Nowadays, in the actual microelectronic packaging process, the requirements for packaging quality and accuracy are becoming higher and higher. The research and prediction of the corresponding parameters of the transfer droplet according to the actual requirements before packaging can not only accurately adjust the relevant configuration parameters of the transfer droplet, but also judge the actual packaging effect preliminarily, and to improve the packaging efficiency and accuracy. Therefore, it is of practical significance to carry out the research on the distribution law and prediction method of transfer droplet parameters. In this paper, based on the needle transfer ultra-micro-volume transfer droplet method, a transfer droplet device that meets the packaging requirements is built, and the reasonable configuration of device parameters is realized through the control system. The pixel method suitable for practical application was found to determine the volume of transfer droplet, and the average deviation of the volume of transfer droplet measured by this method was about 1.85%. By changing the initial distance of the adhesive distribution experiment, it is concluded that the larger the initial distance, the smaller the volume of the transfer droplet, and the smaller the contact area of the transfer droplet. According to the data obtained from the adhesive distribution experiment, the prediction formula of the relationship between the initial distance, the volume of the transfer droplet and the contact area of the transfer droplet is derived. It is found that the average difference rate between the predicted volume and the actual volume is 0.51%, and the average difference rate between the predicted contact area and the actual contact area is 0.56%.
Research Article
Study on Determination and Prediction Method of ultra-micro-volume Adhesive Droplet Volume Parametres
https://doi.org/10.21203/rs.3.rs-2442495/v1
This work is licensed under a CC BY 4.0 License
Journal Publication
published 04 Aug, 2023
Read the published version in The International Journal of Advanced Manufacturing Technology →
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Microelectronic packaging
Adhesive prediction
Initial distance
Contact area
Adhesive volume
In the field of micromechanics, the needle transfer ultra-micro-volume dispensing method is proposed to meet the demand of micro assembly/sealing engineering for the ultra-micro-volume dispensing. Under the control of the micro movement platform, the pipetting needle is used to pass through the capillary tube with adhesive, and a small amount of adhesive is adsorbed at the tip of the pipetting needle. When the tip of the pipetting needle approaches the base, the tiny spherical crown adhesive droplets adsorbed by the tip of the pipetting needle will contact the base. After the pipetting needle leaves the base, part of the adhesive will remain on the base to realize ultra-micro-volume dispensing. By matching the dispensing parameters, the dispensing amount can be controlled.
Dispensing technology has a wide range of applications, ranging from semiconductor packaging industry, integrated circuit industry, SMT/PCB assembly industry to welding, injection coating and sealing in general industry. Dispensing technology plays a vital role [1]. Fugere et al, proposed a screw pump type micro dispensing method, which ensures the size of micro adhesive droplets by means of fine design of dispensing needle and selection of micro screw pump with programmable precision control. The minimum size of adhesive droplets can be controlled at 254µm. However, due to the system response delay in the process of electric machine acceleration and deceleration, it is difficult to control the sampling process quickly and accurately. Shi Y L et al, proposed a time/pressure type micro dispensing method [2–3]. According to the assembly requirements of the connection and sealing between the target and the inflation tube in the inertial confinement fusion experiment, a time/pressure type pL level micro dispensing platform was designed and built. However, since the adhesive was extruded by the pressurization method, the vibration generated during the pressurization process would affect the consistency of dispensing, and the pressure would cause the temperature in the syringe to rise, affecting the viscosity of the adhesive, all these factors affect the control of the dispensing amount. This method is only applicable to the adhesive with a viscosity not greater than 500cPs. Due to the problem of dispensing principle, needle transfer dispensing is difficult to realize micro dispensing with high repetition accuracy. The precise adjustment of dispensing amount is cumbersome, expensive and difficult to clean, and the advantage is that the applicable viscosity range is large [4].
With the miniaturization of mechanical and electronic products, the size of micro assembly components is getting smaller and smaller, and the precision of quantitative and fixed-point distribution of adhesive in dispensing technology is becoming higher and higher [5]. The research of ultra-micro-volume dispensing technology is an indispensable condition to promote the development of precision manufacturing industry, and an indispensable front-end condition for the development of chip industry in China. Therefore, this paper conducts needle transfers ultra-micro-volume dispensing experiment on the premise of ultra-micro-volume dispensing.
In order to highlight the experimental effect and avoid the influence of other factors on the experimental results, a pipetting needle with a uniform tip diameter and an adhesive with the same quality and viscosity were selected in the experiment. By changing the initial distance of adhesive distribution and controlling the contact area between the crown adhesive of the pipetting needle adsorption ball and the base, the size of the formed adhesive droplet can be controlled, and to realize ultra-micro-volume dispensing. In this paper, the method of needle transfer ultra-micro-volume dispensing is realized. By controlling and analyzing the initial distance of adhesive distribution and the contact area of transfer droplets, the diameter and volume of shaped adhesive droplets can be easily changed, and the general rules can be obtained through experimental verification. It is believed that needle transfer ultra-micro-volume dispensing will have broad development prospects in the future.
The significance of studying the needle transfer ultra-micro-volume dispensing method is to realize the precise packaging of the micro system. In general, the needle transfer ultra-micro-volume dispensing process consists of four stages: adhesive taking, extrusion, stretching and gelation [6], as shown in Fig. 1. In the adhesive taking stage, the pipetting needle moves downward through the capillary tube filled with adhesive and attaches a small amount of adhesive to the surface and tip of the pipetting needle [7–8]. In the extrusion stage, the initial droplet at the tip of the pipetting needle contacts the base to form a liquid bridge, and the two solid surfaces have an extrusion effect on the initial droplet, which will continue until the pipetting needle reaches the initial distance of the adhesive distribution [9–10]. In the stretching stage, the pipetting needle moves upward, and the liquid bridge is elongated under the action of adhesive force [11–12]. In the gelation stage, the pipetting needle continues to move upward until the liquid bridge is broken. The adhesive left on the base spreads outward under the action of cohesion and viscous force until a transfer droplet is formed [13].
3.1 On demand design and construction of adhesive distribution device
The adhesive distribution device needs to select a suitable precision drive control platform to meet the requirement of accurate packaging position. When distributing the adhesive, select a suitable distribution device to ensure that the volume of the transfer droplet meets the actual requirements. In order to observe the distribution process and analyze the adhesive distribution results, it is also necessary to configure a suitable micro morphology observation device. Therefore, the designed experimental device needs to meet the requirements of driving, adhesive distribution and observation. The adhesive distribution system designed according to the requirements is shown in Fig. 2(a), and the actual adhesive distribution device built according to the design scheme is shown in Fig. 2(b).
The three-axis drive platform is controlled by the host computer, which can drive the pipetting needle to achieve three degrees of freedom. The host computer is used to write the control program to meet the requirements of the experiment. For convenience, the control function is transmitted to the touch screen through the switch. The control part and motion function of the three-axis drive platform are shown in Fig. 3.
The initial distance, residence time, stretching speed, drive mode, movement direction and other parameters can be set through the touch screen and the host computer. The initial distance refers to the distance from the pipetting needle to the base under the static state, the residence time refers to the time that the pipetting needle stays at the static state until it leaves the initial distance, the stretching speed refers to the speed of the pipetting needle stretching the liquid bridge, the drive mode includes manual control and automatic control, and the moving direction refers to the direction of the three-axis drive platform controlling the movement of the pipetting needle.
The adhesive distribution device can realize the transfer and distribution of adhesive, as shown in Fig. 4. The pipetting needle is the key component of the dispensing device, which is responsible for adhering the adhesive in the capillary tube and transferring it to the base. The tungsten needle with a diameter of tens of microns with good strength and toughness is selected. The capillary tube is responsible for storing the adhesive, and ordinary glass capillary tubes with a diameter of several hundred microns can be selected.
The micro morphology observation device is used to observe the distribution process of adhesive and measure the corresponding data of transfer droplets. The selected super depth of field microscope can achieve 100 ~ 1000 times magnification function, and real-time observation can be carried out through the microscope display. The observation image can be adjusted in real time through the fine-tuning handle to meet the needs of micro-observation [14].
3.2 Application test of adhesive distribution device
Before the experiment, adjust and fix the relative position of the three-axis drive platform. The pipetting needle is fixed at the moving end of the Z-axis drive platform, the moving end is responsible for driving the pipetting needle to move, the capillary tube is fixed at the fixed end of the Z-axis drive platform, and the fixed end is responsible for fixing the capillary tube. After fixing, adjust the relative positions of the pipetting needle and the capillary tube so that they are in the same vertical axis to ensure that there will be no interference in the distribution process of the adhesive. Adjust the relative position between the pipetting needle and the base through the touch screen, and set the initial distance, residence time, stretching speed and other relevant parameters.
The actual process of adhesive distribution is obtained through the experiment. The actual adhesive distribution process observed by the microscope is shown in Fig. 5. The complete process of adhesive distribution can be clearly observed from the figure. This process is consistent with the theoretical analysis process. The diameter of the obtained adhesive droplets is tens of microns, which indicates that the designed and built adhesive distribution device can realize ultra-micro-volume precise packaging on the surface of the object. Therefore, it is of practical significance to study the needle transfer ultra-micro-volume dispensing method.
In the actual micro system packaging, it is usually required to package the material surface of micron size. Therefore, it is the key to ensure the packaging quality to ensure the accuracy of the packaging position and the appropriate volume of the transfer droplet. The accuracy of the packaging position is related to the performance of the drive device, and the volume of the transfer droplet is related to the design parameters. In order to obtain the accurate value of the volume of the transfer droplet with a more convenient method, it is necessary to study and compare the determination methods of the volume of the transfer droplet.
4.1 Determination of adhesive droplet volume by formula method
The theoretical morphology of the transfer droplets formed by the needle transfer ultra-micro-volume dispensing method is shown in Fig. 6. When the adhesive distribution process is in the gelation stage, the adhesive left on the base is mainly affected by the inertial force and surface tension. The inertial force causes the adhesive left on the base to spread outward, and the surface tension prevents the adhesive from spreading outward. Over time, the force of the adhesive reaches an equilibrium state, and the adhesive finally forms a spherical crown transfer droplet on the base [15].
In Fig. 6, θ is the static contact angle between the base and the transfer droplet, r is the radius of the transfer droplet after equilibrium, h is the height maintained by the transfer droplet under the surface tension, and r1 is the radius of the curved surface of the transfer droplet. The transfer droplet can be regarded as a spherical coronal model obtained by rotating the Y-axis as the rotation axis [16], and the volume V1 of the transfer droplet can be obtained as:
$${V_1}=\pi \int_{{{r_1} - h}}^{{{r_1}}} {{x^2}dy} =\pi \int_{{\frac{h}{{\sin \theta }} - h}}^{{\frac{h}{{\sin \theta }}}} {({r^2} - {y^2})dy}$$
1
By integrating Eq. (1), the formula for calculating the volume of transfer droplet is:
$${V_1}=\pi {h^2}(\frac{r}{{\sin \theta }} - \frac{h}{3})$$
2
By analyzing the calculation Eq. (2) of the volume of the transfer droplet, when the adhesive reaches the equilibrium state, the radius r, height h and contact angle θ of the transfer droplet. The relationship between the volume of the transfer droplet and these three variables is that the larger the radius of the transfer droplet, the higher the height of the transfer droplet, the smaller the contact angle of the transfer droplet, and the larger the volume of the transfer droplet. The radius of transfer droplet is related to the diameter of the pipetting needle, and the transfer droplet height and the transfer droplet contact angle are related to the base material [17].
The purpose of this section is to study the method to determine the volume of the transfer droplet. Therefore, it is only needed to select the appropriate pipetting needle, adhesive capillary tube, adhesive and base, and fix the initial distance, residence time and stretching speed. The tungsten needle with a tip diameter of 80µm after electrolytic grinding is selected as the pipetting needle, ordinary glass capillary tube with inner diameter of 0.8mm is selected as the capillary tube, epoxy resin adhesive with viscosity of 1000cPs and density of 1.15 ± 0.5g/cm3 is selected as the adhesive, and the clean glass with ultrasonic cleaning is selected as the base. The initial distance is set to 0µm, the residence time is set to 2s, and the stretching speed is set to 1.5mm/s.
The radius, height and contact angle of the transfer droplet can be measured and marked by the super depth of field microscope to determine the volume of the transfer droplet by the formula method. The actual transfer droplet obtained by the adhesive distribution experiment is shown in Fig. 7. It can be seen from the figure that the diameter of the transfer droplet is 99.9µm, the height is 16.3µm and the contact angle is 52.2°. The calculation result of the volume of the transfer droplet is 48.23pL by substituting the measured value into Eq. (2).
4.2 Determination of the volume of the transfer droplet by pixel method
The principle of pixel method to determine the volume of the transfer droplet is to combine the microscopic morphology of the transfer droplet photographed by the microscope with the image recognition technology and determine the volume of the transfer droplet by scan method, gray-scale processing, removing noise and outline fitting finally.
The volume of the two-dimensional image of the transfer droplet obtained in Fig. 7 is determined by the pixel method. The image comparison before and after the treatment of the transfer droplet is shown in Fig. 8. It can be observed from the figure that the cross-sectional shape of the treated transfer droplet is not a regular spherical crown, and the non-smooth phenomenon of the surface of the transfer droplet does not conform to the actual situation of the smooth and round surface after the fluid spreading. Therefore, the obtained image of the transfer droplet cannot be used directly and needs further processing.
The outline extraction is performed on the image of the transfer droplet after the gray-scale processing. The extracted outline curve of the transfer droplet is shown in Fig. 9(a). It is observed from Fig. 9(a) that the outline of the transfer droplet is not a regular curve. At this time, the calculation of the volume of the transfer droplet will cause a large deviation in the results. Therefore, the outline of the transfer droplet is processed by fitting. The outline of the transfer droplet obtained after the four fitting processes is shown in Fig. 9(b). According to the outline curve of the transfer droplet obtained in Fig. 9(b), the volume of the transfer droplet can be determined by integrating layer by layer, and the volume of the transfer droplet is 47.81pL.
4.3 Determination of the volume of the transfer droplet by scan method
The determination of the volume of the transfer droplet by scan method is based on the principle of scanning imaging and data processing. Since the volume of the transfer droplet is basically at the level of pL, it is very difficult to obtain the three-dimensional image of the transfer droplet through scanning. Due to scan distortion and environmental factors, it is easy to make the measurement of the transfer droplet volume deviate. Therefore, it is necessary to deal with the part with deviation under the condition that the environment is relatively sealed as much as possible.
The three-dimensional image of the transfer droplet obtained by scanning the microscope is shown in Fig. 10(a). In order to obtain accurate value of volume, it is necessary to extract the transfer droplet. The data obtained by scanning are 1600×1200 data points. Each data point is composed of position value and height value. The relevant data points of the transfer droplet are extracted from the data points and the distortion data points are compensated to obtain the model of the transfer droplet. As shown in Fig. 10(b), the volume of the transfer droplet can be determined by integrating the volume of the transfer droplet model with the simulation software. Finally, the measured volume of the transfer droplet is 46.85pL.
4.4 Comparison of determination methods of the transfer droplet volume
The formula method determines the volume of the transfer droplet through the radius, height and contact angle of the transfer droplet, and the default transfer droplet is the spherical crown. The pixel method determines the volume of the transfer droplet through the two-dimensional image of the transfer droplet, and the default section of the transfer droplet is same. The scan method determines the volume of the transfer droplet through the three-dimensional coordinates of the transfer droplet. The volume of the transfer droplet can be determined only after the data points are processed.
The above three methods can determine the volume of the transfer droplet, but there are differences in the volume values determined by different methods for the same transfer droplet. In order to compare the advantages and disadvantages of the three methods and ensure that the experimental conditions are unchanged (select epoxy resin with viscosity of 1000cPs, pipetting needle with diameter of 80µm, initial distance set to 0µm, residence time set to 2s, and stretching speed set to 1.5mm/s.), complete a group of adhesive distribution experiments and select 10 transfer droplets randomly from them for volume measurement by three methods and analyze the measurement results. The results are shown in Fig. 11.
It can be seen from Fig. 11 that for the same transfer droplet, the volume of the transfer droplet measured by the formula method is the largest, and the average volume is 49.03pL. The volume of transfer droplet measured by pixel method was the second, with an average volume of 48.56pL. The volume of the transfer droplet measured by scan method was the smallest, and the average volume was 47.68pL. The formula method has the characteristics of easy parameter measurement and simple calculation. However, the formula method defaults to the round and regular spherical crown, which leads to a certain deviation between the results measured by the formula method and the results obtained by the pixel method and the scan method. The results of the scan method to determine the volume of the transfer droplet are the closest to the real value, but it takes a lot of time to process the data points, which makes the measurement efficiency of the volume of the transfer droplet low and is not suitable for actual. The pixel method determines the volume of the transfer droplet through the real cross-sectional image of the transfer droplet. It has the characteristics of simple measurement and high efficiency, and its average volume is about 101.85% of the volume by the scan method. The measurement result is close to the real value. By comparing and analyzing three methods to determine the volume of transfer droplet, this paper will use pixel method to measure the volume of transfer droplet.
The purpose of this paper is to study the influence of the initial distance of adhesive distribution and the contact area of transfer droplets on the dispensing performance. The key to the technology is to accurately control the initial distance of adhesive distribution. Through reasonable configuration of parameters, the law between the volume of transfer droplets and the parameter configuration is found and applied to the actual packaging process.
5.1 Experiment of adhesive distribution by changing initial distance
In order to ensure that the adhesive distribution experiment is not affected by environmental factors, the experiment is arranged in a closed space with room temperature of 25 ℃ and relative humidity of 50%. The control variable method was used in the experiment, and the initial distance was set as a variable. Other experimental conditions were unchanged, epoxy resin with a viscosity of 1000cPs was selected as the adhesive, ordinary glass capillary tube with an inner diameter of 0.8mm was selected as the capillary tube, clean glass slides with ultrasonic cleaning were selected as the base, select tungsten needle with tip diameter of 80µm as pipetting needle, the residence time was set to 2s and the stretching speed was set to 1.5mm/s, and only the initial distance of adhesive distribution was changed.
In order to ensure the quality of the transfer droplets packaging, it is necessary to test the height of the initial droplet and determine a reasonable initial distance range. A pipetting needle with a diameter of 80µm was used to complete 100 times of adhesive taking and the height of the initial droplet was measured. The measurement results of the initial droplet height are shown in Fig. 12. It can be seen from the figure that the height of the initial droplet is between 16.5µm and 17.8µm, and the average height is 17.09µm. Therefore, the upper limit of the initial distance was set to 15µm, and six groups of experiments were conducted. The initial distance of each group of experiments was set to 0µm, 3µm, 6µm, 9µm, 12µm and 15µm.
In order to reflect the universality of the experimental results, multiple sampling was carried out under the same parameters, and each group completed 100 times of adhesive distribution. The morphology of some transfer droplets under the condition of changing the initial distance is shown in Fig. 13. From the figure, the appearance of transfer droplets is round and there is no obvious defect.
The volume of each group of transfer droplets is measured by pixel method and the average value is taken. The contact area of each group of transfer droplets is calculated and the average value is taken according to the measurement results of the radius of transfer droplets. See Table 1 for specific data. It can be seen from Table 1 that the larger the initial distance, the smaller the volume of the transfer droplet, and the smaller the contact area of the transfer droplet. The average volume of the transfer droplets decreased from 47.27pL to 24.33pL, and the average contact radius of the transfer droplets decreased from 7607.76µm² to 4144.21µm².
|
Initial distance (µm) |
0 |
3 |
6 |
9 |
12 |
15 |
|---|---|---|---|---|---|---|
|
Average volume of transfer droplet (pL) |
47.27 |
39.08 |
31.93 |
28.51 |
26.13 |
24.33 |
|
Average contact area of transfer droplet (µm2) |
7607.76 |
6889.67 |
5376.76 |
4639.71 |
4361.5 |
4144.21 |
The main reasons for the change of parameter configuration law are described as follows. Since the experimental adhesive and the pipetting needle are not changed, the volume of the initial droplet is almost the same after each adhesive taking, so the volume of the liquid bridge formed by the initial droplet contacting the base is almost unchanged. However, as the initial distance increases, the height of the liquid bridge increases, and the contact area between the liquid bridge and the base decreases. Since the volume of the transfer droplet is related to the viscous force [18], the larger the initial distance, the viscous force between the liquid bridge and the base will gradually weaken, the smaller the attraction of the base to the adhesive, so that the volume of the formed transfer droplet will gradually decrease.
5.2 Prediction and verification of parameter allocation law
From Section 5.1, it is concluded that the larger the initial distance, the smaller the volume of the transfer droplet, and the smaller the contact area of the transfer droplet. However, in the actual microelectronic packaging process, there are usually restrictions on the size and volume of the transfer droplet, so it is necessary to predict the relevant values before packaging.
In Section 5.1, many experiments have been carried out on the relationship between the initial distance, contact area and the volume of transfer droplet, and the experimental results are universal. Therefore, the data in Table 1 is used to predict the transfer droplet parameter configuration law. The prediction results of the parameter configuration law are shown in Fig. 14. Extract the relevant data points of the initial distance and the volume of transfer droplet and select the appropriate function and algorithm to perform nonlinear curve fitting on the data points. In order to make the fitting result reliable, 95% confidence band and 95% prediction band are set. After four iterations, the fitting converges, and the predicted results of the volume of transfer droplet are shown in Fig. 14(a). The same method is used to predict the law between the initial distance and the contact area. After five iterations, the fitting converges, and the prediction results of the contact area of the transfer droplets are shown in Fig. 14(b).
According to the fitting curve of the parameter configuration, the prediction Eq. (3) for the volume of the transfer droplet and the prediction Eq. (4) for the contact area of the transfer droplet are derived. In Eq. (3) and Eq. (4), V represents the predicted volume of the transfer droplet, S represents the predicted contact area of the transfer droplet, and x represents the initial distance.
In addition, if the parameter configuration conditions are not considered, the numerical relationship between the volume and contact area of transfer droplet can also be predicted in the adhesive distribution experiment conducted in this paper. The prediction results are shown in Fig. 15.
From the prediction results, the dispensing method proposed in this paper can roughly predict the volume and contact area of the droplet with a volume of 25pL ~ 47pL and a contact area of 4200µm2 ~ 7600µm2. This method can be used to predict the feasibility of microelectronic packaging and improve its reliability and efficiency. In order to facilitate the prediction of the V-S value of the transfer droplet, the V-S prediction Eq. (5) is derived according to the fitting curve, and the relevant data can be used.
$$S=19424.14945 - 1638.94464V+54.49034{V^2} - 0.53114{V^3}$$
5
In order to verify the accuracy of the prediction results, the adhesive distribution experiment was designed to change the initial distance, and the initial distance was set to 1µm, 4µm, 7µm, 10µm and 13µm. The morphology of transfer droplets at different initial distances is shown in Fig. 16. Through observation and test, it is found that the dispensing method proposed in this paper meets the packaging requirements and has application value.
The same method as that in Section 5.1 is adopted for the test. Each group only changes the initial distance, and a total of 5 groups of experiments are conducted. Each group completes 100 sampling and takes the average value of the volume and contact area of the transfer droplets. See Table 2 for the specific experimental data.
|
Initial distance (µm) |
1 |
4 |
7 |
10 |
13 |
|---|---|---|---|---|---|
|
Predicted volume (pL) |
44.03 |
36.18 |
31.01 |
27.59 |
25.34 |
|
Actual volume (pL) |
43.88 |
36.21 |
31.13 |
27.41 |
25.06 |
|
Difference rate of volume (%) |
0.34 |
0.08 |
0.39 |
0.66 |
1.1 |
|
Predicted contact area (µm2) |
7562 |
6339.95 |
5062.97 |
4498.74 |
4261.7 |
|
Actual contact area (µm2) |
7549.21 |
6341.12 |
5086.34 |
4456.27 |
4211.33 |
|
Difference rate of contact area (%) |
0.17 |
0.02 |
0.46 |
0.95 |
1.2 |
It can be seen from Table 2 that the difference between the predicted value and the actual value is small, the average difference rate between the predicted volume and the actual volume is 0.51%, and the average difference rate between the predicted contact area and the actual contact area is 0.56%. Therefore, it is further proved that the proposed method can be applied to the actual microelectronic packaging.
In this paper, based on the mechanism of transferring ultra-micro-volume amount of adhesive by pipetting needle, the influence of the initial distance of adhesive distribution on the volume and contact area of transfer droplets is studied and predicted. The specific conclusions are as follows.
-
Three methods to determine the volume of transfer droplet are proposed. By analyzing the characteristics of these three methods, the pixel method suitable for practical application is found to determine the volume of transfer droplet. The results show that the pixel method has the characteristics of convenient use, high efficiency and accurate measurement. The average volume of the transfer droplet measured by the pixel method is about 101.85% of the volume measured by the scan method.
-
According to the requirements of use and packaging, the adhesive distribution experiment with changing the initial distance was designed. The influence of the initial distance of adhesive distribution on the volume of transfer droplets and the contact area of transfer droplets was studied. It was concluded that the larger the initial distance, the smaller the volume of transfer droplets, and the smaller the contact area of transfer droplets.
-
According to the data obtained from the adhesive distribution experiment, the prediction formula of the relationship between the initial distance, the volume of the transfer droplet and the contact area is derived. It is found that the average difference rate between the predicted volume and the actual volume is 0.51%, and the average difference rate between the predicted contact area and the actual contact area is 0.56%. It further proves that the prediction formula has application value and feasibility.
Funding
This work was supported by the National Natural Science Foundation of China (Grant No. 52175428), Liaoning Revitalization Talents Program (Grant No. XLYC2007072), Shenyang Collaborative Innovation Center Project for Multiple Energy Fields Composite Processing of Special Materials (Grant No. JG210027) and Shenyang Key Technology Special Project of “The Open Competition Mechanism to Select the Best Solution”(Grant No. 2022210101000827, 2022-0-43-048).
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