Efficient and flexible complete machining of V8 and V12 diesel engines

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Efficient and flexible complete machining of V8 and V12 diesel engines

Automated production cell with Heckert HEC 800 machining centers replaces transfer line

Tatra Trucks, the oldest manufacturer of road and off-road vehicles and the second oldest manufacturer of trucks with internal combustion engines in the world, is bringing its engine production up to the latest standards. A production cell with three Heckert HEC 800 machining centers, automated by a pallet system, increases efficiency, and reduces the space requirement to almost a quarter.

Tatra, an automotive manufacturer from Kopřivnice, Czech Republic, started producing carriages as early as 1850 and has been making cars since the end of the 19th century. Today, it is mainly the heavy Tatra trucks that impress with their off-road performance, high reliability, and outstanding utility properties – even in extreme weather conditions such as frost and desert temperatures.

One of the special features of the vehicles is the Tatra concept, a chassis with a central support tube and individually suspended semi-axles, which makes it possible to mount a chassis with any number of axles, from 4 × 4 to 12 × 12 and more. The direct air-cooled V8 and V12 diesel engines of the Tatra T3 series with supercharging and intake air cooler are also among the USPs. Production takes place at the company’s headquarters in Kopřivnice, Czech Republic. The complete chassis for the T158 Phoenix vehicles, which are available with various superstructures such as containers, concrete mixers, tanks, and special superstructures, is produced there. In addition, vehicles from the T815-7 Force series are produced, which are available in both civilian versions (e.g. as fire engines, etc.) and military versions. Technology and Process Manager Martin Kappler explains: “We manufacture almost all components for our Force series vehicles ourselves: the complete chassis, cabin, engine, and gearbox.” Tatra’s production portfolio also includes the Tactic series of medium- sized vehicles, which are designed exclusively for military purposes.

Automated production cell replaces transfer line

As far as the engine equipment is concerned, Tatra Trucks lets its customers choose from several options. Liquid-cooled engines from proven manufacturers and Tatra’s own V8 and V12 engines in various power variants are available. The latter have been manufactured on a transfer line in Kopřivnice since 1980. “Despite its age, the technical condition of this plant is still good,” says Martin Kappler, “but the energy costs are extremely high, as is the consumption of coolants. That’s why we decided to switch engine housing production to a cell with automated machining centers.”

He also argues that the changeover from V8 to V12 on the transfer line takes a long time, usually several production shifts: “In view of the flexibility required today, the new production cell also impresses in this respect. With our universal fixture, we are quick to retool and can customize any motor housing. This means that we are much more efficient with the machining centers, even if the pure machining time of a motor housing on the transfer line is shorter.” As a result, in 2024 the production managers at Tatra Trucks decided to order a Heckert HEC 800 from Starrag as the basis for the planned production cell – supplemented by an automation solution in the form of a Fastems FPC3000 system.

25 years’ experience with Heckert machines

A decision with a history: Tatra replaced an aging machining center back in 2017. Its original tasks were cutting base surfaces and machining index holes, which are required for clamping and positioning the cast parts in the transfer line. Purchaser Libor Kalíšek recalls: “After comparing several suppliers at the time, we decided in favor of a Heckert HEC 800, as it seemed the most suitable and offered a wider range of machining applications.” Since then, Tatra has been using the Heckert HEC 800 to pre-machine 8- and 12-cylinder motor housings. The lower housing section is completely machined in a single operation, including the index holes and all holes for attaching the oil basin. Technologist Dušan Kelnar adds: “We also rough machine the motor housing surfaces on the Heckert HEC 800 and drill holes that cannot be machined on the line. Before we send the pre-machined housing to the transfer line, the motor housing is completely reworked, including the various covers, the pump seat, etc.” Dušan Kelnar points out that he and his colleagues have been familiar with the machine manufacturer Starrag and the Heckert centers for a long time: “We bought the first Heckert CWK 630 for machining gearbox housings 25 years ago.” In the years that followed, Tatra regularly invested in further Heckert machines: two CWK 630s for machining axle housings, three CWK 500s for swing arms and wheel reduction housings and two CWK 500s for components in the Tatra Tactic series. By 2017, three HEC 630 and two HEC 500 machining centers had also replaced other old machines. “That’s why we have extensive experience with Heckert machines,” emphasizes Kelnar. “These machines have proven themselves thanks to their design, reliability and longterm accuracy.”

Production cell is expanded step by step

The new Heckert HEC 800, which was delivered at the beginning of 2025, is the basis for the production cell that has now been put into operation. The machine has special equipment, including, for example, a travel path extended to 81 in. (2,050 mm) in the Z-axis, an NC axis in the spindle for controlling special tools and a magazine for long tools up to 49 in. (1,250 mm). Process Manager Kappler explains: “The cell takes over the complete machining of our 8- and 12-cylinder motor housings and is increasingly replacing the transfer line.” The blanks are cast parts made of copper-alloyed GG20 cast iron with dimensions of around 47 × 24 × 28 in. (1,200 × 600 × 700 mm) and a weight of around 882 lb. (400 kg). Complete machining is carried out in four clamping processes with special hydraulic clamping devices developed and manufactured by Starrag. In a second step, the production cell will soon be expanded to include an identical Heckert HEC 800 machine. And in a third expansion stage, Starrag is integrating the Heckert HEC 800, which is currently still responsible for the external pre-machining of the cast blanks.

A flexible pallet storage system, which consists of a shelf with twelve pallet spaces and a linear conveyor, automates the production cell. The latter handles the pallet transfer between the machines and the machine setup stations. The pallet storage system will also be further expanded as the number of machines grows.

Enormous increase in space productivity

Martin Kappler compares the two production systems: “Our transfer line recently had a capacity of around 1,600 units per year, which we are currently only utilizing half of. Our production cell will also reach this quantity in the final expansion stage in two-shift operation, which is important for us. Because we expect demand to grow strongly. We can cover any further increase in demand with a third shift if necessary.” His enthusiasm for the new production solution is primarily due to its high level of efficiency. There are several reasons for this, as Kappler emphasizes: “Thanks to the automation, our new production cell can be operated by a single employee. Compared to the previous transfer line, the operating costs are considerably lower, and the space requirement of the production cell is just over a quarter at 6,135 sq ft (570 m²).” Purchaser Libor Kalíšek, who initiated the purchase of the Heckert HEC 800, has since retired. His successor Tomáš Holčák also praises the cooperation with Starrag: “All offers and negotiations were at a high technical and commercial level. We greatly appreciate the fact that Starrag supplies us with turnkey machines, as a fully functional unit comprising machine, tools, fixtures, technologies, testing and handover. The technical support, service and maintenance are also excellent.” Based on the positive experience, further projects to modernize and rationalize production are already being planned.