Stell frame cnc 1500X1000. Adjustable table your opinion please

[ba99297]

Dean i made some corrections according to your advices. I am not sure i understood everything you said ( as my english are not excellent)
Let the photos talk


In order to go on with the plans, it would be good if somebody told me about Y and Z rails distances and distance between carriages of X axis. Finally i want your advice about X axis double preloaded ballnuts

Thanks

Vagelis

[Boyan Silyavski]

Hi Vagelis,

Normally people here on the forum use ball nuts and ballscrews bought from China. The most recommended vendors are Fred from BST Automation/aliexpress/ and Chai from linearmotionbearings /ebay/. BST for sure can provide the double ball nuts , i assume Chai also. No reason to buy 2 single, but depends on the design. On Jonathans build i asked about the spacers spring washers, he pointed from where, so the info should be somewhere there. Their prices are very similar, both do perfect machining, so really its up to you.

To resume various advices for my builds, that i received mainly from Dean and Jonathan , for your size machine
if stepper driven 1:1 with short belts and pulleys on all axis:
-short belt HDT5 15 size, if heavy gantry maybe 25 size, pulleys 20t
-z 1605 screw
-gantry 1610 screw if mainly woodworking for faster speeds ,1605 if mainly aluminum
-long axis 2010 or 2005 respectively, i see no reason to go to 25xx size

the following is my personal understanding:

-gantry supports ~ 30cm/normal/ to 40cm/heavy duty/ spacing of the bearing blocks , this including the blocks-
-gantry , depends on the design, but ~20cm spacing vertical and 25 horisontal i see as minimum./ including bearings./ 30 and 30 will make very strong machine/

PS. Dont be cheap and buy Hiwin or cheaper Chinese square rails not round

[JAZZCNC]

Dean i made some corrections according to your advices. I am not sure i understood everything you said ( as my english are not excellent)
Let the photos talk

Yes you have it correct but you can afford to make the triangles little smaller to avoid interfering with material, Or shape them to do same thing.

Now regards the Gantry bearing spacing then 300mm for X axis(long axis) and 200-250mm for Y axis will be fine for most work. Like Silyavski says the wider the more stable but the figures I've given I know work fine esp when using profiled linear bearings.

Regards the twinball nuts then I never use twin ballnuts so can't help here and to be honest I don't see the need for a router type machine. They are Ok for a Milling machines that need to hold tight tolerances but in this case I think your just adding extra expense and work, along with extra maintenance for gains that you don't really need or will probably never see due to other weakness in the machine.?

Remember the machine is only good has it's weakest link and at this size then a single ballnut won't be the weak link so any gains won't be fully seen and the gains you'll get from 2 nuts over 1 nut will be very small to start with and I honestly think you won't see any improvement worth the effort or expense.!!

Ballscrew sizes and pitch then

20mm Diameter 10mm pitch for X axis, don't go with 5mm pitch even if aluminium just change the gearing on the pulleys. Don't use 25mm diameter far to large.!
16mm Diameter 10mm pitch for Y axis, don't go with 5mm pitch even if aluminium just change the gearing on the pulleys. Can use 20mm if you like thou won't accelerate quite has fast 16mm but it will still be plenty good enough and that bit less likely to whip.
16mm diameter 5mm pitch for Z axis.