Max Safe Z Height?

[DanThomson]

What is the highest safe Z height?

I am finding that anything above 2" doesn't seem to work, when the Z makes it second slow plunge and reaches 2" the machine errors.
Is it possible to set the max safe Z height to anything above 2".

I ask because I cut a lot of 3D files (3"-4" tall) and would like to zero to the table, however without being able to set the safe Z height about 2" I am not able to zero to the table and then clear the material.
Am I going about this wrong, or is there a simple setting to allow higher safe Z heights?

[adrianm]

Should be able to. I work with my safe Z at 125mm which is 5 inches and have no issues with the z setting routine.

The Z routine changed recently and in the older version it uses a safez set during the setup process stored in myvars. The newer ones uses the actual safez set on the cutter tab.

If you've got the older version it may be worth checking the values in the setup routine.

[Brady Watson]

Dan,
3" material + 3" long bit + 2" safe Z = 8", which just so happens to be the max stroke on a PRS.

You should be able to get away with a .5 to 1" safe Z without any issues. Why is the 2" number necessary?

-B

[DanThomson]

Brady,

Basically I am thinking along the lines of wanting to for example cut some 2.5" thick material.
I would like to zero to the table, then have the safe Z be above the material (say 2.75" or so) so that I can then move the bit over the material and zero my X and Y and proceed to machine the part.

Am I thinking about this in the wrong way?

[Brady Watson]

If your reference for ALL toolpaths is the bed, then the 2.75" value would be fine with 2.5" material. BUT if you have other toolpaths that reference the top of the material block as your Zzero point, then I can see where there might be some issues and confusion.

Keep in mind that it is not outside the realm of possibility to zero to the bed of the machine, and then move the Z your material thickness (let's say 2.5" - MZ,2.5) and then ZZ to effectively zero the Z to the top of the block. Where this is useful, and more accurate than any other method, is when you are cutting a relief and you lose all of your ambient area to zero the Z with the plate. Just be sure to use the plate in the same exact spot between toolpaths to be consistent. A pencil mark on the table does the trick.

-B

[blackhawk]

Dan - You mention that you are getting an error for any Z height above 2". Type in VL on the Shopbot console and check your settings for the "High Z Limit". I am guessing it is set on 2 and you have limit checking turned on. If you can physically move your Z carriage higher, there is no reason that you can't bump up this setting.

[DanThomson]

Brady-Yes, I am talking about jobs that ALL the toolpaths will be referenced form the table but I am unable to set the safe Z height to anything higher than 2"

Brad- I checked my table limits and my max Z is set to 8" and low Z set to -2", I tried increasing my low Z to -6" with no luck.

Basically the zeroing routine prohibits the Z axis from plunging further than 2" without contacting the plate on the second slow plunge, and I get a Zeroing Failed message.

[bill.young]

If you've installed everything in the default location, use the ShopBot editor to open the zzero.sbp file which is on your C drive in the SBPARTS folder. Look around line 110 and you should see a line that says:

&little_plunge = %(3) - 2

Just change the "2" to a larger number..like:

&little_plunge = %(3) - 4

then save the file and you should be good to go.

[DanThomson]

Thanks Bill!

I went in and edited the Zzero file and all is well.

[bill.young]

Glad it worked.