Lantern sheet laser transfer printing preparation process

Abstract

The laser transfer printing preparation process comprises the following steps that a 200-420-mesh silk screen plate is manufactured, and the size of the screen plate is 3-5% smaller than the actual size of the lantern sheet; a UV gloss oil feeding system is installed on the screen printing machine, and the pressure and angle of a scraper are adjusted; the laser transfer film is installed on a film material conveying system of a cold ironing laser transfer machine with the tension of 5-13 kg; printing a UV gloss oil layer on the sheet; coining transfer of the laser holographic pattern is completed in a cold ironing laser transfer machine; by means of the preparation technology of the scheme, laser transfer printing of 3000 lantern pieces made of PVC materials can be achieved per hour (3000 pressing reflectors are produced), and the semi-automation efficiency is improved by about 1775% compared with the semi-automation efficiency of an existing hydraulic device.

Description

Technical Field

[0001] The invention belongs to the technical field of sheet material production, and in particular relates to a laser transfer preparation process for lantern sheets. Background Art

[0002] The lanterns on the market now add ordinary lighting inside the lantern, and the light passes through the lantern sheet to form various textures that focus and refract various shapes of lighting effects (such as the industry called: Water Cube, Starry Sky and other effect patterns). At present, a nickel material is actually used to form a mold with patterns such as Water Cube or Starry Sky through chemical reactions, and then a flat stainless steel sheet of appropriate thickness is placed on the PVC lantern sheet, and a nickel mold is placed under the PVC lantern sheet, so that the PVC lantern sheet is sandwiched between the stainless steel sheet and the nickel mold. Then, a hydraulic press of a certain tonnage is used, and a heating device is added to the hydraulic press platform. The entire set of stainless steel sheets and nickel molds with PVC lantern sheets are manually placed in the hydraulic press. The hydraulic press presses and heats for a certain period of time to form the lantern. After the hydraulic press presses and heats for a certain period of time, the equipment is released and manually taken out and placed in the cold zone device next to it. The cold zone is then manually taken out from the cold zone device to form various texture effects of the lantern sheet, which is commonly known as: pressed reflective sheet in the industry.

[0003] However, the biggest problem with this "pressed reflective sheeting" production process is its low efficiency (the hydraulic press, heating device, cold zone device and other equipment currently used in the market for "pressed reflective sheeting" can produce about 160 pieces per hour) and high energy consumption (the hydraulic press, heating device, cold zone device and other equipment currently used in the market consumes about 15kWh of electricity per hour). At the same time, the mold manufacturing process generates a series of environmental risks and high labor costs (the hydraulic press, heating device, cold zone device and other equipment currently used in the market need to be equipped with an operator to operate the equipment and pick and place products), which is not conducive to the market-oriented mass production of the product. In view of this, this plan was created. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a lantern sheet laser transfer preparation process, which can greatly improve production efficiency.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a lantern sheet laser transfer preparation process, comprising the following steps:

[0006] S1. Make a 200-420 mesh screen. The screen size should be 3-5% smaller than the actual size of the lantern sheet.

[0007] S2. Install the UV varnish feeding system on the screen printing machine and adjust the scraper pressure and angle;

[0008] S3. Install the laser transfer film on the film material conveying system of the cold foil laser transfer machine with a tension of 5-13kg;

[0009] S4, printing a UV varnish layer on the sheet;

[0010] S5. Complete the embossing transfer of the laser holographic pattern in a cold foil laser transfer machine;

[0011] S6. Performing a gradient cooling process to form a pressed reflective sheet.

[0012] Furthermore, the lantern sheet laser transfer preparation process adopts a lantern sheet laser transfer preparation device for production, and the lantern sheet laser transfer preparation device includes a feeding unit, a screen printing machine, a cold stamping laser transfer machine, a cooling machine and a receiving unit; the sheet is discharged from the feeding unit and passes through the screen printing machine and the cold stamping laser transfer machine for cold stamping laser transfer, and the sheet is then cooled and shaped by the cooling machine to form a pressed reflective sheet, and the receiving unit receives the pressed reflective sheet.

[0013] Furthermore, a bridge lifting assembly is provided at the connection position of the cold foil laser transfer machine and the screen printing machine, and air suction is performed across the bridge when the sheet passes through.

[0014] Furthermore, in step S2, the scraper pressure value is 0.2-0.5 MPa, and the scraper angle is 60-75°.

[0015] Furthermore, in step S3, after the laser transfer film is formed, a centering edge corrector is provided, and the position of the edge correction sensor of the centering edge corrector is adjusted so that the sensing photoelectricity of the edge correction sensor is aligned with the edge of the laser transfer film.

[0016] Furthermore, when the mesh size of the screen is selected to be 200-300 meshes in step S1, a relief effect texture with a depth of ≥50 μm can be produced.

[0017] Furthermore, the thickness of the UV varnish layer is 5-15 μm.

[0018] Furthermore, during the laser transfer preparation process of the lantern sheet, the following method is used to determine whether the laser transfer film is about to fail: failure is determined when any of the following indicators are detected: the holographic diffraction efficiency of the transfer sheet surface drops below 70% of the initial value or the scratch density on the laser transfer film surface is greater than 2 lines / cm 2 Or the release force of the front and rear transfer sheets fluctuates by more than ±15%.

[0019] Furthermore, the cooling machine adopts segmented gradient cooling: the first stage, 80℃→50℃, cooling rate 25-30℃ / min; the second stage, 50℃→30℃, cooling rate 15-20℃ / min; the third stage, 30℃→room temperature, natural cooling.

[0020] Furthermore, the laser transfer preparation process for lantern sheets also includes a quality inspection method: first, the color difference ΔE ≤ 1.5 of the embossed reflective sheet is detected by a spectrophotometer, and then the transfer completeness of the pattern on the surface of the embossed reflective sheet is detected by a laser confocal microscope to be ≥ 98%, and finally the glossiness GU value of the surface of the embossed reflective sheet is detected by a gloss meter to be maintained at 85-95.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] First, compared with the existing process, the lantern sheet laser transfer preparation process provided by the present invention has the function of realizing fully automated production, greatly improving production efficiency. Through the preparation process of this scheme, 3,000 PVC lantern sheets can be laser transferred per hour (producing 3,000 pressed reflective sheets), which is about 1775% higher than the semi-automatic efficiency of the existing hydraulic equipment.

[0023] Secondly, compared with existing processes, the laser transfer printing process for lantern sheet material provided by the present invention significantly reduces labor and equipment costs. According to existing processes, a production capacity of 3,000 sheets per hour requires at least 18 hydraulic presses and corresponding supporting equipment, along with 18 people. However, the laser transfer printing process for lantern sheet material provided by the present invention only requires two people to operate the equipment to achieve an hourly production capacity of 3,000 sheets, reducing labor costs by 800%. Only one set of equipment is required, while existing processes require at least 18 sets of equipment. According to market conditions, equipment costs are reduced by approximately 50%.

[0024] Third, it greatly reduces the power consumption of the equipment. According to the production capacity of 3,000 sheets per hour, the existing process technology requires about 18 sets of equipment to complete it. The power of the hydraulic equipment and the heating and cooling devices on the market is about 15kwh. Based on this calculation, the power consumption per hour is about 270kw. The overall power consumption of the equipment using the present invention (feeding unit, screen printing machine, cold foil laser transfer machine, cooling machine and receiving unit) is about 70kwh, and the power consumption is reduced by about 285%.

[0025] Fourthly, since the present invention only uses laser transfer film and UV varnish, it no longer uses existing nickel molds and hydraulic press equipment, effectively eliminating the environmental problems caused by nickel molds during the production process. The laser transfer film can be reused multiple times (8 to 15 times), effectively solving environmental problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a front view structural schematic diagram of a lantern sheet laser transfer preparation device in the present invention;

[0027] Figure 2 This is a schematic diagram of the die-piercing principle of the laser transfer film in the cold foil laser transfer machine of the present invention.

[0028] Markings in the figure: 1. Feeding unit; 2. Screen printing machine; 3. Cold foil laser transfer machine; 4. Cooling machine; 5. Receiving unit. DETAILED DESCRIPTION

[0029] In order to make the above features and advantages of the present invention more obvious and easy to understand, embodiments are given below with reference to the accompanying drawings for detailed description.

[0030] like Figure 1-Figure 2 As shown, this embodiment provides a lantern sheet laser transfer preparation device including an air compressor, a feeding unit 1, a screen printing machine 2, a cold stamping laser transfer machine 3, a cooling machine 4 and a receiving unit 5; the air compressor cold stamping laser transfer machine 3 acts on the sheet to be discharged from the feeding unit 1 and pass through the screen printing machine 2 and the cold stamping laser transfer machine 3 for cold stamping laser transfer, and the sheet is then cooled and shaped by the cooling machine 4 to form a pressed reflective sheet, and the receiving unit 5 receives the pressed reflective sheet, the feeding unit 1 adopts an automatic paper feeding unit device with a feeder head, and the receiving unit 5 adopts an automatic receiving device without stopping the machine.

[0031] Cooler 4 adopts segmented gradient cooling: first stage, 80℃→50℃, cooling rate 25-30℃ / min; second stage, 50℃→30℃, cooling rate 15-20℃ / min; third stage, 30℃→room temperature, natural cooling.

[0032] When starting the equipment, the air compressor, feeding unit 1, screen printing machine 2, cold foil laser transfer machine 3, cooling machine 4 and receiving unit 5 are started in sequence to warm up the machine and set parameters.

[0033] Preferably, a bridge lifting component, a baffle paper suction fan and an electrostatic blowing device are provided at the connection position of the cold ironing laser transfer machine 3 and the screen printing machine 2. The electrostatic blowing device is provided at the output end of the cold ironing laser transfer machine 3. The operation process of the cold ironing laser transfer machine 3 is as follows: turn on the UV curing lamp of the equipment, adjust the transfer pressure, turn on the electrostatic blowing device, open the bridge lifting component for suction, open the front baffle paper suction fan, and start the transfer operation.

[0034] according to Figure 2 As shown, the laser transfer film is passed through the mold on the roller of the cold foil laser transfer machine 3, which is convenient for adjusting the tension and observing the laser transfer film for subsequent maintenance.

[0035] This solution also provides a lantern sheet laser transfer preparation process, which includes the following steps: using a lantern sheet laser transfer preparation device for production.

[0036] S1. Make a 200-420 mesh screen. The screen size should be 3-5% smaller than the actual size of the lantern sheet.

[0037] S2. Install the UV varnish feeding system on the screen printing machine 2 and adjust the scraper pressure and angle; before starting, add an appropriate amount of UV varnish to the screen of the screen printing machine 2;

[0038] S3, install the laser transfer film on the film material conveying system of the cold foil laser transfer machine 3 with a tension of 5-13 kg;

[0039] S4. Print a UV varnish layer on the PVC sheet; the thickness of the UV varnish layer is 5-15um.

[0040] S5, completing the embossing transfer of the laser holographic pattern in the cold foil laser transfer machine 3;

[0041] S6. Performing a gradient cooling process to form a pressed reflective sheet.

[0042] In step S1, if a relief effect texture with a depth of ≥50 μm is to be provided on the sheet surface, the mesh size of the screen is selected in the range of 200-300 meshes. Actual production is based on this range and is adjusted within this range.

[0043] In step S2, the scraper pressure value is 0.2-0.5 MPa, and the scraper angle is 60-75°.

[0044] In step S3, after the laser transfer film, a centering edge corrector is set, and the position of the edge correction sensor of the centering edge corrector is adjusted. The photoelectric sensing of the edge correction sensor is aligned with the edge of the laser transfer film. When the adjustment sensor light on the edge correction sensor is on, check whether the edge correction sensor response is normal, and debug the tension of the laser transfer film on the equipment and the flatness on each roller of the equipment. There should be no wrinkles and one side is loose and the other side is tight. Turn on the UV curing lamp of the equipment, adjust the transfer pressure, turn on the electrostatic blowing device, open the bridge lifting assembly for suction, open the front baffle paper suction fan, and start the transfer operation.

[0045] The laser transfer preparation process for lantern sheets provided by the present invention has the function of realizing fully automated production, greatly improving production efficiency. Through the preparation process of this scheme, 3,000 PVC lantern sheets can be laser transferred per hour (producing 3,000 pressed reflective sheets), which is about 1775% higher than the semi-automatic efficiency of the existing hydraulic equipment.

[0046] Since the laser transfer film in this solution can be reused 8-15 times, it is necessary to determine whether the laser transfer film is about to fail during the production process. Therefore, this solution proposes a method for determining whether the laser transfer film is about to fail. Failure is determined when any of the following indicators are detected: 1. The holographic diffraction efficiency of the sheet material after transfer drops below 70% of the initial value. When it reaches below 75%, an early warning is issued; 2. The scratch density on the surface of the laser transfer film is greater than 2 lines / cm 2 , it can be replaced when scratches appear. The above scratch density value is the condition that must be replaced after it is reached. 3. The release force fluctuation of the front and rear sheets exceeds ±15%. 4. The increase in the surface roughness Ra value of the laser transfer film is greater than 30%.

[0047] The thickness of the UV varnish layer in this solution is 5-15um, which can meet the holographic pattern replication accuracy required by laser transfer in this solution and is suitable for uniform coating with a scraper.

[0048] This solution also provides a quality inspection method for embossed reflective sheeting (molded lantern sheeting). First, the color difference ΔE of the embossed reflective sheeting is detected by a spectrophotometer to be ≤1.5. Then, the transfer completeness of the pattern on the surface of the embossed reflective sheeting is detected to be ≥98% by a laser confocal microscope. Finally, the gloss meter is used to detect that the glossiness GU value of the surface of the embossed reflective sheeting is maintained at 85-95. When no pattern is set on the transfer sheet, the second step can be skipped.

[0049] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A lantern sheet laser transfer preparation process, characterized by: The following steps are involved: S1. Make a 200-420 mesh screen. The screen size should be 3-5% smaller than the actual size of the lantern sheet. S2. Install the UV varnish feeding system on the screen printing machine and adjust the scraper pressure and angle; S3. Install the laser transfer film on the film material conveying system of the cold foil laser transfer machine with a tension of 5-13kg; S4, printing a UV varnish layer on the sheet; S5. Complete the embossing transfer of the laser holographic pattern in a cold foil laser transfer machine; S6. Performing a gradient cooling process to form a pressed reflective sheet.

2. The laser transfer printing process for lantern sheets according to claim 1, characterized in that: The lantern sheet laser transfer preparation process adopts a lantern sheet laser transfer preparation device for production, and the lantern sheet laser transfer preparation device includes a feeding unit, a screen printing machine, a cold stamping laser transfer machine, a cooling machine and a receiving unit; the sheet is discharged from the feeding unit and passes through the screen printing machine and the cold stamping laser transfer machine for cold stamping laser transfer, and the sheet is then cooled and shaped by the cooling machine to form a pressed reflective sheet, and the receiving unit receives the pressed reflective sheet.

3. The laser transfer printing process for lantern sheets according to claim 2, characterized in that: A bridge lifting assembly is provided at the connection position of the cold foil laser transfer machine and the screen printing machine, and air suction is performed across the bridge when the sheet passes through.

4. The laser transfer printing process for lantern sheets according to claim 1, characterized in that: In step S2, the scraper pressure value is 0.2-0.5 MPa, and the scraper angle is 60-75°.

5. The laser transfer printing process for lantern sheets according to claim 2, characterized in that: In step S3, after the laser transfer film is formed, a centering edge corrector is provided, and the position of the edge correction sensor of the centering edge corrector is adjusted so that the sensing photoelectricity of the edge correction sensor is aligned with the edge of the laser transfer film.

6. The laser transfer printing process for lantern sheet according to claim 1, characterized in that: When the mesh size of the screen is 200-300 meshes in step S1, a relief effect texture with a depth of ≥50 μm can be produced.

7. The laser transfer printing process for lantern sheet according to claim 1, characterized in that: The thickness of the UV varnish layer is 5-15 μm.

8. The laser transfer printing process for lantern sheets according to claim 1, characterized in that: During the laser transfer process of lantern sheets, the following method is used to judge whether the laser transfer film is about to fail: failure is determined when any of the following indicators are detected: the holographic diffraction efficiency of the transfer sheet surface drops below 70% of the initial value or the scratch density of the laser transfer film surface is greater than 2 lines / cm 2 Or the release force of the front and rear transfer sheets fluctuates by more than ±15%.

9. The laser transfer printing process for lantern sheets according to claim 2, characterized in that: The cooling machine adopts segmented gradient cooling: the first stage is 80℃→50℃, with a cooling rate of 25-30℃ / min; the second stage is 50℃→30℃, with a cooling rate of 15-20℃ / min; the third stage is 30℃→room temperature, and natural cooling.

10. The laser transfer printing process for lantern sheets according to claim 1, characterized in that: The lantern sheet laser transfer preparation process also includes a quality detection method: first, the color difference ΔE of the pressed reflective sheet is detected by a spectrophotometer to be ≤1.5, then the transfer completeness of the pattern on the surface of the pressed reflective sheet is detected by a laser confocal microscope to be ≥98%, and finally the glossiness GU value of the surface of the pressed reflective sheet is detected by a gloss meter to be maintained at 85-95.

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