Clearview National March 2016 - Issue 172 - Page 104

MACHINERY The Benefits of CNC Profile Machining »»FOR FABRICATORS planning to visit this year’s FIT Show 2016 with a view to purchasing new CNC profile machinery, what better to be prepared and know more about the basics of the overall mechanics of how the machines work and what operations they can perform. Andy Bates production support and training manager for elumatec UK shares with Clearview some of the basic capabilities of CNC machining and how they can improve manufacturing process. Clearview: How is a CNC profile machining centre controlled? Andy Bates: The CNC profile machining centre’s axis drives are computer controlled, allowing precision movements. These are then linked to either a rack and pinion or ball screw to transfer the drive from the motor to the machine. This gives precise control of the feed rate of the cutter. For example; when drilling a hole a feed rate of precisly 300mm per minute may be required. The drives are also interlinked so they can perform moves in unison; if the machine is routing a slot on the top of a profile at a 45° angle the X and Y axes will need to move synchronously to produce the slot. This is easy for a computer to achieve but not so easy for a human - if you have operated a copy router you will know it is impossible to make the tool move diagonally without a special templates. Clearview: Can you explain a bit more about the axes? Andy Bates: A CNC profile machining centre can have three, four or five moveable axes. On a 3-axis machine these move in the planes labelled X, Y and Z. The X-axis moves side to side along the length of the profile, the Y-axis moves back and forward across the width and the Z-axis moves up and down the height. The distances of these axes vary upon the machine specification. Clearview: How does the tooling specification and selection work on a CNC profile machining centre? Andy Bates: In simple terms, the machine holds a number of tools that can be driven directly from the spindle to machine the faces and/or ends of the profile. The tools are driven by an electro spindle – which looks like an electric motor but is a lot more complex. It allows greater control of the speed, usually to within a couple of RPM. The RPM of the tool is maintained even when cutting load or resistance is placed on it. This consistent rotation speed allows the machine to perform precision operations like tapping. The other main feature of the electro spindle is its ability to locate and pick up the tools. This means you can control and change tooling automatically during the machining process via the CNC Profile Machining Centre’s computer interface 104 » MAR 2016 » CL EARVI E W- UK . C O M The range of tools available is very broad and can accommodate the processing requirments of both fenestration and industry products. Tools include; routers, drills,taps and milling disks. The data for selecting and controlling the tools is input into the machines software. This includes the diameter, maximium drilling depth and the type of tool holder it it set in. elumatec’s CNC machines are controlled by an industrial grade PC. This is similar to an office PC and runs MS Windows but an industrial grade PC has greater protection against vibration and electrical interference allowing it to operate reliably in a manufacturing environment. The 4