slow down cnc movement before otherway move

[prettygoodnotbad]

We got a new CNC in the shop with a controller that can run a heck of a lot faster than our previous model. Which is exciting but now I'm realizing that once I reach certain speeds direction changes are pretty violent and I end up shaking the machine out of its coordinate system.

So I'm now making sure to use feed optimization on everything so that tight corners slow down.

What I'm not sure about is, in situations like in a parallel operation where the tool goes back and forth and turns around 180, can I get it to slow down before it moves over and goes back the other way?

I attached an f3d as example of what I mean, where feed optimization doesn't seem to work.

Maybe this is a situation where settings in the CNC should take care of slowing it down before the linking move? 

[seth.madore]

I'm not seeing a file attached to your post, could you try again (you can't attach files through email).

One suggestion is to use "Smooth" transition types. This would create an arc move (not always, it's dependent on direction of travel), which would make the reversal a bit smoother.

In addition, are there any control options (such as Nano Smoothing) that improve the machine behavior?

How fast are we going?

[prettygoodnotbad]

ok it looks like its in the original post now, dunno why but this is the second time this happens when I add a file to a post. 😕

[seth.madore]

Okay, I see that in this toolpath, "Smooth" has no effect of creating an arc move. What is your machine and control?

[prettygoodnotbad]

The machine is a Legacy Woodworking Maverick 3x5 pro :

https://lwmcnc.com/maverick-3x5-pro-cnc-router/#foogallery-29818/i:2401

The controller is a custom product they developed specifically for this machine.

[RA_Nouveau]

Hello the shop I am at has one of these also. Hopefully you have the newer updated model. I found their tech support less then helpful.

Did you ever figure this out? The issue with this machine is the thing flexes when you change direction so your only options are to run really slowly, really slow down the acceleration, or what I came here for seeing if I can change the feed compensation to make it not jerk as much.

[prettygoodnotbad]

@RA_Nouveau unfortunately not, I've just been going with it, which is not really an ideal solution, so if you come up with something I'd love to hear about it. I've had a fair few issues with these machines over the years that i have just learned to work around. 

[RA_Nouveau]

It's just a sloppy machine. I'd be curious your experiences as well?

The goal is to replace this with something better. It's designed for making kitchen cabinets. End of story. I will tell you this student shop gets lots of visitors from industry and other schools. The new director and I who inherited this machine have nothing good to say about the company, and the complete lack of competent support. I'm glad to say this on a site which will get more SEO. I actually offered to send them the perfected Mach3 profile for their own machine so someone would not have to go through the year of fine tuning I did and they completely ignored me. Anyone else reading this, do not buy their products.

It's in a student shop so we slowed it down which helped on a few things. We reduced the Acceleration to 14 and the top speed to 400IPM. It's to flexible to cut more then at 150 IPM anyway. For precision less then 50. This slot I did at 20 and still it went wide by 10 thou. Again accepting the machine we have.

For detail work I remove the dust hood which weighs 15 pounds that helps a bit. We moved the spindle up in the clamps which also helped. We're limited to that because we do have people who want to use the A axis, and the dust hood clamps on the spindle. Which makes the nod worse also. Trammed it without the hood, everyone else can deal with it being a little out, since it won't matter.

We put wood under the gaps that support the spoilboards and that helped with the surface staying to plane.

It's like a car alignment in that it's going to get out of tram and square just with regular use so check it q 3 mo. It's bunch of screws in slightly slotted holes. It happens. Cam bolts like on a car would have been better.

The bottom Y bearing gets caked with sawdust, but you have to take the alignment screws out to clean it so then you need to re-tram.

It helps to sneak up on your final dimension so the last few cuts there is minimal load. So 2D contour is your friend when it matters. That's how I am doing tenons. Accept you will have to sand the last couple thou on most of your precision parts.

Best of luck to you.