Last week I took my first tentative steps into the sphere of CNC (Computer Numerical Control) programming. At Paul Haslam, several components of nearly every piece of furniture, at some point between raw timber and finished cabinet, are acquainted with one of our two Reichenbacher CNC machines. Both machines incorporate state-of-the-art 5-axis heads with tool changers storing 12-22 different tools, and are controlled by advanced Siemens Sinumerik systems. That’s the blurb but essentially they’re very accurate flat-bed machines with computerised movement.
My father, Paul, bought the company’s first CNC machine in 1990 – a 3-axis machine now sadly retired and replaced after 20 years of faultless service and hundreds of perfectly machined kitchen cabinets. He is completely sold on the benefits of NC machining and will bang on endlessly about the advantages of parametric programming and the limitless potential of 5-axis tool paths to anyone who will listen.
Having some coding experience, the programming language was not as alien to me as it might have been, and I actually found the coding protocol fairly understandable. A series of commands tells the machine to select a certain tool, understand compensations, offsets and machining directions, and sends the machine head, line by line, in various directions in each axis. In its simplest form it reminded me of being at school when early mass-market computers were introduced to us, and using the program Logo Turtle we were able to command a small turtle to travel in perpendicular lines around the screen! Combined with creating parameters for any variable, I was very quickly able to build up a versatile program for machining the component I was designing – in this case a light soffit to be fitted under wall units. Of course, during testing, the spindle speed is set to 0rpm and the program is run at a slow speed block by block, to allow for emergency stops – an accidental extra ‘0’ in the Z axis can prove very costly indeed! Seeing a large machine behave exactly as programmed is a satisfying thing indeed. The robotic movements of CNC routers can be controlled in every imaginable way, and half the fun is surely in seeing those programmed x-, y-, z-, b- and c-axis commands transformed from a text file into beautiful flowing movements. And that’s before it’s cut a millimetre of wood.
Currently there appears to be something of a resurgence in demand for hand-made, hand-finished furniture, made using good old-fashioned woodworking machines and hand tools. For many years I worked at a top violin restoration firm in London and the sum machine inventory amounted to a drill press and a bandsaw. You couldn’t move for reamers, gouges, finger-planes, files and rasps. Violin-making and restoration is an age-old tradition, and especially when dealing with antique instruments it’s vital restorers adhere to the same techniques and principles used by their makers 300 years ago, to help preserve the instruments and because the dimensions being dealt with are in the tenths of millimetres, and often assessed by eye rather than by spirit level and tape measure. But cabinets are not violins, and for our solutions we find the combination of NC and other advanced engineered machinery, with assembly and finishing by hand, gives us the accuracy, consistency and quality our customers require.
In all, my week was a revelatory dip into what’s possible with NC machining. The skill is in turning sketches into computer-friendly commands. That, and imagining objects in 3D space, which becomes far more complex than I at first realised. One things is for sure – the design freedom and manufacturing potential with NC machining really is limitless.
