At its site in Viersen, Germany, KraussMaffei offers complex automation solutions for efficient downstream production steps or rework, such as for the assembly of card pockets, recessed handles and more on car door.

Inside the machine of the robots that are tasked with assembling screws and clips.

The machine from the outside.

KraussMaffei’s team led by plant manager Marcel Joppen developed an intelligent production concept for its customer Yanfeng, to complete the interior trim of the car doors as quickly as possible.

"In our Trimming Technology Center, we can do almost everything that needs to be done after the actual plastic part has been manufactured," said Joppen.

Door panel passes through three assembly stations

Yanfeng drives door panel as a basic carrier past three assembly stations. The door panel is screwed twice, and at the third station, the large composite component is fitted with clips, which will later be used to attach it to the actual metal door.

For even greater efficiency, two door panels are placed in an aluminum frame on a self-propelled load carrier, which transports them past the robots positioned on the left and right. On the way into this assembly tunnel, a magnetic stop and barcode scanner are used to query which door variant is involved and which equipment it should have.

As the base carrier is manually clamped to the frame, the position is also checked by camera to ensure that the screws for the five to seven add-on parts are in exactly the right places. The armrest, the recessed grip and the map pocket are mounted in this way.

The robots (type ABB 1200-7-70) retrieve the 18 screws per door from a dispenser. The cycle time for six screws, including camera measurement, is 24 seconds. Three robots are active per door. 

1.4 seconds per clip with rubber seal

The next step of placing the clips is similarly swift. While the trolley is still moving, a robot (type ABB 1600-145-10) removes nine pieces in 13 seconds, using a vacuum gripper with four double pickers and one single picker. A laser sensor then scans the clip positions in nine seconds and measures their depth, as the door panels can be positioned slightly differently on the aluminum frames.

The clips with rubber sealing lips are then positioned in 1.4 seconds per piece, so that the cycle time for the entire process, including camera and laser measurement, is 29 seconds. The camera system itself works in the blink of an eye: 350 milliseconds to capture and evaluate the image, and to calculate translation and rotation.

Including the time for moving the load carrier between the stations and clamping and unclamping the trolley, the cycle time of the assembly line is 40 seconds. A total of eight robots then produce two interior door panels.

Trimming Center for a wide variety of finishing processes

The three stations can be expanded as required if additional process steps need to be implemented. KraussMaffei also offers a wide range of systems for the post-processing of plastic parts, such as punching, milling, deburring, laser cutting, ultrasonic cutting, ultrasonic welding, flame treatment or scoring.

The latter refers to a cold knife cut that is used, for example, to deliberately weaken the material at the location of the airbag so that it clears the way for the airbag in the event of an accident. The Trimming Technology Center has been dedicated to tasks such as these since 2005.

All automation systems are 100% tailored to the respective project and individually developed. By far the largest share goes to the automotive industry, but the expertise from Viersen is also becoming increasingly interesting for customers from the medical technology sector.