Computer Numerical Control (CNC) Drilling is commonly implemented for mass production. The drilling machine, however, is often a multi-function machining center that also mills and sometimes turns. The largest time sink for CNC drilling is with tool changes, so for speed, variation of hole diameters should be minimized. The fastest machines for drilling varying hole sizes have multiple spindles in turrets with drills of varying diameters already mounted for drilling. The appropriate drill is brought into position through movement of the turret, so that bits do not need to be removed and replaced. A turret-type CNC drilling machine is shown below.
A conventional drill press can be used to machine holes. An operator can place a drill in the drill chuck that is secured in the spindle of the drill press. He can then (manually) select the desired speed for rotation (commonly by switching belt pulleys), and activate the spindle. Then they manually pull on the quill lever to drive the drill into the work piece being machined. But with CNC drills, this sheer amount of manual interaction changes.
A variety of semi-automated drilling machines are also used. An example is a simple drill press which, on command, drills a hole of a set depth into a part set up beneath it.
In order to be cost-effective, the appropriate type of CNC drilling machine needs to be applied to a particular part geometry. For low-volume jobs, manual or semi-automated drilling may suffice. For hole patterns with large differences in sizes and high volume, a geared head is most appropriate. If holes are close to each other and high throughput is desired, a gearless head can locate spindles close together so that the hole pattern can be completed in one pass.

The company's new Air Stik Window Blowoffkeeps the windows of CNC machines clear of coolant and chips so the part and process are visible at all times. The compact design delivers a uniform sheet of air that blows down the surface of the window. The operator can then make decisions affecting the part and process, resulting in faster machine setup and increased productivity, the company says.

The device ejects a small amount of compressed air through a thin slotted nozzle. This quiet, laminar sheet of high velocity air immediately pulls in surrounding air that sweeps down the surface of the window. A peel-and-stick adhesive permanently bonds the aluminum Air Stik to the window of the machine. Compressed air inlets are provided on each end. A shutoff valve with attached bulk head fitting (for closed machines) or magnetic base (for open top machines) gives the operator infinite control of the air velocity so it can be increased when there is a high volume of coolant hitting the window.

The device comes complete with all components necessary for mounting and piping. There are no moving parts to wear out or mechanical wiper blades to scratch the window surface.

The company announces the availability of a new model, the DB 300 CNC EDM machine. This model incorporates a new high speed pulse technology, which is based on faster head action and servomotor control. This series is said to be more efficient, especially in jobs that involve difficult flushing applications, With the company's Erosion Expert System, deeper machining is achieved, while flushing problems are eliminated (which results in the manufacturing of higher precision parts).

The EDM machine can machine deep ribs faster with more precision, as the CNC incorporates technology tables specifically for the machining of ribs. The company says the automatic program generation incorporates conversational operator input to produce the best-suited program for the type of rib or cavity being machined. Also, the Expert Erosion System controls the entire machining of a workpiece, from roughing to final finishing. The machine can operate around the clock in an unattended mode.

The EDM machine incorporates automatic strategy to produce the program needed for the optimal erosion process. By inputting minimum data, the CNC analyzes the optimal erosion process showing the number of requested electrodes and their undersizes and automatically generates and executes the program. With automatic strategy, the user can add his or her own information to the CNC, creating technology tables with automatic strategies. Also, the systems reduce training time.

According to the company, other features of the EDM machine include: simultaneous four-axis machining for a large number of functions; a mechanical structure head design to eliminate vibrations produced by the fast accelerations and decelerations of the EDM machine (this ensures the manufacturing of precision parts); multiple applications through the functions incorporated into the CNC; angular orbiting; a standard fine finish mode (VDI = 0): excellent homogeneous surface finishes obtained on large areas; and compatibility with Hirschmann, Erowa and System 3R tooling systems.

The base, column, head and both X and Y tables are constructed of stabilized fine-grained cast iron blended with graphite in a symmetrical design to keep thermal deformation down to a minimum. Also, a paper cartridge filtering system is standard on the machine. The Dielectric Filtering System, which offers more than 10,000 working hours of filter element life, is offered as an option.

A subcontractor has endeavoured to keep its overheads as low as possible by investing in the most productive machine tools for our particular needs
When Trevor Timpson and Gary Evans decided it was time to put their hard-won engineering knowledge to better use, they took six months to plan every aspect of their new sub-contract machining business. Trevor had spent the previous six years in production management, while Gary's wide-ranging machining expertise had benefited along the way from a four-year stint with the Williams Formula One team.
Taken together, their 40 years-plus experience of motor sport, aerospace, medical and semi-conductor work has enabled Oxfordshire-based Faringdon Precision Engineering to get off to a great start.

'We couldn't move into our 4000ft2 premises until March,' said Timpson, 'But since the summer it has been 'manic'.

We had to buy two more machine tools 12 months before our business plan said they would be needed and we have reached our initial target of a minimum of 10 good customers across a broad range of industry sectors with time to spare.' The Faringdon Precision Engineering plant list now includes two turning centres and two machining centres, one with simultaneous five-axis capability and all supplied by XYZ Machine Tools of Burlescombe, Devon.

XYZ also supplied the 2HP programmable horizontal bandsaw that cuts bar stock into billet lengths as required.

'We set out to do a quality job at a competitive price,' said Evans, 'And we have endeavoured to keep our overheads as low as possible by investing in the most productive machine tools for our particular needs.