If you work in the beverage or packaging industry, you know that every machine downtime is a cost. In this article, we talk about a component that is often underestimated but absolutely critical: the blow molder slewing ring, often called the turntable bearing. You will discover what it is, how it works, what happens when it wears out, and how to intervene quickly and effectively.
What the blow molder slewing ring is
Rotary blow molders are the heart of PET bottle production. They operate continuously, at very high speeds, and each component must ensure precision, stability, and long-term reliability.
Among all mechanical parts, those related to the rotary movement of the turret are among the most stressed.
The slewing ring (or turntable bearing) of the blow molder is the component that allows the rotating part of the machine to turn smoothly and steadily. In rotary blow molders, a turret supports all the blowing stations and must rotate continuously, without jerks or vibrations and, above all, always maintaining proper alignment.
The slewing ring is precisely the element that makes this movement possible: it is a large bearing ring positioned between the fixed part of the machine and the rotating part. On one side, it supports the entire weight of the turret; on the other, it allows it to rotate smoothly.
When the rotation ring begins to wear out or develop play, the consequences can be significant:
- increase in motor current absorption;
- noise and vibrations during rotation;
- misalignment and abnormal gear wear;
- greater stiffness of the carousel during manual rotation;
- possible carousel seizure.
In practice, the slewing ring is like the central pivot of a carousel: it supports the entire weight and allows the structure to rotate without losing balance. Without a properly functioning slewing ring, a blow molder cannot operate correctly.
Why the slewing ring is so critical in rotary blow molders
The blow molder is a highly dynamic machine that continuously rotates, heats, blows, and discharges bottles. The rotation system must therefore withstand heavy loads, dynamic stress, and constant vibrations. The slewing ring operates under significant loads and harsh conditions, which is why its wear must be carefully monitored.
A slewing ring almost never fails suddenly; instead, it sends clear warning signs. Abnormal vibrations, metallic noises during rotation, and motor absorption intensity — which must be carefully checked, as this effect could also be due to improper leveling — are all alarm bells. Ignoring these signals almost always leads to sudden machine downtime, with the risk of damaging other components and significantly extending restart times. Acting in time is always the most cost-effective and intelligent choice.
Slewing ring replacement and immediate production restart
Due to a damaged slewing ring, the SIDEL Universal SBO 8-10 blow molder at Centrale del Latte Brescia came to a stop. The intervention immediately became a production emergency. Upon receiving the call, the BBM team set off right away and arranged lifting equipment to raise the so-called “carousel cup” (3,200 kg) and proceed with the replacement.
Within a short time, the worn slewing ring was removed, an original spare part was installed, complete realignment was performed, and rotation tests were carried out. The machine returned to full operation in a very short time.
Emiliano, BBM senior technician who managed the intervention, explains that this type of operation can be performed on any blow molder, regardless of brand or model. The machine may change, but the principle remains the same: without a slewing ring in optimal condition, production stops, with immediate economic losses.
The importance of proper alignments
During the intervention, the blow molder drive pinions were also inspected and adjusted. When installing new components such as a slewing ring or a large-diameter bearing, it is essential to set all couplings with extreme precision. This phase determines the long-term reliability of the machine.
Emiliano explains that the experience of a blow molding technician truly makes the difference. It is not enough to replace the part; you must know how to adjust it, align it, and ensure it works harmoniously with the rest of the machine. A well-executed intervention guarantees long-lasting benefits, while a superficial one often leads to new issues after only a few months.
The Technical Director of Centrale Latte Brescia, Raffaele Bombardieri, states:
“At the moment the machine stopped, we immediately identified the company BBM, with which Centrale has been collaborating for several years, and within a few hours they were able to organize the work and plan a very complex task for the extraction and, above all, very precise for the assembly of the new Ralla, recognizing the utmost professionalism in the technicians involved in the blow-molding sector.”
BBM Service
BBM Service was created to ensure production continuity for companies in the beverage and packaging sector. It operates on blow molders, fillers, labelers, palletizers, and complete lines, with technicians specialized in machines such as SIDEL, KRONES, SMI, KHS, SACMI, OCME and ACMI. The strength of BBM Service lies in its rapid response, even in emergency situations, combined with the experience of technicians with over twenty years of fieldwork.
BBM does not simply repair a fault; it analyzes the root cause, intervenes in a structured way, and works to prevent recurrence.
Thanks to expertise that combines mechanics, electronics, and process knowledge, BBM supports customers not only in restarting the machine, but also in its continuous improvement.
Centrale del Latte Brescia
Since 1930, without ever interrupting production even for a single day, Centrale del Latte di Brescia has represented a benchmark in the Italian dairy sector. The company has always stood out for its ability to innovate: it was the first in Italy to produce UHT milk in PET bottles and remains the only company in the sector that packages drinking milk exclusively in PET bottles.
Today, Centrale del Latte di Brescia produces a wide range of products, including fresh milk, microfiltered milk, and UHT milk.
Annual production reaches approximately 62 million bottles. The plastic packaging is made using a blend of virgin plastic and RPET (recycled PET), with a recycled material share of 50%, confirming a concrete commitment to reducing environmental impact and promoting a more sustainable production model.
Discover the Latteria Brescia website.
