Summary of high-gloss steam mold design
Time:2025-01-13 09:02:54 / Popularity: / Source:
In traditional injection molding technology, if mold temperature is lowered, although molding cycle can be shortened, it is easy to produce weld marks, resulting in poor appearance quality. On the contrary, when temperature of mold is raised, appearance quality of product surface can be improved, but it is easy to produce warping, deformation, poor size, etc., while extending molding cycle and increasing costs. Therefore, for some products with high gloss requirements such as shell of flat-panel LCD TVs, traditional injection molding technology cannot meet requirements.
High-gloss steam injection molding technology that has emerged in recent years can effectively solve this problem. Principle is to use high-temperature steam to make a balanced heating pipeline on steam mold. When injection molding machine blows in high-temperature steam after mold is closed, mold is first raised to a set value, then plastic is injected into mold cavity; after injection machine completes pressure holding and turns to cooling, cold water is injected, mold temperature quickly drops to a set value before mold is opened, and air is blown into mold to completely blow away cold water formed after steam is cooled, completing the entire injection process.
Since molten resin is injected after mold temperature reaches a temperature that exceeds thermal deformation temperature of resin, a plastic part with no weld marks, no silver streaks, no shrinkage marks, and good surface quality will be formed. After molten resin is injected, cooling process begins, and cooling water is used to quickly drop mold temperature to below thermal deformation temperature of resin. This can shorten molding cycle and solve problem of warping deformation by accelerating curing speed of resin.
High-gloss steam injection molding technology can make filling, shrinkage compensation and cooling of resin in a relatively ideal state within a molding production cycle, so a relatively ideal product can be obtained. At the same time, since its working principle is based on physical change of resin, it can be applied to almost all resin materials. Therefore, some people call high-gloss steam injection molding technology another revolutionary technology after gas-assisted technology.
High-gloss steam injection molding technology that has emerged in recent years can effectively solve this problem. Principle is to use high-temperature steam to make a balanced heating pipeline on steam mold. When injection molding machine blows in high-temperature steam after mold is closed, mold is first raised to a set value, then plastic is injected into mold cavity; after injection machine completes pressure holding and turns to cooling, cold water is injected, mold temperature quickly drops to a set value before mold is opened, and air is blown into mold to completely blow away cold water formed after steam is cooled, completing the entire injection process.
Since molten resin is injected after mold temperature reaches a temperature that exceeds thermal deformation temperature of resin, a plastic part with no weld marks, no silver streaks, no shrinkage marks, and good surface quality will be formed. After molten resin is injected, cooling process begins, and cooling water is used to quickly drop mold temperature to below thermal deformation temperature of resin. This can shorten molding cycle and solve problem of warping deformation by accelerating curing speed of resin.
High-gloss steam injection molding technology can make filling, shrinkage compensation and cooling of resin in a relatively ideal state within a molding production cycle, so a relatively ideal product can be obtained. At the same time, since its working principle is based on physical change of resin, it can be applied to almost all resin materials. Therefore, some people call high-gloss steam injection molding technology another revolutionary technology after gas-assisted technology.
High-gloss steam mold design standards
1 Mold temperature control system
1.1 Arrangement of high-temperature steam pipes and waterways in the front mold core.
There are four sets of high-temperature steam circuits in the front mold core. One set of circuits is designed for each of four areas of product. They are connected to dedicated high-gloss steam mold control machine through stainless steel joints and steel wire braided hydraulic hoses, as shown in blue pipe and yellow joint shown in Figure 2-1 below.
Distance between high-temperature steam pipe and surface of glue position is 5~8mm, diameter can be 8mm, 10mm, and 12mm. Pipes are required to be evenly arranged to ensure that glue position can be quickly and evenly heated, as shown in Figure 2-2 below.
Yellow pipe in Figure 2-1 below is a cold water pipe, which is mainly used to cool hot nozzle. It is best to design an independent cooling circuit for each hot nozzle.
White pipe in Figure 2-1 below is a warm water pipe. During injection molding, it needs to be connected to 75-80℃ warm water for insulation. It mainly plays a role in heat preservation of mold. There are no special requirements.
Distance between high-temperature steam pipe and surface of glue position is 5~8mm, diameter can be 8mm, 10mm, and 12mm. Pipes are required to be evenly arranged to ensure that glue position can be quickly and evenly heated, as shown in Figure 2-2 below.
Yellow pipe in Figure 2-1 below is a cold water pipe, which is mainly used to cool hot nozzle. It is best to design an independent cooling circuit for each hot nozzle.
White pipe in Figure 2-1 below is a warm water pipe. During injection molding, it needs to be connected to 75-80℃ warm water for insulation. It mainly plays a role in heat preservation of mold. There are no special requirements.
1.2 Steam connector
Steam connector used to connect high-temperature steam is shown in Figure 2-3 below.
The total length L in above figure can be adjusted appropriately according to actual situation of mold.
1.3 Steam pipe copper plugging structure
Each steam pipe end on the front mold core needs to be plugged with copper (no need to add a plug), as shown in Figure 2-4 below. Size of plugging copper is pipe diameter plus 2mm, as shown in Figure 2-5 below.
1.4 Front mold temperature measurement structure
Each of four areas of front mold glue position needs to be equipped with a temperature sensing needle to detect temperature of each area so as to accurately control molding temperature of product, as shown in Figure 2-6 below.
When ordering a temperature sensing needle, you need to find out mold production factory. If it is produced domestically, you need to use "K" type, and if it is produced in Europe, you need to use "J" type.
Temperature sensing needle is shown in Figure 2-7 below.
Temperature sensing needle is shown in Figure 2-7 below.
Size of temperature sensing needle installation hole in the front mold core is shown in Figure 2-8 below.
Note: Since diameter of temperature sensing needle is small, air hole on the back of mold core can be appropriately enlarged and deepened to facilitate workshop processing. Installation of temperature sensing needle must be considered during design, because temperature sensing needle is fixed by an external hexagonal screw, so there must be enough air space on the back of A plate to ensure that it can be installed with a wrench. In addition, it is necessary to consider that there is a spring protective cover on temperature sensing needle, there must be enough space to ensure that it will not be crushed when installing hot runner plate, as shown in Figure 2-9 above.
1.5 Design of thermal insulation structure
For front mold core with high-temperature steam, A plate should be separated by a thermal insulation board. Thickness of thermal insulation board is 8mm, and actual installation thickness on mold is 7.5mm, as shown in Figure 2-10 below.
In order to minimize transfer of heat to injection molding machine, panel should be equipped with a thermal insulation board, panel and hot runner plate should be processed with cooling water circuits.
Red position of panel is cooling water circuit, as shown in Figure 2-11 below.
Red position of panel is cooling water circuit, as shown in Figure 2-11 below.
Red position of hot runner plate is cooling water circuit, as shown in Figure 2-12 below.
1.6 Temperature control of highlight area of rear mold
Highlight area of front mold is heated by high-temperature steam, but some products also have highlight requirements in some areas of rear mold glue position. Temperature control of this area is generally heated by passing hot oil. Design of pipeline is same as steam pipeline, as shown in Figure 2-13 below.
For inserts that are passed through hot oil, bottom should be separated from B plate by an insulation board, side and other contact surfaces should be avoided to reduce contact area between parts to reduce heat transferred to other parts.
For joints of oil circuit, use quick-insert form, use Xinrunda standard, male joint model: JP-353, female joint model: JS308.
Oil pipe uses a black leather hydraulic pipe with steel wire.
For joints of oil circuit, use quick-insert form, use Xinrunda standard, male joint model: JP-353, female joint model: JS308.
Oil pipe uses a black leather hydraulic pipe with steel wire.
1.7 Temperature control of non-highlight area of rear mold
For non-highlight area of rear mold, cold water is usually passed for temperature control, and there is no special requirement for design of cooling water circuit. Joint uses a commonly used quick air joint, and throat is generally PT3/8, but countersink needs to be processed on mold plate. Sinker of water transport joint of Huizhou TCL mold is all Φ30*25, and sinker of water transport joint of European Poland TCL mold is all Φ34*30.
1.8 Dew leakage prevention structure
In order to prevent dew generated in process of mold from hot to cold from entering parting surface, front and rear mold cores should be designed near parting surface. See Figure 2-14 below.
Similarly, a sealing ring is added to hot nozzle position on A plate to prevent dew from entering hot nozzle, as shown in Figure 2-15 below.
Similarly, a sealing ring is added to hot nozzle position on A plate to prevent dew from entering hot nozzle, as shown in Figure 2-15 below.
1.9 Other requirements for mold temperature control
1.9.1 All cold water and hot water must be sealed with double sealing rings when passing through another plate. Design of sealing ring groove must be designed according to HASCO standard required by our company. When designing, consider whether position is sufficient, as shown in Figure 2-16 below.
1.9.2 All sealing rings for water and oil circuits use HASCO standards and are required to withstand high temperatures of 180℃. Please pay attention when ordering materials.
1.9.3 Marking
Steam: S-IN/OUT
Oil: O-IN/OUT
Hot water: H-IN/OUT
Hot nozzle cooling water (including all cold water): G-IN/OUT
1.9.3 Marking
Steam: S-IN/OUT
Oil: O-IN/OUT
Hot water: H-IN/OUT
Hot nozzle cooling water (including all cold water): G-IN/OUT
2 Casting system
2.1 Runner and glue inlet design
If customer has no special requirements, a banana-shaped glue inlet is generally used. Glue inlet position is generally set according to flow length of product. Since TV molds are generally large, multiple glue inlet points are often used, and there are more hot nozzles. Sometimes one nozzle is divided into two glue inlets, and sometimes there are three. In order to ensure that flow channel can be taken out at one time when making beer products, some auxiliary flow channels need to be designed to connect main flow channel, as shown in Figure 2-17 below.
2.1 Positioning ring
For TCL molds, if they are produced on ≤200T injection molding machines, a positioning ring with an outer diameter of Φ100 is selected, and if they are produced on >200T injection molding machines, a positioning ring with an outer diameter of Φ150 is selected.
2.2 All nozzle needles must be made into nozzle sleeves, and glue position part must also be made into a single-side slope of 1 degree.
Nozzle needle must be positioned to prevent nozzle from slipping during ejection, as shown in Figure 2-18 below.
2.3 In order to better protect nozzle socket and control valve, European mold needs to install a steel plate on panel to protect socket, as shown in Figure 2-19 below.
Steel plate
3 Molding system
3.1 Shrinkage rate of LCD shell mold is scaled according to 0.3% to 0.35% during design.
3.2 For non-sealed area, avoid air, and pay special attention to front mold avoidance position not to interfere with auxiliary connection flow channel of rear mold, as shown in Figure 2-20 below.
3.3 If product has a change of style, customer will require replacement of insert without removing mold, so when designing replacement insert, consider locking screws from the front.
4 Slider and lifter structure
There are many lifters in hydraulic TV shell mold, ranging from twenty to forty or fifty, and many lifters have columns under them. After lifters are made, many column positions can only be used as pins. Sometimes, they cannot be used directly as pins, must be made into inserts first and then pins.
When column height exceeds 20mm, it is required to make a sleeve, but when there are many lifters, space will appear very tight. Therefore, after design is completed and before 3D drawing is issued, interference check of lifter movement and ejection state must be carried out.
TCL customers have their own requirements for design of lifter seat. We must design according to customer's standards. Form of lifter seat is shown in Figure 2-21 below.
When column height exceeds 20mm, it is required to make a sleeve, but when there are many lifters, space will appear very tight. Therefore, after design is completed and before 3D drawing is issued, interference check of lifter movement and ejection state must be carried out.
TCL customers have their own requirements for design of lifter seat. We must design according to customer's standards. Form of lifter seat is shown in Figure 2-21 below.
Hanging platform of lifter cannot be made into a pin-connected form, but should be designed to be retained in original body, as shown in Figure 2-21 above.
When designing lifter, consider strength of lifter. Lifter with a length of more than 300 should be 15mm (width) * 18mm (thickness) or more.
Moving parts such as sliders and lifters need to be quenched. Lifters are slender parts, which are prone to stress concentration after quenching, resulting in deformation or fracture. In order to prevent this, lifters should be enlarged and thickened as much as possible, and R angle should be chamfered (product can be allowed to increase fillet of R0.5 by adding or reducing glue), as shown in Figure 2-22 below.
When designing lifter, consider strength of lifter. Lifter with a length of more than 300 should be 15mm (width) * 18mm (thickness) or more.
Moving parts such as sliders and lifters need to be quenched. Lifters are slender parts, which are prone to stress concentration after quenching, resulting in deformation or fracture. In order to prevent this, lifters should be enlarged and thickened as much as possible, and R angle should be chamfered (product can be allowed to increase fillet of R0.5 by adding or reducing glue), as shown in Figure 2-22 below.
5 Ejection system
5.1 KO hole
TCL large mold design requires that KO holes for ejection and reset should be designed independently, four for ejection and four for reset, and KO hole inserts should be designed, as shown in Figure 2-23 below.
Connecting screws at reset KO holes must be able to be taken out from needle plate to facilitate fixation with injection molding machine, so B plate needs to have a screw avoidance position, as shown in Figure 2-24 below.
5.2 Travel switch
Travel switch adopts domestic Longjing XCM-A102, Shenzhen Zhongsheng Electronics Co., Ltd.
Sockets of travel switch and temperature sensing line refer to TCL standard. A two-pin socket is used. Size of air avoidance hole of installation depth is at least 30mm, as shown in Figure 2-25 below.
Sockets of travel switch and temperature sensing line refer to TCL standard. A two-pin socket is used. Size of air avoidance hole of installation depth is at least 30mm, as shown in Figure 2-25 below.
5.3 When discharging ejector pin of a large product, pay attention to size of product after shrinkage to avoid interference with ejector pin after shrinkage.
6 Exhaust system
Front mold exhaust should be sufficient. For exhaust of TCL LCD shell mold, refer to data shown in Figure 2-26 below for design. Exhaust groove depth is 0.03mm, air avoidance groove depth is 1mm, exhaust groove should be made in 3D drawing, and air induction area at glue position should be more than 50%.
Standard exhaust insert for Polish customers requires that exhaust insert be parallel to direction of weld mark. Exhaust insert is generally a combination of multiple pieces with a thickness of 5mm, as shown in Figure 2-27 below.
Dissolution mark
7 Mold base and its accessories
7.1 Since mold temperature is very high, square guide pins should be used for guidance (note that one group should be biased to prevent mold from rotating 180 degrees to close mold).
Guide sleeve, middle bracket, guide block installed in the front mold and square guide pin, sliding piece on all sliders, and guide block should be made of aluminum bronze with graphite.
7.2 TCL's mold has requirements for assembly and disassembly sequence of panel, hot runner plate and A plate. Fixing screws of these plates should be designed as shown in Figure 2-28 below.
In order to position three plates, guide pins should be designed on three plates (no need to design positioning pins), guide sleeves should be designed on the back of plate A, and length of guide pins should be 15~20mm longer than the longest hot nozzle, so that guide pins can be guided first when installing hot runner to protect hot nozzle from being damaged, as shown in Figure 2-28 below.
7.3 Precision positioning mechanisms should be installed between front and rear molds, such as guide pin assistants and side locks, as shown in Figure 2-29 below.
7.4 Customer requires that hot runner system of mold can be assembled and disassembled as a whole, so hot runner system should be fixed on hot runner plate.
7.5 Molds with hot runners need to add heat insulation plates on panel. Note that maximum size of heat insulation plate is 1000mm*1000*8mm.
7.6 Return pin and B plate must be spaced 0.5MM on one side, middle support edge and B plate must be spaced 0.25MM on one side.
7.7 Bottom plate, square iron, and B plate must be positioned with pins.
8 Others
8.1 For TCL molds that require gas-assisted injection molding, nitrogen nozzle uses Zhongtuo NPT1/4, and mold is machined with a 25mm deep hole with an inclination (see customer standards).
8.2 TCL customers have special requirements for number of spare parts. Generally, inclined ejector must be 100%, ejector and sleeve of same size must be 20%, the others must be 100%, rubber ring must be 100%, and steam pipe must be 50%.
8.3 TCL customer molds are mainly produced in Huizhou. Contents not specified in this standard are designed according to company's standards. Parts required by TCL must be in accordance with their standards. Modification of molds and products needs to be discussed and confirmed with customers.
Manufacturing standards for high-gloss steam molds
Because high-gloss steam mold is rapidly heated and cooled during injection molding process, and working conditions of mold are extremely harsh, assembly of mold parts must have good stability, wear resistance and thermal fatigue resistance. In mold matching process, it is necessary to ensure that matching parts are closely matched and move smoothly, neither too tight nor too loose. If matching is too tight, parts are prone to burns when working in a high temperature environment. If it is too loose, fluidity of rubber in a high temperature environment is very good, and it is easy to flash, so mold assembly requirements are very high.
Polishing of high-gloss steam mold is also very different from other ordinary mirror polishing. Ordinary mirror polishing generally only requires a bright surface, while high-gloss mold is very sensitive to refraction effect of light because of high-gloss brightness of product surface, and slightest surface defect is revealed. Polishing of high-gloss mold not only has high requirements for polishing itself, but also has high standards for surface flatness, smoothness and geometric accuracy. Therefore, polishing is also primary issue of high-gloss mold.
Polishing of high-gloss steam mold is also very different from other ordinary mirror polishing. Ordinary mirror polishing generally only requires a bright surface, while high-gloss mold is very sensitive to refraction effect of light because of high-gloss brightness of product surface, and slightest surface defect is revealed. Polishing of high-gloss mold not only has high requirements for polishing itself, but also has high standards for surface flatness, smoothness and geometric accuracy. Therefore, polishing is also primary issue of high-gloss mold.
1 High-gloss steam mold assembly standard
1 During injection molding, temperature of high-gloss steam mold is very high, so moving parts of mold, such as ejectors and lifters, must have a larger fit clearance than ordinary molds (generally 0.015mm~0.025mm on one side) to prevent burns caused by friction during movement.
2 Before installing high-gloss steam mold to be produced, all molding parts and parts of ejectors, lifters, etc. that contact molding surface after reciprocating movement must be thoroughly degreased, otherwise oil will rush to surface of product during filling process to cause injection defects. At the same time, oil will solidify on high-temperature mold cavity surface to form mold flowers, even corrode the high-gloss surface of mold and leave pitting.
3 When installing lifter, wipe lifter clean and remove oil, push it to the bottom from front of mold core, and apply a proper amount of lubricating oil to part of guide block exposed on the back of B plate. In this way, lifter is lubricated and grease is prevented from entering molding part at the front of lifter, as shown in Figure 3-1 below.
2 Before installing high-gloss steam mold to be produced, all molding parts and parts of ejectors, lifters, etc. that contact molding surface after reciprocating movement must be thoroughly degreased, otherwise oil will rush to surface of product during filling process to cause injection defects. At the same time, oil will solidify on high-temperature mold cavity surface to form mold flowers, even corrode the high-gloss surface of mold and leave pitting.
3 When installing lifter, wipe lifter clean and remove oil, push it to the bottom from front of mold core, and apply a proper amount of lubricating oil to part of guide block exposed on the back of B plate. In this way, lifter is lubricated and grease is prevented from entering molding part at the front of lifter, as shown in Figure 3-1 below.
Since mold temperature is 75-80℃ and front end of ejector sleeve has a large area of contact with glue during injection molding process, temperature of ejector sleeve can reach about 200℃. Therefore, during assembly, semicircular matching hole of ejector sleeve and periphery of runner insert should have a matching clearance of 0.02~0.03 on one side to allow ejector sleeve to have enough space for thermal expansion. Otherwise, ejector sleeve is easy to expand and crack during injection molding process and block ejector pin.
High-gloss steam mold has high requirements for exhaust. It is necessary to ensure that gas in cavity has a smooth exhaust channel to outside of mold. Exhaust insert should open exhaust groove as shown in Figure 3-3, and each time mold is maintained, plastic precipitates adhering to exhaust groove should be cleaned up to avoid clogging exhaust groove and affecting exhaust effect.
During mold assembly process, special attention should be paid to protection of high-gloss surface of cavity. Do not use high-pressure air to clean high-gloss surface, otherwise impurity particles in high-pressure air and dust adhering to high-gloss surface will easily damage high-gloss surface under action of high-pressure air;
Under normal circumstances, high-gloss surface of mold should be protected with plastic wrap to avoid direct exposure. After mold is assembled, mold making group should not clean high-gloss surface. Professional polishing personnel and quality inspection should clean, inspect mold twice on injection molding machine before final mold closing and before mold trial to confirm high-gloss condition of mold.
Front mold core needs to be checked and tested separately to transport water to eliminate possibility of copper blockage in waterway and water leakage in plug, as shown by red arrow in Figure 3-4 below.
Under normal circumstances, high-gloss surface of mold should be protected with plastic wrap to avoid direct exposure. After mold is assembled, mold making group should not clean high-gloss surface. Professional polishing personnel and quality inspection should clean, inspect mold twice on injection molding machine before final mold closing and before mold trial to confirm high-gloss condition of mold.
Front mold core needs to be checked and tested separately to transport water to eliminate possibility of copper blockage in waterway and water leakage in plug, as shown by red arrow in Figure 3-4 below.
2 Polishing Standard of High-gloss Steam Mold
High-gloss surface of mold is first polished with #220 and #320 oilstones, then polished with sandpapers of #400-#600-#800-#1000-#1200-#1500 in order of number. Each number of sandpaper should be processed with a 45° or 90° grinding direction.
Before changing different types of sandpapers above #1000, use pure cotton or fine paper towels dipped in industrial alcohol with an ethanol purity of ≥97% to carefully wipe polished surface and surrounding parting surface to thoroughly remove residue of previous sandpaper.
Sandpapers above #1500 are only suitable for hardened mold steels above 52HRC because they are prone to burns on the surface of pre-hardened steel parts. High-gloss mold steel generally uses high-quality pre-hardened steel of HRC38-43. It is recommended not to use sandpaper above #1500 for grinding saving, otherwise, it is very easy to produce "orange peel pattern" due to heat of mold polishing surface.
1 Polishing of high-gloss molds must be carried out in a quasi-dust-free workshop. During polishing operation, no other grinding saving operations should be carried out in polishing workshop, and people should be prevented from walking around at will to ensure cleanliness of air in workshop. Because dust, small gravel, even dandruff particles in air fall on polishing surface and cause scratches, which may damage high-gloss surface obtained by hours of polishing.
2 Polishing materials and cotton, flannel, paper towels and other items must be protected from dust to ensure that they are clean and free of any impurities.
3 Use diamond abrasive paste for polishing. When switching from sandpaper grinding saving to diamond abrasive paste polishing, use pure cotton or fine paper towels dipped in industrial alcohol with an ethanol purity of ≥97% to carefully wipe polished surface to thoroughly clean mold surface. When using diamond abrasive paste for polishing, not only working surface must be clean, but polisher's hands must also be carefully cleaned.
4 Order of diamond abrasive paste polishing is 8um (#1800 red) - 6um (#3000 yellow) - 3um (#8000 green) - 1um (#14000 blue). 8um (#1800 red) diamond abrasive paste is used to remove silk-like abrasive marks left by #1500 sandpaper. 6um (#3000 yellow) is used for semi-finishing polishing. 3um (#8000 green) and 1um (#14000 blue) are used for fine polishing.
5 When polishing with diamond abrasive paste below 6um (#3000 yellow), polishing load pressure should be controlled at 100-200g/cm², and polishing time should not be too long. Excessive polishing pressure and long polishing time can easily cause "pinholes" on mold surface.
6 Finally, use a fine flannel with a fiber diameter of ≤5um and 1um (#14000 blue) diamond grinding paste to wipe along longitudinal direction of mold to remove mist-like polishing marks, as shown in Figure 3-5 below.
Before changing different types of sandpapers above #1000, use pure cotton or fine paper towels dipped in industrial alcohol with an ethanol purity of ≥97% to carefully wipe polished surface and surrounding parting surface to thoroughly remove residue of previous sandpaper.
Sandpapers above #1500 are only suitable for hardened mold steels above 52HRC because they are prone to burns on the surface of pre-hardened steel parts. High-gloss mold steel generally uses high-quality pre-hardened steel of HRC38-43. It is recommended not to use sandpaper above #1500 for grinding saving, otherwise, it is very easy to produce "orange peel pattern" due to heat of mold polishing surface.
1 Polishing of high-gloss molds must be carried out in a quasi-dust-free workshop. During polishing operation, no other grinding saving operations should be carried out in polishing workshop, and people should be prevented from walking around at will to ensure cleanliness of air in workshop. Because dust, small gravel, even dandruff particles in air fall on polishing surface and cause scratches, which may damage high-gloss surface obtained by hours of polishing.
2 Polishing materials and cotton, flannel, paper towels and other items must be protected from dust to ensure that they are clean and free of any impurities.
3 Use diamond abrasive paste for polishing. When switching from sandpaper grinding saving to diamond abrasive paste polishing, use pure cotton or fine paper towels dipped in industrial alcohol with an ethanol purity of ≥97% to carefully wipe polished surface to thoroughly clean mold surface. When using diamond abrasive paste for polishing, not only working surface must be clean, but polisher's hands must also be carefully cleaned.
4 Order of diamond abrasive paste polishing is 8um (#1800 red) - 6um (#3000 yellow) - 3um (#8000 green) - 1um (#14000 blue). 8um (#1800 red) diamond abrasive paste is used to remove silk-like abrasive marks left by #1500 sandpaper. 6um (#3000 yellow) is used for semi-finishing polishing. 3um (#8000 green) and 1um (#14000 blue) are used for fine polishing.
5 When polishing with diamond abrasive paste below 6um (#3000 yellow), polishing load pressure should be controlled at 100-200g/cm², and polishing time should not be too long. Excessive polishing pressure and long polishing time can easily cause "pinholes" on mold surface.
6 Finally, use a fine flannel with a fiber diameter of ≤5um and 1um (#14000 blue) diamond grinding paste to wipe along longitudinal direction of mold to remove mist-like polishing marks, as shown in Figure 3-5 below.
After polishing, use a fine paper towel folded into a square and dipped in industrial alcohol with an ethanol purity of ≥97% to gently wipe mold in one direction along longitudinal direction to clean polished surface of mold. After using paper towel once, it needs to be replaced with a new surface or discarded and replaced, and cannot be reused.
Cover polished surface with a layer of fine paper towel, spray a layer of anti-rust oil on paper towel, then protect it with tape.
If mold damages the high-gloss surface during production process, mold cavity temperature must be reduced to below 40℃ before polishing, otherwise mold is very likely to produce "pinholes" during polishing at high temperatures. If mold cavity produces oil spots during production process, you can first wipe it with a fine paper towel dipped in mold cleaning spray or industrial alcohol with an ethanol purity of ≥97%. After oil stains are removed, remaining detergent must be wiped off with a dry fine paper towel, otherwise detergent may leave new oil stains on high-gloss surface due to high-temperature curing.
Cover polished surface with a layer of fine paper towel, spray a layer of anti-rust oil on paper towel, then protect it with tape.
If mold damages the high-gloss surface during production process, mold cavity temperature must be reduced to below 40℃ before polishing, otherwise mold is very likely to produce "pinholes" during polishing at high temperatures. If mold cavity produces oil spots during production process, you can first wipe it with a fine paper towel dipped in mold cleaning spray or industrial alcohol with an ethanol purity of ≥97%. After oil stains are removed, remaining detergent must be wiped off with a dry fine paper towel, otherwise detergent may leave new oil stains on high-gloss surface due to high-temperature curing.
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