First Proper CNC Router

[diycnc]

Thanks for the advice. I will defiantly use fixed supports on both ends of the ball screw. it will add no extra cost, and as JAZZCNC suggests will improve rigidity.

I have been working through some of the final details of the design. major changes since last time are i have added the motors belts and pulleys.

Y axis motor is attached to the gantry end plate (which is now 15mm thick, 10mm just look to flimsy!) with 4 50mm long spacers. 1:1 drive to the screw is achieved with two 15 tooth htd 5 pulleys and 15mm wide belt. Can anyone suggest if this is enough teeth on the pulley, or point me towards the datasheets and formulas to work it out. i assume there is a max load per tooth to keep below.


X axis motors is attached the base frame with a long 5mm thick steel plate (I think i need to added a stiffener to this, looks very long and floppy at the moment!). The motor hangs down quite far to avoid the piece of extrusion connecting the bottom of the gantry end plates. I tried removing this extrusion, and replaced it with two small plates to connect the ball nut to the end plates, but a little FEA showed this was a very bad idea! The long end plates twist allot!!
1:1 drive to screw again with 15 tooth pulleys. I can increase to bigger pulleys here if needed.
Larger taper lock pulleys and 15mm wide belt are used to connect the two screws. I will size the pulleys later to suit the available belt length and tensioner adjustment. Belt tensioner will just be couple of bearing on bolt in a slot, no need for anything complicated here.


Next thing to do is add all nuts and bolts to the model to make sure nothing clashes!

I also managed to pick up a used kress 1050 for little over £100. Would rather have one of the Chinese water cooled ones that everyone else uses, but at 300+ they are pricey. If i dont like the Kress i can always sell it on and probably get back all my money anyways.