Device and method for testing powder removal performance of low-dielectric glass fiber for ultrahigh-frequency high-speed PCB (Printed Circuit Board)

Abstract

The invention belongs to the technical field of printed circuit boards, and particularly relates to a low-dielectric glass fiber powder removal performance testing device and method for an ultrahigh-frequency high-speed PCB. Comprising a sample rack, a yarn sample is arranged on the sample rack, and a first powder removal storage box, a nozzle and a second powder removal storage box are sequentially arranged from the sample rack to the right; a yarn inlet and a yarn outlet which are formed in the left end and the right end of the nozzle are formed in the first powder removal storage box and the second powder removal storage box respectively; a yarn guide roller is arranged in the first powder removal storage box, and one end of the yarn guide roller penetrates through the first powder removal storage box and is vertically connected with an output shaft of a linear motor; a high-speed camera is arranged at the top of the second pollen removal storage box; pressure sensors are arranged at the bottoms of the first pollen removal storage box and the second pollen removal storage box; the device further comprises a controller, and the pressure sensor and the high-speed camera are electrically connected with the controller. According to the invention, the powder removal performance of the yarn can be evaluated quickly, intuitively and accurately.

Description

Technical Field

[0001] The invention belongs to the technical field of printed circuit boards, and in particular relates to a device and a method for testing the powder removal performance of low-dielectric glass fibers for ultra-high frequency and high-speed PCBs. Background Art

[0002] As electronic products develop towards intelligence, lightweight, high-frequency transmission, and low energy consumption, printed circuit boards (PCBs) also require their core matrix material, low-dielectric glass fiber, to have lower dielectric properties and dielectric loss, and effective adhesion with the reinforced substrate.

[0003] At present, there is a large amount of powder removal problem in the production and processing of electronic cloth, the raw material of ultra-high frequency and high-speed PCB. That is, the sizing agent that protects the surface of low-dielectric glass fiber yarn falls off due to friction. On the one hand, this problem weakens the protective performance of the sizing agent on the yarn, causing the yarn to fuzz during the weaving process, and then piercing the copper foil and affecting the performance of the PCB. On the other hand, since the sizing agent powder that is removed is very light, it is easy to float and adhere to the glass cloth to cause poor desizing, affecting the bonding between the glass fiber and the resin, and then causing the failure of the circuit board CAF. Therefore, evaluating the powder removal performance of low-dielectric glass fiber is of great significance to the production and application of high-performance glass fiber yarn and the development of high-end electronic information industry.

[0004] Traditional powder removal performance testing requires testing the amount of powder removed during customer use, mainly through manual tracking and collection. This method has the disadvantages of long test cycle, large sample consumption and large error in test results. More importantly, the traditional powder removal test only evaluates the amount of powder removed, but does not evaluate the composition of the powder removed and the surface state of the yarn after friction. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a low-dielectric glass fiber powder removal performance testing device and testing method for ultra-high frequency and high-speed PCB, which can quickly, intuitively and accurately evaluate the powder removal performance of the yarn.

[0006] The low-dielectric glass fiber de-powdering performance testing device for ultra-high frequency and high-speed PCB of the present invention comprises a sample rack, on which a yarn sample is arranged, and a de-powdering storage box 1, a nozzle and a de-powdering storage box 2 are arranged in sequence from the beginning of the sample rack to the right; the de-powdering storage box 1 is provided with a yarn gathering port, the de-powdering storage box 2 is provided with an outlet, the nozzle is provided with a compressed air inlet, the de-powdering storage box 1 and the de-powdering storage box 2 are connected through the nozzle, and the yarn inlet and the yarn outlet at the left and right ends of the nozzle are respectively arranged in the de-powdering storage box 1 and the de-powdering storage box 2; the de-powdering storage box 1 is provided with parallel yarn guide rollers, the yarn guide rollers are provided with yarn guide holes, and one end of the yarn guide roller passes through the de-powdering storage box 1 and is vertically connected to the output shaft of the linear motor; a high-speed camera is provided on the top of the de-powdering storage box 2, and the high-speed camera shoots and records the surface state of the yarn sample passing through the de-powdering storage box 2; the bottoms of the de-powdering storage box 1 and the de-powdering storage box 2 are both provided with pressure sensors; and a controller is also included, and the pressure sensor and the high-speed camera are both electrically connected to the controller.

[0007] Preferably, auxiliary rods are provided on the left and right sides of the yarn guide roller, and the auxiliary rods are arranged inside a powder removal storage box. The surface of the auxiliary rods is wrapped with felt. There are 2-4 auxiliary rods. The yarn sample passes through the yarn guide hole. At the same time, the yarn samples at both ends of the yarn guide hole are against the surface of the auxiliary rods. A certain angle is always formed between the yarn guide roller and the adjacent auxiliary rods, so that the yarn sample produces a certain tension, further improving the powder removal efficiency.

[0008] Preferably, the nozzle includes a main nozzle shell, one end of the main nozzle shell is fitted into the inner wall of the main nozzle shell and a core body is inserted; a yarn channel is provided in the middle of the core body, one end of the yarn channel is connected to the yarn inlet, and the other end of the yarn channel is connected to the yarn outlet through a tapered mouth, and a tapered rectifier chamber is formed between the outer wall of the tapered mouth and the inner wall of the main nozzle shell; an annular air storage chamber is provided on the periphery of the core body, a gas diverter valve is provided between the annular air storage chamber and the tapered mouth, and the annular air storage chamber is connected to the tapered rectifier chamber through the gas diverter valve; a compressed air inlet is provided on the main nozzle shell, and the compressed air inlet is connected to the annular air storage chamber.

[0009] Preferably, the compressed air inlet is connected to a compressed air control box, which realizes the delivery and stopping of compressed air. The compressed air control box is provided with a compressed air pressure controller and a compressed air time controller, which are respectively used to adjust the compressed air pressure and the compressed air outlet time.

[0010] Preferably, the first powder removal storage box, the second powder removal storage box and the bottom of the nozzle are all provided with a support frame, which is a telescopic support frame.

[0011] Preferably, the inlet of the first powder removal storage box and the outlet of the second powder removal storage box correspond in parallel.

[0012] Preferably, the powder removal storage box 1 and the powder removal storage box 2 are both made of metal, and more preferably made of stainless steel.

[0013] Preferably, both the first and second powder removal storage boxes are provided with upper covers to facilitate the subsequent movement and handling of the powder removal.

[0014] Each yarn is made up of multiple threads. The impregnation agent is placed on the surface of the yarn, which also plays a certain role in gathering the threads. When the impregnation agent is rubbed off, the threads become fluffy and expand to a certain extent under the spraying action of the nozzle, which is manifested as a larger yarn width. The nozzle sprays the yarn under the action of compressed air; the high-speed camera shoots the surface state of the yarn after spraying and records the change in yarn width after friction. The smaller the width change after friction, the better the film-forming property of the impregnation agent on the yarn surface and the better the protection of the yarn; the pressure sensor automatically transmits the detected pressure signal to the controller and converts it into a weight signal, thereby realizing automatic weighing of the de-powdering weight.

[0015] The yarn surface images taken by the high-speed camera are transmitted to the controller, and after being processed by the controller, the yarn width statistics are performed.

[0016] The method for testing the powder removal performance of low dielectric glass fiber for ultra-high frequency high-speed PCB of the present invention adopts the above-mentioned device and comprises the following steps:

[0017] S1, pull out the yarn sample to be tested, enter the inside of the de-powdering storage box 1 through the yarn gathering port at the inlet of the de-powdering storage box 1, pass through the yarn guide hole on the yarn guide roller and enter the yarn inlet, pass through the nozzle and enter the de-powdering storage box 2 from the yarn outlet, and then pull out from the outlet of the de-powdering storage box 2;

[0018] S2, adjusting the height of the powder removal storage box 1, the nozzle, and the powder removal storage box 2, so that the inlet of the powder removal storage box 1, the yarn inlet of the nozzle and the yarn outlet, and the outlet of the powder removal storage box 2 are parallel and corresponding;

[0019] S3, the external compressed air control box is connected to the compressed air inlet through a pipeline;

[0020] S4, data clearing, setting the injection time to 30-120min, the injection pressure to 3-6MPa, the linear motor movement frequency to 500 times / min, the movement amplitude to 1-2cm, the linear motor drives the yarn guide roller to reciprocate up and down, start the compressed air control box, and the yarn sample rubs against the edge of the yarn guide hole, the auxiliary rod, the yarn inlet and the yarn outlet of the nozzle during the injection process. When the set time is reached, the injection stops automatically;

[0021] S5. Record the yarn delivery speed V and the injection time T, obtain the powder removal weight M1 through the pressure sensor, record the yarn state after injection through a high-speed camera, count the yarn width in the picture, record the yarn width W, and evaluate the powder removal performance of the yarn sample.

[0022] Preferably, in step S1, 9 yarn samples in total are evenly arranged in 3 rows and 3 columns on the sample rack; in step S2, the first inlet of the de-powdering storage box, the nozzle yarn inlet and yarn outlet, and the second outlet of the de-powdering storage box are all arranged opposite to the yarn samples in the 2nd row and the 2nd column.

[0023] Preferably, in step S5, the yarn sample powder removal performance evaluation parameters include:

[0024] N: The amount of powder removed per 10,000 meters,

[0025] N = M1 × 10000 / (V × T);

[0026] H: yarn width before spraying,

[0027] I: average yarn width after spraying,

[0028] J: average yarn width before jetting,

[0029] K: expansion degree,

[0030] I=(W1+W2+W3+..+Wn) / n,

[0031] J=(H1+H2+H3+..+Hn) / n,

[0032] K = (IJ) / J; M2: Collect all the powder in the powder storage box 1 and the powder storage box 2, smolder at 625 ° C for 0.5 h, and record the remaining weight after smoldering as M2;

[0033] E: The proportion of inorganic components in the de-powdering process, F: The proportion of organic components in the de-powdering process,

[0034] E=M2 / M1×100%, F=100%-E.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The present invention can set up multiple yarn samples for simultaneous testing to avoid too small a powder loss amount due to a small number of yarn samples, thereby causing a large error, while saving time and reducing errors caused by changes in the test environment.

[0037] 2. The present invention is equipped with an automatic stop system, and the nozzle spraying can be timed. When the friction time reaches the set value, it stops automatically to prevent manual timing errors;

[0038] 3. A high-speed camera is installed on the top of the second powder removal storage box to record the change in yarn width after friction and evaluate the powder removal performance of the yarn;

[0039] 4. Equipped with a pressure sensor to automatically record the weight of powder removal to avoid manual weighing errors;

[0040] 5. The tension can be changed by adjusting the injection pressure, and the adjustment range is 3-6MPa. The appropriate injection pressure can be selected according to different yarn varieties to avoid too little powder removal due to too low pressure and reduce test errors. At the same time, the present invention is provided with a yarn guide roller, and a yarn guide hole is provided on the yarn guide roller. When the yarn passes through the yarn guide hole and is transmitted forward, the linear motor maintains a certain frequency and moves up and down, driving the yarn guide roller to move up and down, thereby increasing the friction effect. When the yarn guide roller moves up and down, the angle between the yarn guide roller and the adjacent auxiliary rod is always maintained, so that the yarn sample forms tension. The surface of the auxiliary rod is wrapped with felt, which further improves the powder removal efficiency.

[0041] 6. Compared with the traditional method of testing the amount of powder removed during use by customers, the first and second powder removal storage boxes in the present invention are both closed devices, which can avoid the powder from being scattered around due to its light weight, and the amount of powder removed is large;

[0042] 7. Since static electricity is easily generated during the friction powder removal process, the powder removal storage box is made of metal materials such as stainless steel to facilitate the conduction of the charge generated by friction and prevent the powder from flying around and being difficult to clean up due to static electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic structural diagram of a device for testing the powder removal performance of low dielectric glass fibers for ultra-high frequency and high-speed PCBs of the present invention;

[0044] Figure 2 It is a schematic diagram of the structure of a powder removal storage box;

[0045] Figure 3 It is a schematic diagram of the structure of the second powder removal storage box;

[0046] Figure 4 is a schematic diagram of the nozzle structure;

[0047] Figure 5 It is the AA section view;

[0048] In the figure, 1. sample rack; 2. yarn sample; 3. powder removal storage box 1; 4. nozzle; 5. powder removal storage box 2; 6. compressed air inlet; 7. yarn guide roller; 8. high-speed camera; 9. main nozzle housing; 10. core body; 11. yarn channel; 12. conical mouth; 13. uniformly tapered rectifier chamber; 14. annular air storage chamber; 15. gas diverter valve; 16. support frame; 17. compressed air control box; 18. auxiliary rod. DETAILED DESCRIPTION

[0049] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings and embodiments. Figure 1-5As shown, in this embodiment, the low dielectric glass fiber de-powdering performance testing device for ultra-high frequency and high-speed PCB comprises a sample rack 1, on which a yarn sample 2 is arranged, and from the sample rack 1 to the right, a de-powdering storage box 1 3, a nozzle 4 and a de-powdering storage box 2 5 are arranged in sequence, and a retractable support frame 16 is arranged at the bottom of the de-powdering storage box 1 3, the de-powdering storage box 2 5 and the nozzle 4; an inlet is arranged on the de-powdering storage box 1 3, an outlet is arranged on the de-powdering storage box 2 5, and a compressed air inlet 6 is arranged on the nozzle 4, and the de-powdering storage box 1 3 and the de-powdering storage box 2 5 are connected through the nozzle 4, and the left and right ends of the nozzle 4 are The yarn inlet and yarn outlet are respectively arranged in the powder removal storage box 1 3 and the powder removal storage box 2 5; the inside of the powder removal storage box 1 3 is provided with a parallel guide roller 7, the guide roller 7 is provided with a guide hole, one end of the guide roller 7 passes through the powder removal storage box 1 3 and is vertically connected to the output shaft of the linear motor; a high-speed camera 8 is provided on the top of the powder removal storage box 2 5, and the high-speed camera 8 shoots and records the surface state of the yarn sample 2 passing through the powder removal storage box 2 5; pressure sensors are provided at the bottom of the powder removal storage box 1 3 and the powder removal storage box 2 5; a controller is also included, and the pressure sensor and the high-speed camera 8 are electrically connected to the controller.

[0050] An auxiliary rod 18 is respectively provided on the left and right sides of the yarn guide roller 7. The auxiliary rod 18 is arranged inside the powder removal storage box 3, and the surface of the auxiliary rod 18 is wrapped with felt.

[0051] The nozzle 4 includes a main nozzle shell 9, one end of which is fitted into the inner wall of the main nozzle shell 9 and a core body 10 is inserted therein; a yarn channel 11 is provided in the middle of the core body 10, one end of the yarn channel 11 is connected to the yarn inlet, and the other end of the yarn channel 11 is connected to the yarn outlet through a tapered mouth 12, and a uniformly tapered rectifying chamber 13 is formed between the outer wall of the tapered mouth 12 and the inner wall of the main nozzle shell 9; an annular air storage chamber 14 is provided on the outer periphery of the core body 10, a gas diverter valve 15 is provided between the annular air storage chamber 14 and the tapered mouth 12, and the annular air storage chamber 14 is connected to the uniformly tapered rectifying chamber 13 through the gas diverter valve 15; a compressed air inlet 6 is provided on the main nozzle shell 9, and the compressed air inlet 6 is connected to the annular air storage chamber 14.

[0052] The compressed air inlet 6 is connected to a compressed air control box 17 .

[0053] The method for testing the powder removal performance of low dielectric glass fiber for ultra-high frequency high-speed PCB comprises the following steps:

[0054] S1. A total of 9 yarn samples 2 are evenly arranged in 3 rows and 3 columns on the sample rack. The yarn samples 2 to be tested are pulled out respectively, enter the interior of the de-powdering storage box 1 through the yarn gathering port of the de-powdering storage box 1 3, pass through the yarn guide hole on the yarn guide roller 7 and enter the yarn inlet. At the same time, the yarn sample 2 abuts against the surface of the auxiliary rod 18 on both sides of the yarn guide roller 7, passes through the nozzle 4, enters the de-powdering storage box 2 5 from the yarn outlet, and then is pulled out from the outlet of the de-powdering storage box 2 5;

[0055] S2. Adjust the height of the powder removal storage box 1 3, the nozzle 4, and the powder removal storage box 2 5 so that the inlet of the powder removal storage box 1 3, the yarn inlet and yarn outlet of the nozzle 4, and the outlet of the powder removal storage box 2 5 are all arranged opposite to the yarn sample 2 in the 2nd row and the 2nd column; in this way, the yarn samples 2 that are symmetrical about the middle yarn sample 2 (i.e., the yarn sample 2 in the 2nd row and the 2nd column) can form a relatively symmetrical tension.

[0056] S3, the external compressed air control box 17 is connected to the compressed air inlet 6 through a pipeline;

[0057] S4, data is cleared, the injection time is set to 100 min, the injection pressure is set to 3 MPa, the linear motor movement frequency is set to 500 times / min, the movement amplitude is set to 1.5 cm, and the compressed air control box 17 is started. During the injection process, the yarn sample 2 rubs against the edge of the yarn guide hole, the auxiliary rod 18, the yarn inlet and the yarn outlet of the nozzle 4. When the set time is reached, the injection stops automatically;

[0058] S5. Record the yarn delivery speed V and the injection time T, obtain the powder removal weight M1 through the pressure sensor, record the yarn state after injection through the high-speed camera 8, count the yarn width in the picture, record the yarn width W, and evaluate the powder removal performance of the yarn sample 2.

[0059] In step S5, the evaluation parameters of the powder removal performance of the yarn sample 2 include:

[0060] N: The amount of powder removed per 10,000 meters,

[0061] N = M1 × 10000 / (V × T);

[0062] H: yarn width before spraying,

[0063] I: average yarn width after spraying,

[0064] J: average yarn width before jetting,

[0065] K: expansion degree,

[0066] I=(W1+W2+W3+..+Wn) / n,

[0067] J=(H1+H2+H3+..+Hn) / n,

[0068] K = (IJ) / J;

[0069] M2: Collect all the powder in the powder storage box 1 3 and the powder storage box 2 5, and smolder at 625°C for 0.5h. Record the remaining weight after smoldering as M2;

[0070] E: the proportion of inorganic components in the de-powdering process, F: the proportion of organic components in the de-powdering process;

[0071] E=M2 / M1×100%, F=100%-E.

[0072] Samples 1-4 were tested for powder removal performance through the above steps, with a spraying time of 100 minutes and a spraying pressure of 3 MPa. The results are shown in Table 1.

[0073] Table 1 Powder removal performance test table of samples 1-4

[0074]

[0075]

[0076] Among them, tex represents the weight of yarn per kilometer, unit: g / km;

[0077] Glass type E represents ordinary alkali-free glass, and T represents high-strength and high-modulus glass;

[0078] Wetting agent type Y represents a starch-based wetting agent.

[0079] Table 2 Rating table of glass fiber yarn de-powdering performance

[0080]

[0081] According to Table 2, the powder removal performance test level of samples 1 and 2 is A, and the powder removal performance test level of samples 3 and 4 is C.

[0082] Through analysis, sample 1 has the smallest powder removal amount and expansion degree after friction, the highest content of de-powdered organic matter, and the best de-powdering performance.

[0083] By comparing samples 1, 2, and 3, it is shown that the finer the fiber diameter, the better the powder removal performance.

[0084] By comparing samples 3 and 4, it is shown that the powder removal performance of ordinary alkali-free glass is better than that of yarn products of high-strength and high-modulus glass. The reason may be that the yarn products of high-strength and high-modulus glass are hard, brittle, not wear-resistant, and have more powder removal.

[0085] The powder removal amount is detected by the powder removal device method through data, which is consistent with the on-site use situation and has a good evaluation effect. The invention provides a research direction for the development of low-dielectric glass fiber spun yarn products.

[0086] The low dielectric glass fiber powder removal performance testing device and testing method of the embodiments of the present invention described above in combination with the drawings are used to achieve the powder removal performance detection and evaluation of low dielectric glass fiber yarns, solving the problems existing in the prior art.

Claims

1. A low dielectric glass fiber powder removal performance test device for ultra-high frequency high-speed PCB, characterized in that: The invention comprises a sample rack (1), on which a yarn sample (2) is arranged, and a first de-powdering storage box (3), a nozzle (4) and a second de-powdering storage box (5) are arranged in sequence from the sample rack (1) to the right; the first de-powdering storage box (3) is provided with a yarn gathering port, the second de-powdering storage box (5) is provided with an outlet, the nozzle (4) is provided with a compressed air inlet (6), the first de-powdering storage box (3) and the second de-powdering storage box (5) are connected through the nozzle (4), and the yarn inlet and the yarn outlet at the left and right ends of the nozzle (4) are respectively arranged in the first de-powdering storage box (3) and the second de-powdering storage box (5); A yarn guide roller (7) arranged in parallel is arranged inside the first de-powdering storage box (3), the yarn guide roller (7) is provided with a yarn guide hole, one end of the yarn guide roller (7) passes through the first de-powdering storage box (3) and is vertically connected to the output shaft of the linear motor; a high-speed camera (8) is arranged on the top of the second de-powdering storage box (5), and the high-speed camera (8) takes pictures and records the surface state of the yarn sample (2) passing through the second de-powdering storage box (5); pressure sensors are arranged at the bottom of the first de-powdering storage box (3) and the second de-powdering storage box (5); and a controller is also included, and the pressure sensor and the high-speed camera (8) are both electrically connected to the controller.

2. The low dielectric glass fiber powder removal performance testing device for ultra-high frequency high-speed PCB according to claim 1 is characterized in that: Auxiliary rods (18) are also provided on the left and right sides of the yarn guide roller (7), and the auxiliary rods (18) are arranged inside the powder removal storage box (3), and the surface of the auxiliary rods (18) is wrapped with felt.

3. The low dielectric glass fiber powder removal performance testing device for ultra-high frequency high-speed PCB according to claim 1 is characterized in that: The nozzle (4) comprises a main nozzle housing (9), one end of the main nozzle housing (9) being fitted with the inner wall of the main nozzle housing (9) and having a core body (10) inserted therein; a yarn channel (11) is provided in the middle of the core body (10), one end of the yarn channel (11) is connected to a yarn inlet, the other end of the yarn channel (11) is connected to a yarn outlet via a conical opening (12), and a uniformly tapered rectifying chamber (13) is formed between the outer wall of the conical opening (12) and the inner wall of the main nozzle housing (9); an annular air storage chamber (14) is provided on the outer periphery of the core body (10), a gas diverter valve (15) is provided between the annular air storage chamber (14) and the conical opening (12), and the annular air storage chamber (14) is connected to the uniformly tapered rectifying chamber (13) via the gas diverter valve (15); a compressed air inlet (6) is provided on the main nozzle housing (9), and the compressed air inlet (6) is connected to the annular air storage chamber (14).

4. The low dielectric glass fiber powder removal performance testing device for ultra-high frequency high-speed PCB according to claim 3 is characterized in that: The compressed air inlet (6) is connected to the compressed air control box (17).

5. The low dielectric glass fiber powder removal performance testing device for ultra-high frequency high-speed PCB according to claim 1, characterized in that: A support frame (16) is provided at the bottom of the first powder removal storage box (3), the second powder removal storage box (5) and the nozzle (4).

6. The low dielectric glass fiber powder removal performance testing device for ultra-high frequency high-speed PCB according to claim 1, characterized in that: The inlet of the powder removal storage box 1 (3) and the outlet of the powder removal storage box 2 (5) correspond in parallel.

7. A method for testing the powder removal performance of low dielectric glass fiber for ultra-high frequency high-speed PCB, using the device described in any one of claims 1 to 6, characterized in that: The steps include: S1, the yarn sample (2) to be tested is pulled out, enters the interior of the de-powdering storage box one (3) through the yarn gathering port of the de-powdering storage box one (3), passes through the yarn guide hole on the yarn guide roller (7) and enters the yarn inlet, passes through the nozzle (4) and enters the de-powdering storage box two (5) from the yarn outlet, and then is pulled out from the outlet of the de-powdering storage box two (5); S2, adjusting the height of the powder removal storage box 1 (3), the nozzle (4), and the powder removal storage box 2 (5) so that the inlet of the powder removal storage box 1 (3), the yarn inlet of the nozzle (4), the yarn outlet, and the outlet of the powder removal storage box 2 (5) are parallel and corresponding; S3, an external compressed air control box (17) is connected to a compressed air inlet (6) via a pipeline; S4, data is cleared, the spraying time is set to 30-120 min, the spraying pressure is set to 3-6 MPa, the linear motor movement frequency is set to 500 times / min, the movement amplitude is set to 1-2 cm, the linear motor drives the yarn guide roller (7) to move up and down, and the compressed air control box (17) is started. During the spraying process, the yarn sample (2) rubs against the edge of the yarn guide hole, the auxiliary rod (18), the yarn inlet and the yarn outlet of the nozzle (4). When the set time is reached, the spraying stops automatically; S5, record the yarn delivery speed V, the injection time T, obtain the powder removal weight M1 through the pressure sensor, record the yarn state after injection through the high-speed camera (8), count the yarn width in the picture, record the yarn width W, and evaluate the powder removal performance of the yarn sample (2).

8. The method for testing the powder removal performance of low dielectric glass fiber for ultra-high frequency high-speed PCB according to claim 7, characterized in that: In step S1, 9 yarn samples (2) are evenly arranged in 3 rows and 3 columns on the sample rack (1); in step S2, the inlet of the first de-powdering storage box (3), the yarn inlet and yarn outlet of the nozzle (4), and the outlet of the second de-powdering storage box (5) are all arranged opposite to the yarn samples (2) in the second row and the second column.

9. The method for testing the powder removal performance of low dielectric glass fiber for ultra-high frequency high-speed PCB according to claim 7, characterized in that: In step S5, the evaluation parameters of the powder removal performance of the yarn sample (2) include: N: The amount of powder removed per 10,000 meters, N = M1 × 10000 / (V × T); H: yarn width before spraying, I: average yarn width after spraying, J: average yarn width before jetting, K: expansion degree, I=(W1+W2+W3+..+Wn) / n, J=(H1+H2+H3+..+Hn) / n, K = (IJ) / J; M2: Collect all the powder in the powder storage box 1 (3) and the powder storage box 2 (5), and smolder at 625°C for 0.5h. Record the remaining weight after smoldering as M2; E: The proportion of inorganic components in the de-powdering process, F: The proportion of organic components in the de-powdering process, E=M2 / M1×100%, F=100%-E.

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