Toolmaking Lead Time Reduced by More Than a Week

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For toolmaking, toolcraft has invested in the five-axis machining center Micro HD. Equipped with Erowa automation, running times of over 150 hours are not uncommon.

From founder to Chairman of the Supervisory Board - Bernd Krebs has always kept a watchful eye on his company, toolcraft AG, since 1989. Around five years ago, he placed the operational business in younger, equally competent hands when the company was renamed AG.

And so his company continues to develop steadily and today employs almost 500 people. With high-precision machining, additive manufacturing, robotics and automation as well as injection molding and toolmaking based in Spalt near Nuremberg - with 90 employees - toolcraft has a wide range of innovative services in its portfolio.

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Bernd Krebs sees the high culture of motivation and trust in his company as crucial to the positive development. He is convinced: "Only when the working atmosphere is right do employees realize their full potential and contribute ideas that really help us move forward." The fact that this is successful is not only evident from the good figures in generally difficult times, but can also be seen everywhere when you look at the friendly faces of the employees.

Johannes Herzog, team leader in toolmaking, also appreciates the pleasant environment at toolcraft. In addition, the trained tool mechanic and industrial foreman emphasizes the innovative attitude of his employer: "Bernd Krebs and our board members always have an open ear when it comes to investing in modern technology that makes us better."

This was confirmed not least in 2024, when a major investment was made in toolmaking with the high-precision Kern Micro HD five-axis machining center. A well-considered step. The company has been in regular contact with Kern Area Sales Manager Barbara Bergmann for a good ten years now.

Since the market launch of the Kern Micro HD in 2019, contact has intensified further. Various visits to Kern in Eschenlohe included. What Johannes Herzog and his colleagues saw there impressed them: "The employees there are just as motivated as we are. They treat each other with respect and there is a noticeably good working atmosphere. That left us with a really good feeling every time."

After the performance demonstrations of the Micro HD in the application technology department, it quickly became clear that this precision milling center was the best possible solution for toolcraft toolmaking. The only small fly in the ointment: the machinable component size does not quite correspond to the optimum.

If we could clamp pallets measuring 320 millimetres x 320 millimetres, that would be perfect. However, once we discovered that the compact Micro HD can machine individual components up to a diameter of 350 millimetres and also enables jig grinding, our last doubts were dispelled.

Johannes Herzog, Team Leader in Toolmaking, Toolcraft

The decision was made in March 2024 and the Kern Micro HD went into operation a good five months later. Due to the cramped conditions in the Spalter tool shop, some adjustments were still necessary during this time. To name just one: The spindle cooling unit, which is normally located separately on the floor or on the hybrid unit, was placed above the belt filter thanks to a special design by the Kern designers. This means that the entire machine, including automation and the necessary accessibility, only takes up an area of around 5 meters × 5 meters (~16 feet x 16 feet).

For Johannes Herzog, this is just one of many examples of the exceptionally good cooperation with Kern. He explains: "The technological superiority of the machine is one thing. Together with the constantly supportive application technology from Kern Microtechnik, the offer is unbeatable."

At toolcraft, 90 percent of hard contour components are milled and ground with the Kern Micro HD. The range of materials is broad: mainly tool steels, but also stainless steel, titanium, copper, HSS and carbide. The machine is only used for electrodes when exceptionally good surfaces are required.

In general, the demands on production quality in tool and mold making are often extreme. Toolcraft sometimes requires surfaces of Ra = 0.015 micrometers and accuracies in the range of 1.5 micrometers. According to Herzog, the optionally integrated grinding package plays a decisive role in achieving these values with process reliability.

Our main focus here is on accuracy. Every micrometer reduced on the component saves us costs and lead time.

Johannes Herzog, Team Leader in Toolmaking, Toolcraft

We can coordinate-grind ejectors and core bores with the Micro HD, particularly in the case of burr-prone molds for liquid silicone. Thanks to this "honing" grinding in the bores, wear on the ejectors is also significantly reduced.

Extremely Reduced Throughput Times in the Production Process

Particularly important to Herzog are the process optimizations achieved in the production sequences thanks to the Kern Micro HD. Specifically, his team used to manufacture typical components in six or seven steps. After roughing on a five-axis milling machine, the next step was hardening. This was followed by five-sided surface grinding. This was followed by further milling in two clamping operations, before holes were drilled using wire erosion and die-sinking was the final machining step.

Manual Rework Often Essential

"Today, we need two to three steps less - for example the time-consuming surface grinding," says Johannes Herzog happily. After roughing and hardening, the component is completely milled with the Kern Micro HD in just two clamping operations, including external dimensions and coordinate-ground holes. If it cannot be produced by milling and coordinate grinding, die-sinking and wire-cutting are then carried out. Manual reworking is only necessary in the rarest of cases.

"This reduces our throughput time by at least a week," says the team leader, quantifying the process improvements. He uses the example of a gate valve to illustrate this:

By eliminating surface grinding, we save around four hours of machine time, and about the same again for wire EDM. We also need less working time, as our employees used to have to familiarize themselves with each component, program it and clamp it.

Johannes Herzog, Team Leader in Toolmaking, Toolcraft

That may not sound like more than a week's improvement in throughput time at first. But if you consider that all production stations at toolcraft are well utilized, it quickly becomes clear that capacity peaks can also lead to idle times for components before the next processing step.

Temperature Management, Micro-Gap Technology, and Sanding Package Make the Difference

When asked what makes the Kern Micro HD different from other five-axis precision machining centers, Johannes Herzog sees several factors. He highlights one in particular: "The temperature management of the entire machine in combination with the 45,000 revolutions per minute high-speed, shaft-cooled spindle is unique." Added to this is Kern's patented micro-gap technology in all linear axes, which Johannes Herzog and Kern sales consultant Barbara Bergmann both emphasize. The engineer adds: "Our developers have managed to combine all of these individual innovations perfectly." Bergmann cites the option of milling with oil as a further advantage - especially in conjunction with the grinding package: "This increases process reliability even further and enables optimum machining results with a wide variety of materials."

To maximize machine utilization, toolcraft has equipped its Kern Micro HD with an Erowa ERC-80 automation system. The system has space for 11 ITS50/72 pallets and 48 ITS148 pallets. Running times of over 150 hours are therefore no longer a rarity. Unmanned 24/7 operation is therefore almost feasible - even over weekend shifts. Employees can therefore normally rely on single-shift operation. A not insignificant advantage in the search for competent specialists.