Sumitomo (SHI) Demag: Fully electric multi-component machine for Swiss PB Tools

(Image: Sumitomo (SHI) Demag.)

(Image: Sumitomo (SHI) Demag.)

Sumitomo (SHI) Demag Plastics Machinery has built a highly complex manufacturing cell for Swiss PB Swiss Tools AG, Wasen/Bern, consisting of an IntElect fully electric injection molding machine with three-component technology, MuCell technology, indicator board drive and full automation. The successful acceptance of the system in Schweig took place at the end of May 2024, followed by delivery to Switzerland in July, with commissioning scheduled for the end of August.

“PB Swiss Tools is a so-called ‘lighthouse customer’ in Switzerland,” says Urs Kocher, who manages the project for Mapag Maschinen AG, Bern, which represents Sumitomo (SHI) Demag in Switzerland. “We are proud that we were able to win such a customer. This was only possible thanks to the high performance of everyone involved – from project planning to implementation and delivery to the customer,” he says. “Sumitomo (SHI) Demag was able to demonstrate its expertise as a technology leader in the field of fully electric injection molding machines, multi-component technology, and the full utilization of special applications and automation.”

According to the supplier, the production line can be used with great flexibility: New ergonomically shaped handles for hand tools are manufactured in addition to those in the existing PB Swiss Tools product range. The old production line is replaced by a new one. Several different handle sizes are also produced. The various shot weights and tool data sets with gripper recognition have to be coordinated with each other – a very complex challenge for the arrangement in the tool and the assignment of plastic materials. First, the handle core is fed with MuCell material. This handle core is then molded with a hard, integrated material for increased stability and strength. A soft component made of TPE is then applied for high torque and optimal feel.

The heart of the fully enclosed production cell is the IntElect 350/830-1100H-450L-450Y. Large tool space, high precision, perfectly coordinated injection shaft drives, low energy consumption, short cycle times and parallel dynamic movements are the most important features of the all-electric machine. “In principle, we have four stations,” explains Klaus Rahnhofer, Chief Engineer BD Automation and Robotics at Sumitomo (SHI) Demag. The certified expert in multi-component technology has extensive experience in tooling and mechanical engineering as well as automation solutions. He designed and implemented the entire project together with Kocher.

Foam cores with MuCell, two solid components, tactile element
“In the first station, the MuCell-coated handle cores are produced in the injection molding tool on the operator’s side. After opening, the ejector moves forward and lifts the plate. Then rotates it 90 degrees counterclockwise. The ejector moves back and the tool closes. By pulling the index plate, the parts are fed into the next station,” he describes the process. “The second station is the L-shaped injection unit, in the tool below. Here the inner cores are cast with the second base material. After opening, the ejector moves forward and lifts the plate, rotates it 90 degrees counterclockwise and moves back again. “The tool closes,” says Rahnhofer.

The third station is the Y-shaped injection unit located in the middle, and is arranged opposite the operator in the tool. Here the touch element is formed from TPE. The process is the same as in the previous two stations. Finally, in the fourth station, the parts are stripped using a hydraulic core puller; the stripper is located at the top of the tool. “The stripping is done by a robot. The special thing is that it is done from the closed mold while the other three injection processes are operated,” explains Ranhofer. “The fourth station is open at the top of the tool, there are no peripheral inserts. The handles are exposed on both sides of their spikes. This way the robot can strip them and grab them.

Removal from closed tool saves cycle time.
In this way, the removal process does not determine the cycle time and about five seconds are saved. “This is very impressive,” explains the expert and points out other special features of the project, such as the special positioning of the modules: “Originally, the third module was supposed to be placed in a lying position. But to facilitate the change of screws, we decided to arrange the three injection modules horizontally, the second (L) at a 90° angle and the third (Y) at a 40° angle.

A special design had to be chosen for the 6-axis robot from ABB as part of the SAR system planned by Sumitomo (SHI) Demag. “It is on a higher base so that it can reach the rails of the injection molding machine. At the same time, the ceiling height of the production hall, only 3.30 meters, was a limiting factor. “But we were able to overcome this challenge,” says Ranhofer. After removing it from the top, the robot places the finished parts on the conveyor belt. He adds that the system and the robot are also designed to serve the existing range.

Servo motors, automatic steering pull and fully electric dosers to ensure high precision.
PB Swiss Tools builds the handles for the tool handles themselves – and adapts them to different sizes. “For each new handle size, three pairs of new inserts are required. The toolmaker has done an excellent job here,” says Rahnhofer, looking back and pointing out that the highest levels of precision were also required for the fully electric injection molding machine. “Since so many variables and so many arrangements were implemented in the project, and therefore so many changes were necessary, a particularly high level of precision was required in order to keep start-up waste to a minimum,” he sums up.

According to further information from the supplier, the IntElect 350/830-1100H-450L-450Y works particularly precisely and efficiently thanks to internal servo motors from Sumitomo (SHI) Demag. “A special feature of the machine is the automatic pull-out of the handle on the operating side. It has now been adapted to fully electric machines by pulling the rods that are used in hydraulic machines,” says Rahnhofer. In addition, the servo motor for the index drive has been integrated into the control. In addition, the dosing is carried out entirely electrically – all with the aim of ensuring the highest precision.

“The precision of the fully electric injection molding machine was an important criterion,” emphasizes Mathias Gerber, Director of Plastics Engineering at PB Swiss Tools. However, the decisive factor in winning the contract from Sumitomo (SHI) Demag was the good service and innovative implementation of the requirements. “We asked several machine manufacturers, but the solution from Schweig was the best,” he explains. “By removing the fourth position in the closed mold, we save cycle time and get a faster return on investment. Previously, the three components were carried out by robots, now by an index drive. This is a big step forward that immediately convinced the investment management,” says Gerber.

“When the decision was made to go with Sumitomo (SHI) Demag, we were very excited. The first thought was that the two had found each other,” says Urs Wiesbe, production manager for the injection molding workshop at PB Swiss Tools. “I have known the company and the Mapag representative for almost 30 years through other production facilities and have always been very satisfied. On the one hand, the machines are not prone to failure, and on the other hand, the service is excellent: they offer very good telephone support, i.e. direct, low-level contact and are ready to help. In this way, many problems are solved before someone has to leave the car at great expense. If something goes wrong and needs to be fixed, a service technician will arrive within 24 hours – something that many competitors do not offer.

PB Swiss Tools produces around 13 million professional hand tools and medical products each year from around 400 tons of high-quality steel with its own recipe at two locations in Switzerland. The range includes 3,000 advanced, ergonomically perfect hand tools, most of which are guaranteed by the manufacturer for life.

additional information:
www.sumitomo-shi-demag.eu, www.pbswisstools.com, www.mapag.ch