zero from table

[ccwerks]

Could someone give me a quick run through of how the machine acts when using the table as the zero point and then milling to a specific thickness.

my issue.. Im cutting carbon fiber plate.1 inch thick. The plate is flat on the bottom and inconsistent on the top, in order to mill the top to the proper thickness Im wondering if using the table as a starting point and give it the required depth of cut will work. it seems completly backwards to me. any thoughts would be great.
Mark

[adrianm]

If you're using partworks/vcarve just do everything you would normally and set the zero to the table (in the software and on the 'bot).

The software handles all the calculations for you and it's no different to zeroing from the top of the material.

So if your material is 1" thick and you want to remove 0.1" leaving a uniform 0.9" you would set the material thickness to 1" and the toolpath to 0.1".

[ccwerks]

ok I get that ..... Im being asked for specific depths and Im taking 0.2 bites at a time.
so this 1 inch plate needs to be .625 the machine will figure this out? thrrough normal tool path?

[Kyle Stapleton]

Yes it will.
For an end thinkness of .625 type in z-.625= and it will cut what it needs to to get the .625 in your case it will read .375.

[Joe Porter]

http://forum.vectric.com/viewtopic.php?f=18&t=19905&p=141076&hilit=zero+to+the+table#p141076 Mark, this post on the Vectric Forum may help you especially the explanation by Paul Rowntree. There are no negative numbers...joe

[ccwerks]

thanks Joe. Im still not sure of it but did an air cut and it did act like i expected it to.
The next issue is how to divide up the cuts in to .0312 at a time passes over the material.

[adrianm]

Either set the depth on the tool in the tool database or click on the Edit Passes button in the toolpath.

[curtiss]

The dust from carbon fiber can be dangerous to your health, be careful....

[Chuck Keysor]

Today I needed to take some old Styrofoam which has a rough surface, and thickness it to an exact dimension. I did this once a long time ago, but normally I zero off the top and that works for what I am usually doing.

I couldn't recall how to cut to an exact thickness except that I needed to zero from the table surface. So I did a search through the old posts, and found this one. It answered my question of how to cut to a specific thickness.

However, it did bother me, that most everything I don't know how to do in Aspire, makes sense after I see what is supposed to be done. But in this case, the requirement of entering Z-desired end thickness really doesn't make any sense to me.

Next time Aspire is revised, wouldn't it be logical to make this function of thickness planing to a predetermined thickness more obvious? If someone selects the bed as the zero reference in the material set-up, having the pocketing data input window reflect the needed inputs in an obvious way would be an improvement.

I have attached an image of what is displayed now when performing the thickness planing function. The second image as a start, would seem to make this functionality more obvious and therefor more user friendly.
This is just a first pass stab, so more knowledgeable users could refine the variables while meeting the intention of making this function more obvious/self-documenting.

Thanks, Chuck

[adrianm]

You're overcomplicating it.

If you've got material that is 2.5" thick and you want to plane it down to 1" thick then you set the cut depth to 1.5" REGARDLESS of where the Z zero is set.

Aspire/VCarve does all the calculation when producing the code to ensure that what is left is nominally 1" thick.

The depth of cut is always based on thickness of material.

[Chuck Keysor]

Thanks Adrian for your reply. I remain confused. The piece of Styrofoam I have is a big 4 x 8 sheet, with a flat smooth back, and square cut sides. But the top surface is highly irregular. So I can't say what the thickness is. With what you have suggested that I need to do, I don't even know what thickness to input in the original Aspire diagram that I posted previously since the thickness is highly variable.

Doing a simulation using what Kyle Stapleton recommended for my crooked Styrofoam works. His directions do not require knowing what the starting thickness of the part is. You enter "0" for the start depth. And to get the finished thickness X, you enter z-X into the cut depth data field. Again, what Kyle Stapleton suggested to me doesn't make sense to me, but it DOES work.

I can't simulate what you have suggested, because there is no unique height for my stock, because it is all over the place.

So, I am trying to take what Kyle Stapleton directed, that makes no sense, but works, and then suggesting a modification to the Aspire input requirements, so that the needed inputs to get a part planed to a specific thickness are self evident. I am not saying how the software would carry this out, simply that as an end user, to do what I want to do, I would like to see Aspire input requirements that are simple, direct and obvious.

I hope this makes some sense. Thanks again for replying, Chuck

[adrianm]

You have to put a value into the material thickness regardless of how you do it. Every job has a material thickness defined when it's created.

With foam it's not that important that it's more than just in the ballpark but with hardwood you would need to be reasonably accurate on the thickest part as otherwise the first pass may cut too deep.

Same issue with zeroing to the top. If you zeroed to a low spot then the first pass may be too deep when it hits a high spot.

The Z value is just a place holder for the material thickness entered. If you put 2" in for the thickness when you created the job and put "z-0.97" in the cut depth box then basically what you've put in is "2-0.97" and 1.03" will be used for the cut depth.

You can imagine what would happen on the first pass if you put in a material thickness of 2" when the material is actually 6" thick.

The start depth would always be zero whether you put in a direct cut depth or not or whether you zeroed to the surface or not.

My point is that whether you're zeroing to the machine bed or the material surface nothing changes as far as the software goes. You enter the same values in everything so there's no need to change any input screens IMO.

Of course the end result would be different if you zeroed such a wavy board to the surface in anything other than the lowest spot but that's nothing to do with the toolpath setup.

[jerry_stanek]

The way I do it is in Aspire or Vcarve pro I set the material at the thickest and zero to the bed. I the figure how much material I want left and subtract that from the thickness and that is what I use as to how deep I want to go.