The CNC Machinist

CNC MACHINE UTILIZATION

2008-05-05T20:28:00.000-07:00

From the CNC Machinist
The introduction of CNC machine tools has revolutionized manufacturing process. These CNC machines have many advantages over the conventional machines like better scheduling, flexibility, increased productivity, reduced setup and lead time, reduced tool cost, reduced material scrap, and most importantly production of superior quality products. CNC machines are many times expensive than their conventional counterparts.

The CNC machinist should know that the maintenance of the machine and control system, process planning, part programming, tooling and fixtures, management, and inspection are the factors influencing the utilization of CNC machines.

The CNC machinist should know that the CNC machines are high-tech machines and require highly skilled maintenance engineers. A good maintenance program could be worked out including, daily, weekly, monthly, quarterly, bi-annually, and annually as per the requirements. As the CNC machinist knows for reducing the idle time,the CNC machines require tremendous overall planning procedures and systematic careful selection and applications of tools, tool holders, and work holding fixtures, etc.

CNC Lathe and Mill by The CNC Machinist.

2008-05-05T20:27:00.000-07:00

A lathe is a machine which remove material from a rotating workpiece by the movements of various cutting tools the movements of which are usually linear. The cutting tools are tool bits, drill bits ect. The conventional lathes are very fastly replaced by CNC lathes. Once the program file is uploaded, the machine with the supervision of the CNC machinist will continue to turn the parts.

Milling machine is used in complex shaping of metals and other solid hard materials. The basic part of the milling machine is a rotating cutter/endmill which rotates in the spindle axis silimar to a drilling machine with a movable table where the workpiece is fixed. The cutting tools being stationary the table on which the work piece is fixed moves. Milling machines are used for drilling, rebating, routing, slot cutting and other complex operations.

As the CNC machinist is aware of, the CNC milling machines are also called machining centers and are vertical milling machines which are controlled by a computer. They can also move the spindle along the Z- axis.

CNC Router by The CNC Machinist

2008-05-05T20:26:00.000-07:00

The CNC wood router is one of the most sought after machine by both CNC machinists and hobbyists. The CNC router is a machine similar to metal CNC mill but the spin rate is faster in them up to 25,000 RPM. The CNC router as the CNC machinist knows uses smaller tools than a CNC mill. The CNC router has a smaller tool holders as the tools are smaller than that of CNC mills. The CNC router and CNC mills are controlled a same way.

As the CNC router is predominantly used for wood carving, the soft wood and hard wood needs different spindle speeds and tools depending on their grain size. The wood CNC routers are also used for many soft materials including plastic. The wood CNC routers are much bigger than the metal CNC mills and have three dimensional movements xyz. These wood CNC routers are much bigger in size which are utilized in cabinet making.

Some wood CNC routers have multiple separate heads that work both simultaneously and also separately. The wood CNC routers have dust sucking air ducts which are used in sucking up the chips and dust created by machining the wooden parts and plastic parts and are collected in a dust collecting chamber. The wood CNC router hold wood with suction provided by vacuum suction tubes.

CNC Information From The CNC Machinist

2008-05-05T20:23:00.000-07:00

The abbreviation CNC stands for computer numerical control, and refers specifically to a computer "controller" that reads G-code instruction and drives a machine tool, a powered mechanical device typically used to fabricate components by the selective removal of material. CNC does numerically directed interpolation of a cutting tool in the work envelope of a machine. The operating parameters of the CNC can be altered via a software load program. The introduction of CNC machines radically changed the manufacturing industry. Curves are as easy to cut as straight lines, complex 3-D structures are relatively easy to produce, and the number of machining steps that required human action have been dramatically reduced. With the increased automation of manufacturing processes with CNC machining, considerable improvements in consistency and quality have been achieved with no strain on the operator. CNC automation reduced the frequency of errors and provided CNC operators with time to perform additional tasks. CNC automation also allows for more flexibility in the way parts are held in the manufacturing process and the time required to change the machine to produce different components. In a production environment, a series of CNC machines may be combined into one station, commonly called a "cell", to progressively machine a part requiring several operations. CNC machines today are controlled directly from files created by CAM software packages, so that a part or assembly can go directly from design to manufacturing without the need of producing a drafted paper drawing of the manufactured component. In a sense, the CNC machines represent a special segment of industrial robot systems, as they are programmable to perform many kinds of machining operations (within their designed physical limits, like other robotic systems). CNC machines can run over night and over weekends without operator intervention. Error detection features have been developed, giving CNC machines the ability to call the operator's mobile phone if it detects that a tool has broken. While the machine is awaiting replacement on the tool, it would run other parts it is already loaded with up to that tool and wait for the operator. The ever changing intelligence of CNC controllers has dramatically increased job shop cell production. Some machines might even make 1000 parts on a weekend with no operator, checking each part with lasers and sensors.

The complete part program to produce a component is input and stroked in the computer memory and teh information for each operation is fed to the machine tools i.e. motors etc. The part program can be stored in the memory of the computer and used in the future. The conventional NC machine tools are not much in use these days. CNC machine tools are widely used due to many new control features avialable on these machines. Some of the additional features available in CNC machine tools are:-

The part program can be input to the controller unit through keyboard or the paper tape can be read by the tape reader in the control unit. The part program once entered into the computer memory can be used again and again. The part program can be edited and optimized at the machine tool itself. If there is any change in the design of the component the part program can be changed according to the required. The input information can be reduced to a great extent with the use of special sub programs developed for repetitive machining sequences. For common operations such as drilling holes on a pitch circle, special cycle program can be built and stored in the computer memory. These sub programs or subroutines can be retrieved and used any number of times within a part program only certain parameters have to be specified and the computer control carries out the necessary calculations and subsequent actions.

The CNC machines have the facility for checking the part program without actually running it on the machine tool. The control system processes the part program and the movement of the cutting tool in each operation is shown on the monitor screen. The shape of the component which will be produced after machining is also shown on the screen without actual machining taking place.