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बैकप्रेशर इंजेक्शन मोल्डिंग

ऊपर का दवाब ( बैकप्रेशर ) बाद में पिघले हुए शॉट की तैयारी के दौरान पेंच के पिछड़े आंदोलन के प्रतिरोध को इंगित करता है। यह दबाव प्लास्टिक द्वारा स्क्रू पर डाला जाता है, जबकि इसे शॉट चैंबर (बैरल के आगे के छोर, स्क्रू के सामने) में फीड किया जा रहा है। दबाव में पेंच और मैटेरियल के रोटेशन के दौरान, प्लास्टिक का पूरी तरह से मिश्रण प्राप्त किया जाता है, और कुछ तापमान में वृद्धि भी होती है। गर्मी-संवेदनशील और कतरनी-दर-असंवेदनशील प्लास्टिक से निपटने में, इस मूल्य को निर्धारित सीमा के भीतर रखने के लिए सावधानी बरतनी चाहिए। समीक्षा की गई कार्रवाई एक पारंपरिक पेंच से संबंधित है जहां प्लास्टिक के संसाधित होने के लिए अन्यथा मामूली प्रदर्शन करने वाले स्क्रू की पिघलने की विशेषताओं में सुधार के लिए बैक प्रेशर का उपयोग किया जाता है। दो-चरण वाले स्क्रू के साथ, पहले चरण को दूसरे चरण के स्क्रू से हाइड्रॉलिक रूप से अलग किया जाता है, जो कि अपूर्ण विचलन क्षेत्र द्वारा होता है। नतीजतन, पिघलने को प्रभावित करने के लिए बैक प्रेशर का उपयोग नहीं किया जा सकता है। बैक प्रेशर लगाने से केवल दूसरा चरण प्रभावित होता है और...
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TROUBLESHOOTING WELD LINES / FLOW MARKS IN INJECTION MOLDING

 WELD LINES AND FLOW MARKS MAJOR CAUSES FOR THE DEFECT : Molten plastic material is too cold in the mold after injection. when there is an excessive mold lubricant in the mold. Mold is too cold . Injection speed is slow. Low injection pressure. Volatile gas are been trapped in the mold. Air unable to escape from the mold as fast as it should.           TROUBLE SHOOTING : Increase injection pressure. Increase injection speed. Increase plasticizing capacity of machine if possible. TEMPERATURE : Increase Barrel / Cylinder temperature. Increase Nozzle temperature. Increase Mold Temperature. Make proper/even/balanced cooling system for the mold. MOLD : Add proper vent on the mold. Increase the runner system in the feed channel. Increase the gate system. Increase the opening of sprue. Make necessary adjustment for the mold adjustment. Thick the particular area where the welded part is too thin. Filling rate of the material in the mold should be equal. Incre...
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TROUBLESHOOTING FLASH IN INJECTION MOLDING MACHINE

FLASH IN INJECTION MOLDING PRODUCT Flash is Nothing but just an extra material over the molded product , Flash causes loss of material at the time of molding and sometimes it also destroys the surface beauty of the product . MAJOR CAUSES OF FLASH 1. Material Too Hot at the time of injection and in the mold. 2. Injection pressure is too high. 3. Excessive Feeding of the material in the mold. 4. Improper or Uneven feeding of the material. 5. Poor parting line or the mating surfaces of the mold. 6. Mold deficiency means problem in the mold manufacturing. 7. Injection Pressure is higher than Clamping pressure. 8. Erratic or uneven or improper cycle time. TROUBLE SHOOTING THE FLASH TEMPERATURE :   Check the cylinder temperature that means check the temperature of your barrel make it low if it is higher. Reduce the temperature  of the nozzle that is an important aspect. Reduce the mold temperature if it is higher. MOLDING SETTINGS : Increase the clamping force to make proper cl...
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IMPORTANT SAFETY MEASURES FOR INJECTION MOLIDNG MACHINE PART -1

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  T he injection molding machine is equipped with a range of safety devices to provide the machine operator with maximum safety from accidents. Service, maintenance and repair work should only be carried out by personnel who are sufficiently qualified in their field and who have specific knowledge of injection molding machinery.  Safety devices must under no circumstances be removed or rendered in-operative. Should this be unavoidable during setting or repair work it is essential first to switch OFF the mains switch 1-Q0 (this completely disconnects the machine from the mains) If the safety equipment malfunctions or a fault occurs in it, the machine must be immediately shut down and the following actions must be taken:   Actuate emergency stop button  (Front)   Actuate emergency stop button (Rear)   Switch off isolator   Close down the cooling water supply after about 20 min.   Inform the person in charge at once   Before putt...
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BARREL TEMPERATURE

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   The barrel heating has a soft switch on the IBED for switching it on. Pressing the switch again will switch the heaters off.     Each heating zone has a set value, an actual value, positive and negative tolerances, and an actual percent of utilization.     If the value of zero is set for a particular zone, then that zone is omitted from the monitoring process.     Appropriate positive and negative tolerances can be set quite independently and separately for each zone.     When the tolerance band is re-entered then screw rotation is prevented for the set cold start protection time.   If the temperature rises above the upper tolerance during Automatic operation, then the alarm CYLINDER TEMPERATURE TOO HIGH is set and ALARM PRESENT appears on the top of the screen and heating is switched OFF.     When the temperature sinks to below the lower tolerance, then the machine continues until the cycle is completed (as in semi-a...
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INTRUSION IN INJECTION MOLDING

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Intrusion   If the intrusion time is set greater than zero, then the screw will be rotated during this time immediately prior to injection. Material will thus be introduced into the mould.     Both pressure and screw rotation speed can be set separately.  Cold Slug Removal  If it is necessary to remove the cold slug from the nozzle before injection, the appropriate selection can be made from the program options together with a time when the slug is to be removed by injection.   Both injection pressure and speed can be set separately.     This operation occurs before injection unit moves forward.           
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INJECTION AND HOLDING PROFILE

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Injection Profile   The injection profile can be programmed in 6 steps with 5 stroke trigger points.    The injection start position is taken as the current stroke position at that time.    Example Step 1:    Injection from screw stops position to 70.0 mm with speed            30mm/s    Step 2:     With 20mm/s speed upto 55.0 mm    .... and so on as per the profile programmed.    With time dependent switch over to hold on pressure, the actual switch over stroke will be indicated.    With stroke dependent switch over to hold on pressure, it will occur at 5.0 mm.    If steps are switched out, then the next trigger point is merged in its place for injection speed. Therefore the speed value of the last point remains unchanged until switch over to hold on phase. .... and so on as per the profile programmed.    With time dependent switch over to...
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