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Why Injection Blow Molding

The injection blow molding (IBM) process produces billions of plastic containers each year. Ranging in size from 1 ml to 2 liters, these containers  meet exacting standards of consistent weight, volume and tolerance, and are popular around the world for a myriad of applications from pharmaceuticals to toiletries to automotive to household use.

IBM Bottle attributes

  • Exact Neck dimensions
  • Thick, even walls
  • Nearly invisible parting lines
  • Variety of different finishes are possible

IBM Process attributes

  • No scrap
  • No trimming
  • No waste
  • Not much auxiliary equipment required

Compare Injection Blow Molding to Extrusion Blow Molding


Injection Blow Molding Extrusion Blow Molding
No scrap 20-40% scrap during production
Uniform wall thickness Wall thickness variation
Bottle weight variation of 1% Bottle weight variation of 3%
Slower cycle time / more cavities Fast cycle time / less cavities
Thin walls difficult to control Thick & thin wall capabilities
Hollow Handleware not possible Hollow Handleware
Necks made with injection molded tolerances Necks made with blow molded tolerances
One technician per 4-6 machines One technician per 1-2 machines
Process  is controlled and repeatable with no adjustments Variable process requiring constant adjustment
Almost no ancillary equipment Lots of ancillary equipment needed

Typical Products for Injection Blow Molding


These are made in PP, HDPE, PS, MIPS, SAN etc. Jars are made in a wide variety of materials. The process advantage is that no secondary trimming (scrap) is required when making the neck finish. Ovaloid neck (petroleum jelly) jars can be made by injection molding the neck finish.

Dropper Bottles

Usually produced in virgin LDPE. Jomar IBM machines are installed in clean manufacturing environments worldwide. The bottles can be stripped from the core rods whilst still very hot and transported to the clean room in sterile air for packing.


CYLINDRICALS AND BOSTON ROUNDS – These bottles are made in HDPE, LDPE, PP. Up to 24 cavity molds from 10-15 second cycles. QUALITY PRODUCTS do not cause problems on decoration, filling or capping lines, and are less liable to bring customer complaint.

One Piece Roll-on Deodorants

Available in PP and HDPE. Close tolerance of the injection molded ball seating allows for an even application of the deodorant product. Snap-on ball housings are also used on SAN and PET bottles used for clarity.

Tablet and Pill Bottles

These are made from PP, HDPE, LDPE and PS. These bottles can be designed with complicated injected neck finishes for Child Resistance or pilfer-proofing. Also the neck finish is excellent for barrier seals against moisture with a plug seal closure, and also very flat for tamper foil application.

Miscellaneous Uses

Some other uses include the production of Bellows, Laboratory ware, Christmas tree balls, Light globes, Fish bowls, Flower vases and bowls, wash balls, lemons, etc.
More than half of the injection blow mold machines in use throughout the world today were built by Jomar.
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