Both processes make hollow plastic containers, but they suit different products. In one line: extrusion blow molding is for cans, drums and handled bottles; injection blow molding is for small precise bottles with an accurate neck and no flash to trim.
| Extrusion Blow Molding (EBM) | Injection Blow Molding (IBM) | |
|---|---|---|
| How it works | Extrudes a parison, closes the mould, blows it | Injection-moulds a preform, then blows it |
| Best products | Jerry cans, drums, tanks, handled & household bottles | Small pharma, cosmetic, dropper & food bottles |
| Size range | ~100 ml to 1000 L | 2 ml to 1,000 ml |
| Neck accuracy | Good (trimmed) | Excellent (injection-moulded, no weld line) |
| Scrap / flash | Flash trimmed & reground | No flash to trim; very little regrind |
| Handles | Yes | No |
How to choose
Does the container have a handle, or is it bigger than about 1 L (a jerry can, drum or tank)? Choose extrusion blow molding. Clear PET bottles are made by stretch blow molding — see PET stretch blow moulds. Is it a small bottle that needs a precise neck and no flash to trim — pharma, cosmetic, dropper or food? Choose injection blow molding. Many packers run both processes; AMAN supplies the machines and makes the matching moulds for each and will recommend the right one from your container and target output.
FAQ
What is the difference between extrusion blow molding and injection blow molding?
Extrusion blow molding (EBM) extrudes a molten tube (parison), closes a mould around it and blows it into a hollow container - good for jerry cans, drums, handled bottles and large sizes. Injection blow molding (IBM) first injection-moulds a preform on a core, then blows that preform into a bottle on the same machine - giving very accurate necks, no flash to trim and very little regrind, best for small precise bottles. For the six EBM stages in detail, see the extrusion blow molding process, step by step.
Which makes better bottle necks?
Injection blow molding. Because the neck is injection-moulded, threads and sealing surfaces are highly accurate with no weld line or flash - ideal for pharma, cosmetic and dropper bottles that need a perfect cap fit. EBM necks are trimmed from the parison and are fine for cans, drums and household bottles.
Which has less scrap?
Injection blow molding has no flash to trim and very little regrind. Extrusion blow molding leaves flash at the pinch-off and neck, which is trimmed and reground - a small amount of rework that is normal for cans and drums.
What sizes suit each process?
Injection blow molding suits small containers, from 2 ml up to 1,000 ml. Extrusion blow molding covers roughly 100 ml up to 1000 L - the only choice for jerry cans, drums, IBC tanks and any container with a handle.
Can one machine make handled jerry cans and precise cosmetic bottles?
No single machine does both well. Handled jerry cans and drums need extrusion blow molding; small precise cosmetic and pharma bottles need injection blow molding. Many packers run both - AMAN supplies EBM and IBM machines and the matching moulds for each.
How do I choose between EBM and IBM?
Ask two questions: does the container have a handle or is it larger than about 1 L? Then extrusion blow molding. Is it a small bottle that needs a precise neck and no flash to trim (pharma, cosmetic, food)? Then injection blow molding. Send us your container and target output and we'll recommend the right process, machine and mould.
Get a machine quote for your bottle
No drawing yet? Photos of a sample bottle work too. This is all we need to match the machine and quote it:
- ✓Bottle drawing, 3D file, or photos from all sides
- ✓Volume, bottle weight and neck size
- ✓Material, e.g. HDPE, PP or PET
- ✓How many you need per hour or per day