Robotics How A Cleaning System is Automated With the Help of Eight Robots

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In order to be able to react better to fluctuating order volumes, the specialist HMT had Minitec automate a cleaning system for industrial parts to a greater extent. The success was clear.

"Not just clean, but pure" was once the promise of a well-known detergent advertisement. HMT— Häseler Metalltechnik GmbH from St. Georgen has a similar claim when it comes to cleaning technical components. Founded in 1983, the company specializes in stamping and forming technology as well as component cleaning with very high technical cleanliness requirements. Its customers are mainly in the automotive sector. The workpieces are mostly stamped components that come into contact with electrical components and circuit boards.

Two cleaning systems are in use at HMT. They work in two shifts at normal capacity, which enables around 40 million components to be passed through each year. In the past, many activities in the cleaning process were carried out by employees. However, the general shortage of labor became increasingly noticeable. Cooperation with personnel service providers did not provide a satisfactory solution. The reason for this was the volatile weekly changes in the order backlog, according to Joachim Hölzl, Technical Managing Director of the company: "This made it difficult to plan resources properly - and also to react to new circumstances at short notice. One week the requirements go up and by the time you have integrated the capacities via the personnel, the week is almost over."

For the future, Hölzl wanted to be able to plan and control this much more reliably and react more flexibly to fluctuations in capacity. This goal was to be achieved through greater automation—the focus here was on loading the transport racks with the components for the cleaning process and subsequent removal.

Automation for More Flexibility

The first step was to sit down with in-house specialists—under the leadership of Tobias Seemann, team leader of the automation department at HMT. They drew up an ABC analysis of the components and discussed possible solutions. Hölzl explains: "We built our own internal laboratory and started the first tests with a training robot. The results were very impressive. We then contacted Yaskawa, who provided us with one of their robots for the next steps. When we were finally sure of the feasibility, we got in touch with Minitec as the system integrator. We presented our vision to automation expert Peter Müller and discussed with him what the system could look like based on our requirements and specifications. He then developed a concept for implementing the solution and we got down to work."

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The result was a highly complex system in which the removal of the cleaned components and their storage and retrieval are fully automated. The design with two identical removal stations ensures sufficient capacity. A total of eight Motoman GP12 robots are used to remove the parts carriers. The robots in the GP series are characterized by high speeds, acceleration and repeat accuracy. The whole system is coupled with a fully automatic storage system. With a size of 66 ft × 33 ft, the system has considerable dimensions.

Procedure Today

The customer components to be cleaned arrive at HMT in various types of packaging (mesh boxes, wooden boxes, cardboard boxes, etc.). At the pick-up point, they are removed from the containers—still manually today—and fixed onto cleaning racks.

The system then collects the racks from the buffer store. They pass through the cleaning process via an overhead conveyor in various zones over a length of 197 feet. From there they go to the drying room, then to the cooling room and finally to the clean room. Depending on the technical specification of the components, the cleaning rack then either remains there for removal or continues into the clean room, where the removal stations with the robots are located.

Because the components can still move during the cleaning process, there may be a difference from one handle to another when the robot removes them. This is why a camera check is carried out here, which determines the coordinates so that the components can be placed correctly in the KLTs. This ensures that the order of these components is not lost when they are passed on to other departments.

Sophisticated Control System

During loading, the cleaning racks receive information on a barcode about which parts are involved and to which removal station they must travel. At the removal station, the item-specific information is transferred via an interface between the cleaning system and the robot cells. Joachim Hölzl explains: "This means that the robot knows exactly which part is coming and in what quantity. And it also knows that it has to remove this quantity. And if a component is lost, it calculates the target quantity minus 1. So we always have the correct quantity removed."

Each robot has a KLT in front of it. It removes the components from the cleaning rack and places them correctly in the box. When it has reached the specified quantity, the KLT automatically moves out and the robot is provided with another empty box.

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The filled KLT now travels automatically along a conveyor line to a storage rack. The conveyor technology is an FMS system from Minitec. This is a transfer system where the boxes are then transported onwards via curves or turntables. A special feature of the HMT version is that the usual workpiece carriers (pallets) are not used here, instead the KLTs are driven directly by the roller chains.

Storage And Retrieval By Shuttle

A storage and retrieval unit (shuttle), also developed by Minitec, is located on the storage rack. This takes care of the automatic storage of the KLTs and moves back and forth. It also transports components for visual inspection. This area has a control station where the employees can see which components are in the storage system. They can then request the parts to be inspected via a control panel. The shuttle then starts the retrieval process and makes the KLTs available for visual inspection via a conveyor system. There, the parts are inspected according to the customer's defect catalogs. If they are OK, they are packed in the customer-specific packaging.

The great benefit is flexibility. Today, we have the decisive advantage of being able to increase capacity at any time, even at short notice.

Joachim Hölzl, Technical Director HMT

Joachim Hölzl already felt the benefits of the system after the first start-up time: "The big benefit is the flexibility. Today, we have the decisive advantage of being able to increase capacity at any time, even at short notice." Hölzl is also satisfied with the course of the project: "The collaboration in this three-man team of Minitec, Yaskawa and HMT worked very well and ultimately led to an excellent result."

Further Expansion of Automation As A Goal

In general, the HMT boss is very open to the topic of automation. He is already thinking about switching from manual to robotic assembly of the cleaning racks. Another topic is the removal of components in the cleanroom. "We have many approaches here, not just in production. There are also numerous automation options in administration, some of which we have already implemented. In future, we want to look at all areas to see which processes can be automated in order to minimize human error as much as possible." Accordingly, the automation department has now grown to four people. And Yaskawa and Minitec will also be on board again in the future due to their positive experiences.

*Stefan Wache is Head of Marketing and Communication at Minitec GmbH

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