Looking for a CNC machine? Things to consider

May 26, 2014 8:45 am

Selecting the right CNC machine for an application is an important task to perform before making an investment. This article summarises the key parameters one must consider before purchasing a CNC equipment
 With a large variety of CNC (computer numerically controlled) machines available in the market today, loaded with advanced features and multitasking capabilities; it is really a critical task to select the right machine. The machine should have the ability to boost productivity and profitability, and hence one must look beyond just comparing the technical specifications and initial cost. 
According to Vikas Taneja, Vice President (Marketing), Jyoti CNC Automation Ltd., “Future plans have to be kept in mind while making the selection as the machine should not only fulfil current requirement but also should be capable of handling future challenges.” Mr Taneja underlines following considerations which would help in making the wise selection:
Define need:  The machine type and work envelop are defined based on the operations to be performed on components to be machined.  Multitasking / 5-axis machines can also be considered if the component geometry and relative accuracies demand complete machining in a single set-up.
Machine structure: Cast iron is considered to be the most vibration damping material for machine tool casting.  Machine base should be heavily ribbed, thus increasing the rigidity and strength for better performance and reliability. Advanced machine features like servo motor turret, torque motor driven rotary tables, LM guideways, efficient chip management, etc. greatly compliment productivity, hence require important consideration.
Accuracies: CNC machines are equipped with high-resolution rotary encoders for position feedback, and the option of precision glass scales can be opted for achieving better geometrical accuracies on the component.
Spindle: Spindle power and torque, spindle taper, high-speed electro-spindles, selection largely depends on application, component material and cutting tools used. High speed machining (HSM) is the buzzword today, and helps in high material removal and better surface finish using high cutting parameters.
Control system: CNC controllers from Fanuc and Siemens are capable of handling complex applications, supporting the leading CAD/CAM software. 
5-axis machining option provides more versatility and allows machining of intricate geometries in single set-up, achieving high accuracy levels for complex parts. 
After-sales support from the CNC machine manufacturers is of very high importance.  Every CNC machine needs periodic maintenance and may call for immediate service attention during odd hours.  The machine breakdown hours erodes the profitability of any company and thus availability of immediate services and spare parts during critical hours take top priority in final selection of a CNC machine. Indian machine tool manufacturers offering advanced and latest technology featured CNC machines today, with localised after sales support, score highly on this important aspect.
Whereas Mandeep Singh Thanjal, Partner at Agam Enterprises said, “To buy a CNC machine, one has to consider the mechanical aspects of the machine. The quality and features play a major part in this. For quality, we prefer machines from renowned companies only as they have a good life in terms of casting.”
He also suggests, “In a CNC turning centre, one must check the guideways of the machine. In case of a high precision job, machine with linear motion guideways are preferred. However, if the machine has to be used for heavy cutting, a machine with box guideways is suitable.”
———————————–Vikas Taneja, Vice President (Marketing), Jyoti CNC Automation
Future plans have to be kept in mind while making the selection as the machine should not only fulfil current requirement but also should be capable of handling future challenges————————————Mandeep Singh Thanjal, Partner, Agam Enterprises
To buy a CNC machine, one has to consider the mechanical aspects of the machine. The quality and features play a major part in this