A machining center is a tool that is capable of doing multiple operations on a work part in a single setup. Recent CNC-Machines-tools are equipped with a lot of features which can increase the production and time-saving. Time-saving on CNC-Machines-tools is a huge profit for the company.
The machining center designation refers to the orientation of the machine spindle, and is categorized as below:
1)Vertical machining center (VMC):
These machine centers have its spindle on a vertical axis relative to the work table and always perpendicular to the machining bed. This type of machining center is typically used for flatwork that requires tool access from the top. E.g. mold and die cavities, large components of aircraft. These machines are relatively cheaper compared to the other machining centers.
2)Horizontal machining center (HMC):
This type of machining center has the Z-axis in the horizontal position and the part is loaded on the table vertically in X and Y direction. A horizontal boring machine is used for machining the cube-shaped parts where tool access can be best achieved on the sides of the cube. The number of setups can be reduced when we compare it with the Vertical machining centers. Some horizontal machines have their bed in the X and Y-axis perpendicular to the spindle and some have in X and Z axis parallel to the spindle.
3)Universal machining center (UMC):
Universal machining centers are the machines which have 5 or more axis. It has a work head that can swivel its spindle axis to any angle between horizontal and vertical. Thus, making this a highly flexible machine tool. The complex parts like Aerofoil shapes, curvilinear geometries can be machined using these machines.
The universal machining center works on the swivels spindle axis which is called the pivot point. Most of these machines are used for finishing of parts as it can achieve high accuracy.
Key Features of advanced horizontal machining/boring centers:
Usually, the CNC machines are designed with many features to reduce non-productive time. Some of the features are:
1)Automatic tool changer (ATC):
The Cutting tools are stored in the storage space called the “tool magazine” which is integrated with the machine tool and named with the tool numbers. When a tool number is called by the tool number the magazine rotates accordingly and an automatic tool changer (ATC) with the program control, exchanges the tool in the spindle for the tool in the tool storage cabinet. The Capacities of the tool magazine generally range from 16 to 80 cutting tools. These Automatic tool changes save the manual tool changing time and the big save on the cycle time or the operation time.
2)Automatic work part positioned:
The feature of Automatic work part positioning acts as a rotary axis rotating the part and gives access to the cutting to a machine, many horizontal, as well as vertical machining center, have the capability to align the work part relative to the spindle. The table can be aligned at any angle about a vertical axis to permit the cutting tool to access almost the entire surface of the part in a single setup.
These automatic work part positions are programmed by the programming software. The positioning of the rotation is very crucial and the tool needs to move to a safety plane when there is a big rotation in the rapid process. With these features, we can reduce the number of setups and save huge time and achieve a drastic increase in productivity.
3)Automatic pallet changer:
Recent Machines are equipped with two (or more) separate pallets that can be changed using an automatic pallet changer. While machining operation is performed with one pallet in position at the machine, the other pallet remains in a safe location out of the machine.
The machine operator can unload the finished part and then fixture the raw work part for the next cycle with the pallet outside the machine. Using these features in machines, the time of loading and unloading the part can be minimized and the machine will be loaded continuously. Machines with these features are very helpful in mass-production activity.