Do you know the Precautions when Using Ultrasonic food cutter
principle
Ultrasonic food cutting knife uses ultrasonic energy to locally heat and melt the material being cut to achieve the purpose of cutting, so there is no need for a sharp edge. Commonly used for cutting difficult-to-cut materials, such as thermoplastic resin sheets, sheets, films, and laminates, carbon fiber composites, fabrics, and rubber. The output power is 100W, the casing is made of stainless steel, and the cutter head uses a 0.6mm thick hard wear-resistant alloy blade. The user can replace the blade by himself, extending the service life of the cutting knife and saving costs.
When the ultrasonic food cutting knife cuts, the temperature of the blade head is lower than 50°C, so smoke and odor will not be produced, eliminating the risk of injury and fire during cutting. Because ultrasonic waves cut through high-frequency vibration, the material will not adhere to the surface of the blade, and only a small amount of pressure is required during cutting. Fragile and soft materials will not be deformed or worn. The fabric will be automatically edge-sealed at the same time, without causing collapse. side. Therefore, there is no need for a sharp cutting edge, the blade wears less, and the cutter head can be replaced by yourself. It can be applied not only to mousse cakes, nougat, chocolate, biscuits, and frozen meat. It can also be used in various textile materials and plastic sheets, such as natural fibers, synthetic fibers, non-woven fabrics and knitted fabrics.
Precautions
Because the ultrasonic waves emitted by the ultrasonic food cutting knife during the cutting process have high energy, operators should also pay attention to the following precautions when using them:
1. Although high-quality ultrasonic food cutting knives have good protection, because there is a high-voltage electrical circuit inside the equipment, a power connector must be prepared when using it to avoid danger. At the same time, operators should not disassemble or modify without authorization. Cutting knife to avoid accidental risks caused by improper operation.
2. When using the cutting knife, the operator should be careful not to let the equipment come into contact with water. When cleaning the cutting knife, be careful not to let water enter the inside of the cutting knife to avoid short circuits and accidents. .
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3. When in use, the blade will accumulate a large amount of ultrasonic energy, so when operating, be careful not to point the blade towards the person's face or other body parts to avoid accidents caused by improper control.
4. When using, be careful to use professional matching blades instead of installing non-matching blades to prevent failure to vibrate or reduce cutting efficiency.
5. After the operation is completed, the power supply of the ultrasonic food cutting knife must be cut off in time, and the remaining material debris or foreign matter on the blade must be removed until the cutting knife completely stops.
The ultrasonic food cutter is a kitchen appliance that utilizes ultrasonic vibrations to cut through various types of food. It is designed to provide precise and efficient cutting results.
In terms of user attention, the ultrasonic food cutter generally requires some level of caution and attention during operation. While it offers several advantages, such as clean cuts without crushing or tearing the food, it also requires proper handling to ensure safety.
Here are a few points to consider regarding user attention when using an ultrasonic food cutter:
Familiarize Yourself with the Appliance: Before using the ultrasonic food cutter, it's important to thoroughly read the user manual and understand how the appliance works. Pay attention to any safety precautions, operating instructions, and recommended food types for cutting.
Safety Precautions: Follow the safety guidelines provided by the manufacturer. This may include wearing protective gloves, avoiding contact with the ultrasonic blade, and keeping fingers or other body parts away from the cutting area.
Focus on the Task: When operating the ultrasonic food cutter, maintain your focus on the task at hand. Avoid distractions and ensure that you have a clear workspace to prevent accidents or injuries.
Food Preparation: Properly prepare the food before attempting to cut it using the ultrasonic food cutter. Ensure that the food item is stable, secure, and positioned correctly on the cutting surface to avoid any unexpected movements during cutting.
Cleaning and Maintenance: Regularly clean and maintain the ultrasonic food cutter according to the manufacturer's instructions. This includes removing any food debris, ensuring the blade is in good condition, and storing the appliance properly.
Remember, user attention is crucial when operating any kitchen appliance, including the ultrasonic food cutter. Always prioritize safety and follow the recommended guidelines to ensure a positive and safe cutting experience.
Do you know the ultrasonic spray nozzle?
Do you know the ultrasonic spray nozzle?
What is the ultrasonic spray nozzle?
An ultrasonic spray nozzle is a device that uses ultrasonic vibrations to create a fine mist or spray of liquid. It consists of a piezoelectric transducer that converts electrical energy into mechanical vibrations. These vibrations are then transferred to a liquid, typically through a nozzle or atomizing plate, causing the liquid to break up into small droplets. Ultrasonic nozzles are a type of spray nozzle that use high frequency vibrations produced by piezoelectric transducers acting upon the nozzle tip that create capillary waves in a liquid film. Once the amplitude of the capillary waves reaches a critical height (due to the power level supplied by the generator), they become too tall to support themselves and tiny droplets fall off the tip of each wave resulting in atomization.The primary factors influencing the initial droplet size produced are frequency of vibration, surface tension, and viscosity of the liquid. Frequencies are commonly in the range of 20–180 kHz, beyond the range of human hearing, where the highest frequencies produce the smallest drop size.
What is the Advtanges of ultrasonic spray nozzle?
Ultrasonic spray nozzles have several advantages over traditional spray nozzles. They can produce a more uniform spray pattern with smaller droplet sizes, which can be beneficial for applications such as coating, painting, humidification, and cooling. The smaller droplet sizes also enable better surface coverage and improved penetration into porous materials.
Additionally, ultrasonic spray nozzles are often more efficient in their use of liquid compared to conventional nozzles, as they require lower liquid flow rates to achieve the desired spray coverage. This can result in cost savings and reduced waste.
Overall, ultrasonic spray nozzles offer precise and efficient spray control, making them suitable for various industrial, medical, and research applications.
What is the Application of ultrasonic spray nozzle？
Ultrasonic spray nozzles have a wide range of applications across various industries. Some common applications include:
Coating and painting: Ultrasonic spray nozzles are used for precise and uniform coating of surfaces. They can be employed in industries such as automotive, electronics, and aerospace for applying protective coatings, paints, adhesives, and lubricants.
Semiconductor manufacturing: Ultrasonic spray nozzles are utilized in semiconductor manufacturing processes for the precise deposition of photoresist, dielectric coatings, and other thin films. They offer better control and coverage compared to traditional spin coating methods.
Pharmaceutical and medical applications: Ultrasonic spray nozzles are used in pharmaceutical and medical industries for drug delivery systems, coating of medical devices, and creating inhalable or transdermal formulations. They can produce fine droplets for targeted and controlled drug administration.
Food and beverage industry: Ultrasonic spray nozzles find application in the food and beverage industry for flavoring, coating, and preserving food products. They can be used for spraying oils, flavors, and coatings onto bakery items, confectionery, and meats.
Agriculture: Ultrasonic spray nozzles are employed in precision agriculture for pesticide and fertilizer application. They can deliver precise amounts of agrochemicals onto crops, reducing waste and improving efficiency.
Printers and 3D printing: Ultrasonic spray nozzles can be used in inkjet printers for high-resolution printing and precise droplet placement. They are also utilized in 3D printing for the deposition of materials and coatings.
Fuel cells: Ultrasonic spray nozzles are used in the fabrication of fuel cells for the precise deposition of catalyst layers and electrolytes, improving the performance and efficiency of fuel cell systems.
Nanotechnology and research: Ultrasonic spray nozzles are employed in research laboratories for various applications, including nanoparticle synthesis, surface modifications, and thin film deposition.
What is the difference between ultrasonic cutting and laser cutting?
What is the difference between ultrasonic cutting and laser cutting?
Now in the cutting industry, laser cutting and ultrasonic cutting are relatively high-end and high-tech cutting methods. Just like laser cutting and waterjet cutting, there are big differences in principles, costs, cutting methods and applications. So today we will talk about the difference between laser and ultrasonic cutting.
The principles are different
(1) Laser cutting principle
The principle of laser cutting: Laser cutting uses a focused high-power density laser beam to irradiate the workpiece, causing the irradiated material to quickly melt, vaporize, ablate or reach the ignition point. At the same time, the molten material is blown away by a high-speed airflow coaxial with the beam, thereby Achieve cutting the workpiece. Laser cutting is one of the thermal cutting methods.
(2) Principle of ultrasonic cutting
When ultrasonic technology is used for cutting, the back-and-forth vibration generated by the ultrasonic vibrator installed behind the spindle is transmitted to the outer circumferential part of the grinding wheel blade through the spindle and the base of the grinding wheel blade, and is converted into expansion motion in the radial direction. Through this vibration conversion method, the ideal vibration direction required for ultrasonic processing can be obtained.
The mechanical vibration energy generated by the ultrasonic generator exceeds 20,000 blade vibrations per second, which locally heats and melts the material being cut, causing the molecular chains to quickly break apart to achieve the purpose of cutting the material. Therefore, ultrasonic cutting does not require a particularly sharp blade or a lot of pressure, and will not cause chipping or damage to the material being cut. At the same time, due to the ultrasonic vibration of the cutting blade, the friction is small, by reducing the material is not easy to stick to the blade. Especially effective for sticky and elastic materials that freeze, such as food, rubber, etc., or where it is inconvenient to add pressure to reduce objects.
Different characteristics
(1) Laser cutting characteristics
As a new processing method, laser processing has gradually been widely used in the leather, textile and clothing industries due to its advantages of accurate processing, fast processing, simple operation, and high degree of automation. Compared with traditional cutting methods, laser cutting machines are not only lower in price and consumption. And because laser processing puts no mechanical pressure on the workpiece, the effect, accuracy and cutting speed of the cut products are very good. It also has the advantages of safe operation and maintenance Simple and other features. Can work continuously for 24 hours. The edges of the dust-free non-woven fabrics cut by the laser machine will not turn yellow, and will automatically close up without loose edges. They will not deform or harden, and will have consistent and precise dimensions. They can cut any complex shape; they are highly efficient and cost-effective. Computer designed graphics can cut lace of any shape and size. Fast development speed: Due to the combination of laser and computer technology, users can realize laser engraving output as long as they design on the computer and can change the engraving at any time. They can design and produce products at the same time.
(2) Characteristics of ultrasonic cutting
Ultrasonic cutting has the advantages of smooth and reliable incision, accurate edge cutting, no deformation, no edge warping, fluffing, stringing, and wrinkles. The avoidable "laser cutting machine" has shortcomings such as rough cutting edges, burnt edges, and pilling. However, the automation of ultrasonic cutting machines is currently more difficult than that of laser cutting machines, so the efficiency of laser cutting is currently higher than that of ultrasonic cutting.
Different applications
Laser cutting application areas
Machine tools, engineering machinery, electrical switch manufacturing, elevator manufacturing, grain machinery, textile machinery, motorcycle manufacturing, agricultural and forestry machinery, food machinery, special automobiles, petroleum machinery manufacturing, environmental protection equipment, household appliance manufacturing, large motor silicon steel sheets and other machinery manufacturing processing industry.
Ultrasonic application fields
Another great advantage of ultrasonic cutting is that it has a fusion effect at the cutting site while cutting. The cutting area is perfectly edge-sealed to prevent the tissue of the cut material from loosening (such as flashing of textile materials). The uses of ultrasonic cutting machines can also be expanded, such as digging holes, shoveling, scraping paint, engraving, slitting, etc.
1. Plastic and thermoplastic door cutting and die cutting.
2. For non-woven or woven cutting, textile cutting, clothing lace, fabric cutting. The edges are sealed while being cut.
3. Artificial resin, rubber cutting, raw rubber, soft rubber cutting.
4. Cutting of tapes and various types of films.
5. Paper cutting, printing industry cutting, printed circuit boards, trademarks.
6. Cut food and plants, such as frozen meat, candy, chocolate.
7. For PVC, rubber, leather, plastic, cardboard, acrylic, polypropylene, etc.
8. Clothing fabric cutting
9. Packaging material cutting
10. Cut curtains and blackout fabrics
11. Cutting in the automotive industry
what is the ultrasonic graphene dispersion？
What is the ultrasonic graphene dispersion?
Ultrasonic graphene dispersion refers to a process that uses ultrasonic waves to disperse graphene particles in a liquid medium. Graphene is a single layer of carbon atoms arranged in a hexagonal lattice, and it exhibits remarkable properties such as high conductivity, strength, and flexibility. However, graphene tends to agglomerate or form clusters, which can limit its effective use in various applications.
The ultrasonic dispersion process involves the use of ultrasonic waves to break down these agglomerates and disperse the graphene uniformly in a liquid, typically a solvent. Ultrasonic waves create high-frequency pressure waves that generate cavitation bubbles in the liquid. When these bubbles collapse, they create intense local forces that help break apart the graphene clusters, leading to a more even dispersion in the liquid.
This method is commonly employed to enhance the stability and homogeneity of graphene dispersions, making it easier to incorporate graphene into various materials, such as composites, coatings, or inks. The resulting dispersion can be utilized in applications ranging from electronics and energy storage to biomedical devices and sensors. The ultrasonic graphene dispersion process contributes to improving the performance and functionality of materials incorporating graphene.
Why should use ultrasonic machine to dispersion the graphene？ What is the advantage?
Using an ultrasonic machine for graphene dispersion offers several advantages:
Improved Dispersion Quality: Ultrasonic waves provide effective and uniform dispersion of graphene particles. This results in a more homogeneous distribution of graphene throughout the liquid medium, reducing agglomeration and ensuring better overall quality.
Reduced Agglomeration: Graphene tends to form agglomerates or clusters, which can impact its properties and functionality. Ultrasonic dispersion breaks down these agglomerates into smaller particles, leading to improved stability and preventing the formation of large clusters.
Increased Surface Area: Ultrasonic dispersion increases the surface area of graphene sheets. This is beneficial for applications where a higher surface area is desired, such as in energy storage devices or catalysts, as it enhances the material's performance.
Enhanced Material Properties: The uniform dispersion achieved through ultrasonication can lead to improved mechanical, electrical, and thermal properties of materials containing graphene. This is crucial for applications like composites, coatings, and inks.
Process Efficiency: Ultrasonic dispersion is a relatively fast and efficient process. It allows for the production of well-dispersed graphene in a shorter amount of time compared to other dispersion methods, making it a practical choice for large-scale manufacturing.
Versatility: Ultrasonic dispersion is applicable to various liquid media and solvents, providing flexibility in terms of the types of solutions and materials that can be used in the dispersion process.
Scalability: The ultrasonic dispersion process is scalable, making it suitable for both laboratory-scale research and industrial-scale production. This scalability is important for transitioning from research and development to large-scale manufacturing.
Overall, the advantages of using an ultrasonic machine for graphene dispersion contribute to the improvement of graphene-based materials' performance and facilitate their integration into a wide range of applications.
Do you have the graphene dispersion customer?
Yes, of course. We already sold this machines to different customers. Not only for lab test, but also for industrial use. For circulation processor.Here is the feedback of our customer:
How is the ultrasonic machine to improve Dispersion quality?
Ultrasonic machines improve the dispersion quality of graphene through a process called ultrasonication. Here's how the ultrasonic machine achieves this:
Cavitation Effect: Ultrasonic waves create high-frequency pressure waves in the liquid medium. These waves lead to the formation of microscopic bubbles in the liquid, a phenomenon known as cavitation.
Bubble Collapse: The cavitation bubbles generated during ultrasonication undergo rapid expansion and collapse. When these bubbles collapse, they create localized high temperatures and pressures.
Shear Forces: The collapse of cavitation bubbles near graphene agglomerates generates intense shear forces. These forces act on the graphene particles, breaking down agglomerates into smaller particles.
Homogeneous Dispersion: The shear forces and pressure variations induced by ultrasonication result in the separation and dispersion of graphene sheets in the liquid. This process breaks up large clusters and ensures a more uniform distribution of graphene throughout the medium.
Preventing Re-agglomeration: As the dispersed graphene particles are subjected to the ultrasonic waves, the process helps prevent the re-agglomeration of particles. Continuous ultrasonication maintains a stable dispersion by inhibiting the formation of large clusters.
Increased Surface Area: The mechanical action during ultrasonication increases the surface area of graphene sheets. This increased surface area can be beneficial in applications where a higher surface-to-volume ratio is desirable, such as in catalysts or energy storage devices.
Efficiency and Speed: Ultrasonication is a relatively fast process, allowing for efficient dispersion within a short duration. This efficiency is crucial for industrial applications where large quantities of dispersed graphene are needed.
Customization: Ultrasonic machines often provide control over parameters such as intensity, duration, and frequency. This allows users to customize the dispersion process based on the specific properties of the graphene and the requirements of the application.
In summary, ultrasonic machines improve dispersion quality by leveraging the cavitation effect and generating intense shear forces that break down graphene agglomerates. This results in a more homogeneous and stable dispersion, contributing to improved material properties and performance in various applications.
How to use FEM ANSYS parameter optimization and probability design of ultrasonic welding horn
How to use FEM ANSYS parameter optimization and probability design of ultrasonic welding horn
Foreword
With the development of ultrasonic technology, its application is more and more extensive, it can be used to clean tiny dirt particles, and it can also be used for welding metal or plastic. Especially in today's plastic products, ultrasonic welding is mostly used, because the screw structure is omitted, the appearance can be more perfect, and the function of waterproofing and dustproofing is also provided. The design of the plastic welding horn has an important impact on the final welding quality and production capacity. In the production of new electric meters, ultrasonic waves are used to fuse the upper and lower faces together. However, during use, it is found that some horns are installed on the machine and cracked and other failures occur in a short period of time. Some welding horn The defect rate is high. Various faults have had a considerable impact on production. According to the understanding, equipment suppliers have limited design capabilities for horn, and often through repeated repairs to achieve design indicators. Therefore, it is necessary to use our own technological advantages to develop durable horn and a reasonable design method.
2 Ultrasonic plastic welding principle
Ultrasonic plastic welding is a processing method that utilizes the combination of thermoplastics in the high-frequency forced vibration, and the welding surfaces rub against each other to produce local high-temperature melting. In order to achieve good ultrasonic welding results, equipment, materials and process parameters are required. The following is a brief introduction to its principle.
2.1 Ultrasonic plastic welding system
Figure 1 is a schematic view of a welding system. The electrical energy is passed through the signal generator and the power amplifier to produce an alternating electrical signal of ultrasonic frequency (> 20 kHz) that is applied to the transducer (piezoelectric ceramic). Through the transducer, the electrical energy becomes the energy of the mechanical vibration, and the amplitude of the mechanical vibration is adjusted by the horn to the appropriate working amplitude, and then uniformly transmitted to the material in contact with it through the horn. The contact surfaces of the two welding materials are subjected to high-frequency forced vibration, and the friction heat generates local high temperature melting. After cooling, the materials are combined to achieve welding.
In a welding system, the signal source is a circuit part that contains a power amplifier circuit whose frequency stability and drive capability affect the performance of the machine. The material is a thermoplastic, and the design of the joint surface needs to consider how to quickly generate heat and dock. Transducers, horns and horns can all be considered mechanical structures for easy analysis of the coupling of their vibrations. In plastic welding, mechanical vibration is transmitted in the form of longitudinal waves. How to effectively transfer energy and adjust the amplitude is the main point of design.
2.2horn
The horn serves as the contact interface between the ultrasonic welding machine and the material. Its main function is to transmit the longitudinal mechanical vibration outputted by the variator evenly and efficiently to the material. The material used is usually high quality aluminum alloy or even titanium alloy. Because the design of plastic materials changes a lot, the appearance is very different, and the horn has to change accordingly. The shape of the working surface should be well matched with the material, so as not to damage the plastic when vibrating; at the same time, the first-order longitudinal vibration solid frequency should be coordinated with the output frequency of the welding machine, otherwise the vibration energy will be consumed internally. When the horn vibrates, local stress concentration occurs. How to optimize these local structures is also a design consideration. This article explores how to apply ANSYS design horn to optimize design parameters and manufacturing tolerances.
3 welding horn design
As mentioned earlier, the design of the welding horn is quite important. There are many ultrasonic equipment suppliers in China that produce their own welding horns, but a considerable part of them are imitations, and then they are constantly trimming and testing. Through this repeated adjustment method, the coordination of horn and equipment frequency is achieved. In this paper, the finite element method can be used to determine the frequency when designing the horn. The horn test result and the design frequency error are only 1%. At the same time, this paper introduces the concept of DFSS (Design For Six Sigma) to optimize and robust design of horn. The concept of 6-Sigma design is to fully collect the customer's voice in the design process for targeted design; and pre-consideration of possible deviations in the production process to ensure that the quality of the final product is distributed within a reasonable level. The design process is shown in Figure 2. Starting from the development of the design indicators, the structure and dimensions of the horn are initially designed according to the existing experience. The parametric model is established in ANSYS, and then the model is determined by the simulation experiment design (DOE) method. Important parameters, according to the robust requirements, determine the value, and then use the sub-problem method to optimize other parameters. Taking into account the influence of materials and environmental parameters during the manufacture and use of the horn, it has also been designed with tolerances to meet the requirements of manufacturing costs. Finally, the manufacturing, test and test theory design and actual error, to meet the design indicators that are delivered. The following step-by-step detailed introduction.
3.1 Geometric shape design (establishing a parametric model)
Designing the welding horn first determines its approximate geometric shape and structure and establishes a parametric model for subsequent analysis. Figure 3 a) is the design of the most common welding horn, in which a number of U-shaped grooves are opened in the direction of vibration on a material of approximately cuboid. The overall dimensions are the lengths of the X, Y, and Z directions, and the lateral dimensions X and Y are generally comparable to the size of the workpiece being welded. The length of Z is equal to the half wavelength of the ultrasonic wave, because in the classical vibration theory, the first-order axial frequency of the elongated object is determined by its length, and the half-wave length is exactly matched with the acoustic wave frequency. This design has been extended. Use, is beneficial to the spread of sound waves. The purpose of the U-shaped groove is to reduce the loss of lateral vibration of the horn. The position, size and number are determined according to the overall size of the horn. It can be seen that in this design, there are fewer parameters that can be freely regulated, so we have made improvements on this basis. Figure 3 b) is a newly designed horn that has one more size parameter than the traditional design: the outer arc radius R. In addition, the groove is engraved on the working surface of the horn to cooperate with the surface of the plastic workpiece, which is beneficial to transmit vibration energy and protect the workpiece from damage. This model is routinely parametrically modeled in ANSYS, and then the next experimental design.
3.2 DOE experimental design (determination of important parameters)
DFSS is created to solve practical engineering problems. It does not pursue perfection, but is effective and robust. It embodies the idea of 6-Sigma, captures the main contradiction, and abandons "99.97%", while requiring the design to be quite resistant to environmental variability. Therefore, before making the target parameter optimization, it should be screened first, and the size that has an important influence on the structure should be selected, and their values should be determined according to the robustness principle.
3.2.1 DOE parameter setting and DOE
The design parameters are the horn shape and the size position of the U-shaped groove, etc., a total of eight. The target parameter is the first-order axial vibration frequency because it has the greatest influence on the weld, and the maximum concentrated stress and the difference in the working surface amplitude are limited as state variables. Based on experience, it is assumed that the effect of the parameters on the results is linear, so each factor is only set to two levels, high and low. The list of parameters and corresponding names is as follows.
DOE is performed in ANSYS using the previously established parametric model. Due to software limitations, full-factor DOE can only use up to 7 parameters, while the model has 8 parameters, and ANSYS's analysis of DOE results is not as comprehensive as professional 6-sigma software, and can't handle interaction. Therefore, we use APDL to write a DOE loop to calculate and extract the results of the program, and then put the data into Minitab for analysis.
3.2.2 Analysis of DOE results
Minitab's DOE analysis is shown in Figure 4 and includes the main influencing factors analysis and interaction analysis. The main influencing factor analysis is used to determine which design variable changes have a greater impact on the target variable, thereby indicating which are important design variables. The interaction between the factors is then analyzed to determine the level of the factors and to reduce the degree of coupling between the design variables. Compare the degree of change of other factors when a design factor is high or low. According to the independent axiom, the optimal design is not coupled to each other, so choose the level that is less variable.
The analysis results of the welding horn in this paper are: the important design parameters are the outer arc radius and the slot width of the horn. The level of both parameters is "high", that is, the radius takes a larger value in the DOE, and the groove width also takes a larger value. The important parameters and their values were determined, and then several other parameters were used to optimize the design in ANSYS to adjust the horn frequency to match the operating frequency of the welding machine. The optimization process is as follows.
3.3 Target parameter optimization (horn frequency)
The parameter settings of the design optimization are similar to those of the DOE. The difference is that the values of two important parameters have been determined, and the other three parameters are related to the material properties, which are regarded as noise and cannot be optimized. The remaining three parameters that can be adjusted are the axial position of the slot, the length and the horn width. The optimization uses the subproblem approximation method in ANSYS, which is a widely used method in engineering problems, and the specific process is omitted.
It is worth noting that using frequency as the target variable requires a little skill in operation. Because there are many design parameters and a wide range of variation, the vibration modes of the horn are many in the frequency range of interest. If the result of modal analysis is directly used, it is difficult to find the first-order axial mode, because the modal sequence interleaving may occur when the parameters change, that is, the natural frequency ordinal corresponding to the original mode changes. Therefore, this paper adopts the modal analysis first, and then uses the modal superposition method to obtain the frequency response curve. By finding the peak value of the frequency response curve, it can ensure the corresponding modal frequency. This is very important in the automatic optimization process, eliminating the need to manually determine the modality.
After the optimization is completed, the design working frequency of the horn can be very close to the target frequency, and the error is less than the tolerance value specified in the optimization. At this point, the horn design is basically determined, followed by manufacturing tolerances for production design.
3.4 Tolerance design
The general structural design is completed after all design parameters have been determined, but for engineering problems, especially when considering the cost of mass production, tolerance design is essential. The cost of low precision is also reduced, but the ability to meet design metrics requires statistical calculations for quantitative calculations. The PDS Probability Design System in ANSYS can better analyze the relationship between design parameter tolerance and target parameter tolerance, and can generate complete related report files.
3.4.1 PDS parameter settings and calculations
According to the DFSS idea, tolerance analysis should be performed on important design parameters, and other general tolerances can be determined empirically. The situation in this paper is quite special, because according to the ability of machining, the manufacturing tolerance of geometric design parameters is very small, and has little effect on the final horn frequency; while the parameters of raw materials are greatly different due to suppliers, and the price of raw materials accounts for More than 80% of horn processing costs. Therefore, it is necessary to set a reasonable tolerance range for the material properties. The relevant material properties here are density, modulus of elasticity and speed of sound wave propagation.
Tolerance analysis uses random Monte Carlo simulation in ANSYS to sample the Latin Hypercube method because it can make the distribution of sampling points more uniform and reasonable, and obtain better correlation by fewer points. This paper sets 30 points. Assume that the tolerances of the three material parameters are distributed according to Gauss, initially given an upper and lower limit, and then calculated in ANSYS.
3.4.2 Analysis of PDS results
Through the calculation of PDS, the target variable values corresponding to 30 sampling points are given. The distribution of the target variables is unknown. The parameters are fitted again using Minitab software, and the frequency is basically distributed according to the normal distribution. This ensures the statistical theory of tolerance analysis.
The PDS calculation gives a fitting formula from the design variable to the tolerance expansion of the target variable: where y is the target variable, x is the design variable, c is the correlation coefficient, and i is the variable number.
According to this, the target tolerance can be assigned to each design variable to complete the task of tolerance design.
3.5 Experimental verification
The front part is the design process of the entire welding horn. After the completion, the raw materials are purchased according to the material tolerances allowed by the design, and then delivered to the manufacturing. Frequency and modal testing are performed after manufacturing is completed, and the test method used is the simplest and most effective sniper test method. Because the most concerned index is the first-order axial modal frequency, the acceleration sensor is attached to the working surface, and the other end is struck along the axial direction, and the actual frequency of the horn can be obtained by spectral analysis. The simulation result of the design is 14925 Hz, the test result is 14954 Hz, the frequency resolution is 16 Hz, and the maximum error is less than 1%. It can be seen that the accuracy of the finite element simulation in the modal calculation is very high.
After passing the experimental test, the horn is put into production and assembly on the ultrasonic welding machine. The reaction condition is good. The work has been stable for more than half a year, and the welding qualification rate is high, which has exceeded the three-month service life promised by the general equipment manufacturer. This shows that the design is successful, and the manufacturing process has not been repeatedly modified and adjusted, saving time and manpower.
4 Conclusion
This paper starts with the principle of ultrasonic plastic welding, deeply grasps the technical focus of welding, and proposes the design concept of new horn. Then use the powerful simulation function of finite element to analyze the design concretely, and introduce the 6-Sigma design idea of DFSS, and control the important design parameters through ANSYS DOE experimental design and PDS tolerance analysis to achieve robust design. Finally, the horn was successfully manufactured once, and the design was reasonable by the experimental frequency test and the actual production verification. It also proves that this set of design methods is feasible and effective.
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