Still No Solution...Help me please! :)

[sevans]

Hello All. Check out the quality of this V Groove. I've posted this before but still have not solution. Anybody got thoughts? Many thanks for looking! -Sarah Evansphoto.JPG

[srwtlc]

Hi Sarah,

Assuming that your machine is mechanically sound, attach the file for us to take a look at. Could the chosen font be of poor quality? Meaning that it may have a jagged outline that can't be seen until you zoom in on it. Does it have many nodes instead of just a few (in node edit mode)?

Is the material held securely or is it vibrating slightly under the cutting forces.

Cutter quality. Dull, not exactly the angle degree that it should be.

Worn collet.

Is that blue foam? How's the cut in another material?

[dlcw]

Hi Sarah,

Assuming that your machine is mechanically sound, attach the file for us to take a look at. Could the chosen font be of poor quality? Meaning that it may have a jagged outline that can't be seen until you zoom in on it. Does it have many nodes instead of just a few (in node edit mode)?

Is the material held securely or is it vibrating slightly under the cutting forces.

Cutter quality. Dull, not exactly the angle degree that it should be.

Worn collet.

Is that blue foam? How's the cut in another material?

I would be looking closely at the material vibrating while being cut. Does every letter show the same characteristics? If so, that would lead me to possible material hold down.

Try some MDF to see how that cuts.

[gene]

are you using a router or spindle? if its a spindle id the collet locked in the nut before its put on the spindle?

[sevans]

yes, of course.

[sevans]

I gotta tell you, I just can't see how it could be vibrating. You can barely pull it off the table after you turn the vacs off.

[sevans]

Are there physical indications of a worn collet? Something in particular I can do/see to tell if it is worn?

[Chuck Keysor]

Sarah, how large are those letters? And what cutting speeds are you running at (Inches per second)?

The smaller the letters, the slower the IPS seems to be for me to keep the vibrations down with my heavy 5hp Columbo spindle. Just watch your machine as it is reversing directions, it is really quite amazing to see this huge weight of the spindle getting jerked this way, then instantly being yanked that way. If everything is not tight and solid, it is easy to see how your entire spindle bit assembly would be vibrating after each instantaneous direction change!

For my finest letters, 1/4 high, 1IPS to 1.5 IPS is where I usually run. Someone else posted the other day, running WAY slower than I am in order to get clean results.

And I was not even able to experiment on this level until I had tried a couple of other brands of bits. In my case, I hadn't needed to do any added fixing, just figure out how fast I could run (IPS) before I had pushed the shakiness of my machine too far!

Chuck

[sevans]

That does make sense. It is jerky for sure. These letters are 1.5" or so in height. I used a 120 degree her saf bit and fed it at 1.2. Spindle 18000 rpm's. how slow can you feed? Or should I?

[bill_l]

Sarah,

If I understand, you're feed is 1.2 ips? If so, slow it down and cut your spindle speed back. When carving letters I use the 90 degree her saf and use a feed of .5 to .75 ips feed and almost never exceed 10-12K rpm on the spindle. If the letters are really small I move slower still.

By running some tests you can find the "sweet spot" that will net the best results.

Bill