Seminar Report

Medical Plastics : Materials, Applications And Processing

For Medical Devices And Pharmaceuticals Industries

SUCCESSFUL INJECTION MOLDING FOR MEDICAL COMPONENTS

Plastic materials processing.................

70 to 80% polymers used in medical applications are....

PVC-P

PP

PE

PS

Other materials are........

PC, PPSU (Polyphenyl Sulfone)

PA (Nylon), PET

PU, UHMWPE

 

Medical Component Material Disposable Syringes Barrel/ plunger plunger PP HDPE Needle cover PP Syringe port/Spike port PVC-P Port cap PVC-P Dosing containers P

Medical Component Material Syringe seals, caps, vial closures TPE Valves, extensions, connections PA (Nylon) Respiratory humidifier PSU/PC Hip reversion tools PPSU Body & limb support PU Heart Valve UHMWPE/PS

 

Injection Molding Cycle Time
Factors influencing optimized quality molding.......   Machine Homogenous melt at constant temp., Fill as fast as possible Keep melt flow front velocity constant Changeover from fill to pack as late as possible Precise changeover Consistency of follow up (hold on) pressure and time
Mould Constant mould wall temp., Constant rate of cooling Material From Single Grade and Same Batch Monitored Parameters Plasticizing Time - Cycle Time Fill Time Changeover Position Melt Cushion Peak Injection pressure - short hold on time
Recommended Minimum & Maximum Utilizations of Dosing Stroke for Cylinder L:D 20:1 & 24:1
Influences of process parameters on most important quality characteristics (Yellow : Great Influence)   Process parameters/ Quality characteristics Injection Speed Mould Temp- erature Melt  Temp- erature Follow  Up  Pressure Follow  Up  Pressure time Clamp  Close Screw  Speed Screw  back  Pressure Dimension Stability                 Low Shrinkage                 Good Surface                 Homogeneity                 Colour Dispersion
Feed Throat Temperature Control Influences the co-efficient of friction of plastics granules with steel. To maintain desired feed rate feed throat temp. control is necessary It also regulates packing of screw flights by granules/melt Effects the torque requirement for plasticizing By keeping the temperature in narrow range, consistency of melt quality is ensured.	Material Temp. PS 20-30°C SB 20-30°C ABS 35-40°C PA 60-80°C PE 20-30°C PP 20-30°C POM 30-40°C PMMA 50-60°C PC 70-90°C PVC, Rigid 30-40°C PVC, Plast 40°C PPO 40°C CA 40°C CAB 40°C CAP 40°C CP 40°C