A mold applied to a step type doctor blade

Abstract

The application provides a mold applied to a step type ink scraping knife, and is used for a mold body of integrally injection molding a step type ink scraping knife; the mold body comprises a lower mold block and an upper mold block used for buckling the lower mold block; the inner cavity of the upper mold block and the inner cavity of the lower mold block are buckled to each other to form a mold cavity matched with the shape of the step type ink scraping knife. Through the specific design of the mold cavity, the molding effect of the ink scraping knife is remarkable, the structure strength is high, the use time of the constant ink scraping amount of the step type ink scraping knife is prolonged, the grinding damage to the anilox roller is reduced, the integrally molding effect is remarkable, and the production cost is reduced.

Description

Technical Field

[0001] This application relates to the field of foam plastic processing technology, and in particular to a mold for use in stepped doctor blades. Background Technology

[0002] The doctor blade is a frequently replaced consumable in packaging printing equipment. It is installed on the doctor blade cavity of the equipment, with its blade contacting the rotating anilox roller. It scrapes away excess water-based ink or coating liquid adhering to the surface of the anilox roller, ensuring that the water-based ink or coating liquid in the anilox roller cells is evenly transferred to the flexible resin plate or substrate material. The flexible resin plate then evenly transfers the water-based ink or coating liquid onto the printing surface such as corrugated cardboard. The doctor blade's effect should ensure that each transfer to the corrugated cardboard or other printing surface meets printing standards, with uniform color and full, vibrant text and patterns. The doctor blade's effect is affected by wear and tear during use, and this wear is influenced by the material and shape of the blade.

[0003] Due to the consumable nature of doctor blades, they require integral injection molding during manufacturing. Existing doctor blades have a series of cutting edges with angles such as 45° and 30° during the molding process; for example: see attached... Figure 1 and attached Figure 2 As shown, attached Figure 1 The diagram shows a schematic of an existing doctor blade with a 45° blade angle. The blade (A1) has a 45° angle (α3) and is made of plastic with a blade thickness of 1.6mm. Testing shows that the doctor blade (A1) achieves the best doctoring effect when its thickness is around 1.6mm. However, the blade (A1) gradually widens due to wear from prolonged contact and friction with the anilox roller. After a period of use, the widest point of the blade is measured at K2 (3.15mm), at which point the doctoring effect is significantly affected. In existing technology, this type of doctor blade can only maintain a blade thickness of 1.6mm for a very short period. To ensure the doctoring effect, frequent blade replacements are necessary, resulting in short blade life and frequent downtime.

[0004] As attached Figure 3 and attached Figure 4 As shown, attached Figure 1The diagram shows a schematic of an existing doctor blade with a 30° blade angle. The blade (A2) has a 30° angle (α4) and is made of plastic with a blade thickness of 1.6mm. Testing shows that the doctor blade (A2) achieves the best doctoring effect when its thickness is around 1.6mm. However, the blade (A2) gradually widens due to wear from prolonged contact and friction with the anilox roller. After a period of use, the widest point of the blade is measured at K3 (3.12mm), at which point the doctoring effect is significantly affected. In existing technology, this type of doctor blade can only maintain a blade thickness of 1.6mm for a very short period. To ensure the doctoring effect, frequent blade replacements are necessary, resulting in short blade life and frequent downtime.

[0005] It is evident that the doctor blades produced by existing molds with cavities of a single tilt angle have a shorter service life and poorer ink scraping effect; furthermore, the single mold cavity structure results in greater wear and tear on the doctor blades, increasing manufacturing costs. Utility Model Content

[0006] This application provides a mold for a stepped doctor blade, which adopts a specific cavity design to meet the manufacturing requirements of stepped doctor blades, extend the service life of doctor blades, and reduce manufacturing costs.

[0007] This application provides a mold for use with stepped doctor blades, including a mold body for injection molding of the aforementioned stepped doctor blade; the mold body includes a lower module and an upper module for engaging the lower module; wherein, the inner cavity of the upper module and the inner cavity of the lower module engage with each other to form a mold cavity adapted to the shape of the stepped doctor blade.

[0008] In this application, a specific mold cavity design method is used to ensure that the stepped doctor blade has a significant integral molding effect. The specific blade tip cavity shape extends the service life of the stepped doctor blade, reduces manufacturing costs, and ensures that the finished doctor blade has a significant doctoring effect.

[0009] In one specific implementation scheme, the lower module is provided with multiple trapezoidal positioning blocks, and the upper module is provided with trapezoidal positioning grooves that correspond one-to-one with the multiple trapezoidal positioning blocks. The upper and lower modules are tightly closed.

[0010] In one specific implementation, the mold cavity includes a lower mold cavity formed on the lower module and an upper mold cavity formed on the upper module; the height of the mold cavity is H, the vertical height of the lower mold cavity is <H / 2, and the vertical height of the upper mold cavity is >H / 2. This asymmetrical height distribution creates a stepped section with higher structural strength during injection molding.

[0011] In one specific implementation, the lower mold cavity has a bottom cavity and a beveled cutting edge, the beveled cutting edge having an angle of α1; the upper mold cavity has a blade cavity, a stepped cavity, and a chamfered bevel, with a forming slope with an angle of α2 between the blade cavity and the stepped cavity. The integral formation of the cutting tip is highly effective.

[0012] In one specific feasible implementation, H is 1.6mm~1.65mm.

[0013] In one specific implementation, the tilt angle of α1 is 27°~30°.

[0014] In one specific implementation, the tilt angle of α2 is 45°~48°. Attached Figure Description

[0015] Figures 1-4 This is a schematic diagram of the structure and usage of an existing scraper blade. Figure 5 This is a schematic diagram of the mold provided in the embodiments of this application; Figure 6 A schematic diagram of the split structure of the upper and lower modules provided in the embodiments of this application; Figure 7 This is a schematic diagram of the structure of the lower module provided in an embodiment of this application; Figure 8 This is a schematic diagram of the upper module provided in an embodiment of this application; Figure 9 This is a schematic diagram of the stepped doctor blade provided in the embodiments of this application; Figure 10 An enlarged schematic diagram of the tip of the stepped doctor blade provided in the embodiments of this application; Figure 11 This is a schematic diagram illustrating the usage state of the stepped doctor blade provided in the embodiments of this application.

[0016] Icon labels: Blade section -100; Cutting tip - 200, stepped section - 210, connecting bevel section - 220, chamfer - 230, initial cutting edge - 240; Lower module-300, trapezoidal positioning block-310; Upper module-400, trapezoidal positioning groove-410; Mold cavity-500, lower mold cavity-510, bottom mold cavity-511, cutting edge bevel-512, upper mold cavity-520, cutting edge cavity-521, stepped cavity-522, forming bevel section-523, chamfer bevel-524. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0018] It should be noted that, unless otherwise defined, the technical or scientific terms used in one or more embodiments of this specification should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar words used in one or more embodiments of this specification do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0019] To facilitate understanding of the mold for a stepped doctor blade provided in this application embodiment, its application scenario is first explained. Existing doctor blades have a normal service life of 120-180 hours, and the time required to replace them is 1.5-2.5 hours. Frequent doctor blade replacements significantly impact production efficiency. Furthermore, after replacing a doctor blade, a break-in period is required between the doctor blade and the anilox roller. Generally, printing text and patterns requires 4-6 hours of break-in, while printing large solid areas and color blocks requires 6-10 hours. For some specially structured doctor blade cavities, the break-in time can reach approximately 20 hours. During the break-in process, the ceramic anilox roller, being a core component of water-based ink printers, is expensive. After replacing the doctor blade, a pressurized water-cooled break-in process is required. Because the operating environment of water-based ink printers is relatively harsh, with ink residue inside the machine and sand particles in the water, this pressure break-in process can cause ink residue and sand particles from the doctor blade to be carried into the blade as it flows. The doctor blade may trap some of this residue and sand between the ceramic anilox roller and the printing roller. This can cause circumferential scratches on the anilox roller after about ten to twenty minutes. Scratches on the anilox roller will result in defective products during printing, and in severe cases, production will be halted, requiring the replacement of the anilox roller. The damage to the anilox roller caused by the doctor blade break-in is irreversible. Therefore, this application provides a mold for a stepped doctor blade, enabling the produced stepped doctor blade to have a high and constant ink scraping time, allowing it to be used directly on the machine without break-in, reducing damage to the anilox roller and improving printing quality.

[0020] First, in conjunction with the appendix Figure 1 and attached Figure 2As shown, attached Figure 1 The diagram shows a schematic of an existing doctor blade with a 45° blade angle. The blade (A1) has a 45° angle (α3) and is made of plastic. The blade thickness is 1.6mm. Testing shows that the doctor blade (A1) achieves the best doctoring effect when its thickness is around 1.6mm. However, the blade (A1) gradually widens due to wear from prolonged contact and friction with the anilox roller. After a period of use, the widest point of the blade is measured at K2 (3.15mm), indicating severe dulling of the blade, which significantly affects the doctoring effect. Furthermore, in existing technology, this type of doctor blade can only maintain a blade thickness of 1.6mm for a very short period. To ensure the doctoring effect, frequent blade replacements are necessary, resulting in short blade life and frequent downtime.

[0021] Combined with appendix Figure 3 and attached Figure 4 As shown, attached Figure 1 The diagram shows a schematic of an existing doctor blade with a 30° blade angle. The blade (A2) has a 30° angle (α4) and is made of plastic. The blade thickness is 1.6mm. Testing shows that the doctor blade (A2) achieves the best doctoring effect when its thickness is around 1.6mm. However, the blade (A2) gradually widens due to wear from prolonged contact and friction with the anilox roller 20. After a period of use, the widest point of the blade is measured at K3 (3.12mm), at which point the doctoring effect is significantly affected. In existing technology, this type of doctor blade can only maintain a blade thickness of 1.6mm for a very short period. To ensure the doctoring effect, frequent blade replacements are necessary, resulting in short blade life and frequent downtime.

[0022] Therefore, it is evident that existing molds with cavities featuring a single tilt angle result in doctor blades with a short service life and poor ink scraping performance. Furthermore, the single mold cavity structure leads to greater wear on the doctor blades, increasing manufacturing costs. Doctor blades produced by existing molds have a short normal service life, and during use, wear causes the blade width to increase, leading to uneven ink scraping, significant waste of water-based ink, and poor printing results. Existing doctor blades maintain a constant ink scraping volume within a reasonable range for 120-180 hours. When wear becomes severe and affects the scraping effect, replacement is required every 1.5-2.5 hours, and the replacement doctor blade requires a lengthy break-in period. The damage caused to the anilox roller 20 by the doctor blade during the break-in process is irreversible, limiting the lifespan of the ceramic anilox roller 20 to approximately two years after break-in. However, the stepped doctor blade of this application requires no break-in and can be directly applied to the machine, extending the lifespan of the ceramic anilox roller 20 to 3-4 years. This significantly improves product quality while substantially reducing production costs. Furthermore, the service life of the stepped doctor blade is extended to 160-240 hours, which greatly increases the service life, reduces the break-in process, and provides better doctoring effect.

[0023] Please refer to the above. Figure 5 As shown in the illustration, this application also provides a mold for integrally injection molding the aforementioned stepped doctor blade. In one specific embodiment, the mold is used for integrally injection molding a stepped doctor blade from UHMWPE material. UHMWPE possesses extremely high wear resistance, impact resistance, self-lubrication, and chemical stability. After the UHMWPE is hot-melted and injected into the mold cavity 500, the mold temperature during injection molding helps the melt flow, reduces internal stress, and improves surface gloss. Therefore, the mold in this application selects a mold temperature of approximately 80°C, and after cooling and molding, it undergoes demolding to form an integral stepped doctor blade.

[0024] Specifically, the mold body includes a lower module 300 and an upper module 400 for engaging the lower module 300; wherein, the inner cavity of the upper module 400 and the inner cavity of the lower module 300 engage with each other to form a mold cavity 500 that conforms to the shape of the stepped doctor blade. The vertical height of the mold cavity 500 is H, and the vertical height, width, and length of the mold cavity 500 are all matched with the corresponding model of stepped doctor blade, which is divided into various types, which will not be described in detail here.

[0025] Combination Figure 6 As shown, the lower module 300 is provided with multiple trapezoidal positioning blocks 310, and the upper module 400 is provided with trapezoidal positioning grooves 410 that correspond one-to-one with the multiple trapezoidal positioning blocks 310. The upper module 400 and the lower module 300 are tightly closed. By having the multiple trapezoidal positioning blocks 310 inserted one-to-one into the trapezoidal positioning grooves 410, a high degree of tightness is ensured, and the forming effect of the mold cavity 500 is significant.

[0026] Furthermore, the blade body 100 and blade tip 200 of the stepped doctor blade are integrally formed using this mold. The blade body 100 has a solid structure, while the blade tip 200 has multiple structures including a stepped section 210, a preliminary cutting edge 240, and a chamfer 230. The inner cavities of the upper module 400 and the lower module 300 are matched to form an integral mold cavity 500. Specifically, in conjunction with... Figure 7 and Figure 8 As shown, the mold cavity 500 includes a lower mold cavity 510 formed on the lower module 300 and an upper mold cavity 520 formed on the upper module 400. The vertical height of the mold cavity 500 is H, the vertical height of the lower mold cavity 510 is < H / 2, and the vertical height of the upper mold cavity 520 is > H / 2. With this asymmetrical height distribution, a stepped portion 210 with higher structural strength is formed during injection molding. Therefore, the height of the upper mold cavity 520 is greater than the height of the lower mold cavity 510, enabling integrated injection molding of the irregular structure of the stepped doctor blade.

[0027] The lower mold cavity 510 is used to form the lower part of the blade portion 100, the lower part of the stepped portion 210, and the completed initial cutting edge 240; the upper mold cavity 520 is used to form the upper part of the blade portion 100, the upper part of the stepped portion 210, and the completed chamfer 230; specifically, the lower mold cavity 510 has a bottom cavity 511 and a cutting edge bevel 512, the angle of the cutting edge bevel 512 being α1; the upper mold cavity 520 has a blade cavity 521, a stepped cavity 522, and a chamfer bevel 524, and a forming inclined section 523 with an angle of α2 is located between the blade cavity 521 and the stepped cavity 522. The integral formation of the cutting tip 200 has a significant effect.

[0028] As can be seen from the above structure, the bottom cavity 511 of the lower mold cavity 510 forms an integral lower part of the blade part 100 and the step part 210, and the blade bevel 512 with an inclination angle of α1 forms the initial blade edge 240, the inclination angle α1 being 27°. It should be understood that in other embodiments of this application, for injection molding of different models of stepped doctor blades, the inclination angle α1 of the blade bevel 512 can also be other angles, such as the inclination angle of the initial blade edge 240 being 30°, then the inclination angle α1 of the blade bevel 512 is the corresponding 30°, which will not be elaborated further here.

[0029] The upper mold cavity 520 and the bottom cavity 511 of the lower mold cavity 510 combine to form a blade portion 100 with a height of H, and a stepped portion 210 is formed by a stepped cavity 522 and the bottom cavity 511. A forming inclined section 523 is used to form a connecting inclined section 220 between the blade portion 100 and the stepped portion 210, and the inclination angle α2 of the forming inclined section 523 also matches the inclination angle of the connecting inclined section 220. In one specific embodiment of this application, the inclination angle of the connecting inclined section 220 is 45°, and the inclination angle α2 of the forming inclined section 523 is also 45°. The chamfered surface 524 of the upper mold cavity 520 is used to form a chamfer 230 of the stepped doctor blade, thereby making the front end of the stepped doctor blade a pointed tip.

[0030] In this application, by using a specific mold cavity 500 design, the service life of the stepped doctor blade with constant ink volume is extended, the wear damage to the anilox roller is reduced, the one-piece molding effect is significant, and the production cost is reduced.

[0031] Additionally, refer to Figure 9 As shown, Figure 9This application describes a doctor blade body manufactured using the mold body described in the present application. The stepped doctor blade includes a blade body mounted on a doctor blade holder and used to control the uniform ink application to the anilox roller. The blade body is made of ultra-high molecular weight polyethylene (UHMWPE) material, possessing high toughness. The blade body includes a blade body 100 that cooperates with the doctor blade holder 10, and a blade tip 200 that presses against the anilox roller and provides a constant ink application rate. The blade body 100 is mounted on the doctor blade holder 10 via a fastening assembly. The length of the blade body is cut to correspond to different anilox roller models. The thickness of the blade body 100 is H; in one specific embodiment of this application, H is 1.6mm to 1.65mm. The universal blade design reduces the number of specifications; common widths are 32mm, 35mm, 38mm, and 40mm, making selection simple and straightforward for operators. Figure 10 and Figure 11 As shown, the thickness of the blade tip 200 is ≤H / 2. Therefore, the blade body 100 is positioned on the doctor blade holder 10, and the blade tip 200 contacts the anilox roller to scrape ink. As the blade tip 200 gradually wears down, the doctor blade cavity applies pressure to ensure that the blade tip 200 is always under reasonable pressure with the anilox roller. The overall thickness of the blade tip 200 is approximately 0.8mm, making the contact end of the blade tip 200 relatively thin, and the bevel width of the initial cutting edge 240 is between 0.88mm and 1.32mm. Thus, even after prolonged wear, the contact tip of the blade tip 200 always meets the usage requirements of the widest point K1. Specifically, the blade tip 200 includes a stepped portion 210 and a preliminary blade edge 240 located at the front end of the stepped portion 210 with an inclination angle of α1. A chamfer 230 is provided between the preliminary blade edge 240 and the stepped portion 210, and a connecting inclined section 220 with an inclination angle of α2 is provided between the stepped portion 210 and the blade body 100. Thus, by providing a connecting inclined section 220 with an inclination angle of α2 between the blade body 100 and the stepped portion 210, the overall connection strength of the stepped portion 210 is ensured, and the preliminary blade edge 240 contacts the anilox roller at an inclination angle of α1. In a specific embodiment of this application, the inclination angle of α1 is 27°~30°. No break-in is required for direct application. The inclination angle of α2 is 45°~48°. It possesses good connection strength.

[0032] In this application, the stepped portion 210 is integrally formed in the mold cavity 500 as a component of the blade tip portion 200. After the initial blade edge 240 wears down from prolonged contact with the anilox roller, the stepped portion 210 transforms into a middle blade edge. Pressure is applied to the scraping chamber by a cylinder or air bladder, allowing the middle blade edge to uniformly contact the anilox roller. This scrapes off excess water-based ink or coating liquid from the surface of the anilox roller during its rotation, ensuring that the water-based ink or coating liquid in the anilox roller cells is uniformly transferred to the flexible resin plate or substrate material. The flexible resin plate then uniformly transfers the water-based ink to the surface of the corrugated cardboard, ensuring that the water-based ink on the text and patterns transferred to the corrugated cardboard is uniform, full, and consistent in color. Furthermore, the doctor blade in this application can be directly used on the machine without the need for break-in, thereby reducing damage to the anilox roller during the break-in process. The blade tip 200 presses and rubs against the anilox roller and is located in a first set working state and a second set working state. When the blade tip 200 is in the first set working state, the plane of the initial blade edge 240 and the connecting tip of the chamfer 230 are in contact with the anilox roller without the need for break-in, and the widest point of the initial blade edge 240 is ≤ K1. When the blade tip 200 is in the second set working state, the initial blade edge 240 and the chamfer 230 wear and extend to the step portion 210, and the step portion 210 forms a middle blade edge that rubs against the anilox roller, and the widest point of the middle blade edge is ≤ K1. In a specific embodiment of this application, the widest point of the initial blade edge 240 and the widest point of the middle blade edge satisfy: K1 ≤ 1.59 mm. Maintaining a constant ink volume for a high duration ensures printing effect, extends the service life of the doctor blade, and reduces the replacement frequency.

[0033] Therefore, the doctor blade in this application extends the service life from the existing 120-180 hours to approximately 160-240 hours, while maintaining a consistently high ink volume, thus improving printing quality. It reduces replacement frequency, directly increasing printing efficiency. Simultaneously, it eliminates the break-in process, avoiding the need for pressurized water-cooled break-in after blade replacement, which is necessary in water-based printing presses due to their harsh operating environment (ink residue inside the machine, sand particles in the water, etc.). During pressurized break-in, these impurities may be carried into the doctor blade, trapping some of them between the ceramic anilox roller. This can cause circumferential scratches on the anilox roller within ten to twenty minutes, resulting in defective products and, in severe cases, production stoppages requiring replacement with a new anilox roller. The original doctor blade required a break-in period of approximately two years for the ceramic anilox roller. The doctor blade body in this application can be used directly after installation without break-in, and the ceramic anilox roller has a service life of 3-4 years. This improves product quality while significantly reducing production costs.

[0034] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this disclosure (including the claims) is limited to these examples; within the framework of this disclosure, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of this specification, which are not provided in detail for the sake of brevity.

[0035] Additionally, to simplify the description and discussion, and to avoid obscuring one or more embodiments of this specification, well-known power / ground connections for other components may or may not be shown in the provided drawings. Furthermore, the apparatus may be illustrated in block diagram form to avoid obscuring one or more embodiments of this specification, and this also takes into account the fact that the details of implementation of these block diagram apparatuses are highly dependent on the platform on which one or more embodiments of this specification will be implemented (i.e., these details should be fully understood by those skilled in the art). While specific details have been set forth to describe exemplary embodiments of this disclosure, it will be apparent to those skilled in the art that one or more embodiments of this specification may be implemented without these specific details or with variations thereof. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0036] One or more embodiments of this specification are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of this specification should be included within the scope of protection of this disclosure.

Claims

1. A mold for use with stepped doctor blades, characterized in that, Including the mold body for one-piece injection molding of stepped doctor blades; The mold body includes a lower module and an upper module for engaging the lower module; wherein, The inner cavities of the upper module and the lower module interlock to form a mold cavity that matches the shape of the stepped doctor blade.

2. The mold applied to a stepped doctor blade according to claim 1, characterized in that, The lower module is provided with multiple trapezoidal positioning blocks, and the upper module is provided with trapezoidal positioning grooves that correspond one-to-one with the multiple trapezoidal positioning blocks.

3. The mold for a stepped doctor blade according to claim 2, characterized in that, The mold cavity includes: a lower mold cavity formed on the lower module, and an upper mold cavity formed on the upper module; The height of the mold cavity is H, the vertical height of the lower mold cavity is <H / 2, and the vertical height of the upper mold cavity is >H / 2.

4. The mold for a stepped doctor blade according to claim 3, characterized in that, The lower mold cavity has a bottom cavity and a cutting edge bevel, the angle of the cutting edge bevel is α1; The upper mold cavity has a blade cavity, a stepped cavity, and a chamfered slope, and there is a forming slope with an inclination angle of α2 between the blade cavity and the stepped cavity.

5. The mold for a stepped doctor blade according to claim 4, characterized in that, The value of H is 1.6mm to 1.65mm.

6. The mold for a stepped doctor blade according to claim 4, characterized in that, The tilt angle of α1 is 27°~30°.

7. The mold for a stepped doctor blade according to claim 6, characterized in that, The tilt angle of α2 is 45°~48°.

Images