Free Newsletter
Register for our Free Newsletters
Advanced Composites
Amorphous Metal Structures
Analysis and Simulation
Asbestos and Substitutes
Associations, Research Organisations and Universities
Automation Equipment
Building Materials
Bulk Handling and Storage
CFCs and Substitutes
View All
Other Carouselweb publications
Carousel Web
Defense File
New Materials
Pro Health Zone
Pro Manufacturing Zone
Pro Security Zone
Web Lec
Pro Engineering Zone

Vertical IM design helps automate overmolding

DTI Globalwatch : 20 October, 2006  (Technical Article)
The Engel production cell at ZIMK overmolds complex and delicate metal parts and does full inspection unattended. Overmolding
The first example of the new generation of Engel Insert vertical molding machines is the heart of a slick overmolding production cell making complex automotive conductors. ZIMK GmbH of Zehdenick, Germany is a vertically integrated specialist in metal and plastic combination structures, many of them automotive applications. With production exceeding 10 million units annually, ZIMK decided to add a fully automated cell to overmold the metal grids used as conductors in ABS, ESP, and automatic transmission controls in a variety of automobiles.

Company engineers worked with their counterparts from long-term machinery supplier Engel to create a high-performance, fully automated cell based on a 90-metric-ton version of the new Engel Insert series of vertical rotary table machines.

Raising the Table Stakes
The design of the new vertical machines includes improved ergonomics and a larger rotary table than previous models, 1600 mm vs. the 1400 mm previously standard on a 90-ton machine. This supports larger molds that, by the nature of overmolding’s smaller shot sizes, don’t require the clamp force or injection capacity of a larger machine, or its higher cost. ZIMK’s approach is a two-station system that uses two bottom mold halves opposite each other on the table. While the stamped metal parts are overmolded on one side, the other bottom half is being robotically unloaded at the front of the machine and a new metal lattice structure inserted.

The Engel ERC linear robot handling these functions sports a sophisticated double-sided end-of-arm tool that has a lot to do. The stamped metal lattice structures that the robot moves from a staging magazine into the mold are described as “flimsy.” One of them, as an example, is just .6 mm thick with 15 conductors between 1.2 and 1.8 mm wide that are angled within the overall 60-mm length.

The gripper picks up the part and then pulls it slightly taut to allow accurate placement in the cavity. The similarly clever demolding side incorporates sprue cutter/separators in the gripper head. Sprues are placed in a collection station and the parts are stacked in trays managed by an Engel ETS 4 Trayserver that sends them down a conveyor belt. Next, a fully automated finishing and testing station developed by ZIMK production specialists restamps the parts to remove the connecting webs that held the metal lattice together until it could be overmolded with PA. Removing the webs ensures conductivity of the individual connectors.

The resulting flat metal/plastic cable harnesses are then each automatically tested to 100% of functionality before they are passed on as “reliable for installation.”

Improved Ergonomics
ZIMK’s total automation concept doesn’t use one major advantage of the new Engel Insert Series: The 850-mm working table height, the result of thorough ergonomic research, means manual insertion and removal can be done comfortably, and without the raised platforms commonly in use. A working height of 1000 mm from the floor to the tabletop had been a de facto standard.

The reduced height results from a new compact design for the rotary table that eliminates the need for a hydraulic lifting cylinder. Also designed in is a high-performance parallel hydraulic system that not only indexes the table fast, but also operates in parallel with the open-close of the moving platen and the nozzle forward motion.

ZIMK definitely took advantage of that feature, taking nonproductive hold-and-wait time to the absolute minimum, thereby cutting overall cycle time. For future use, the larger rotary table makes it easy to go to three or four stations, while still not being forced to a higher-clamp-force machine by the size of the molds.

Clamp forces of the new-generation Engel Insert V-Series (vertical IU) machines range from 50-150 tons, while the new Engel Insert H Series (horizontal IU) offers 25-300-ton clamps.
Bookmark and Share
Home I Editor's Blog I News by Zone I News by Date I News by Category I Special Reports I Directory I Events I Advertise I Submit Your News I About Us I Guides
   Â© 2012
Netgains Logo