10 to 12 years ago I conceived the idea of building my own CNC machines for Foam cutting and routing, and after moving to Europe for a few years and then career and the lack I space I bench the idea, and kept buying parts for the machines. about 4 weeks back a friend and myself where chatting and he said he has space by him lets build it. The Foam CNC requirements changed over the years, so the CNC Foam cutter changed as well, but the CNC router, was still a go. I’m not sure what the feeling is among local modellers is with regards to DIY CNC, but I will take some pictures along the way. Feel free to ask questions and I will answer them as best I can.
We started assembling the machine now having framed the table and put the Gantry base on. All the alignment is perfect. This is all lying on the gravity feed Foam cutter we made for Long wings a little while back.
I am using for the some,
12mm Linear Motion Bearing like this:
20mm Linear Flang Bearings like this:
You should be able to cut pretty much any soft material and non-ferrous metal, with cutter head cooling (via compressed air) and multiple passes. Nylon block may melt and clog the cutter if cooling is not applied at all. The stiffer the machine at the end of the day the harder the material you should be able to cut. I would stop at Aluminium though.
I was asked about costs (in ZAR terms divide by 10 for the USD price)
Price wise in this build would be a little misleading, because I have purchased many parts over a few years, that said though I can compile a list of the items at the prices I can source the goods at. Many are imported and some are bought Locally, so the prices would exclude shipping.
MDF, Pine and plywood R1100 Thus far
Sundry screws and Adhesives R300
20mm Flange Linear Bearing X 4 R640
12mm Linear Motion Bearing X 8 R560
8mm Metal Pillow Block Bearing with Flange X 3 R210
25mm Bearing CNC Aluminium Rail Linear Motion Shaft Support Series Slide X2 R160
20mm Linear Rail Shaft Support SHF Series X 4 R240
Stepper Motor Flexible Coupler X R250
12mm TR12 by 3D Trapezoidal Ballscrew / lead screws Acme 1250mm, 665mm, 350mm £1.80 per 100mm available locally but only to 1000mm +- R600, So I import the long ones. Last time shipping was £78 (available from TheScrewMan in Pretoria)
12mm Nylon nuts & 12mm flanged Brass Nut X 3 (12×3 Trapezoidal I have the Tap for these so I make them myself) works out to about R500 for the 6 pieces, beats R328 each locally
NEMA 23 Dual Shaft Stepper Motors 270oz – 300oz Depends on the supplier but R1500 MAX. These are Wantai Stepper Motors
As above with Stepper and Driver board And Power Supply R2500 MAX (I use a HobbyCnc board by Dave Rigotti)
20mm linear bearing Rod 2500mm
12mm Linear bearing Rod 665mm R1900 locally for this and the above together
Seems the local Supplier I got the rod from doesn’t list it on the Site any more. These Induction Harden rods are available from HoningCraft In Johannesburg
In South African Terms less the Shipping on the products the machine costs About R7800, with R2000 max for Shipping thus extra So R9800. price will increase if you want a ground Lead screw, by about R3000 to R6000. So serious Ouch on the 3 “improvements”
I sourced all the bearings from the suppliers I have build a relationship with over the years. It comes directly from China so the lead time is round 4 weeks. I’m sure if convinced, and there is a need, I could draw up a set of plans and a kit to manufacture the Machine. I have already been asked when I am building number 2 and 3.
regarding the Cutter. You can put anything on it you would like, that can cut. You could even Buy a Laser for it, if you protect the top from getting cut into. I will try my Dremel, An AEG Router / Pencil Grinder and I am thinking of putting in a brushless EDF motor in it. Mainly because of the Noise factor. You can also buy an actual CNC Spindle Motor for £60 excl. shipping from ebay.
Ok, had a little time off to get some work done on the backlash nuts, turned them on the Unimat DB/SL. Clearly the vintage of the Lathe shows in the pictures, because some of the cuts are not smooth, this is mainly because the lathe is not stiff enough and the motor is not strong enough, but fear not I am upgrading this to 12V more on that in a Later Tutorial.
I made the Nuts myself because at R320 each it made more sense to buy the tap for R470 and make as many as I wanted. here are my first three.
The tap was imported from Kevin Marchant owner of MarchantDice in the UK, either email him www.worldofcnc.om or contact him via eBay you should also be able to source it directly from China too, but Kevin has shipped me loads of stuff and I recommend his services and products
http://www.ebay.co.uk/itm/Trapezoidal-T … 337fe76730
Simple way to line up to brass, is to put the bar on the cross feed and tighten the chuck
then the LONG turning time starts
When I got to this point I filed a flat on the one piece and Tapped the screw and parted the end off
Does it work, here is the end result. it just need 4 holes drilled for holding it in place. two more to go
Steppers arrive today so on with the build
The X-axis is fitted. I made a jig to grind down the ends of the lead screws to 8mm which is the meat left just after you remove the thread part of the screw. One end is supported by a flange bearing with two grub screws and the other end is supported by the stepper motor and the compensation “goody”, yes that is a technical term 😆
Usually, the lead screw is supported on one end by a Fixed bearing (usually a Thrust Bearing) and the other a floating bearing on long screws and nice expensive ground lead screws. I only have one fixed bearing & Nope it’s not a thrust Bearing. This other bearing has yet to be Fitted. I will be using a 12mm Flange bearing for this purpose
I hadn’t added to the machine for quite a while so, I decided that it would be best to take it home and complete it at leisure. So First things first I started to build a Bearing block that holds the bearing for the Y & Z axis. I did it this way round because it less complicated and takes up less space, allowing more free movement of that axis. I also decided to make the parts from 12mm Plexiglas. once the machine is running I will as I have said before build another machine and then make it from Aluminium, so I will part out pieces in this machine for aluminium as I go along. I must say the Perpex is very nice, but surprising more pain in the butt to work with
Some more pictures, some are out of order so you need to check them. Anyway I used the trust old Unimat to cut the perspex to size. Definitely must fit that 12v motor I have to the Machine.
I never worked off a plan as such, to me these are the things that made sense to me to maximise the travel on the relevant axis’. It could definitely be done different with a stronger material Like aluminium
It seems that after having started this project many MOONS it’s finally coming to an end. Bar two lead Nuts (that go under the machine) need to be fitted, then the hardware side of the machine is complete. I will do the wiring and then it’s down the troubleshooting and getting it going, as soon as I have sorted out my house building and the PC
I have learnt a lot from this machine, and I will definitely be building another machine. I have already started ordering the parts to complete the foam cutter I started even before this one. While this machine is not 100% yet, I will update it with the electronics side soon. So keep and eye on this tutorial