Gripper lid locking system plug-and-play to South Africa

Details: Released: 25.09.2017; Last updated: 02.06.2023; Hits: 6803

Global competition does not stop at South Africa and calls for increasing automation. In the course of this, Bowler Plastics automated two Arburg injection molding machines, thus ending the monotonous manual closing of plastic caps for food or cosmetic bottles. Thanks to the gripper systems and the automatic lid closing machine from Gimatic, this monotonous, labor-intensive activity is now a thing of the past.

Less than a year has passed after Arburg received an inquiry for a customer application from the South African Bowler Plastics (Pty) Ltd. from Cape Town at Gimatic Vertrieb GmbH in Hechingen. “We then always prepare our offers very promptly so that we don't lose them. Because our customers usually need the requested products as quickly as possible, ”describes Jens Reinfrank, Project Planning System Technology at Gimatic, the approach in the offer phase. Just one month later Friedel Sass, CEO of Bowler Plastics, visited the Gimatic booth at the plastics trade fair K. Promptly, at the trade fair, he placed the order for the development and production of six removal grippers and two automatic lid closing machines for caps.

Plastic made in South Africa, injection molding machine in Germany

The company, founded in 1972, started the production of plastic parts with an Arburg machine. Today, Bowler Metcalf, as a group with around 800 employees in four individual companies, produces over 500 million parts per year using injection molding, silk screen printing, digital printing or hose extrusion for over 200 customers. Large references are for example Revlon, Johnson & Johnson, SCJ, Unilever and Tiger Brands. And so Bowler is indirectly active globally, even if the products often only reach the whole world via the end customer.

One area of the group is the Bowler injection molding division, in which 320 injection molding machines are manufactured on 54 injection molding machines. "Our main focus is on supplying the cosmetics and household industry, even if we are open to all hard plastic products," says Wayne Knutsen, Head of Injection Molding at Bowler Plastics. CEO Friedel Sass, by the way, is of German descent and therefore attaches great importance to machines made in Germany. And so 49 machines come from Arburg.

Robot grippers and EOAT solutions

Monotonous error-prone work seeks automation solution

Hitherto, in the application, a machine operator without a vent has manually closed the sealing caps (fliptops) ejected from the injection molding machine. Four covers are simultaneously removed from the machine with a cycle time of 13 seconds. Six different lid variants are possible. This approach has continued to be cost-effective, until recently the labor costs have risen and the production processes have been prolonged. "So Bowler decided to automate this operation. In the future this will also eliminate the risk of quality through human errors. The main challenge was to maintain the flexibility of the machine operator with improved quality and lower costs.

"With the automation solution from Gimatic, we should be able to use our existing 3D negative moldings. In addition, it should be simple and reliable, "says Wayne Knutsen, describing the task booklet. The closure process can now be automated with relatively little loss in the cycle time, which is usually about one second. "The fliptops are taken out of the machine immediately and at the same time, which improves the thermostability and reduces rejects," says Wayne Knutsen. And the machine is now much more efficient than an employee, considering that it produces 24 hours on 7 days a week. Based on labor cost savings, Bowler estimates that the investment has paid for itself in about seven to twelve months without taking the savings from reduced committees and increasing customer satisfaction into account.

These vacuum grippers handle everything

"We had only a little experience with such a lid closing system so far. Bowler also wanted to cover six different cover types, "says Jens Reinfrank, describing the challenge for Gimatic in this application. Moreover, the company does not sit around the corner. "Many of our customers are close to us so we can be there as often as necessary," Jens Reinfrank points out. And since this was not the case at all, the complete order processing from offer to commissioning took place from a distance.

Workflow: Reach-Transport-Save-Close

"The various caps must be taken out of the injection molding machine immediately after they are created so that the hinges do not break during cooling and the plastic does not shrivel. Otherwise, the covers in the application would not be sealed later, "describes Wayne Knutsen's application.

The extraction unit is equipped with four vacuum grippers adapted to the lid shape. It removes the identical plastic cover from the injection molding machine and deposits it on four corresponding 3D negative moldings in the lid closing system. This consists of two synchronously running linear axes which each close two covers. For structural reasons, the linear axes have been mirrored. Therefore, the removal unit has to rotate the lower two components during the removal process in order to be able to store them subsequently in a storage-bearing manner. The linear axis then travels over the deposited covers. To prevent the covers from being damaged, they first flip a so-called flock by an 90 degree before pressing a pneumatic cylinder tightly. As the removal gripper moves out again in order to get the next components, the sealed covers are rotated one by one by an 180 degree and ejected into a standing container by means of an air jet.

Three different lid-closing systems with three grippers each were developed for three covers. "In order to facilitate the conversion to the individual formats, we have marked the few components that need to be changed," explains Jens Reinfrank. The replacement is very simple: loosen the screws, disconnect the pneumatic and electrical plug and the complete unit can be removed.

Almost all components from our own portfolio

The two systems were built almost exclusively with Gimatic components. The components of the extraction gripper, such as vacuum suckers, suspension suspensions and the quick-change system "MSI-A41", were attached to the in-house profile rail system.

The lid closing system is based on a profile frame frame and is bolted to the floor by means of strong feet. The compressed air is connected via the injection molding machine or via the robot hand. For this purpose, a special interface in the form of a valve terminal was generated. The control is also taken over by the injection molding machine. For the linear axes two linear units type LP07 with two guide cars are used, which are driven by a pneumatic cylinder. Small OFC cylinders fix the covers on an 3D printed negative mold.

The cylinders are equipped with a thermally high-strength rubber with high friction properties so that the component does not slip or be damaged during the closing process. An OFL cylinder presses the cover shut from above. For this, the pressure can be set depending on the component. RT 25 rotating units finally eject the lids. These rotating units have an integrated air duct and are around 20 percent smaller and cost around 30 percent less than comparable products on the market with the same force. The entire system is queried, evaluated and monitored by magnetic sensors in communication with the injection molding machine. “We worked directly with Arburg on interfaces and the machinery directive,” reports Jens Reinfrank.

Intercontinental cooperation

The managers of both companies are very satisfied with the cooperation so far: "Arburg had suggested to us as a possible partner for the Gimatic project, and a meeting between the two managing directors Friedel Sass and Johannes Lörcher of Gimatic was organized at the Kunststoffmesse. From the moment of the project's emergence, a great partnership between Bowler and Gimatic began, which we greatly value here - especially because of the great support of Mr. Lörcher and Mr. Reinfrank to find the optimal solution, "says Wayne Knutsen.

The Gimatic team, on the other hand, was immediately supported during the construction by sufficient information, data and samples from Bowler. "From the very first meeting, the discussions were constructive and goal-oriented," says Johannes Lörcher, Managing Director of Gimatic Vertrieb GmbH, who summarized the quality of the cooperation. "In the end, the trust was so great that the delivery took place against invoice without the otherwise usual bank letter of credit."

The commissioning also worked smoothly. Hechingen had already been prepared to travel to South Africa. But that was not necessary at the end. "We have succeeded in producing a real plug-and-play system. We had no time to travel to Africa and put these machines into operation, "says Jens Reinfrank. The plant was built and assembled in Hechingen. William Johnstone, from the company Hestico as representative for Arburg in South Africa, Colin Jacobs, machine installer at Bowler and Wayne Knutsen, they then took off on site before they were sent to Africa.

gripper | pneumatic + electric from various manufacturers

Jens Reinfrank still sees a lot of potential for further automation: "Bowler seems to have come to the taste of how great it is to automate. Wayne Knutsn also sees other automation potential together with Gimatic: "We have just started to automate processes and would like to expand the cap concept to other injection molds". So the work on a new possible project with Gimatic has already begun, but at this early stage is not yet too much to be betrayed.