The solution to the poor welding effect of plastic ultrasonic welding
When we encounter plastic ultrasonic welding is not strong, we must first find out the factors that cause the welding to be weak, and then we can find out the treatment method. We will use the elimination method to find the root cause. Under normal circumstances, there will be machine failures and equipment accuracy, mold damage and manufacturing accuracy, as well as debugging parameters, air supply pressure stability, plastic materials and structural design.
The first factor that causes the ultrasonic welding to be weak is the air pressure
Many ultrasonic welding machine manufacturers are troubled by the unstable air pressure in the customer's factory workshop after selling the machine, resulting in poor welding. Instability of air pressure is also an important factor leading to instability of ultrasonic welding. First of all, the new machine will undergo strict internal testing before leaving the factory and will not be shipped normally until no problems are found. However, when the customer uses the machine, there will be various problems of poor welding. Before purchasing the machine, the customer usually takes samples and tests the machine, and will only ship it after confirming that the machine verification test is correct. So, why do customers have problems with poor welding? The ultrasonic generator parts have been tested repeatedly and no problems have been found. So what is the problem?
After a long period of observation, it was found that the unstable air pressure in the customer's factory workshop was the cause. Only when the machine stops working, it works normally and there is no welding failure. When it worked normally, the problem reappeared. Therefore, we judge that the instability of the air pressure affects the normal welding of the ultrasonic welding machine. Because there are many devices that require gas to work at the same time during normal operation, the pressure will drop when the gas passes.
Solution: If a large machine is welding smaller products, please try to replace a smaller cylinder, or add an independent air compressor to supply air to the ultrasonic welding machine.
The second factor that causes the ultrasonic welding to be weak is that the machine is not precise enough.
Ultrasonic welding machine seems to be a device without any difficulties other than an ultrasonic system. In fact, this is a wrong view. Ultrasonic generator is the core component of ultrasonic welding machine. In addition to the generator part, there is also the problem of the plastic welding machine frame. If a set of frame design is not reasonable enough, and the processing is not precise enough, it is likely to directly affect the welding pass rate of the product during use. The unreasonable design of the machine will also affect the welding fastness of the product. If the machine is tilted backwards, if the processing is not accurate, the best balance position of the mold cannot be found when changing the mold, and the product may not be welded.
Solution: directly replace a better rack, try to do a good job of purchasing before purchasing the machine, and understand the relevant information of the equipment.
The third factor that causes the ultrasonic welding to be weak is the unequal force and design error in the installation of the ultrasonic fixture.
It is generally believed that as long as the product is in precise contact with the mold surface during the ultrasonic operation, the ultrasonic welding machine can obtain the welding effect. In fact, this is just a superficial view. Since ultrasonic waves are frictional vibrations, sound wave propagation occurs.
If we only observe the stability of the hardware (mold) and ignore the integrated ultrasonic operation mode, we will definitely eliminate the cost or misjudgment consequences. Therefore, we must first emphasize that the operating mode of ultrasonic welding is to conduct sound waves, thereby converting vibration and friction into heat and welding. At this time, under the same pressure, the stability of the ultrasonic mold, the height of the product cross-section, the thickness of the meat, the depth and texture of the material must not be 100%.
On the other hand, the energy output by the upper mold has an error value at each point, rather than the energy emitted by the entire surface is the same. In general, it will inevitably produce differences in the degree of fusion of the product fusion line. Therefore, it must be corrected. How to correct it depends on the horizontal screw of the ultrasonic welding machine itself, or sticking a thinner tape or aluminum foil.
The fourth factor that causes the ultrasonic welding to be weak-whether the ultrasonic welding parameter setting is reasonable
Improper selection of ultrasonic welding parameters, including delay time, welding time, pressure holding time, pressure size, cylinder rise (fall) speed, etc., will have a great impact on the welding effect and production efficiency.
Solution: Newly set welding parameters, increase welding time and holding pressure time.
The fifth factor leading to weak ultrasonic welding-insufficient ultrasonic power
Insufficient power of the ultrasonic generator is also a factor leading to poor welding. Considering that many factories will choose cheap machines when buying machines, one thing that has been overlooked is processing and using other products in the later stages of the machine. If the ultrasonic power is not large enough, the area of the welded product exceeds the welding range, which will also lead to poor welding.
Solution: Try to buy a high-power plastic welding machine to ensure subsequent use.
The sixth factor that causes the ultrasonic welding to be weak-the problem of the plastic material itself
There are many plastic materials that can be ultrasonically welded. If other materials are added to the ultrasonic welding material, the welding fastness will also be affected. For example, if glass fiber is added to the computer, the welding fastness will be affected.
Solution: Use a single thermoplastic material.
