.
Then the stamped fezzes enter the washing tunnel, where the oils used in the press are washed off with alkaline solutions, the initial roughness is given (remember, this is necessary for the adhesion of the coating and aluminum) and dried. After this procedure, touch the fez with bare hands prohibited, as greasy fingerprints may remain on them, which will result in the coating peeling off from the metal in these places.
As with roller application, in this case The coating is applied in several layers with preliminary drying after applying each layer. The fez is placed in a rotating holder and a coating is supplied from the nozzle, which is laid on the surface in an even layer around the circumference, layer by layer.
Reference
The rotation speed of the holder is 120 rpm.
After applying the last layer, the fez goes into the oven for final drying. Then the fez is placed upside down on rotating holders and a layer of coating is applied on the other side using the same technology.
Some design products require a design to be applied to the bottom using silk-screen printing. If such an operation is necessary, a semi-automatic silk-screen printing machine is installed in our production. After applying the design, the fez once again goes into the oven to dry the paint.
After painting, the fezzes are found again on the assembly line.
Assembly
Economy class cookware begins its assembly journey with a press, on which the painted disc is stamped, giving it the required shape. The operator behind the stamp starts the press with two buttons, pressing them with both hands at once, which almost completely eliminates injuries when using the press. The workpiece is placed in the mold and the press squeezes the pan out of it with gentle pressure and not impact, which prevents tearing, chipping, and scratching the coating or metal.
The next operation is similar for all types of products - turning the finished fez. Skovo's assembly lines have two lathes, each with two cutters. Two operations are performed at once: folding the edge and grooving the bottom.
Reference
At modern materials coating, the bottom groove has a purely decorative function. Previously, when using non-stick coatings, it was impossible to make continuous decorative surfaces in places where the bottom of the frying pan was actively heated, due to the fact that large surfaces of the coating cracked when heated due to ruptures as a result of thermal deformation. It was necessary to reduce the surface of the coating by circular grooving. In modern conditions, this measure may not be technologically applicable.
The myth about regulating heating by the size and discreteness of the grooves has no basis in itself, since the heating surfaces of the plates (any) provide uniform heat to the entire bottom of the product, therefore, every square centimeter of the bottom is heated evenly, regardless of the distance from the center of the heating element.
The next operation: installation of the handle, it is carried out in two ways - with riveting and with goujon.
The handle is riveted in one operation using two or three aluminum rivets, depending on the design of the handle. The operation is monotonous, but the quality of the riveting depends only on how “stuffed” the hand of the specialist performing the operation is.
The welded handle design is used on heavy frying pans with solid handles. To attach such a handle to a fez, an aluminum fastener, a goujon, is first welded to it. The goujon has a different angle at the attachment point depending on the shape of the fez; it must be welded exactly parallel to the heating surface of the pan. The cut angle of the goujon is selected for each frying pan individually.
After welding it to the fez, a handle is screwed through the flame-extinguishing aluminum or steel screen. The flame-extinguishing screen protects the plastic of the handle from hot air from the heating surface, and it also serves as a screen to protect the place where the goujon is welded to the fez.
The next operation is the personalization of those types of frying pans on which the SKOVO logo is not stamped. As a rule, these are economy class products, on which our logo is extruded in the center of the groove.
There is just a little bit left until the product is 100% ready for sale.
A label is put on or glued to the frying pan, each product is marked with a barcode label and packed in protective film or a polystyrene foam bag. If necessary, the product is equipped with a lid. We do not screw the boss to the lid, but insert a set of boss, washer and bolt separately.
Reference
Skovo company products are packaged in three types of packaging
1. Label insert + protection with shrink film
2. Open label + polystyrene foam bag
3. Individual box
On mid- and premium-class products, the lid is tightly attached to the product with a heat-shrinkable belt.
The individually packaged product is placed according to the packaging cards in corrugated boxes for palletizing and transportation to the finished product warehouse.
Petr Cherenkov
Photo - Eduard Milokumov (www.Goodwine.livejournal.com), posudka.ru
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