CNC Router

Just like most people I suppose I only peruse those sections of a supplier’s catalogue that really interest me and/or are relevant to my needs. I hadn’t therefore previously encountered the video included in the High Speed Spindles, Motors & Inverters section of Arceurotrade’s on-line catalogue. On this occasion I did so just by chance.

There followed a good number of viewings of YouTube videos of CNC routers and readings of good number of the posts at the mycncuk .com forum. I wondered whether MEW could cover the subject in some depth in the not too distant future. Those of us who have been subscribers for a few years will , of course, remember the router construction series over three issues in early 2009, nos, 148, 149 & 150 where several of the components were made of wood.

I feel sure that the technology must have advanced a good deal and suppliers become more numerous since, witness for example, the Arceurotrade inventory. My own interest would lie in using such a machine for horological activities, therefore, a machine rigid enough to cut brass would be a pre-requisite.

Is there someone out there who could author a series for MEW with the Editor’s permission of course, in reviewing the current technology, listing suppliers, providing a glossary of terms and abbreviations and, foremost, detailing the construction of a viable machine.

As an aside it doesn’t take a Professor Brian Cox to realize that one of the contributors to mycncuk is a frequent poster here also, could his ancestor have had something to do with ‘The Rocket’ locomotive perhaps? Slightly different spelling though I believe. Perhaps he could identify an author.

Edited By Niloch on 04/02/2013 23:15:21

I suspect that I have come in the opposite direction to most of the ME forum readers in developing an interest in CNC tools. Having spent a lifetime working in the world of computers and electronics (including spending much of the 1990s as editor of ME and MEW’s then sister magazine Electronics Today International) I have over the last few years been exploring computer aided design and manufacture, and from that have developed an interest in 3D printer technology and the possibilities that this technology offers.

A 3D printer is of course a 3axis CNC machine that uses an extruder to add material to build up a component, as opposed to a 3 axis CNC mill with uses a rotating cutting head to cut the component out of a bar or block. This means that 90% of the mechanics, software, and electronics in both these types of CNC system are functionally, if not mechanically, identical. Indeed this generic similarity applies to all sorts of other CNC machines such as laser cutters, wire benders, or electronic component pick and place machines.

Having built a couple of 3D printers, and used them to make various items including the parts for the second printer I have become interested in the concept of using a 3D printer as a machine to create other machines. In particular the combination of standard aluminium extrusions, with printed plastic parts, off the shelf electronics, and open source software, a combination which opens up the possibility of creating a wide variety of different types of CNC machine. I am currently working on the design of a small table top CNC router using this design philosophy and capable of drilling and milling wood, plastic, casting wax, composites, and possibly also aluminium and perhaps brass.

If the editor is interested I would be delighted to do some pieces along the lines suggested by Niloch.

Articles are always welcome.

regards david

Edited By David Clark 1 on 20/02/2013 19:56:25

I suspect therefore that a converted small mill might be more appropriate.

Russell.

Now that relatively affordable bench top CNC routers are readily available and modern end mill cutter capability extends to warp speed and light cuts making reasonable metal removal rates are potentially possible on moderately stiff machines I wonder if its time to re-think the standard approach to model engineering machinery. Currently we go for the" tool-room but lots smaller" way which means a lot of gear and problems with stiffness / size / work envelope of machines (especially small mills). Imaginative, rather than industrial made small style, use of modern PC and instrumentation capability is also conspicuous by its absence.

Standard small CNC router moving gantry layout is fine for woodworking and co-ordinate drilling but stiffness limitations mean that its never going to be very good with metal. Once upon a time small, usually hand operated, planers were common and considered effective metal removing devices. So consider using CNC router components with a fixed gantry and moving bed planer style. Should be stiff enough for metal working. The CNC end won't care if the bed or gantry moves but probably needs servo rather than stepper drive to shift the table at adequate speed. Three heads high speed spindle for milling, drilling head and planer tool carrier. Drilling and planer heads do the rough work of getting close to size, milling spindle gets it right. Warp speed capable cutters are relatively expensive for home shop use so its silly to use them to excess.

Expanding on the concept consider a fifth axis, with tail stock if need be, to do lathe type work. With modern probes we don't need sub tenth thou removal and re-fit capability. So long as its close the machine can figure its actual position and work from there. For most ME stuff I suspect a vertical lathe arrangement would be appropriate anyway. Long stock? Hole in the middle of bed'n bench for up to inch is diameter should suit.

Makes a big investment seem bigger as its a one-time hit but could well be cheaper overall once the cost of piecemeal assembly of a full shop is added up. I refuse to add up what I've spent over the years!

Clive