Aerospace | Machining technology

A passion for Aerospace

With Dr. Burkhart Grob’s passion for aerospace came the founding of Grob Aerospace in 1971, a German aircraft manufacturer specializing in gliders and general aviation. In 1974, Dr. Grob designed one of the first GROB aircrafts, a single seat fiberglass Club Class sailplane named G102.

INTERESTING FACT: On February 17,1986, Robert Harris set a world altitude record of 49,009 ft flying a G102 Standard Astir III. This record lasted until 2006 and the glider can be found today in the National Air & Space Museum in Washington D.C.

In the 1980s, GROB Systems was founded in Bluffton, OH because of Dr. Grob’s passion of aircrafts. With the airfield nearby, Bluffton met the requirements of a modern machine manufacturing factory, as well as the demands of a modern glider plant. While Grob Aerospace was sold to H3 Aerospace in 2009, the passion for aerospace is still prevalent within the GROB Group.

A partner for 4- & 5-axis machining

We focus on what we do best. GROB offers a uniquely superior horizontal solution for 4- and 5-axis machining. This means our people are experts in 4- and 5-axis applications and are ready to help you achieve your goals. As a family owned company, we continuously invest in our future by innovating to solve problems in the industry. Many of the features that make our machines unique address the day-to-day challenges in the component manufacturing process.

In addition to our superior machine design and kinematics, our applications team in Bluffton, OH is dedicated to providing the process support you need. We partner with the best suppliers in the industry for controls, CAD/CAM, tooling, etc., and can provide automation and Industry 4.0 solutions from our GROB product line. We come to you with a comprehensive solution from a single source.

Machine solutions

GROB designs and builds universal machining centers that are in a league of their own. Our machines are different from other 4- and 5-axis machines in several important ways:

The unique retractable spindle virtually eliminates the chance for collisions during tool change while maximizing the usable work area.
Ergonomic design that allows easy access to the work area and requires less floor space than other machines with the same work zone (buy one size smaller!).
Capabilities to invert the table and machine upside down for optimal chip evacuation.
A wide range of automation is available to achieve lights out production with optimal spindle utilization and production efficiency.
The superior horizontal design guarantees consistent rigidity through the entire Z-axis stroke, leading to unmatched accuracy. Our machine is the most rigid when the Z-axis is out at the part! This guarantees better tool life and productivity.

G150

Details

G150

Working travels: 450/670/665
in X-/Y-/Z-axis (mm)

Speeds (max.): 50/40/60
in X-/Y-/Z-axis (m/min)

Interference diameter: 580
(mm)

G350

Details

G350

Working travels: 600/855/750
in X-/Y-/Z-axis (mm)

Speeds (max.): 70/45/90
in X-/Y-/Z-axis (m/min)

Interference diameter: 720
(mm)

G550

Details

G550

Working travels 800/1,020/970
in X-/Y-/Z-axis (mm)

Speeds (max.): 65/50/80
in X-/Y-/Z-axis (m/min)

Interference diameter: 900
(mm)

G750

Details

G750

Working travels: 1,000/1,100/1,175
in X-/Y-/Z-axis (mm)

Speeds (max.): 60/50/75
in X-/Y-/Z-axis (m/min)

Interference diameter: 1,280
(mm)

G350T

Details

G350T

Working travels 600/855/750
in X-/Y-/Z-axis (mm)

Speeds (max.): 70/45/90
in X-/Y-/Z-axis (m/min)

Interference diameter: 620
(mm)

B-axis speed: 1,200
n_max (rpm)

G550T

Details

G550T

Working travels: 800/1,020/970
in X-/Y-/Z-axis (mm)

Speeds (max.): 65/50/80
in X-/Y-/Z-axis (m/min)

Interference diameter: 900
(mm)

B-axis speed: 800
n_max (rpm)

G750T

Details

G750T

Working travels: 1,000/1,100/1,175
in X-/Y-/Z-axis (mm)

Speeds (max.): 60/50/75
in X-/Y-/Z-axis (m/min)

Interference diameter: 1,280
(mm)

B-axis speed: 500
n_max (rpm)

G440

Details

G440

Working travels: 800/800/800
in X-/Y-/Z-axis (mm)

Speeds (max.): 70/60/60
in X-/Y-/Z-axis (m/min)

Interference diameter: 800
(mm)

G640

Details

G640

Working travels: 1,050/800/1,050
in X-/Y-/Z-axis (mm)

Speeds (max.): 70/60/60
in X-/Y-/Z-axis (m/min)

Interference diameter: 1,050
(mm)

G840

Details

G840

Working travels: 1,400/1,200/1,400
in X-/Y-/Z-axis (mm)

Speeds (max.): 50/50/50
in X-/Y-/Z-axis (m/min)

Interference diameter: 1,400
(mm)

Manufacturing of a blisk

The perfect solution for your aerospace component: GROB mill-turn machines enable a complete machining of complex and extremely stable components.

Advanced options

We know standard and average aren’t good enough when it comes to producing aerospace parts. Through research and innovation, GROB has developed options to specifically meet the rigorous demands of the aerospace industry.

Table options

Standard tables

T-slot or pallet clamping

Dynamic table

Highly efficient machining of large parts with short tools with an A-axis swivel range from -260^○/ +80^○

Tandem drive table

Suited for long, narrow components, such as blades

Accuracy package

Accuracy is the most important measurement in the aerospace industry. As a partner of the industry, GROB has developed an accuracy package to further improve the accuracy of the parts machined on a GROB. Our accuracy package features:

Innovative volumetric compensation cycles developed by GROB
Straightness measurements and compensation taken by laser at your facility
Thermal stabilization with 12 cooling points: motor spindle, A- and B-axis torque motors, X-, Y- and Z-axis servo drives, X- and Z-axis housing ball screw nut, X-, Y- and Z-axis guide ways, and coolant chiller

Emergency tool retract

GROB has implemented hardware and software to prepare machine and process for power outages or failures. The stop and retract function separates the part from the tool quickly and without risk of damage to the part.

Oil-machining solutions

We know that oil-machining is widely used in the aerospace industry, so our machines can be equipped with the following to meet the specific requirements of this specialized approach:

Filtration system (bag filter, cyclonic filter, vacuum rotation)
Safety features including adjusted enclosure and fire extinguishing systems
Special mist collector solutions

Drive Tuning

We can tune the machine and drives to your parts and process. This well help you achieve the best performance and airfoil surface while maintaining process safety and part accuracy.

Typical machining operations

Single Blade

Dimensions of raw material (mm)	100x50x180
Material	Titanium
Motorized spindle	16,000 rpm
Power/torque	32 kW/206 Nm

Blisk Segment

Dimensions of raw material (mm)	Ø 150x80
Material	Titanium
Motorized spindle	16,000 rpm
Power/torque	32 kW/206 Nm

Structural component

Dimensions of raw material (mm)	380x70x120
Material	Aluminium
Motorized spindle	16,000 rpm
Power/torque	32 kW/206 Nm

Titanium pillow block

Dimensions of raw material (mm)	150x150x110
Material	Titanium
Motorized spindle	16,000 rpm
Power/torque	32 kW/206 Nm

Aluminium part

Dimensions of raw material (mm)	650x110x32
Material	F7050
Motorized spindle	16,000 rpm
Power/torque	32 kW/206 Nm

Structural housing

Dimensions of raw material (mm)	390x250x200
Material	Aerospace aluminium
Motorized spindle	30,000 rpm
Power/torque	32 kW/206 Nm

Made in the USA

Our machines are built at our impressive 400,000 square foot production facility located in Bluffton, Ohio. This means we have a complete inventory of every replacement part and factory-direct service is provided by the same team of experts who build the machines.

Aerospace expertise

Airfoils

Blisks

Valves and Manifolds

Structural Parts

Why manufacturers in aerospace choose GROB

"We had never seen a machine configured like this, and we were excited to see how the swiveling and rotating capability were combined in the table."

"You’re dealing with factory direct parts [GROB manufactures machine tools at its Bluffton, OH, plant] and technicians that are very knowledgeable and that was a big appeal for us.”

“We like the unique configuration of the spindle versus the worktable as the spindle comes in horizontally... You can machine unique cutting geometries and hard to reach areas. The configuration is also good for chip control.”

“If we have a problem that we’re trouble shooting, I can call GROB. They can log right into our machine, which is something that we’ve never had on any machine before, and they’ll trouble shoot for us. It really is a partnership with GROB.”

Want to know more?

Experts in Aerospace

GROB designs and builds universal machining centers that are in a league of their own. Our machines are different from other 4- and 5-axis machines in several important ways:

Table options

Accuracy package

Emergency tool retract

Oil-machining solutions

Drive Tuning