{"id":1210,"date":"2026-08-18T08:04:58","date_gmt":"2026-08-18T08:04:58","guid":{"rendered":"https:\/\/ever-powers.com\/?p=1210"},"modified":"2026-08-18T08:16:27","modified_gmt":"2026-08-18T08:16:27","slug":"one-step-isbm-vs-two-step-sbm-food-container-cost","status":"publish","type":"post","link":"https:\/\/ever-powers.com\/it\/application\/one-step-isbm-vs-two-step-sbm-food-container-cost\/","title":{"rendered":"ISBM vs SBM blow molding \u00b7 one step injection stretch blow molding \u00b7 food container production cost"},"content":{"rendered":"

Every food container manufacturer choosing blow molding equipment faces the same process choice: one-step injection stretch blow molding (ISBM), where the preform is injected and blown in the same machine and cycle; or two-step stretch blow molding (SBM), where commercially sourced preforms are reheated and blown on a separate machine. The decision determines capital outlay, per-unit production cost, quality control architecture, and operational flexibility for the next 10\u201315 years of the machine’s service life. Getting it wrong in either direction has quantifiable consequences.<\/p>\n

\"Comparison<\/p>\n

 <\/p>\n

\n

Process Architecture: How One-Step and Two-Step Differ<\/h2>\n<\/div>\n\n\n\n\n\n\n\n\n\n
Process Stage<\/th>\nOne-Step ISBM (HGA Series)<\/th>\nTwo-Step SBM (Reheat Blow)<\/th>\n<\/tr>\n<\/thead>\n
Preform production<\/td>\nInjected in the same machine as part of the ISBM cycle. Machine controls all preform parameters: wall thickness distribution, neck finish dimensions, IV retention.<\/td>\nPurchased externally from preform suppliers, or produced on a separate injection molding machine. Preform quality is a supply chain dependency.<\/td>\n<\/tr>\n
Thermal history<\/td>\nPreform goes from injection melt to conditioning to blow without cooling to ambient. One thermal cycle \u2014 minimum degradation, minimum AA generation.<\/td>\nPreform cools to ambient after injection, then is reheated from ambient to blow temperature. Two full thermal cycles \u2014 higher cumulative AA generation, higher risk of IV degradation.<\/td>\n<\/tr>\n
Equipment footprint<\/td>\nOne machine performs all operations. Footprint: 2,525\u20136,200mm \u00d7 1,525\u20132,150mm depending on model.<\/td>\nPreform injection machine + storage + reheat blow machine. Combined footprint typically 2\u20133\u00d7 larger than equivalent ISBM output.<\/td>\n<\/tr>\n
Output scalability<\/td>\nCavity count determines output \u2014 1 to 6 cavities, 600\u20134,600 bph for food jar formats. Each additional cavity requires mold investment; output scales in discrete steps.<\/td>\nReheat blow machines can run 6\u201332 cavities at 10,000\u201350,000 bph for standard beverage bottles. For food jars, throughput is limited by wide-mouth preform availability and handling complexity.<\/td>\n<\/tr>\n
Minimum viable volume<\/td>\nEconomically viable at 500,000\u20135,000,000 units\/year per machine depending on jar format. Below ~500,000 units\/year, ISBM capital is difficult to recover.<\/td>\nTwo-step is viable at lower volumes for standard preform sizes where commercial preform supply is reliable. For wide-mouth food jar formats, commercial preform supply is limited and the two-step economic advantage diminishes.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\"Comparison<\/p>\n

\n

AA Generation Comparison: Why One Thermal Cycle Matters for Food Compliance<\/h2>\n<\/div>\n

Acetaldehyde (AA) generation in PET is cumulative across thermal exposures. Every time PET is heated above its glass transition temperature (Tg \u2248 72\u201376\u00b0C), additional AA is generated from chain-end thermal scission reactions. The amount generated per thermal exposure depends on temperature, duration, and the PET resin’s AA-generating tendency (expressed as the resin supplier’s reported AA generation rate in \u00b5g\/g\u00b7pass).<\/p>\n\n\n\n\n\n\n\n\n\n
Process Stage<\/th>\nOne-Step ISBM<\/th>\nTwo-Step SBM<\/th>\n<\/tr>\n<\/thead>\n
Injection melt (270\u2013275\u00b0C)<\/td>\n\u2713 Present (unavoidable)<\/td>\n\u2713 Present (unavoidable)<\/td>\n<\/tr>\n
Preform cooling to ambient<\/td>\n\u2717 Not present<\/td>\n\u2713 AA migrates to preform surface during storage<\/td>\n<\/tr>\n
Preform reheating (IR oven, 95\u2013120\u00b0C)<\/td>\n\u2717 Not present (one-step conditioning differs)<\/td>\n\u2713 Additional AA generation cycle<\/td>\n<\/tr>\n
Conditioning station (ISBM)<\/td>\nMinor (surface only, \u2264118\u00b0C ceiling)<\/td>\n\u2717 Not applicable<\/td>\n<\/tr>\n
Estimated total AA in finished container<\/td>\n3\u20136 \u00b5g\/g (typical food-grade PET)<\/td>\n6\u201312 \u00b5g\/g (due to second thermal cycle)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\n

EU 10\/2011 context:<\/strong> The EU AA migration limit for PET in contact with water and beverages is 6 \u00b5g\/kg food. One-step ISBM containers typically land within this limit without resin modification. Two-step SBM containers for the same application often require AA-scavenger-containing PET resins (which add cost) to achieve sub-6 \u00b5g\/kg migration in wide-mouth food jar formats where the container-to-food contact area-to-volume ratio is higher than in narrow-neck bottles.<\/p>\n<\/div>\n

<\/p>\n

\n

Cost-Per-Bottle Analysis: One-Step ISBM vs Two-Step SBM for Food Jars<\/h2>\n<\/div>\n

The following analysis uses a 1,000ml food jar (condiment or honey format) as the reference container, with production at 1,800 bph on a 2-cavity machine running 16 hours\/day, 250 days\/year = 7.2 million jars\/year. All cost figures are indicative; actual values depend on local energy tariffs, resin pricing, and labor rates.<\/p>\n\n\n\n\n\n\n\n\n\n\n
Cost Category<\/th>\nOne-Step ISBM (HGA.ES-2C130)<\/th>\nTwo-Step SBM (Preform + Reheat)<\/th>\n<\/tr>\n<\/thead>\n
Machine capital (amortized over 10 yr)<\/td>\nSingle machine investment<\/td>\nInjection machine + blow machine (2\u00d7 capital)<\/td>\n<\/tr>\n
Resin cost (PET, 28g jar)<\/td>\nLower \u2014 no AA-scavenger resin needed<\/td>\nHigher \u2014 AA-scavenger grade for food compliance adds ~$80\u2013120\/ton premium<\/td>\n<\/tr>\n
Preform supply cost<\/td>\nZero \u2014 preform produced in-machine<\/td>\nWide-mouth jar preforms: supply limited, typically $0.04\u20130.07\/preform premium vs standard beverage preforms<\/td>\n<\/tr>\n
Energy consumption (per 1,000 jars)<\/td>\n~8\u201312 kWh (one thermal cycle)<\/td>\n~14\u201320 kWh (two thermal cycles + reheat oven)<\/td>\n<\/tr>\n
QC scope<\/td>\nOne process to monitor and control<\/td>\nTwo processes (injection + blow) + incoming preform inspection program<\/td>\n<\/tr>\n
SKU flexibility<\/td>\nFull mold change = new jar format; no external preform dependency<\/td>\nNew jar format requires new preform tooling + new blow mold; external preform supply for wide-mouth formats is constrained<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Annual Energy Saving \u2014 One-Step vs Two-Step (7.2M jars\/year reference)<\/p>\n

\n\n\n\n\n\n\n
Metric<\/td>\nISBM One-Step<\/td>\nTwo-Step SBM<\/td>\nAnnual Saving<\/td>\n<\/tr>\n
Energy per 1,000 jars<\/td>\n10 kWh<\/td>\n17 kWh<\/td>\n7 kWh \/ 1,000 jars<\/td>\n<\/tr>\n
Annual total at 7.2M jars<\/td>\n72,000 kWh<\/td>\n122,400 kWh<\/td>\n50,400 kWh<\/td>\n<\/tr>\n
Annual cost saving @ $0.10\/kWh<\/td>\n\u2014<\/td>\n$5,040\/year<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

<\/p>\n

\n

Decision Framework: When Each Process Wins<\/h2>\n<\/div>\n\n\n\n
\n
One-Step ISBM is the correct choice when:<\/div>\n\n\n\n\n\n\n\n\n
\u2713<\/span>Container requires a neck finish diameter above 68mm \u2014 wide-mouth food jar preforms are not commercially stocked at scale<\/td>\n<\/tr>\n
\u2713<\/span>Food compliance requires minimum AA levels \u2014 one thermal cycle produces 40\u201350% lower AA than two-step processing<\/td>\n<\/tr>\n
\u2713<\/span>Annual volume 500,000\u201310,000,000 jars\/year \u2014 economic sweet spot for ISBM capital amortization<\/td>\n<\/tr>\n
\u2713<\/span>Multiple SKUs with different neck finishes requiring preform format changes \u2014 one-step avoids external preform supply management per SKU<\/td>\n<\/tr>\n
\u2713<\/span>Facility space is constrained \u2014 one machine vs two-machine setup<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/td>\n<\/tr>\n
\n
Two-Step SBM may be preferred when:<\/div>\n\n\n\n\n\n\n
\u25b6<\/span>Volume exceeds 15\u201320 million units\/year of a standard format \u2014 at this scale, high-output reheat blow machines become more capital-efficient<\/td>\n<\/tr>\n
\u25b6<\/span>Container is a standard narrow-neck beverage bottle format (28mm PCO or similar) where commercial preform supply is abundant and competitive<\/td>\n<\/tr>\n
\u25b6<\/span>The operation already has injection molding capacity that can be repurposed for preform production<\/td>\n<\/tr>\n
\u25b6<\/span>Container size range is narrow and stable \u2014 no need to manage multiple preform formats or wide-mouth neck tooling<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

<\/p>\n

\n

Domande frequenti<\/h2>\n<\/div>\n
\n\u25b6 \u00a0What is the typical payback period for a one-step ISBM food jar machine vs a two-step setup at 2 million jars\/year?<\/summary>\n
At 2 million jars\/year, the one-step ISBM machine (e.g., HGA.ES-2C130 at 1,800 bph) avoids the preform sourcing cost and second thermal cycle energy. If wide-mouth preforms for 1,000ml jars are priced at $0.05\u20130.07 per preform from external suppliers, the preform cost saving alone at 2 million units\/year is $100,000\u2013140,000\/year. Combined with energy savings of approximately $1,400\/year at $0.10\/kWh and elimination of incoming preform inspection costs, the annual operating saving of one-step over two-step in this scenario is typically $110,000\u2013160,000. Against a machine capital difference of $80,000\u2013150,000 (depending on configuration), the payback period is 1\u20132 years. This calculation is most favorable for wide-mouth jar formats where external preform supply is limited and expensive; for standard narrow-neck formats where preforms are commodity-priced, the payback period extends to 3\u20135 years.<\/div>\n<\/details>\n
\n\u25b6 \u00a0Can the HGA ISBM machine accept externally sourced preforms instead of injecting its own?<\/summary>\n
No. The HGA series is a true one-step ISBM machine \u2014 the injection station is integral to the machine architecture and the cycle. It does not have a preform loading station for externally sourced preforms. If your production plan requires the flexibility to run both in-house produced and externally sourced preforms, a two-step blow machine (configured for preform loading) would be the correct equipment choice. The HGA ISBM machine is specified when in-house preform production from virgin or recycled resin is the intended operating model.<\/div>\n<\/details>\n
\n\u25b6 \u00a0How does wall thickness control compare between one-step and two-step for food jars?<\/summary>\n
One-step ISBM has a fundamental wall thickness control advantage: the injection stage produces a preform whose wall thickness distribution is set by the injection mold design, and this distribution is preserved directly into the blow stage without intervening storage or reheating. On a two-step line, the preform’s thermal history during storage (residual AA outgassing, crystallinity development at the gate zone, moisture absorption) can shift the effective stretch behavior compared to a freshly injected preform. For food jars requiring consistent sealing surface geometry (\u00b10.08mm flatness), one-step ISBM with HGA servo-controlled injection and clamping delivers tighter cycle-to-cycle consistency than a two-step process where preform storage variables introduce batch-level variation.<\/div>\n<\/details>\n
\n\u25b6 \u00a0Is one-step ISBM suitable for organic and natural food products marketed as “minimum processing”?<\/summary>\n
The one-step ISBM process produces food-grade PET containers from virgin or approved recycled resin with minimum thermal exposure \u2014 which aligns well with the “minimum processing” positioning some organic and natural food brands apply to their packaging. The lower AA content of one-step processed containers (3\u20136 \u00b5g\/g versus 6\u201312 \u00b5g\/g in two-step) and the elimination of external preform supply chain handling both support clean-label packaging claims. However, “minimum processing” as a marketing claim for packaging refers to the production method, not to the container’s chemical properties, and it is the brand owner’s responsibility to define and support any such claim. The machine supplier can provide process documentation confirming thermal parameter ranges and single-cycle processing architecture to support brand compliance documentation.<\/div>\n<\/details>\n

<\/p>\n

\n

Evaluating one-step vs two-step for your food jar line?<\/p>\n

Share your annual volume, container format, fill product, and target market \u2014 receive a process comparison with cost-per-bottle modelling for your specific production parameters.<\/p>\n

Discuss Your Food Jar Line Requirements \u2192<\/a><\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"

Every food container manufacturer choosing blow molding equipment faces the same process choice: one-step injection stretch blow molding (ISBM), where the preform is injected and blown in the same machine and cycle; or two-step stretch blow molding (SBM), where commercially sourced preforms are reheated and blown on a separate machine. The decision determines capital outlay, […]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[43],"tags":[],"class_list":["post-1210","post","type-post","status-publish","format-standard","hentry","category-isbm-machine-blog"],"_links":{"self":[{"href":"https:\/\/ever-powers.com\/it\/wp-json\/wp\/v2\/posts\/1210","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ever-powers.com\/it\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ever-powers.com\/it\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ever-powers.com\/it\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ever-powers.com\/it\/wp-json\/wp\/v2\/comments?post=1210"}],"version-history":[{"count":3,"href":"https:\/\/ever-powers.com\/it\/wp-json\/wp\/v2\/posts\/1210\/revisions"}],"predecessor-version":[{"id":1215,"href":"https:\/\/ever-powers.com\/it\/wp-json\/wp\/v2\/posts\/1210\/revisions\/1215"}],"wp:attachment":[{"href":"https:\/\/ever-powers.com\/it\/wp-json\/wp\/v2\/media?parent=1210"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ever-powers.com\/it\/wp-json\/wp\/v2\/categories?post=1210"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ever-powers.com\/it\/wp-json\/wp\/v2\/tags?post=1210"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}