{"id":987,"date":"2026-09-07T08:38:00","date_gmt":"2026-09-07T08:38:00","guid":{"rendered":"https:\/\/isbmmolding.com\/?p=987"},"modified":"2026-09-07T08:38:00","modified_gmt":"2026-09-07T08:38:00","slug":"what-are-the-steps-involved-in-the-isbm-molding-process-2","status":"publish","type":"post","link":"https:\/\/isbmmolding.com\/sv\/what-are-the-steps-involved-in-the-isbm-molding-process-2\/","title":{"rendered":"Vilka steg ing\u00e5r i ISBM-gjutningsprocessen?"},"content":{"rendered":"

Vilka steg ing\u00e5r i ISBM-gjutningsprocessen?<\/h1>\n
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The ISBM moulding process \u2014 injection stretch blow moulding \u2014 converts raw plastic resin into a finished hollow container through a precisely sequenced series of steps. Each step occurs at a dedicated station on the machine\u2019s rotary table, and all stations operate simultaneously on different preforms within the same machine cycle. Understanding what happens at each step, and what controls quality at each point, is essential for anyone operating or specifying ISBM equipment.<\/p>\n

Overview: How Many Steps Does ISBM Have?<\/h2>\n

A one-step ISBM machine performs between three and six steps depending on its station count. Three-station machines perform the minimum required steps \u2014 injection, stretch-blow, and ejection. Four-station machines add a dedicated conditioning step. Six-station machines further add post-blow cooling and a second conditioning zone. All configurations produce the same type of finished container; the additional stations enable more precise control over complex bottle geometries and higher cycle speeds.<\/p>\n

\"4-station<\/p>\n

4-station ISBM rotary table \u2014 all four steps run simultaneously on different preforms within each machine cycle.<\/p>\n

Step 1: Resin Drying and Preparation<\/h2>\n

Before any ISBM cycle begins, the resin must be prepared correctly. PET \u2014 the dominant resin in ISBM production \u2014 is hygroscopic: it absorbs moisture from the air. Moisture in the resin causes hydrolytic degradation during processing, reducing intrinsic viscosity (IV) and producing acetaldehyde (AA), a compound that creates off-flavour in food and beverage containers.<\/p>\n

Standard PET drying: desiccant dryer at 160\u2013170\u00a0\u00b0C, minimum 4\u20136 hours, target moisture below 50\u00a0ppm. The dryer\u2019s dew point should be verified at \u221240\u00a0\u00b0C or below before processing begins. This step happens upstream of the machine and is not part of the machine cycle itself, but it determines the quality of every bottle the machine produces.<\/p>\n

Step 2: Injection \u2014 Forming the Preform<\/h2>\n

The first in-machine step is injection moulding. Dried resin is fed from the hopper into a heated barrel where a reciprocating screw melts and conveys it. The melt \u2014 at 270\u2013295\u00a0\u00b0C for standard PET \u2014 is injected at high pressure into the preform mould cavity, forming the thick-walled intermediate tube known as a preform.<\/p>\n

Key parameters controlled at this step:<\/p>\n