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RAW MATERIAL: Polyethylene raw material is produced from LLDPE low density linear polyethylene with stabilizer MOLD: It is designed and made from DKP sheet / aluminum according to the desired product. BAKING: The mold filled with raw material is placed in the furnaces operating with electricity or natural gas. It is started to rotate with a walking rail car running at approximately 145 rpm. When the powdered raw material becomes liquid and reaches a temperature of 250 degrees, the mold is rotated in the oven for another 1 hour. When the time is up, the mold is removed from the oven and left to cool. REMOVAL FROM THE MOLD The cooled product is removed from the mold with the help of a crane with suitable lifting capacity or manually. OPERATOR CONTROL: The product, which has come out of the oven and cooled down, is checked by the oven operator. If the length, diameter and thickness of the water tank are suitable, it is sent to the storage area. If it is not suitable, it is sent to recycling and its production is restarted to be used in cover production after it turns into powder. Recycling Products that are not suitable for shipment are first shredded by jigsaw, then crushed into smaller pieces with a 4-blade crusher. STORAGE: The polyethylene product removed from the mold is checked by the oven operator and sent to the storage area if it is in the desired size and specifications. SHIPPING: Orders waiting in the storage area are shipped. MOLDING SHOP: Material Supply: Materials such as DKP sheet metal / aluminum, profile, angle iron, flat bars are supplied. Ø Cutting: After the material is dimensioned by the operator according to the desired size in line with the need, the cutting process is carried out with the help of oxygen, hand saw or monster stone. Ø Folding: The cut material is manually folded by the operator on the plate or cylinder. Mold Bottom and Top Cover: Mold bottom and top plate covers are manufactured. Mold Making: The upper and lower covers produced with the crimped material are combined by the operator on a flat surface with the help of a gas metal arc welding machine and the mold is formed. Control: The finished mold is checked for dimensions (diameter of the mold, body length, total length) Cleaning: The mold is cleaned with tools such as grinding and sandpaper. Manufacturing: The finished mold is taken into production with the raw material prepared in the rotation section.
Characteristics of Rotation Technology
The most salient feature of rotation technology is the length of production time. For a normal product; 20 minutes cooking, 15 minutes cooling, 5 minutes mold preparation and 5 minutes demolding time should be taken into consideration. This means that 1 product is taken from 1 mold in 45 minutes. This time can even exceed 2 hours depending on the difficulty/size of the product. In this respect, we are talking about a very slow process compared to injection and blow molding technologies. This low speed normally increases the overhead costs on the product and the resulting product is more expensive compared to other technologies. Despite the disadvantage of low speed and high price, rotary technology has many advantages. For products with low consumption, the mold cost per unit is low. Although the product price is expensive, the mold price is considerably lower than other technologies. If the product to be produced is a product with low annual consumption, rotation technology is preferred due to mold depreciation. For example, a tractor fuel tank is a product that will not be sold tens of thousands a year due to its structure. It does not make sense to make a blow mold for a fuel tank that is planned to be produced 1000-2000 units per year. Moreover, a new model will be made before the mold can pay for itself. Tractor companies in Turkey are oriented towards rotation technology for diesel tanks. They are suitable for products that cannot be made in other technologies. Sometimes there is no alternative other than rotation technology due to the size of the product. Water tanks larger than 1 ton are the most suitable example. For example, a 40-ton water tank is pressed at a weight of 850 to 950 kg. No other technology is suitable for producing such a heavy product in one piece. Sometimes the product geometry is monolithic and complex. In this case, rotation technology is the only solution with its flexible structure. Rotation products are robust compared to other plastic products. Since rotation is not formed by pressure during production, there are no stresses during production. This makes rotation products incomparably stronger than injection molding, blow molding and polyester products, even if the same thickness and raw materials are used. Product wall thickness can be changed without being dependent on the mold. In rotation technology, the product wall thickness is proportional to the raw material put into the mold. In this way, there is no need to decide what the product thickness should be during design (except in some special cases). In addition, different quality products can be produced from the same mold by putting more or less raw material into the same mold. For example, water tank manufacturers in Turkey produce an economical and a robust model with the same mold by changing only the weight of the product. Double-walled products can be printed in rotation, and foam can be filled in the gap between them during or after production. Rotation technology is suitable for printing double-walled products, so-called double walls.
In this way, double-layered water tanks increase the robustness of the product, allow the inner and outer parts of the product to be molded, and the space in between can be used functionally. If desired, the space in between can be filled with various raw materials that foam with heat during production or polyurethane foam after production. In this way, various products that need to provide heat insulation (such as food transportation containers /termoboxes) can be easily produced. Rotation allows various parts to be added to the product during production. Parts such as flanges, nuts, screws, etc., which would normally be attached to the product later, can be attached to the product during manufacturing. If these additional parts are designed correctly, they are very robust. In this way, assembly labor after production is reduced. The flanges on diesel tanks, the connection nuts of the seats used in public transportation vehicles can be given as examples. Since the coloring agent is added to the raw material, the finished product does not need to be dyed. In rotation technology, the raw material is used as powder. The raw material is dyed with colorants referred to as powder paint. In this method, powder dye is added into the powdered raw material and the raw material is dyed by mixing. In the second method, the raw material is passed through the extruder while it is still in granule form and at this stage it is dyed with masterbach. The raw material, which comes out of the extruder colored, is turned back into granules and passed through the powder mill to obtain colored powder plastic. In this method, the result is of high quality as the color penetrates into the structure of the raw material. However, obtaining colored powder with this method takes longer than dyeing the raw material with powder paint and it is not profitable to dye small amounts of raw material. Production can be made with different colored raw materials on the same product. During production, different colors can be produced inside and outside. For example, the inner surface of the water tanks can be produced in white, the middle part in black and the outer part in blue; the inner surface is suitable for food, the middle surface is resistant to impacts, and the outer surface prevents mossing as it does not transmit sunlight. It is also possible to produce different colors on the same surface in rotation. An aesthetic appearance with different color transitions can be achieved in most products.
Rotation Machine Park
What kind of equipment do we need to produce with rotation? 1) Rotation Machine: Basically, a machine that rotates in 2 axes is considered sufficient for production. However, for some special products other than water tanks, the machine must have some special features. 2) Powder Mill: In rotation technology, raw material is used as powder. It is possible to buy raw material directly in powder form, or it is more convenient to buy raw material in granules and make powder with a mill. Because granular raw material is more suitable than powder raw material. In addition, if color production is desired and the dyeing process is not desired to be done with powder paint, finding powder in different colors is also a problem. Therefore, a powder mill is a must for a rotation plant. 3) Extruder If colorful production is desired, an extruder is essential for dyeing the raw material. Although painting can be done with powder paint, it would be the right method to choose the extruder to achieve quality results. It is necessary to have these basic components for rotary production. However, since large products are mostly produced in rotation, a large space is needed for storing molds and products.