Plastic materials are used throughout many industries. The characteristic property of polymeric materials, after melting, to acquire mechanical rigidity and strength, is widely used not only in the manufacture of various products, but also when carrying out repairs at home.
This connection of plastic materials, called welding, is the most technologically sound and economical way to repair a variety of products. Welding plastic allows you to create high-strength butt joints. Moreover, the process technology and equipment used for welding is not particularly difficult for home use.
Basic Welding Methods
With all the wide variety of technological methods of the welding process, plastic welding methods can be divided into two main groups:
- cold welding is carried out with the help of special chemicals that effectively promote the connection of plastic products,without melting surfaces;
- hot welding is a combination of plastics at the molecular level, when surfaces are heated to a semi-liquid state.
The task of a welded joint, of any type, is to create a strong contact between polymeric materials through a smooth transition of one substance into another. Plastic welding can be carried out with or without special additives.
Cold welding method
With the development of the chemical industry, cold welding for plastics has gained the most popularity not only among professionals, but also among ordinary people who repair products at home. In principle, this name is more in line with the scientific term, which denotes the type of compound of polymeric materials. In general, this is a technology for gluing plastic parts using chemically active substances.
Currently, manufacturers produce three types of necessary components for welding:
- One-component composition looks like a simple office glue. The versatility of this composition allows you to weld almost any polymeric materials with high quality. The most common one-component adhesive is used for welding plastics at home.
- Two-component adhesive consists of epoxy resin and hardener, which are supplied to the consumer in separate containers. Mixing of components is carried out in a certain proportion,just before the job is done.
- The active reagent rod has an outer shell of hardener and an inner shell filled with epoxy resin. Having cut off the desired piece of the rod, it must be carefully kneaded with your fingers until a homogeneous plastic mass is formed.
All work on the preparation of the adhesive composition must be carried out strictly according to the manufacturer's instructions.
Cold Welding Technology
Before welding plastic, it is necessary to prepare the surfaces of the products to be joined. For this purpose, it is necessary to process the edges of the parts with abrasive material (sandpaper, file). This treatment makes it possible to create a surface roughness, which significantly increases the adhesion of the plastic material.
Welding technology is as follows:
- After pre-treatment, just before work, it is necessary to degrease the surfaces of the products to be joined. Almost any alcohol-based solvent can be used for this.
- Further, according to the instructions, an adhesive composition is applied to the edges of the parts to be joined.
- Surfaces are tightly pressed against each other. Moreover, compression should be carried out until the composition is completely solidified.
- After the components have completely dried, the plastic welding process is considered complete.
The main advantage of cold joining is the ability to effectively weld surfaces of dissimilar materials, while additionalno equipment required. The disadvantage of the method is the low vibration resistance of the seam, so the use of cold welding is limited in moving mechanisms.
Plastic hot welding
The hot method of welding plastic materials is based on the molecular interaction of molten surfaces to a viscous state. In this case, it is necessary to take into account the nature of the reaction of the polymer to the temperature effect. According to this principle, plastic materials are divided into thermoplastics and thermoplastics.
Thermoplastics do not change their performance and chemical properties, even with repeated transition to the molten state. And most importantly, when returning to the original hardness after cooling, the materials do not lose their strength. Unlike thermoplastics, thermoplastics, returning to their original state, almost completely lose their plastic properties. Such a reaction of the material does not allow it to re-pass into the viscous phase, completely losing strength. Most plastics are thermoplastics.
Heat welding methods
Depending on the method of supplying thermal energy to the zone of connection of polymeric materials, there are the following types of hot welding:
- hot gas stream;
- with a special heated tool;
- exposure to the edges of products melted additive;
- using ultrasonic flow;
- using infrared or laser light;
- heating the joint by friction;
- exposure to high frequency electric current.
The first three methods are effective when welding plastic with your own hands at home. The rest are most often used directly in industrial enterprises in the manufacturing process.
Hot gas welding
The joint can be heated with a gas burner using nitrogen or argon. But the safest and most cost-effective is the welding of plastics with a hairdryer, since the edges of the joined products are heated by hot air.
Production and repair of plastic products is carried out by industrial or household hot air guns. Structurally, this equipment for welding plastics is arranged in the same way. Industrial hair dryers have high power, the adjustment of which is carried out automatically, and are also equipped with a number of additional functions and various nozzles.
Welding plastic with a hot air gun is carried out in several stages:
- The type of plastic is determined, according to which the heating temperature is selected, as well as the nozzle suitable for work.
- The edges of the products to be joined are cleaned and degreased.
- The blanks are firmly fixed so that they do not move during work.
- The joint is heated to a molten state, at which the materials merge.
- After creating a weld, the product must cool in natural conditions. Additional cooling is not recommended.
- Thenthe final cleaning of the seam.
Heater resistance welding
The simplest type of plastic welding at home is the direct heating of the edges of the product with a hot tool. The technological process of contact welding is considered the simplest and most easily applicable in domestic conditions, as it does not require the use of sophisticated equipment.
Welding can be divided into two main steps:
- Fusing the edges of the parts to be joined.
- Dense compression of molten surfaces and holding until complete cooling.
The time between these operations should be minimal so that the material does not have time to cool. Otherwise, the quality of the weld will be insufficient.
At home, for minor repairs, they often use a simple soldering iron equipped with special nozzles.
Using welding consumables
To increase the strength and quality of the seam, when joining plastic materials, special additives are widely used. Plastic rods or strips are used as such material.
Adding an additive to the weld composition greatly improves the welding process using hot air heating. The main condition for a high-quality connection of plastics is the correspondence of the composition of the additive and the polymer material.
Also, a very effective option for using filler material is to use a welding hand extruder. This thermomechanical device, which looks like a gun, first heats the polymer material to a viscous state, and then automatically extrudes the additive onto the surfaces to be joined.
Welding of plastic products is widely used both in production workshops and at home. The technology of the welding process is easy to master even for an inexperienced person, while it is necessary to remember the observance of safety measures for work.
