The right DNA for agricultural machinery

Heckert machining centers helping to get food problems under control thanks to tailor-made production technology

The world is facing a dilemma: the rising population of the earth needs more food, while the number of agricultural holdings is decreasing. Robust and flexible agricultural machinery that works around the clock very reliably and with high out-put is in demand. Its use is reliant on engines, gearbox housings, axis and other heavy XXL components. The Starrag Group took on this challenge at an early stage. Machining centers in the Heckert product range have proved their worth in the production of these heavy, large and robust cast iron and steel components.

Car, truck and bus: when talking about vehicle construction, these terms will quickly come to mind unprompted for most people. Few people think of tractors, combine harvesters, ploughs, harrows, seed and planters or fertilizer spreaders. Amazingly, our survival depends on this automotive technology. But no matter whether it’s a tractor, plough or fertilizer spreader: every type of agricultural machinery technology shares several common denominators. They are usually produced in small batch sizes and are often available in many variants. The requirements placed on production technology are equally high. “For agricultural vehicles, the light-weight solutions commonly used in 
passenger cars are hardly ever appropriate,” says Kai Bohle, Starrag’s Director Sales DACH (Germany, Austria and Switzerland) for the “Tranportation and Industrial” segment. “Robust mechanical engineering is in demand, because components made of steel and cast iron are used predominantly. In many cases, they are large, heavy and demanding in contouring.”

Heckert DNA increases process reliability

For example, machining axis, gearbox housings, engine blocks, cylinder heads and hydraulic components requires high-performance machining centers that ensure precise and safe production processes thanks to their torsional rigidity. “These properties are in a sense part of the ‘DNA’ of the horizontal Heckert HEC machining centers produced in Chemnitz,” explains Bohle. “This is why many agricultural machinery manufacturers use our compact Heckert centers, ranging in pallet sizes from 16 to 32 in. (400 to 800 mm). But there is also a high demand in the agricultural sector for the large machines from the Heckert Large Athletic series as these machines feature pallet sizes starting at 39 in. × 32 in. (1,000 mm × 800 mm) and can be used for large-volume and heavy components”.

part of a motor block

Many agricultural machinery manufacturers use Heckert machines for machining axis, gearbox housings, engine blocks, cylinder heads and hydraulic systems.

Cut costs with compact machines

The rigid, thermosymmetrically designed major components, digital AC feed drives, complex profile rail guides and ball-screw spindles in all linear axes are the key to the machines. Chemnitz also equips them with robust, powerful high-torque spindles with high torque that guarantee long-lasting high precision and reliable processes, even in the case of materials that are difficult to machine. The free chip fall, which has proven to be particularly effective in the case of high chip build-up when cutting cast components with large material allowance, also contributes to process safety. In addition, the axis travel distances are relatively large in relation to the pallet size. Bohle: “The customer may, in certain circumstances, be able to opt for a machine that is a size smaller and thus cut costs”.

Tailor-made to increase productivity

Tailor-made products are often in demand in agricultural machinery manufacturing. Torsten Leistner, Team Leader Quotation Engineering in Chemnitz, is the specialist for this demanding task. He has been working on customer specific options for a long time – especially for agricultural machinery. Leistner is supported by experts in application technology, automation, layout creation and special designs. “We are able to meet the requirements of agricultural engineering with bespoke, customer specific solutions based on our Heckert machining centers”, Leistner explains. “Together with the customer, we develop the machining technology and design the fixtures and the automation systems that best suit the batch size”.  The team adapts the solutions individually to on-site conditions and also takes on the optimization of ergonomics.

Upon request, Starrag can equip its Heckert machines with an NC quill that can extend up to 19 in. (500 mm) in the Z-direction on compact models. “With the NC quill, we have a unique selling point for the compact machining centers that can be used in many versatile ways in agricultural engineering applications.”

NC quill enables axes gears to be machined

A standard process in agricultural machinery manufacturing is the machining of half-axis and axes drives. Heckert machines can also be equipped with an NC quill that can be ex- tended in the Z-direction by 20 in. (500 mm), for example, for processing the bearing seats in the interior. It has a diameter of 5 in. (125 mm) and operates at a maximum speed of 4,000 rpm. For the larger machining centers with a pallet size starting from 39 in. (1,000 mm), there is also a quill measuring 6 in. (150 mm) in diameter and with a traverse path of 30 in. (760 mm).

Safe, stable and versatile complete machining

When quills are used, users can do without expensive, vibration-damped tools that require extensions and can use inexpensive standard tools instead. Process stability is also increased thanks to the improved length-to-diameter ratio. One thing is clear for Torsten Leistner: “With the NC quill, we have a unique selling point for the compact machining centers that can be used in many versatile ways in agricultural engineering applications. This is because they can be also be used for machining gearbox housings and half-axis with long axis funnels that would otherwise require long tools that are consequently susceptible to vibrations.”

Tool magazines with up to 450 places allow automatic insertion and replacement of up to 55 in. (1,400 mm) long tools and bridge tools with a maximum width of 37 in. (950 mm).

“An axis clamped above cheek height can be machined on both front faces using a Heckert HEC 800 X5 without the need for reclamping.”

Ideal for high-precision engine machining

However, the user cannot always dispense with long tools: they are necessary, for example, when drilling crank and cam shafts on the straight-four or straight-six engines commonly used in agricultural machinery. Long-life drives are called for here. This requires high-precision drilling in a train, since transshipment holes would not guarantee the required quality. A special Starrag solution allows drilling over 39 in. (1,000 mm) long from one side: the Heckert HEC 800 machining center is provided with a Z-axis with a travel path extended to 81 in. (2,050 mm) as a fixed option. The user can now position a 55 in. (1,400 mm) boring bar in front of the workpiece to drill in a process-safe and stable manner even when drilling deeply.

Tool magazine adds flexibility

In deep drilling, productivity only increases with automation; this is only possible with special peripherals. These include, for example, Starrag tool magazines with a maximum of 450 places: depending on the version and machine, they are able to automatically insert and replace tools of up to 55 in. (1,400 mm) in length as well as bridge tools with a width of up to 37 in. (950 mm). The magazines are also designed for face milling cutters with a maximum diameter of 13 in. (340 mm) that handle the finishing of large sealing surfaces on the combustion chamber side of cylinder heads and blocks. Larger tools weighing in excess of 110 lb. (50 kg) or that have an overturning moment of more than 52 ft-lb (70 Nm) can alternatively be installed and replaced from the fixture in the spindle using a pick-up system.

The HEC 800 machining center has an optional 98 in. (2,500 mm) Z-path for crank and camshaft bores in straight-four or straight-six engines with long boring bars.

Increased productivity thanks to the five-axis design

Heckert HEC centers in a five-axis design are suitable for many machining applications: the HEC 500 to HEC 800 compact centers are equipped with a rotary swivel table for this purpose, while large centers have a swivel head for the fifth axis. With these five-axis machining centers, cylinder heads, axis and complex hydraulic control blocks can be machined much more productively, because the number of clamping positions and unproductive downtime decreases.

The advantages of the five-axis Heckert centers can also be leveraged when machining the bulky swing axis of agricultural equipment. An axis clamped above cheek height can be machined on both front faces using a HEC 800 X5 without the need for reclamping. The user can also position and precisely fit attachment points along the longitudinal axis by adjusting the fifth axis. They then benefit from greater accuracy and shorter tool changing times.

Precise complete machining of planetary gear carriers

An additional core capability of the five-axis Heckert machines: then enable complete machining of the planetary gear carriers installed in the gearboxes and sometimes also in the axis of agricultural machinery. The complete machining ensures precise positioning and thus accurate adherence to the required dimensional and position tolerances of the holes. The integrated turning function eliminates the need to transfer the workpiece to a turning machine. Lastly, the ability to carry out direct toothing in one clamping operation increases the profitability of the machining process. It’s amazing what’s in the ‘DNA’ of horizontal Heckert HEC machining centers.