Using Table Bed as Zero

[rayman]

They say if you don't ask you will never know so..I usually zero all my material from the material top..but I have seen where some Zero from their table top. My question is how do you set it up? For instance,I have a piece of material 1.5" thick, I have a model that is 1.25 inches thick . How would I set that up on my machine using the bottom of the material as the zero? I have Buddy 48 PRS running Aspire 4.0..Lost, don't understand, confused..:eek:

[myxpykalix]

Somewhere in the program is something like "material setup" where you set your material thickness, 0,0 for center or edge of material and where you place your Z, either material top or machine top. Then when you set your bit instead of setting your aluminum plate on top of your material and Z'ing there, you set it on the table top and Z there.

[srwtlc]

Raymond,

Two places that it can be set. One in job setup on the Drawing tab and also in material setup on the Toolpaths tab. Check out the tutorials on the disk also, as you'll need to position the model within your material.

[Billions]

Raymond - I deal with this often as I sometimes carve the entire top surface of my piece of material and therefore the top surface I start out with (the one I would zero to if I zeroed to the top of the material), is no longer there when the rough pass is done and the over-all material height has lowered - making it almost impossible to easily zero the next bit for another tool-path.

In those cases, I zero to the table surface next to the wood, and like Scott showed, there is a place in the VCarve/Partworks/Aspire software in set-up where you can set your zero point to top or bottom, center of material or a corner point.

In Partworks3D (is the Shopbot version still called that?) there is a setting on the material set-up page (second page after the model import and sizing). I set all parameters for the size of the material I am carving on the Shopbot - in your case you would put the thickness at 1.5". Also on that page there is a setting called 'Depth of Model Below Surface'. In your case, as your model is 1.25", you would enter a value of "-.25" and the program would know what you are up to. The 3D preview to the right would show your model, and it would be flush to the bottom plane of the clear box representing the material, with .25" above it.

I think those guys covered it but I think I should mention that switching back and forth between zeroing on the table and the top of the material was an excellent way for me to snap bits off! I learned after breaking three $50 bits over the span of 30 days. The reason was the Shopbot has a setting for a safe Z height to jog a tool around the carving area - and when you have it set to say, half an inch above the Z-zero height like I did, everything is fine as long as you are zeroing to the top of your material - you're clearing it by half an inch. However, if you zero to the table, and you're cutting your 1.5" material, if you don't find that safe Z height setting and put it higher than 1.55", the Shopbot, cruising along at what it thinks is "safe" at .5", won't know it's about to bump into the 1.5" material you have mounted to your table - it's over an inch too low. And if you start a carve, the bit scoots across the X/Y axis' to the area it wants to start at, and you can snap your bit as it hits the 1" curb in front of it. Or your clamps.

This setting used to be fairly easy to find in the older Shopbot Control software, but I haven't seen it since I updated to the new one with the "Easy" button and settings. Maybe you don't even need to worry about this any more.

So yeah - long story short: If you switch zeroing between top of material and the table surface, just make sure you also check that "Safe Z height" setting and make sure it's clearing your material as you jog around or start a carve.

[steve_g]

Raymond…
Because switching back and forth between zeroing methods is an accident waiting to happen…

When V- carving, it’s imperative that you zero from the top of the material but when building cabinets, zeroing from the bed will make it so that material thickness variations don’t cause variations in the size of the outside of the cabinet.

What I do… I always leave my software set to zero from the top, and when V-carving all is well. When doing work that should be zeroed from the bed, I zero from the bed but then re-zero the DESIGN thickness of the material above the bed. This makes it so I don’t have to switch back and forth in my software, eliminating one possibility of error!
SG

[Simops]

I like to zero to the spoilboard when using sheet goods (whether alum or timber) as it allows for some variation in material height ...... Especially if you don't have vacuum. On the other hand when I use jigs to cut slots on aluminium or similar I zero to the top of material as it takes in account the jig height.

Problem I have is if I put a full sheet that covers my Buddy's 4 x 4 area and then want to change bits during the cut I don't have anywhere to set the zero plate to zero from the spoilboard bed.......:eek: In these cases where more than one bit is used I have to zero to top of material as have no choice....

Cheers