Q+A: behind the scenes with the new Grove GMK6400-1

The new Grove GMK6400-1 all-terrain crane is one of the most hotly anticipated launches from the Company. We talked to three of the team members involved in its development to get some insight into the process.

The Grove GMK6400-1 inherits many of the well-loved features of its predecessor but adds several updates, including the Crane Control System (CCS), MAXbase variable outrigger positioning system, and the latest emissions-compliant EUROMOT 5 engine. Looking Up spoke to three of the project team members to get their personal thoughts on the design and development process and to hear what users can look forward to.

Despite having the best load chart in its class, Grove GMK6400-1 can increase the already impressive capacity by nearly 70% with the self-rigging MegaWingLift attachment.
Despite having the best load chart in its class, the Grove GMK6400-1 can increase the already impressive capacity by nearly 70% with the self-rigging MegaWingLift™ attachment.

Q. What prompted the Company to update the Grove GMK6400 to the GMK6400-1?

Andreas Cremer

AC: We are constantly reviewing our products, so it was natural we would look to refresh our 400 t offering. One of the key reasons to update the crane was to comply with the latest engine emissions legislation (EUROMOT 5 in Europe). We also wanted to standardize the crane control system of all our cranes and the GMK6400 was one of the few Grove cranes not to feature Manitowoc’s Crane Control System (CCS).

Q. What are the advantages of integrating CCS into a crane that did not have it before?

JSR: By introducing CCS, it allowed us to include our MAXbase variable outrigger positioning system. This enables operators to vary the outrigger set up to suit available space plus it enhances the crane's capacity. It’s a feature customers love. Besides that, it made sense to have CCS on the crane - it is a common control system that is very familiar to customers. It offers many operational advantages, such as a better display with a more intuitive menu, lift previews, and more.

Q. How much of the crane development is governed by the Voice of the Customer process?

Andreas Cremer

AC: Voice of the Customer feedback is incorporated throughout the product development process. We conduct interviews that give us a deep understanding of customer likes and dislikes. These conversations happen remotely and in-person. Customer input provides tremendous value to us. For example, with the GMK6400-1, many expressed their appreciation for MAXbase. So, we wanted to include that. We also learned what not to lose. For example, several customers highlighted the speed of setup and operation of the GMK6400 and emphasized they didn’t want to lose that. It even goes down to the smallest detail – we had some requests to brighten the work lights. So, we added that too. We take all these insights, then discuss and evaluate them before adding them to our engineering process to ensure the GMK6400-1 is the preferred choice for customers.

Grove GMK6400-1 presents its impressive loading capacity at the testpad in Wilhelmshaven
The Grove GMK6400-1 presents its impressive loading capacity at the testpad in Wilhelmshaven.

Q. We know that Manitowoc customers love the speed of the crane. Are there any other features they wanted to keep in the new model?

Malte Schroeder

MS: Many customers love the removable outrigger boxes. Also, the self-rigging MegaWingLift™ is one of the most prominent features of the Grove GMK6400. This self-rigging attachment can be set up in just 20 minutes and enhances lifting capacities. And many customers enjoy the existing luffing jib design as it can easily be converted to a fixed jib. So, we have kept this. As well as keeping much-loved features, we also added several updates. This included a focus on ergonomic working conditions, with special handrails on the boom, well-positioned ladders and walkways, and a new ambient lighting option.

Q. What were the biggest challenges at the design stage?

JSR: One of the major challenges was developing CCS to work with the new GMK6400-1. It takes a lot of work to adjust the system to fit the crane’s higher capacity, extensive jib reach, luffing jibs, and the MegaWingLift™. Getting CCS to work with the luffing jib needed a lot of visualization. You have to think about which way you can rig the boom and at which angle. It was a complex process, but the end result is a high-capacity crane that is more straightforward to use – and customers will really appreciate that.

Q. Can you talk a little about how you incorporated the new engine? Was it bigger or more complex?

Malte Schroeder

MS: We moved from a V8 engine to a 6-cylinder engine. It was a challenge to incorporate the engine into the carrier frame and make it work with all the different characteristics of the crane. The additional weight of the engine also had to be factored into the design and layout of other components. Clearance around the engine was reduced because of the larger cooling system and exhaust after-treatment system (which is needed for emissions compliance). Finally, we had to ensure that any design changes did not impact the space required to set up the self-rigging MegaWingLift™ on the carrier.

Grove GMK6400-1 is the strongest six-axle crane on the market with an impressive 79 m (259.2 ft) luffing jib, 64 m (210.0 ft) fixed lattice extension
The Grove GMK6400-1 is the strongest six-axle crane on the market with an impressive 79 m (259.2 ft) luffing jib, 64 m (210.0 ft) fixed lattice extension.

Q. How did you utilize the two prototypes once you moved to the testing stage?

Andreas Cremer

AC: We build two prototypes so when one undergoes a load test, we can conduct superstructure tests and driving tests on the other. This speeds up testing and helps us understand the design better to make any adjustments we feel are necessary.

Q. What did you learn in the testing phase?

Malte Schroeder

MS: We learned that the new hydraulic system in the GMK6400-1 is approximately 10% more powerful than that of its predecessor. But even with this, we also saw that noise levels for the operator were reduced through improved design and layout. In practical terms, we saw how the hydraulics significantly improved operations. One of the operators running tests was quick to point out how smooth the hoisting, telescoping, and lifting is. Compared to the GMK6400, fuel consumption was reduced by around 30%.

The GMK6400-1 is making its public debut at bauma 2022 between October 24 and 30 in Munich, Germany.