Extrusion Mold transfer forward
Mold closing Cut
Mold transfer backward Blowing pins down Blowing Cooling Mold opening Taking out Blowing pins up Unsprueing
// with mono extrusion, same machine, but:
If 1 material , then 1 hoppepers => 3 cylinders/screws.
Outside layer 45 %
middle layer 10 %
Cycle:
Co Extrusion Blow Molding:
Same principle than mono extrusion blow molding, but: extrusion step a bit different
Mono extrusion = one material Co extrusion = Several materials (1, 2, 3, 4,…)
INTRODUCTION OF THE PROCESS:
- Technology for making hollow plastic products: bottles, air ducts of automobiles, chemical tanks.
EXTRUSION
BLOW
MOLDING
Air is blown into a “molten” plastic tube, called a "parison" to form hollow products. Then, plastic is hardened and shaped in a mold mold
≠ with injection blow molding
- The pre form called “parison” is a molten tube. (not a small bottle) - The screw turns continuously => material always goes out of the machine. - The extruder is composed of a head which is determinant for the final dimensions of the bottle.
Inside layer 45 %
50% HDPE.
1
50% ADMER.
8% Colorant.
2
100% EVOH
50% HDPE. 50% ADMER.
3 8% Colorant.
Mechanical adjustments:
3 layers adjustment:
Training:
“Co extrusion blow molding”
process
TRAINING SCHEDULE:
1. Introduction to the process. 2. Products. 3. Extrusion Blow Molding Principle. 4. Co Extrusion Blow Molding. 5. Mechanical adjustments. 6. Illustration on the Machine. 7. EHS 8. Skyhigh process: 9. Range of defects linked to the process. 10. Questions.
Products:
▪ Production of hollow parts: ▪ Bottles, flacons, ▪ Tanks, (even fuel tank) ▪ Automobile parts (engine parts)
• Differences with injection blow molding: – Observation on the bottle. – Precisions of the dimension. – Stability of the process.
Extrusion Blow Molding:
▪ blow:
- Extrusion of a tube “parison”. - Transfer of the mold under die head. - Closing of the mold. - Cutting of the parison. - Transfer of the mold to the blowing post. - Blowing pins go down. - Blowing of the parison in the mold - Cooling of the parts. - Opening of the mold. (parts stayed on the pins) - Transfer of take out device (& transfer of the mold) - Closing of the take out device (& closing of mold) - Blowing pins go up. - Transfer (backward) of the take out device.
Extrusion Blow Molding:
▪ Extrusion:
// with injection blow molding (NOVAPAX)
- Plastic material is inserted in a “hopper” - Heated cylinder and screw rotation ensure the material melting. - No movement of the screw forward and backward.