[boydage]

My build is version...... maybe 5? This machine started as a timber frame. One Nema 23 for the Y. Absolutely totally loose and gained nothing except for starting a hobby that has been awesome. Anyways I am at a point I need some help to get over some of the build hurdles and mistakes I must have made. Currently the machine is running a 4.5Kw 3 phase spindle. I bought a heap of linear rails years ago. Cost me about $1.5k all up. Including the SBR30.

I use the machine for my small joinery business - this is the reason for the vices all in a long row. And I use it for alloy components. I was lucky enough to import a bunch of vices that are ok..... some needed shimming the manufacturing process they sit 0.5mm lower or higher. So needed setting up to align them.

The frame is welded 6mm thick box section sizes 100*100, 152*76mm and some other pieces of box section I had. Nothing under a 4mm wall thickness. I have filled the main rails with sand and some of the verticle. I cross braced the nana out of the frame. Its level and dyna bolted into the floor.

The T table is 1100*900*100mm solid cast. About 750kg (guess cant remember)

The gantry sides are cut out of 25mm mild steel. And have the old alloy bracing screwed to it because I liked it. This was an upgrade. The rear of the gantry is timber in the centre. With 100/70/8mm unequal mild steel angle screwed deep into the timber. Also bolted to the side pieces. Gantry is sitting on several SBR30 blocks. The front of the gantry holding the X is 6mm alloy. Also screwed into the timber. The X is running on 2 x SBR20 linear rails.

The Y is run by 2 closed loop Nema 34s on 2600mm 2510 screws. The X is also a Closed Nema 34 1400mm 2510 screw. The Z is a 1605 screw.

The Z. Is made out of 16mm thick alloy rear, and spindle mount on front. The sides are braced with 6mm alloy screwed onto the sides. Using SBR20 linear rails. Has about a 280mm travel. This I think I need to rebuild.

The machine is reasonably heavy. Level. And machines timber like butter. Alloy goes ok. Just ok but awesome results provided I program correctly. Ok. I am in total understanding that the round linear rails are ****e. I did think that by building the gantry that this would be minimilised.

My problem and I have tried to address this before. If I use a 6mm endmill, or a 14mm endmill. I can climb or conventional mill cut alloy no problem. If I cut a large circle (or small) as the endmill travels around the circle, it will vibrate the whole gantry in a low resolution brrrrrp vibration. Only in certain directions and worst when both X and Y are running together (on a curve) Strange though, on a test today, the machine actually performed better when climb cutting. It is very apparent that there is something fundamentally wrong with my design if this even happens using a tiny 6mm endmill??? Now I can swing off the spindle and its tight. Real solid. Obviously if I put a dial indocator on it I can see movement. But nothing loose. I think the Z is not heavy enough. I think I need to get rid of the round rails. Dont get me wrong this machine is pretty good. I just cringe, everytime I hear the resonance. It will show in the cut too.

So heres the thing. Do I rebuild a whole X axis assy. And a whole new Z axis assy. And bolt it onto the front of the gantry? I can also remove the round SBR30 rails the Y is sitting on too. But in all honestly? I am certain the main issue is in the Z. Resonating. I could do that. Build a new assembly. Take the time. And the change over would be rapid. But gee. I just dont want to waste my time. So. Please. Some help advice? Ive taken pics this time.