[Lbrown]

Hi, I've had an Pro 4896 by AVID CNC for about a year now and, becuase I like to tinker, I've been trying to come up with ideas to further improve on it's mass and rigidity. My plan is 2 fold... #1 is attach full pieces of MDF to all four sides of the leg kit to help further brace it much like the spoil board bolted to the top helps brace it. This will also serve to add more mass (wieght) to the machine then just adding diagonal strapping. #2 is to add some sort of craddle to the framing under the spoilboard and then place 4" x 48" pvc tubes filled with concrete (they should be 50# each) to help add wieght and resist table jerkiness, shaking, vibration, etc.... Any thoughts/opinions on these two ideas?

[Jim Dawson]

I think your ideas are sound. Any stiffening should be of some help. You solution is inexpensive and simple, let us know how it works out.

[peteeng]

Hi LB - Can you screw the machine to the floor? That makes it the weight of the earth... Peter

[subnoize]

Yeah, already tried all that. It dampens the ringing but not flex.

#1 source of the flexing is where the linear rails are mounted to the 8020

#2 source is the risers and the attach points to the gantry


Last thing to remember, Don't add weight to the gantry. Remove as much weight from the gantry as you can. One of my early dust collection and tool magazines was on the gantry. I had all sorts of problems with flex. And I mean really, really bad flex. It also destroys your bearings. That gantry is already heavy as its shipped.

I am now to the point where I quit trying to fix the flex and have just accepted the ringing. It is the con to that pro of a super cheap, monster sized machine.

20% of the published speed of the machine not just improves the effects of flex and ringing but it also accuracy. That rack and pinion doesn't perform well with high acceleration. Another price compromise.

My favorite saying is my machine has a "SPRING in its STEP!"

CNC jokes