CNC technic

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Details of mechanical drawings

Details of cabling / wiring schematics

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Photos of Claude Festin machine.

In Reunion island,
it is summer...

Note the vat around the machine, to recover coolant.

  Above, Claude had get a long belt made 'on demand' and have modified X transmission. With two sprockets and his thick aluminium plate, the second sprocket was too far outside.
He have used trapezoidal threaded rods, with a pitch of 2mm. So he had modified the transmission ratio. And now he have replaced the trapezoidal screws by ballscrews (not on photos).


Drawings of the machine 3Dcoup are derived from my experience with the machine 'Otocoup'.
3Dcoup have a working area of 500 mm x 940 mm x 190 mm (20" x 37" x 7.5")
Overall dimensions are 1040 mm x 1300 mm x 800 mm.
It was studied to be able to machine aluminium parts, which is not possible with 'Otocoup' machine
Carrying movement is done with standard M8 screws. Experience i have with that system on Otocoup Z axis being positive, i've generalised that principle. With that ordinary screws, efficiency is bad (fromm 20 to 25%), and this is why high torque steppers are required, as i recommend (2.6V, 2A bipolar 6.2 kg.cm), to be able to turn screws (Transmission does multiply screw speed, not reduce it !).
My aim was to realise, with 'Coquery' technic based upon rollers ball bearings, a machine as stiff as possible, while maintaining the inherent simplicity of this design. Then the machine is considerably reinforced if compared to an 'Otocoup' machine, a lot of bearings are doubled, angles have been reinforced, beam support screw have also been reinforced.
A lot of people are doubtful about ordinary screw transmissions, particularly because it is difficult to go fast.
In reality, it is mainly related to your electronic board and software quality. With a good board, you can go up to 10 rotations per second on stepper, which gives 15 rotations per second on screw, so a carrying speed of 19 mm/sec.(1.14 m/min, 45 inch/min). It is way sufficient for most uses.
It is fairly possible to use trapezoïdal screws, of much better efficiency and precision, but they are more difficult to find, more costly, and you are obliged to create a more complex containment box for the nut and modify sprocket and belt size. Though, that will allow you to increase the Y range up to 1 meter (increase machine length by 80 mm).
I've not realised myself this machine, but others have done with few modifications to my drawings.
I will not give any technical support, except for the very first one who will finish the machine !
These plans are offered for free and i don't guaranty anything. Read carefully the chapter about safety.
These plans are supplied for amateur use, excluding any commercial use. They cannot be copied nor rediffused. I consider it is in the general interest to come back on the Internet site to get the last version.
Beware of electrical parts. You must be aware of what you are doing.
I ask to every builder to register, in order to maintain a minimum follow-up of the evolution. I will not do any commercial use of the builders list.
Please inform about mistakes and improvements, and send me photos.
So, good luck and please inform ! That plans and site represent a significant amount of work and i will be happy to have some feedback.See Drawings of the mechanic, PDF format, 0.8 Mo, 9 sheets.
And the 'Z' carriage drawing
and CABLING schematics, 0.9 Mo, 9 sheets

Rev. 16 aug 2003 : First diffusion
Rev. 17 aug 2003 : Add cable-carrying chains
Rev. 20 sep 2003 : Transmission first stage with timing belts, corrections bars A,B, creation bar I, Option only one stepper on X axis.
Rev. 28 sep. 2003 : Correction mistake on router position and associated parts
Rev. 12 oct. 2003 : Added terminals on electrical box. Layout of electrical box
Rev. 25 oct. 2003 : Modification of transversal beam reinforcment
Rev. 25 oct. 2003 : Modifs in electrical diagram. Modifs in electrical box construction layout.
Rev. 01 dec. 2003 : Added counterplate on transmission screw X, X'. Aspiration and cable support
Rev. 14 dec. 2003 : Alternatives : 'Long nose' router, Trapezoidal screw
Rev. 27 dec. 2003 : Correction of tubes for 'Z' carriage

Rev. 05 dec. 2004 : New version with transversal beam in steel. New licence allowing redistribution (cc by-nc-sa).

Source drawing files (file format Autocad12 DXF) : Drawings 3Dcoup

And for those who wish to design themselves, here is DXF file of Kress router, there is only to design a machine around it...

Details of the mechanical drawings :


Beam view
Side view
Top view

Parts cuts
Installation details

Beam assembly

For cabling / wiring schematic
see also page Cabling

Ensemble diagram
Electrical box schematic

Electrical BOM
Electrical box construction
Simplified schematic

Connectors panel
Limit switches

To write me :