The new grinding machine from Haas needed to be small, compact, and space saving. And that is exactly how it turned out. For the Multigrind® CU, we decided to go with the classic Gantry design with central drive. In order to gain space, we modified the axis configuration usual for Gantry machines. The X, Y, and Z axes were moved up. The C-axis moved from above to below where it also moves the A-axis, which is used to swivel the machine table, and as such, the workpiece. The C-axis also moves the tool magazine located below the machine table, which is simply lifted up for loading.
The design with a fixed spindle results in 50 percent less rotary motion, and as a result, a considerable increase in stability and precision. This means we were able to increase travel when in rapid motion to 30 m/min, with disruptive Coriolis forces eliminated thanks to the fixed spindle.
The entire machine is built so that the user only needs to access the front or the back. Loading and unloading as well as loading the tool changer is carried out at the front side; maintenance is carried out exclusively from the back side. The sides on the left and right are completely closed, which means that several machines can be lined up next to each other in one production line.
In the CU you can grind machining tools and other workpieces up to a length of 300 mm and 180 mm in diameter to the nearest micron.
We equip the CU standard with a Haas HSK 50 E grinding spindle with 8,000 revolutions per minute and 12 kW. We can also equip the machine with an 18,000 rpm spindle, if so desired. In addition, we can also provide high-speed spindles upon request. All Haas spindles are developed and manufactured in Trossingen. The rotating parts are finely balanced and many use hybrid bearings.
With a clamping surface measuring 800 × 290 mm, the Multigrind® CU’s rotating machine table offers lots of space. The workpiece holder on the A-axis and the machine table move the tool around, but always in one place. As such, the axes only need to be minimally repositioned, making them considerably more accurate.
Anyone who places considerable value on flexibility – such as the manufacturers of precision tools – needs a generously sized, rapid tool changer. Despite only being 1,600 mm wide, the CU is equipped with a tool magazine with up to 14 spaces. This is enough space to load the changer with nine grinding wheels measuring 200 mm each. The user loads the changer from above at the front of the grinding machine. Just like the entire machine, the changer is programmed and precision-controlled using our Multigrind® Horizon grinding software. And since we wanted to build a truly compact machine, we used a special technical trick and positioned the changeover wheel under the machine table.
Today cost-effective automation is one of the main requests from tool manufacturers. In this regard, we equipped the CU with an integrated automation unit. This unit is comprised of four pallets (259 × 200 mm) which can be quickly loaded and unloaded with a pivot drive and a gripper arm. Thanks to the five NC axes and the two “half” axes, the CU has levels of freedom that come close to that of a robot. To make things even better, the CU’s automation unit requires neither additional space nor an extra budget.
Maintenance and Supply
The CU can be easily accessed from behind to supply, maintain, and examine all supply elements and measurement levels. The central cooling unit, maintenance cabinet, and electronics unit are arranged in a clear and ergonomic manner. The integrated cooling unit supplies all three cooling circuits. Data streams are controlled in a fail-safe manner via a central bus.
Cool Machine Bed
The CU’s machine bed is precision-cast from stable mineral composite. The machine bed houses the coolant in two large tanks. This means the machine bed is constantly cooled, which in turn results in higher precision and a more reliable grinding process.
If you want to precision-grind to the nearest micrometer, you need grinding tools that are exactly right. The dressing unit in the CU is positioned in an easily accessible location next to the machine table. With it you can parallel dress or get wheels into perfect shape using the cross dressing method. Dressing is controlled using the Multigrind® Horizon grinding software.
Positioning Machines in One Row
Since the sides of the CU are completely closed, several CU grinding machines can be neatly positioned in a row, saving space.
Precision and cost-effectiveness begin when programming the grinding program. With our intuitive Multigrind® Horizon grinding software and the Siemens Sinumerik 840D sl continuous path control system, the CU is superbly equipped as far as software is concerned.
Ergonomics and Safety
The double-glazed safety glass and stable enclosures create a safe protective barrier. All operating and maintenance elements are positioned in an ergonomic manner.
Supply units on the back side