Move Speed - Help me understand what is going on

[Guillemot]

I was having a hell of a time cutting a wood piece involving thin sections of wood (see image - the light color ring in front).

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I tried a couple different milling strategies to deal with grain splitting issues and glitches. I found a system that did will with the grain, but could not eliminate the glitches.

The part would be cutting fine, and then the milling would stop, router would shut down and then the computer would lock up and crash.

I tried running the program free-run without the router on and it worked fine. I then tried milling some pink foam. I couldn't make it through without the system locking up several times. Cutting wood was hopeless, with continuous and frequent locking and crashing.

During the free-run, router off test I noticed that the machine rattled a lot on some sections of the operation as if it was rapidly starting and stopping.

This operation was basically cutting a smooth, sweeping oval, which by my logic should allow a smooth motion for the tool.

Based on the grain chipping issues I was getting, I assumed a slow feed speed would be best, but after hearing the rattling motion, I chose to increase the move speed.

The faster speed allowed the program to run smoothly all the way through without any glitches or computer crashing.

So, why does the faster speed allow the program to run without problems, where the slow speed cause the machine to lockup and the computer to crash.

Below is an edited video of the machining process playing back at 3x speed. Actual move speed was 4 in/sec.


https://www.facebook.com/GuillemotKayaks/videos/10153885770373474

[bobmoore]

Can't really understand what you are doing here. Is that a new machine? Have you cut other parts successfully? What size part are you cutting and what are your settings? What kind of machine do you have. Welcome to the forum by the way. I have always admired your boats.

[Guillemot]

I'm relatively new to all of this with a 48" Buddy (PRSstandard BT48 ) purchase last winter. I bought the tool to make these seats:

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In this case I was trying something completely new for me. The part shown in the photo below is about 4" long x 2" wide with a wall thickness of 1/16". Made from a block of curly maple. It is a coaming for a kayak display model.

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Router speed 16,000, Feed Rate 4 in/sec, depth/pass 0.09". When I experienced problems, I was running at 1 in/sec.

I have cut other thing such as the seats quite successfully, but have ongoing, intermittent issues with glitching and crashing and I'm just trying to get a better handle on whats going on.

I am trying to get a better understanding on why increasing the feed rate on this project improved the reliability running the program. My speculation at this point: at the low speed the servos don't generate enough torque to overcome the drag of the pushing the bit through the material on the short moves required to create the curve thus the tool location gets messed up and the system gets confused. But I may be totally off base.