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Drying Temperature | vacuum dehumidification equipment：140℃--150℃；hot air circulation：150℃--170℃ | |
Drying Time | 4-6H | |
Air flow of dry gas | >0.065m3/minute kg/h（1cfm 1b/h） | |
Dry air dew point | <-30<>℃（-40℃ better） | |
Residual water content | <0.05%<>（500ppm） | |
Drying cylinder | capacity | 6-8 times（output）kg/hour |
height to diameter ratio | >2:1, 3:1 better for embolic flow | |
heat insulation | good insulation improves efficiency | |
supervisory control | internal temperature and dew point | |
Screw type | conventional L/D the best aspect ratio is 20:1,compression ratio 16:1-24:1 the check valve should be more suitable for the type of sliding check ring. | ||||||||||||
General guidance | ·screw speed：minimal to prevent excessive shearing ·buffer layer size：minimal to prevent excessive thermal degradation（3-13mm） ·buck：reduce rogue ·back pressure：minimum，but it is necessary to increase back pressure to reduce air bubbles ·holding pressure/time：reduce shrinkage and voids ·cleaning：use undried PPA or cleaning agent | ||||||||||||
Typical processing conditions | ·machine size：75 ton .actual amount of glue：5.2 oz ·barrel temperature
#The mold temperature is the actual mold surface temperature value. #If the cycle or thin-walled product is accelerated, the temperature can be increased. #Water cooling or a feeding bag using a screw can increase the blanking. #The illustrated processing conditions are conventional processing conditions, and the content will vary in similar applications. #Cool the blanking bushing to prevent sticking. |
Drying Temperature | vacuum dehumidification equipment：70℃--80℃；hot air circulation equipment：90℃--100℃ | |
Drying Time | 2-4H | |
Air flow of dry gas | >0.065m3/minute/kg/h（1cfm /1b/h） | |
Dry air dew point | <-30<>℃（-40℃better） | |
Residual water content | <0.05%<>（500ppm） | |
Drying cylinder | capacity | 6-8times（Output）kg/H |
height to diameter ratio | >2:1, 3:1better for embolic flow | |
insulation | good insulation improves efficiency | |
monitor | internal temperature and dew point | |
Screw type | conventional L/D = more than the 18:1,compression ratio 1.75:1 to 2.5:1 Ring check valve is more suitable | ||||||||||||
General guidance | ·Screw speed: minimum to prevent excessive shear ·Buffer layer size: minimum to prevent excessive thermal degradation（3-13mm） ·Buck: reduce rogue ·Back pressure: minimum, but it is necessary to increase back pressure to reduce air bubbles ·Packing / time: reduce shrinkage and voids ·Cleaning: use undried PP/PK or cleaning agent | ||||||||||||
Typical processing conditions | ·Machine size：75ton。Actual amount of glue：5.2 oz ·Barrel temperature
#Maximum upper temperature limit of warm melt temperature≤235℃. #If you accelerate the cycle or thin-walled products, you can raise the slightly high temperature. |
Drying Temperature | Vacuum dehumidification ：70℃--80℃；hot air circulation ：85℃--95℃ | |
Drying Time | 4-8h | |
Air flow of dry gas | >0.065m3/minute/kg/h（1cfm /1b/h） | |
Dry air dew point | <-30<>℃（-40℃better） | |
Residual water content | <0.05%<>（500ppm） | |
Drying cylinder | capacity | 6-8times（Output）kg/h |
height to diameter ratio | >2:1, 3:1better for embolic flow | |
insulation | good insulation improves efficiency | |
monitor | internal temperature and dew point | |
Screw type | conventionalL/D = 18--25,compression ratio3:1 ， Feed section length selection reference: Crystalline materialL1=(60%--65%)L；Amorphous materialL1=(10%--20%)L | ||||||||||||
General guidance | ·Screw speed: adjusted according to the actual product size ·Buffer layer size: minimum to prevent excessive thermal degradation（3-13mm） ·Buck: reduce rogue ·Cleaning: use undried PET, PS or cleaning agent | ||||||||||||
Typical processing conditions | ·Machine size：35model ·Barrel temperature
#If the cycle or thin-walled product is accelerated, the extruder screw speed or melt temperature can be increased. #Water cooling or a feeding bag using a screw can increase the blanking. #The examples are conventional processing conditions, and the content will vary in similar applications. #Cool the blanking bushing to prevent sticking. |
Good cooling design can effectively shorten the molding cycle and prevent mucous membranes. Locations such as mold gates, corners, and column positions should be reinforced. If necessary, these parts can be considered to be made of beryllium copper with high thermal conductivity (such as Ampco TM 940 or Moldmax?). The cooling water channel of the mold should be as small as possible and designed to keep turbulent when the cooling water flows.
Mainstream design and cooling:
Copolyester is relatively easy to mucous membranes, and the following measures can be taken:
• Use up and down rotation around the main road.
• The main channel bushing should be assembled with an interference fit (0.005 mm) to ensure smooth heat transfer from the bushing to the formwork.
• Use high thermal conductivity materials to make mainstream bushings such as beryllium copper.
• The length of the main channel bushing should not exceed 80 mm and the slope of the single side should be at least 2°.
• Polish the main channel bushing in parallel.
The design of the runner:
The system settings for the runners can follow the design principles of most engineering plastics, including balanced runners, fillet transitions, cooling wells, vents, full or semi-circular runner sections, and more.
Gate design:
A large enough gate and smooth runner can effectively reduce the gate grain and prevent the gate from freezing prematurely. The thickness of the edge gate is about 50~80% of the wall thickness of the product, and the size of the tunnel gate is larger than φ1. The size of the 6 mm, three-plate die nozzle is 0.75 to 1.1 mm.
Hot runner:
SK copolyesters can be designed with hot runners and a valve-controlled hot runner design is recommended.
Exhaust tank:
For small parts or vents close to the gate, it is recommended that the depth of the venting groove be 0.012 to 0.025 mm, and for larger products, the depth should be 0.025 to 0.038 mm.
Mold polishing:
Moderate polishing of the mold contributes to demolding of the product, and if the surface is highly polished on a surface having a small draft release, a vacuum may be generated during demolding to hinder demolding.
Demoulding slope:
The unilateral draft angle is recommended to be 1°. If the bone position and the column position are required, the unilateral draft angle can be considered to be 0.5°. It is forbidden to use the 0° draft angle. Products with etched lines should be properly considered. Increase the draft angle.
Bone design:
At least 0.5 mm of chamfering should be added to the bottom of the bone. The radius of the chamfer is preferably 0.2 to 0.5 times the thickness of the bone, which can effectively reduce the stress of the product.
Undercut design:
The "grain-grain" snap ring or the linear boss is buckled in the relevant thin-walled parts, which can reach 2~3% of the diameter of the part. The inverted buckle must be rounded and chamfered for smooth mold release.
Injection molding machine
Injection amount / clamping force:
The actual amount of glue (including products and runners) should be 40~70% of the maximum shot size of the injection molding machine. It is recommended that the clamping force be 400~700kg/cm? (3~5tons/in.?).
Screw:
The recommended compression ratio is 2.8:1~3.2:1, and the aspect ratio is 18:1~20:1.
Shot:
The general-purpose large-diameter cone type nozzle is preferred.
Processing technology
dry:
The copolyester must be dried before processing. Good drying can effectively reduce the degradation of the material. It is recommended to use a dehumidifying dryer (with a dew point below -30 °C). The temperature of the hot air dryer is set at 75 ° C for more than 6 hours, and the air inlet is as small as possible.
Material temperature:
Typical material melt temperatures range from 245 ° C to 265 ° C. The material temperature should be based on the actual measured glue temperature. Please refer to the relevant data for the specific processing temperature of different models.
Injection speed:
Usually slow injection helps to reduce the number of shots near the gate. The first-stage injection speed should be 10~20%, and the second-stage injection speed can be increased to 40~80%.
buffer layer:
It is recommended to use a buffer layer of 5 to 10 mm to prevent degradation of the material due to excessive residence time and to reduce the loss of injection pressure.
Back pressure:
Appropriate back pressure can enhance the plasticization of the rubber and the function of helping the exhaust. It is recommended to use 5~10kg/cm?.
Clearing machine:
The most effective cleaning material is a polymer similar to the production material, avoiding the use of PP, PE cleaning machine. Before processing, you can use PC to clean the machine, and use PMMA, PS and other materials to clear the machine when the machine is stopped.
Use of return materials:
The clean and fully dry return material can be reused up to 100%, and the recommended ratio is generally 10~30%.
Adhesive precautions
1. Different substrates should be made of different materials. For example, the material of the PP package may not be packaged with ABS, and the material of the package ABS may not be packaged with PA or the like.
Nowadays, the rubberized TPE on the market can be divided into the following categories: PP rubber, ABS plastic, PETG plastic, PC plastic, PA plastic and so on.
2. The thickness of the TPE rubber layer:
In most rubber molding applications, a wall thickness range of 1.5-3.0mm will ensure a good bonding effect. If the TPE glue position is too thin, the injection molding is difficult, the bonding strength is low, and the hand feel is also poor. . If the TPE glue position is too thick, on the one hand, the cost is high, on the other hand, it is easy to produce defects such as shrinkage and bubbles.
The wall thickness of the TPE glue position should be as uniform as possible to achieve the optimum forming cycle. The transition between different wall thicknesses should be gradual to reduce problems caused by fluid flow, such as gas lines and bubbles. 3. Arcs (minimum radius 0.5mm) should be used at sharp corners to reduce local stresses. Deeper, non-vented, enclosed air chambers or arched sections should be avoided, and if necessary, sufficient venting slots (0.015-0.025 mm) can be added at the end of the TPE glue position. Insufficient exhaust gas may cause undesirable phenomena such as trapped air, burnt glue, and insufficient adhesion.
4. Adding a buckle to the substrate or making some well-designed deep and concave portions is helpful for improving the adhesion of the TPE.
5. Processing of the mold surface:
The mold should be polished to obtain a smooth or clear surface.
In order to produce the matt appearance of the thermoset rubber surface, a rougher mold surface is required. In general, the rough surface produced by the cavity after electrical discharge machining (EDM) will produce a good appearance of the workpiece and make demolding easier. Grinding methods such as steam jet, sandblasting or shot peening, as well as chemical etching, etc., can also be used to produce surfaces having different gloss and appearance.
In order to facilitate demolding, a release coating may be applied to the cavity or core, for example, after sandblasting or electrical discharge machining (EDM), followed by a layer of PTFE (polytetrafluoroethylene). Impregnated nickel.
6. Avoid using a release agent on the substrate. The surface of the substrate should be cleaned to avoid contact with dust.
7. The processing temperature of the TPE compound should be based on the measured melting temperature of the rubber compound, not the display temperature of the injection molding machine.
8. If the TPE is required to be coated on a metal part, a suitable adhesive may be used as an aid.
Drying Temperature | Vacuum dehumidification：100℃--120℃；hot air circulation：120℃ | |
Drying Time | 4-6h | |
Air flow of dry gas | >0.065m3/minute/kg/h（1cfm /1b/h） | |
Dry air dew point | <-30℃（-40℃better） | |
Residual water content | <0.05%（500ppm） | |
Drying cylinder | capacity | 6-8times（Output）kg/h |
height to diameter ratio | >2:1, 3:1better for embolic flow | |
insulation | good insulation improves efficiency | |
monitor | internal temperature and dew point | |
Screw type | conventional L/D = more than the18:1,compression ratio2.5:1to3.5:1 Ring check valve is more suitable | ||||||||||||
General guidance | ·Screw speed: minimum to prevent excessive shear ·Buffer layer size: minimum to prevent excessive thermal degradation（3-13mm） ·Buck: reduce rogue ·Back pressure: minimum, but it is necessary to increase back pressure to reduce air bubbles ·Packing / time: reduce shrinkage and voids ·Cleaning: use undried PA or cleaning agent | ||||||||||||
Typical processing conditions | ·Machine size：75ton。Actual amount of glue：5.2 oz ·Barrel temperature
#The mold temperature is the actual mold surface temperature value. #If you accelerate the cycle or thin-walled products, you can raise the slightly high temperature. #Water cooling or a feeding bag using a screw can increase the blanking. #The examples are conventional processing conditions, and the content will vary in similar applications. #Cool the blanking bushing to prevent sticking. |
Drying Temperature | Vacuum dehumidification：100℃--120℃；hot air circulation：120℃ | |
Drying Time | 4-6h | |
Air flow of dry gas | >0.065m3/minute/kg/h（1cfm /1b/h） | |
Dry air dew point | <-30<>℃（-40℃better） | |
Residual water content | <0.05%<>（500ppm） | |
Drying cylinder | capacity | 6-8times（Output）kg/h |
height to diameter ratio | >2:1, 3:1better for embolic flow | |
insulation | good insulation improves efficiency | |
monitor | internal temperature and dew point | |
Screw type | conventionalL/D = more than the18:1,compression ratio2.5:1to3.5:1 Ring check valve is more suitable | ||||||||||||
General guidance | ·Screw speed: minimum to prevent excessive shear ·Buffer layer size: minimum to prevent excessive thermal degradation（3-13mm） ·Buck: reduce rogue ·Back pressure: minimum, but it is necessary to increase back pressure to reduce air bubbles ·Packing / time: reduce shrinkage and voids ·Cleaning: use undried PA or cleaning agent | ||||||||||||
Typical processing conditions | ·Machine size：75ton。Actual amount of glue：5.2 oz ·Barrel temperature
#The mold temperature is the actual mold surface temperature value. #If the cycle or thin-walled product is accelerated, the temperature can be increased. #Water cooling or a feeding bag using a screw can increase the blanking. #The examples are conventional processing conditions, and the content will vary in similar applications. #Cool the blanking bushing to prevent sticking. |
Drying Temperature | Vacuum dehumidification ：70℃--80℃；Hot air circulation：90℃--100℃ | |
Drying Time | 1 - 3 H | |
Air flow of dry gas | >0.065m3/minutekg/h（1cfm /1b/h） | |
Dry air dew point | <-30<>℃（-40℃better） | |
Residual water content | <0.05%<>（500ppm） | |
Drying cylinder | capacity | 6-8times（Output）kg/h |
height to diameter ratio | >2:1, 3:1better for embolic flow | |
insulation | good insulation improves efficiency | |
monitor | internal temperature and dew point | |
Problems caused by insufficient drying
·Reduced mechanical properties due to reduced molecular weight of polyketone groups and degradation of other additives.
·It has an adverse effect on the color of the product.
·Processing parameters are difficult to control, such as melt pressure, flow properties and energy consumption.
·Bubbles and silver.
2.Injection molding
Screw type | conventional L/D = more than the 18:1,compression ratio 1.75:1 to 2.5:1 Ring check valve is more suitable | ||||||||||||
General guidance | ·Screw speed: minimum to prevent excessive shear ·Buffer layer size: minimum to prevent excessive thermal degradation（3-13mm） ·Buck: reduce rogue ·Back pressure: minimum, but it is necessary to increase back pressure to reduce air bubbles ·Packing / time: reduce shrinkage and voids ·Cleaning: use undried PP/PK or cleaning agent | ||||||||||||
Typical processing conditions | ·Machine size：75ton。Actual amount of glue：5.2 oz ·Barrel temperature
#Maximum upper temperature limit of warm melt temperature≤255℃. #If you accelerate the cycle or thin-walled products, you can raise the slightly high temperature. |
Drying Temperature | Vacuum dehumidification ：70℃--75℃；hot air circulation ：80℃--85℃ | |
Drying Time | 4-6 h | |
Air flow of dry gas | >0.065m3/minute/kg/h（1cfm /1b/h） | |
Dry air dew point | <-30<>℃（-40℃better） | |
Residual water content | <0.05%<>（500ppm） | |
Drying cylinder | capacity | 6-8 times（Output）kg/h |
height to diameter ratio | >2:1, 3:1better for embolic flow | |
insulation | good insulation improves efficiency | |
monitor | internal temperature and dew point | |
Problems caused by insufficient drying
. Reduced mechanical properties due to reduced molecular weight of the polyester group and degradation of other additives.
. It has an adverse effect on the color of the product.
. Processing parameters are difficult to control, such as melt pressure, flow properties and energy consumption.
. Bubbles and silver.
Screw type | conventional L/D = more than the 18:1,compression ratio 2.5:1 to 3.5:1 Ring check valve is more suitable | ||||||||||||
General guidance | ·Screw speed: minimum to prevent excessive shear ·Buffer layer size: minimum to prevent excessive thermal degradation（3-13mm） ·Buck: reduce rogue ·Back pressure: minimum, but it is necessary to increase back pressure to reduce air bubbles ·Packing / time: reduce shrinkage and voids ·Cleaning: use undried PC, PET, PS or cleaning agent | ||||||||||||
Typical processing conditions | ·Machine size：75ton。Actual amount of glue：5.2 oz ·Barrel temperature
#The mold temperature is the actual mold surface temperature value, and special structural products require ice water equipment. #If the cycle or thin-walled product is accelerated, the temperature can be increased and the molding cycle is shortened. It is recommended to use a frozen water cycle. #Water cooling or a feeding bag using a screw can increase the blanking. #The examples are conventional processing conditions, and the content will vary in similar applications. #Cool the blanking bushing to prevent sticking. |
Melting Temperature：350℃----400℃，Upper limit＜420℃，Note: Carbonization has occurred when the product is discolored or bubbles occur. The heating system of the injection molding equipment should be checked, and it is difficult to release the mold!
Mold temperature setting：150℃-200℃.Thin wall products are recommended to have a mold temperature of about 200 °C.
Drying Temperature | vacuum dehumidification：100℃--110℃；hot air circulation：110℃--120℃ | |
Drying Time | 3- 5 H | |
Air flow of dry gas | >0.065m3/minute kg/h（1cfm 1b/h） | |
Dry air dew point | <-30<>℃（-40℃ better） | |
Residual water content | <0.05%<>（500ppm） | |
Drying cylinder | capacity | 6-8 times（output）kg/ hour |
height to diameter ratio | >2:1, 3:1 better for embolic flow | |
insulation | good insulation improves efficiency | |
monitor | internal temperature and dew point | |
Problems caused by incomplete drying of materials：
1.Decreased mechanical properties due to reduced molecular weight of polyketones and degradation of other additives;
2.Water ripples, bubbles, silver streaks, markings, edulis, flower, flushing, etc.;
3.Inconsistent melt flow rates, resulting in gloss changes in the corresponding article;
4.When the actual temperature of the barrel reaches the set temperature, the inlet of the small blower can be adjusted;
5.The molding process is difficult to control;Screw type | conventional L/D = more than the 18:1,compression ratio 1.75:1 - 2.5:1 aring check valve is more suitable. | ||||||||||||
General guidance | ·screw speed：minimal to prevent excessive shearing ·buffer layer size：minimal to prevent excessive thermal degradation（3-13mm） ·buck：reduce rogue ·back pressure：minimum，but it is necessary to increase back pressure to reduce air bubbles ·compress time：reduce shrinkage and voids ·cleaning：use undried PP/PK or cleaning agent | ||||||||||||
Molding condition | ·machine size：75 ton。actual amount of glue：5.2 oz ·barrel temperature
#Melt temperature maximum upper limit≤245℃. #If the cycle or thin-walled product is accelerated, the slightly higher temperature can be raised. |