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EspañaHow to Matain Bottle Blowing Machine
In the process of daily use of the Bottle Blowing Machine, it is inevitable that you will encounter some problems. In this article, you will learn how to matain your Bottle Blowing Machine so that you can avoid panicking when you encounter these common problems.
In stretch blow molding, the location and pressure of the molded part are the two most important determining factors in quality. Whether they are correct or incorrect, these issues can have a major impact on the quality of the blown part.
1. Pre-blowing
The pre-blowing process on a bottle blowing machine is an important step that helps the molten PET resin to assume its shape while also stretching the material longitudinally to increase its lateral strength. It is an essential part of the bottle blowing machine operation that improves the quality of the finished product.
During the pre-blowing phase of the bottle blowing process, a proportional pre-blowing valve is actuated to supply pre-blowing pressure to a cylinder containing a preform in a mold cavity. The stretch rod is then positioned within the cylinder to stretch the preform in a longitudinal direction, increasing its lateral strength and reducing its weight.
In order to provide adequate proportional control, the proportional pre-blowing valve must be able to accommodate the high pressure/flow rate that is required during the pre-blowing phase. This presents several problems, some of which are described below.
2. High-pressure blowing
A bottle blowing machine is a high-pressure air compressor used to blow PET preforms into bottles. The pressures needed are high, and they must be consistent in order to produce a quality product.
There are many different types of blowing machines available on the market, and the process can be confusing to new users. It is important to understand how the system works and what components are involved in order to make the right choice for your application.
The main elements of the blowing machine are: a stretching solenoid valve, a high-pressure blowing valve, a pull-body sealing cylinder, and a movable sealing seat. When the system is running, the piston in the stretching cylinder is driven through the directional control valve to drive the stretching rod.
During the blowing process, the preform is heated using an infrared preheater and then bottom blown. The length and thickness of the preform are then manipulated to achieve the desired shape. The pressures required are also adjusted to suit the container’s design and blow speed.
3. Exhaust
During the blowing process, air consumption is driven by the air pressure and actual bottle volume. In addition, air that is "hidden" between the blow valves and cavity needs to be exhausted in each blow cycle.
This is a major cost for the user as it is difficult to calculate. Machines with high dead air volumes are particularly susceptible to this waste.
Krones' new stretch rod system reduces this air consumption by utilizing an electromagnetic stretching system.
A key benefit of this technology is that it doesn't use compressed air; therefore, the machine doesn't require an additional reheat stage.
The exhaust valve also eliminates the possibility of sand flowing past it becoming stagnant and compacted. This was an issue with previous exhaust valve arrangements that could lead to sand being trapped inside the connection pieces between the blow valve and cavity. This was a serious problem that needed to be rectified. Moreover, the exhaust valve can monitor pressure in the mold and release the air when it gets excessive.
4. Demoulding
Blow moulding is a process used to form hollow plastic containers and bottles with complex shapes and designs. It is used in many industries, including soda, water, cleaning products, and more.
The first blow molding machines were invented in 1939, and today there are hundreds of different types of blow molds available to suit a variety of applications. The technique is used to produce a variety of plastic bottles and containers, including glass and PET, as well as other materials.
The extrusion blow molding method uses low-pressure air to force a tubular parison of thermoplastic resin into the mold cavity. The parison then shrinks and clings to the inside of the mold. The process is commonly used to make high-volume bottles of Low-Density Polyethylene (LDPE), High-Density Polyethylene (HDPE), and Polypropylene (PP). It can also be used to create a wide range of other plastic containers and bottles with intricate shapes and designs. It is one of the most widely used processes in the world for making plastic products.
