The Halter Big LoadAssistant tending a Mazak i-200S turn-mill centre at Heinz Knöpfle GmbH

Located in the Bavarian town of Schwabmünden, family-run sub-contractor Heinz Knöpfle GmbH is taking maximum advantage of the productivity potential of automation. It has recently installed five robot load/unload systems supplied by Halter in the Netherlands, whose range of LoadAssistant robotic machine tending equipment is sold in the UK by Salisbury-based 1st Machine Tool Accessories.

Heinz Knöpfle specialises in turning, turn-milling and milling components in a range of batch sizes down to one-offs for customers in a wide variety of industries, including medical, drives, printing, plastics, aerospace, packaging, food and construction.

Around 16 years ago, the company acquired its first machine from Mazak, which was automated a year later with a bar feeder. Despite Heinz Knöpfle employing just five people, there are currently 22 Mazak machining centres and lathes on the 1,500m² shopfloor, all of which are automated with pallet change systems or bar magazines.

The sub-contractor’s entry into robotic automation began in 2018 when second-generation managing director Christian Knöpfle (pictured below), who took over the company in 2009 with siblings Suzanne and Andreas, became aware of Halter during a discussion with a Mazak sales manager. A short time later, the first turn-mill centre, a Mazak Integrex i-200ST, was coupled with a Halter Universal Premium.

All Halter automation solutions are compact, versatile robot cells in a variety of designs for CNC lathes, machining centres or both, as in the case of the Universal Premium. They have been developed for automated loading and unloading of rotationally symmetrical and prismatic workpieces. A wide variety of grippers is also available, as well as grid plates that act as buffer storage for components.

While the robot loads and unloads a machine, an operator at the rear of the automation cell can replenish the system with raw material and remove machined components, without having to interrupt the ongoing production. A cell can be repositioned from one machine to another, if desired, and reinstalled quickly.

The benefits of the first robotic cell were so convincing that Heinz Knöpfle has since invested in four further automation solutions from Halter - two additional Universal Premiums for a CNC turn-mill centre and a 3-axis machining centre, a Halter Big for a Mazak i-200S turn-mill centre and a Halter Turnstacker Compact 12 for a Mazak Quickturn Nexus 250-II MSY lathe.

Compact, versatile robot cells
The Halter Big is a loading system specially designed for heavy workpieces and shafts up to 800mm long. The compact, robust solution has an integrated robot with a load capacity of 70kg. The Turnstacker Compact, on the other hand, has a total of 12 stacking stations for a large number of billets and buffer storage for holding up to 385 finished parts.

According to Christian Knöpfle, automation has forced him to think even more carefully about processes. Among other things, attention must be paid to temperature to ensure high precision during machining, as well as to tool wear and availability, adequacy of coolant supply and efficiency of chip removal.

Provided that these and other critical requirements are managed, processes are stable and workpiece quality is consistently high. At the same time, productivity is noticeably increased due to a significant rise in periods of unattended production.

Heinz Knöpfle GmbH has succeeded in ensuring that production continues around the clock over three shifts, with operator attendance throughout day shifts but none during the other two. The machines also run at weekends with minimal attendance, increasing production capacity even further. Spindle running time on some machines that are coupled with LoadAssistant cells has been increased threefold. Overall, company turnover has doubled in the last two years.

The company has been able to increase its effectiveness as a sub-contractor due to its strategy of automation. Production is better planned, quality and reliability of deliveries are high, and prices charged to customers are competitive. As a result, the company has not only been able to fulfil more orders from existing customers but has also attracted a large amount of new business.