Convert FLA 100 to V Bearings?

[zeeway]

Well, they say the grass is always greener on the other side.

My FLA (Fine Line Automation) 100 works very well on flat work and v carving. I am starting to do a lot more 2-1/2 D carving projects, and my machine seems to bounce a lot at feed rates of about 100ipm in x/y and 20 ipm Z. I have tightened everything up, including the bearings on the ways, and the issue persists even with new cutters. If I slow it way down to 50 ipm or less, with a plunge rate of 5, everything is more or less okay, but that sure makes for a long cycle time.

So I am looking for ways to make my machine more rigid. I see that Mechmates and Joe's Hybrid CNC both use v bearings, with either a dual gantry (Mechmate) or a gantry that grabs on the backside (Joe's), so I am wondering if it is a good idea to redo my machine to incorporate both the v bearings and some version of a dual gantry. Would it also be effective to change the z slide for a K2 z slide?

Have any of you refitted a FLA 100 with v bearings? How do you like the redo? Or alternatively, those with v bearing machines, do you like them, or do you long for some other method?

Ahren or Nate, do you have any secret hardware for doing this?

Thanks,
Angie

[CNC Lurker]

What diameter is your bit and how deep is each plunge you are taking? Are you cutting the full depth or 1/4" at a time or what?

There are some chip bit calculators that some have posted that will help calculate the optimum speed and depth of cut for the bit. Maybe someone else who knows a bit more about it can add to this.

I know this doesn't directly answer your post, but just food for thought.

[zeeway]

Hi Paul,

Thanks for your reply. On roughing I am using a .25 inch ball end bit taking .125 inch depth of cut at a pass.

Angie

[ger21]

I am starting to do a lot more 2-1/2 D carving projects, and my machine seems to bounce a lot at feed rates of about 100ipm in x/y and 20 ipm Z.

Do you have a video showing what you're talking about?

If you grab the router by the collet, can you move it?

I'm wondering if it's really flex? My machine is wood, with skate bearings on pipe. The Z axis has enough flex, that I can move it about 1/16" each way if I push hard. But I routinely cut at 150ipm, and have my Z axis at 55ipm, with no problems at all.

[zeeway]

Hi Gerry,

Sorry no video. But when I grab it by the collet, it doesn't really move, but it kinda feels like it lfexes, if that makes sense.

Do you do 3-d work at those feed rates? If so what are your accel values?

Angie

[ger21]

My machine is a bit underpowered, so my X and Y are 10, and the Z is 7.

I just don't know what you really mean by "bounce".

[zeeway]

By "bounce", I mean that as the bit starts across a 2-1/2 D carving, it is okay on the flat portions...but when it starts on the actual contour with z moves, it jerks around and leaves little pock marks on the surface - this was at my normal feed rates of 100 ipm in x and y and 50 in z. Accel rates were set at 50 for x and y and 20 for Z. When I cut way back on feed rates and accel rates, the jerkiness and the resultant pock marks mostly (95%?) disappeared. From your post, sounds like I can up the feed rates, and keep the accel rates low, and it should work perhaps the same at a faster cycle time.

Thanks,
Angie

[ger21]

If you're using Mach3, make sure your in CV mode, and all CV OPTIONS are turned off, both on the settings page, and in general config.
Try that first.

[zeeway]

Okay, Gerry...will try that.

Thanks,
Angie