Bottle Cap Manufacturing: From Crown Corks to ABB

Bottle cap manufacturing looks simple until you count. One moulding line can turn out thousands of caps a minute, and each cap has to thread, seal and, in Europe, stay attached to the bottle. This post follows the cap from William Painter's crown cork of 1892 through screw closures to today's tethered designs and compression moulding lines. It covers what the September 2026 news changed for cap makers, where an ABB robot such as the IRB 360 FlexPicker could handle caps after the press, and what remains hard about cost, rules and skills.

A plastic bottle with its cap tethered to the neck ring, as sold in Europe. Photo: Tony Webster / Wikimedia Commons (CC BY 2.0)

How crown corks and screw caps replaced the cork stopper

Before the metal cap, bottlers pushed corks into bottle necks, often with a hand tool. A corking machine used at the Lemp brewery had an operator's seat, a hand lever holding cork holders in several sizes, and a foot mechanism that raised the bottle up to the cork. It supplied the force needed to seat the stopper, but every bottle still needed a person, a separate cork and a fair amount of effort at the bench. The machine is now in the collection of the Missouri History Museum.

A hand and foot operated bottle corking machine from the Lemp brewery. Photo: C. Seidel / Missouri History Museum via Wikimedia Commons (public domain)

In 1892 William Painter, a Baltimore inventor, patented, on 2 February 1892, a cheap, single use metal cap with a cork disc inside, crimped over a lip on the bottle neck. The cork wafer sealed the drink and kept it from touching the metal. He founded the Crown Cork & Seal Company in Baltimore the same year, and by 1920 it supplied about half the world's bottle caps. Painter's original patents expired in 1909, and competitors moved in. ASME later listed a crown cork and soda filling machine as a landmark of engineering history.

Metal crown caps lying on a table, showing the crimped rim and plastic liner. Photo: Steven Lilley / Wikimedia Commons (CC BY-SA 2.0)

Filling lines grew around the cap. A Keystone View Company stereograph shows an automatic machine filling and capping milk bottles while workers load crates beside it. Screw closures came later. The French firm Le Bouchage Mecanique sold an aluminium screw cap called Stelcap from 1959, first on spirits and aperitifs. The Italian maker Sacmi, which would later turn to plastic caps, built its first complete crown cap machine between 1948 and the early 1950s. Plastic screw caps later became the usual choice on PET bottles, which the PET bottle manufacturing post covers from the preform side.

An automatic machine filling and capping milk bottles, shown on a Keystone View Company stereograph. Photo: Keystone View Company via Wikimedia Commons (public domain)

Tethered caps, compression moulding and robots after the press in 2026

Caps made the news this September. Since 3 July 2024, EU rules have required caps on single use beverage containers of up to three litres to stay attached. Packaging Europe reported on 9 September that a Commission notice, C/2026/4813, excludes sealed aluminium foil lids from the tethering requirement, while the plastic cap on such a container is still covered. Glass or metal containers with plastic caps are also exempt, so closure makers now run tethered and untethered designs side by side. Packaging Insights lists plastic sports caps and flip top caps among those still covered.

A moulded plastic screw cap with a tamper band on a brown bottle. Photo: Andrey Romanenko / Wikimedia Commons (CC BY-SA 4.0)

Mould makers are adapting. On 17 September Packaging Insights reported that Husky Technologies had upgraded its HyCAP 4.0 tooling for beverage closures. Polymer bushings reduce metal to metal contact and wear, and the tool handles tethered and non tethered caps. Husky gave no speed figures, so the claims are the company's own. Compression moulding is the other route: Sacmi developed its version between 1990 and 1994, dropping a dose of molten plastic into a rotary wheel of moulds, and its CCM80SB is rated at 4,000 flat top HDPE caps a minute.

A heap of moulded plastic screw caps in many colours. Photo: Basilicofresco / Wikimedia Commons (CC BY-SA 4.0)

ABB does not build cap presses, and I found no source showing ABB robots on a cap line, so this is where they could fit, as a possibility and not a reported project. Caps leave the mould small, light and endless, which suits an IRB 360 FlexPicker running PickMaster with vision guidance and conveyor tracking to sort caps into bags and cartons. Washdown versions are rated up to IP69K. An IRB 1200 could tend a sampling station, and IRB 460 or 660 palletizers stack the cartons. Programs for cells like this are usually built and tested first in RobotStudio.

ABB robots handling glass bottles at Gerresheimer in Essen. Photo: ABB

Lighter caps, stricter rules and what factories still have to solve

Caps will keep getting lighter and more varied. Husky describes its platform as suited to ultra lightweight closures, and a gram saved on one cap multiplies across billions. Packaging Insights ties the tool to tethered closure rules in several markets. A tether adds a hinge or strap to the part, so moulds, assembly and inspection all get harder. On 13 October Packaging Insights reported that KHS and Rhodius are scaling up resealable aluminium bottle production in Germany, so metal closures keep competing with plastic ones under the same rules.

ABB IRB 360 FlexPicker robots packing small items at high speed. Photo: ABB

On the factory floor, the open problem is checking every tether. A cap that detaches under a thumb, or a strap that tears, is a compliance problem and an annoyance for the customer. Inspecting each cap is a vision job, and robots mostly enter after the press for feeding, pulling rejects and packing. Safety follows from that: fast delta robots over open conveyors need guarding or speed limits, which SafeMove can help set up. Similar packing cells appear across food and consumer goods plants.

A hopper and chute feeding RingCrown caps to a capping turret rated at 40,000 bottles an hour. Photo: Kotkan18 / Wikimedia Commons (CC BY-SA 4.0)

For homes, the change is visible on the kitchen counter. Tethered caps annoy some drinkers, and Packaging Europe asked on 10 September how bottle caps became a victim of the culture wars. Costs matter too: India CSR reported on 6 September that Bisleri opposed a tethered cap mandate in the National Green Tribunal, citing compliance and transition costs. HUL also sought dismissal from the same tribunal case. Plants will need people who can service moulds and set up vision, and the rules may keep shifting as the Commission issues further clarifications.

The new generation ABB IRB 1200, launched in 2025, a compact arm for machine tending and small parts. Photo: ABB

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