- \n
- Target Moisture Content:<\/strong> Below 5%, ideally between 2% and 3%<\/strong>.<\/li>\n
- Recommended Method:<\/strong> Use a vacuum drying oven at 75°C – 90°C<\/strong> for approximately 2 hours<\/strong>.<\/li>\n<\/ul>\n
📦 Storage and Hopper Loading<\/strong>\nOnce dried, materials must be sealed immediately to prevent re-absorption of moisture from the air. Using a drying hopper<\/strong> is highly recommended as it continuously supplies hot, dry material to the injection molding machine. This simplifies operations, maintains cleanliness, improves quality, and allows for faster injection rates.<\/p>\n
- \n
- Tipp:<\/strong> The loading capacity of the drying hopper should generally be 2.5 times<\/strong> the hourly material consumption of the injection machine.<\/li>\n<\/ul>\n
![\"Industrial](\"https:\/\/ideal-pro.com\/wp-content\/uploads\/2026\/05\/the-ultimate-guide-to-tprtpe-injection-molding-process-parameters-troubleshooting-3.jpg\")
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\nColoring TPR\/TPE Compounds<\/h2>\n
TPR materials based on SBC (Styrenic Block Copolymers) generally offer superior colorability compared to other elastomers. They require less masterbatch to achieve vibrant colors, resulting in a cleaner, more pure finish.<\/p>\n
Matching Carrier Resins<\/strong>\nTo ensure uniform dispersion, the viscosity of the masterbatch (colorant) should be lower than that of the TPR base material. Here are the recommendations based on the specific TPR substrate:<\/p>\n
- \n
- SBS-based TPE:<\/strong> Use Polystyrol (PS)<\/strong> carriers.<\/li>\n
- Hard SEBS-based TPR:<\/strong> Use Polypropylen (PP)<\/strong> carriers.<\/li>\n
- Soft SEBS-based TPR:<\/strong> Use Low-Density Polyethylene (LDPE)<\/strong> or EVA<\/strong> copolymers. \n
- \n
- Anmerkung:<\/em> Avoid PP carriers for soft grades as they may negatively affect the hardness of the compound.<\/li>\n<\/ul><\/li>\n
- Overmolding Applications:<\/strong> Be cautious with Polyethylene (PE)<\/strong> carriers, as they might adversely affect the adhesion bonding to the substrate.<\/li>\n<\/ul>\n
\nMachine Setup: Barrel Cleaning<\/h2>\n
Whether you are using a new machine, changing products, switching raw materials, or changing colors, cleaning the barrel is crucial. Contamination or degraded plastic can cause significant defects.<\/p>\n
For TPR materials, the most effective method is material purging<\/strong>. Simply use the new TPR material to displace the old transition material until the purge is clean.<\/p>\n
\nTemperature Settings: The Key to Success<\/h2>\n
Accurate temperature control determines the外观 (appearance) and performance of the final product.<\/p>\n
Barrel and Nozzle Temperatures<\/strong><\/p>\n
- \n
- Feed Zone:<\/strong> Keep temperatures relatively low to prevent blockage at the feed throat and allow trapped air to escape.<\/li>\n
- Transition Zone:<\/strong> Set above the melting point of the masterbatch to improve mixing.<\/li>\n
- Metering\/Nozzle Zone:<\/strong> Set close to the desired melt temperature.<\/li>\n<\/ul>\n
\n\n
\n \nZone<\/th>\n Recommended Temperature Range<\/th>\n<\/tr>\n<\/thead>\n \n Barrel<\/strong><\/td>\n 160°C – 210°C<\/td>\n<\/tr>\n \n Nozzle<\/strong><\/td>\n 180°C – 230°C<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Form Temperatur<\/strong>\nThe mold temperature should be set higher than the condensation temperature of the injection zone to prevent moisture contamination and surface streaks. While higher mold temperatures increase the cycle time, they significantly improve weld lines and overall appearance.<\/p>\n
- \n
- Recommended Mold Temp:<\/strong> 30°C – 40°C<\/strong>.<\/li>\n<\/ul>\n
![\"Injection](\"https:\/\/ideal-pro.com\/wp-content\/uploads\/2026\/05\/the-ultimate-guide-to-tprtpe-injection-molding-process-parameters-troubleshooting-2.jpg\")
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\nInjection Process: Filling, Packing, and Cooling<\/h2>\n
Optimizing the filling phase is critical to preventing short shots and excessive pressure drops. If filling performance is poor, consider adjusting the gate location, injection pressure, or even the part geometry.<\/p>\n
Pressure Control Strategy<\/strong>\nInjection pressure is typically divided into primary (injection), secondary (holding\/packing), and sometimes tertiary stages.<\/p>\n
- \n
- Switch-over Point:<\/strong> Proper timing prevents over-packing (flash) or under-packing (short shots).<\/li>\n
- Holding Pressure:<\/strong> Usually set at 50% – 65%<\/strong> of the maximum filling pressure (approx. 0.6 – 0.8 MPa lower than injection pressure). This reduces hydraulic load and energy consumption.<\/li>\n
- Cushion (Buffer):<\/strong> Always leave a small amount of melt at the end of the screw stroke. This cushion allows for effective holding pressure transfer to compensate for shrinkage.<\/li>\n<\/ul>\n
Abk\u00fchlungszeit<\/strong>\nCooling time depends on melt temperature, wall thickness, and cooling efficiency. Harder materials solidify faster than softer ones.<\/p>\n
- \n
- Standard Parts:<\/strong> Approx. 10 – 15 seconds<\/strong> per 0.100\" wall thickness (cooled from both sides).<\/li>\n
- Overmolded Parts:<\/strong> Approx. 15 – 25 seconds<\/strong> per 0.100\" wall thickness (due to limited cooling surface area).<\/li>\n<\/ul>\n
![\"Injection](\"https:\/\/ideal-pro.com\/wp-content\/uploads\/2026\/05\/the-ultimate-guide-to-tprtpe-injection-molding-process-parameters-troubleshooting-1.jpg\")
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\nTroubleshooting Common Defects<\/h2>\n
Even with careful planning, issues can arise. Here is a quick troubleshooting guide for common TPR\/TPE molding defects.<\/p>\n
🚫 Incomplete Filling (Short Shots)<\/strong><\/p>\n
- \n
- Insufficient material feed (too little or too much cushion).<\/li>\n
- Injection pressure too low or injection time too short.<\/li>\n
- Injection speed too slow.<\/li>\n
- Material or mold temperature too low.<\/li>\n<\/ul>\n
⚠️ Flash (Overflow)<\/strong><\/p>\n
- \n
- Injection pressure or speed is too high.<\/li>\n
- Excessive material charge.<\/li>\n
- Barrel, nozzle, or mold temperatures are too high, causing low viscosity and excessive flow.<\/li>\n<\/ul>\n
🌪️ Silver Streaks, Bubbles, and Voids<\/strong><\/p>\n
- Overmolded Parts:<\/strong> Approx. 15 – 25 seconds<\/strong> per 0.100\" wall thickness (due to limited cooling surface area).<\/li>\n<\/ul>\n
- Holding Pressure:<\/strong> Usually set at 50% – 65%<\/strong> of the maximum filling pressure (approx. 0.6 – 0.8 MPa lower than injection pressure). This reduces hydraulic load and energy consumption.<\/li>\n
- Switch-over Point:<\/strong> Proper timing prevents over-packing (flash) or under-packing (short shots).<\/li>\n
- Transition Zone:<\/strong> Set above the melting point of the masterbatch to improve mixing.<\/li>\n
- Overmolding Applications:<\/strong> Be cautious with Polyethylene (PE)<\/strong> carriers, as they might adversely affect the adhesion bonding to the substrate.<\/li>\n<\/ul>\n
- Hard SEBS-based TPR:<\/strong> Use Polypropylen (PP)<\/strong> carriers.<\/li>\n
- SBS-based TPE:<\/strong> Use Polystyrol (PS)<\/strong> carriers.<\/li>\n
- Recommended Method:<\/strong> Use a vacuum drying oven at 75°C – 90°C<\/strong> for approximately 2 hours<\/strong>.<\/li>\n<\/ul>\n
![\"Common](\"https:\/\/ideal-pro.com\/wp-content\/uploads\/2026\/05\/the-ultimate-guide-to-tprtpe-injection-molding-process-parameters-troubleshooting-4.jpg\")
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