Conundrum:

[steve_g]

Conundrum:
Ever since I got my Bot back in 06 I have used double stick tape as my hold down method... Ever since working on the "Router Bit Basics" article, I have been trying to get my chipload right. Doing this has increased my thrust loads, consequently I'm seeing enough failures that I'm experimenting with things I should have done as a beginning novice... Like "tabs". Where I'm running into issues is when cutting with an "Onion skin" strategy. On the second or conventional pass, I want the initial depth to be full depth and just skim the last 10-15 thousandths off the perimeter and eliminate any water marks from previous step-downs... this however wipes out any tabs that have been programmed into the path... I'm curious how others are handling the tab / onionskin mix.

Thanks! SG

[tmerrill]

Steve,

The Vectric products will remember the tab locations and calculate the final cutout toolpath accordingly.

Here is an example. Set up you initial cutout toolpath with onion skin and tabs and calculate it. Now, with the same vector selected set up another profile toolpath and the minute you click the box to Add Tabs they should appear in the same locations. Now recalculate that toolpath.

Tim

[steve_g]

Tim
That's' what I'm doing... but the second time I make the initial depth to be the full depth of the material and the tabs are gone... even though I can see the little marks on the tool path indicating that they are there.

SG

[Brady Watson]

I have been trying to get my chipload right. Doing this has increased my thrust loads, consequently I'm seeing enough failures that I'm experimenting with things I should have done as a beginning novice...

Steve - Sometimes you have to violate ideal chipload numbers in order to get around less than ideal hold down solutions. If you lighten up your chipload, then you'll gain back your hold down. So you sacrifice a few feet of cutting length in order to keep the parts held down...so what? Tooling costs should be built into the job so that if you HAVE to run super light on the chipload to get the job out the door, you are covered. If not, you put the extra bit in your spares/rainy day box and move on to the next job.

-B

[tmerrill]

Steve,

If you mean by Initial Depth the Start Depth then yes, that will cut through the tabs. In the Vectric products the total depth of a cut is equal to the Start Depth plus Cut Depth, so in this case you see the tabs in the 2D toolpath but they are below the bottom of the material.

Do this instead:

Leave Start Depth set to 0.0, set Cut Depth for the depth of the cut you want, then Edit the tool and set Pass Depth to equal what you have set for Cut Depth. This will give you a single pass toolpath that will observe the tabs.

Tim

[steve_g]

Brady
I understand what you're saying... however I'm happier with my cut quality now. This may be due to the fact that I'm much more conscience of my cut direction and don't just accept the default, whatever it may be!

Tim
OK, that makes sense... I'll just define two bits to have two different depths of cut, that way I won't have to constantly be editing back and forth...

SG

[tmerrill]

Or use Toolpath Templates.

[steve_g]

Tim

I have to admit I have never used templates... sounds like it's time to investigate!

SG

[adrianm]

The toolpath templates make it a snap to set up. For 95% of my projects I use templates. No chance of forgetting things like ramps that way.

If you're using the latest versions of the software you can use the Edit Passes button to set the number of passes to 1 for the second toolpath. That way you don't need to change anything in the tool setup

[curtiss]

Two sided tape since 2006 ? That might be a record.

On say .75 thick materials, moderate size items, I like the spiral toolpath for a final cut.

I set the pass depth at .2 final depth at .8 / Use a profile "start point" on the "far side" of the material. Use a home position on the "far side" of the material.

With a spiral toolpath, the bit will follow the profile, and the z will constanly drop and cut .2 inches deep on each lap around. This continues to .8 when it makes the final lap at .8 inches deep.

The item will "gently break free" somewhere on the final lap which simply requires a little "push down" with an orange stick until the toolpath ends and the bit raises on the far side of your item. Might not be a beginner method but does not require 2x tape.