Accurate Strong Gantry

**vargai** · 27-11-2014

Hi,
Incredibly detailed piece, very nice done.
The patterns are so sharp even in a mm .
What sort of material is it?

**vargai** · 28-11-2014

Originally Posted by silyavski

What i meant was, lets say it in other words- that if you don't have a machine shop at home or access to one, it seems more easy to do it with 2 motors, cause no money will be saved buying all that stuff from internet, postage, custom bores and so, plus later the very careful alignment. It could pay off if 1 servo instead of 2, money wise, but like you say Dean, servo is the good way to go with 2 motors. So at the end is just a personal preference. I simply don't like that long belts. In reality my small machine works in a lot of dust and never had any problem with the belts.

I red about dual drive on other sites and heard of several complaints- homing, running faiulre, etc. I also do not say it is wrong rather say it is an elegant solution but like anything it can get out of order.
If it is happens I can not find on heaven and earth in Hungary expert to repair or without being robbed.
So that is way I get closer to the things from the simple side and it will be a future development.

**JAZZCNC** · 28-11-2014

Originally Posted by vargai

Hi,
Incredibly detailed piece, very nice done.
The patterns are so sharp even in a mm .
What sort of material is it?

Aluminium 6082T6 cut with a simple 90degree spot drill nothing fancy.

Regards the belts and cutting conditions let me just say my machine 99% of the time it's been built has cut nothing but aluminium and the belts are completely uncovered being exposed to millions of flying sharp and very hot chips so are working in the worst enviroment and I've only ever had to replace two belts. This wasn't because of wear it was because I left a pulley loose which fell off after adjustments for a bracket for sensing belt breakage. (It was a very good real world test of my new belt E-stop.!

)
The other I trapped and damaged moving the machine due to not being covered. (So do as I say, not do as I DO, and cover your belts from the start other wise it never get done.!!)

**vargai** · 28-11-2014

at first sight thought painted wooden, but it cannot be done so sharp

**JAZZCNC** · 28-11-2014

Originally Posted by vargai

at first sight thought painted wooden, but it cannot be done so sharp

Yes probably because of poor video done with phone camera.! . . .Looks much better in real life and very shiny.

**Sven** · 28-11-2014

I have a similar set up just 90 mm wider. I would not do it again, setting it up without backlash is a pain.

Next one wil have a dual stepper, a leadshine easy servo, which is a stepper with encoder.

In this design I would box up the 4 beams so they become one, that is much stiffer.

**vargai** · 28-11-2014

Hi Sven,

Yes , the four box should be redesigned somehow, originally I wanted to tie the boxes with 3, 4 plates to work together after placing the
ball screw
What does the similar exactly-how did you make the synchronising?
Nothing is written in stone-just thought to skip the step with stepper and make higher grade machine but do not know too much about stepper.
I hear of lead shine and certainly stepper technology becomes better so if there is an reliable option instead the more expensive servo why not.
My friend who is member of a CNC DIY group made a 5axis machine with steppers for woodwork upon order.
They mates from the group says: everything is ok but why did not you use servos.
Probably stepper is undervalued in public awareness.

**Sven** · 28-11-2014

I have the second setup in your diagram, with the motor in the middle. It is impossible to get enough tension in the belt without putting big loads in the spindle bearings.
I added a guide to push the middle section of the belt above the motor to reduce floppiness. still not good.

**vargai** · 28-11-2014

So you are a doubter of using belt based on your experience.
Others have well working machine with this set up.
I am just an outsider at the moment, the best thing is to ask Dean to show a short video of a working machine .
Would you be so kind to do it, Dean?

**vargai** · 28-11-2014

Originally Posted by Sven

I have the second set up in your diagram, with the motor in the middle. It is impossible to get enough tension in the belt without putting big loads in the spindle bearings.
I added a guide to push the middle section of the belt above the motor to reduce floppiness. still not good.

Let me know about the data bearing type, size, belt type, size and experienced phenomenon
angular bearing on drive side it can bear more load than single row
20/10 ball screw with Dia 15 machined end -bearing can hold let's say max 1 Tons here